ORCID Profile
0000-0003-3384-0375
Current Organisation
University of South Australia
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Environmental Impact Assessment | Environmental Science and Management | Colloid and Surface Chemistry | Nanotoxicology, Health and Safety | Geochemistry | Environmental Monitoring | Inorganic Geochemistry | Isotope Geochemistry | Nanomaterials | Crop and Pasture Nutrition | Physical Chemistry of Materials | Geology | Chemical Characterisation of Materials | Synchrotrons; Accelerators; Instruments and Techniques | Plant Biology | Marine Geoscience | Igneous and Metamorphic Petrology | Functional Materials | Nanotechnology | Environmental Chemistry (incl. Atmospheric Chemistry) | Materials Engineering | Quaternary Environments | Soil Sciences | Macromolecular and Materials Chemistry | Crop and Pasture Production | Physical Chemistry (Incl. Structural) | Soil Chemistry | Exploration Geochemistry | Plant Cell and Molecular Biology | Proteomics and Intermolecular Interactions (excl. Medical Proteomics) | Other Physical Sciences | Soil Chemistry (excl. Carbon Sequestration Science) | Genetically Modified Field Crops and Pasture | Environmental Nanotechnology | Nanofabrication, Growth and Self Assembly
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Chemical Sciences | Environmental Policy, Legislation and Standards not elsewhere classified | Expanding Knowledge in the Earth Sciences | Expanding Knowledge in the Physical Sciences | Wheat | Environmentally Sustainable Manufacturing not elsewhere classified | Expanding Knowledge in the Environmental Sciences | Mineral Exploration not elsewhere classified | Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use) | Cancer and Related Disorders | Chemical fertilisers | Fresh, Ground and Surface Water Flora, Fauna and Biodiversity | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Nutraceuticals and Functional foods | Chemical Fertilisers | Expanding Knowledge in Technology | Bakery Products | Urban and Industrial Soils | Diagnostic Methods | Expanding Knowledge in Engineering | Expanding Knowledge in the Biological Sciences | Copper Ore Exploration |
Related Links
Publications
Density changes around phosphorus granules and fluid bands in a calcareous soil
Publisher: Wiley
Date: 05-2006
Absorption of foliar applied Zn is decreased in Zn deficient sunflower (Helianthus annuus) due to changes in leaf properties
Publisher: Springer Science and Business Media LLC
Date: 25-10-2018
Silver sulfide nanoparticles (Ag2S-NPs) are taken up by plants and are phytotoxic
Publisher: Informa UK Limited
Date: 10-09-2015
DOI: 10.3109/17435390.2014.999139
Abstract: Silver nanoparticles (NPs) are used in more consumer products than any other nanomaterial and their release into the environment is unavoidable. Of primary concern is the wastewater stream in which most silver NPs are transformed to silver sulfide NPs (Ag2S-NPs) before being applied to agricultural soils within biosolids. While Ag2S-NPs are assumed to be biologically inert, nothing is known of their effects on terrestrial plants. The phytotoxicity of Ag and its accumulation was examined in short-term (24 h) and longer-term (2-week) solution culture experiments with cowpea (Vigna unguiculata L. Walp.) and wheat (Triticum aestivum L.) exposed to Ag2S-NPs (0-20 mg Ag L(-1)), metallic Ag-NPs (0-1.6 mg Ag L(-1)), or ionic Ag (AgNO3 0-0.086 mg Ag L(-1)). Although not inducing any effects during 24-h exposure, Ag2S-NPs reduced growth by up to 52% over a 2-week period. This toxicity did not result from their dissolution and release of toxic Ag(+) in the rooting medium, with soluble Ag concentrations remaining below 0.001 mg Ag L(-1). Rather, Ag accumulated as Ag2S in the root and shoot tissues when plants were exposed to Ag2S-NPs, consistent with their direct uptake. Importantly, this differed from the form of Ag present in tissues of plants exposed to AgNO3. For the first time, our findings have shown that Ag2S-NPs exert toxic effects through their direct accumulation in terrestrial plant tissues. These findings need to be considered to ensure high yield of food crops, and to avoid increasing Ag in the food chain.
Speciation and Localization of Arsenic in White and Brown Rice Grains
Publisher: American Chemical Society (ACS)
Date: 15-01-2008
DOI: 10.1021/ES702212P
Abstract: Synchrotron-based X-ray fluorescence (S-XRF) was utilized to locate arsenic (As) in polished (white) and unpolished (brown) rice grains from the United States, China, and Bangladesh. In white rice As was generally dispersed throughout the grain, the bulk of which constitutes the endosperm. In brown rice As was found to be preferentially localized at the surface, in the region corresponding to the pericarp and aleurone layer. Copper, iron, manganese, and zinc localization followed that of arsenic in brown rice, while the location for cadmium and nickel was distinctly different, showing relatively even distribution throughout the endosperm. The localization of As in the outer grain of brown rice was confirmed by laser ablation ICP-MS. Arsenic speciation of all grains using spatially resolved X-ray absorption near edge structure (micro-XANES) and bulk extraction followed by anion exchange HPLC-ICP-MS revealed the presence of mainly inorganic As and dimethylarsinic acid (DMA). However, the two techniques indicated different proportions of inorganic:organic As species. A wider survey of whole grain speciation of white (n=39) and brown (n=45) rice s les from numerous sources (field collected, supermarket survey, and pot trials) showed that brown rice had a higher proportion of inorganic arsenic present than white rice. Furthermore, the percentage of DMA present in the grain increased along with total grain arsenic.
Combining diffusive gradients in thin films (DGT) and spectroscopic techniques for the determination of phosphorus species in soils
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.ACA.2019.01.037
Abstract: A wide range of methods are used to estimate the plant-availability of soil phosphorus (P). Published research has shown that the diffusive gradients in thin films (DGT) technique has a superior correlation to plant-available P in soils compared to standard chemical extraction tests. In order to identify the plant-available soil P species, we combined DGT with infrared and P K- and L
Speciation mapping of environmental samples using XANES imaging
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/EN13189
Abstract: Environmental context Recently developed fast fluorescence detectors have opened the way to the development of element speciation mapping, i.e. X-ray absorption near edge spectroscopy (XANES) imaging, of environmental s les. This technique is potentially very informative but is also highly data intensive. Here, we used XANES imaging to explore the distribution of Cu species in biosolid materials, destined for agricultural use, as this is of importance in relation to the bioavailability and potential toxicity of this metal. Abstract Fast X-ray detectors with large solid angles and high dynamic ranges open the door to XANES imaging, in which millions of spectra are collected to image the speciation of metals at micrometre resolution, over areas up to several square centimetres. This paper explores how such multispectral datasets can be analysed in order to provide further insights into the distribution of Cu species in fresh and stockpiled biosolids. The approach demonstrated uses Principal Components Analysis to extract the ‘significant’ spectral information from the XANES maps, followed by cluster analysis to locate regions of contrasting spectral signatures. Following this model-free analysis, pixel-by-pixel linear combination fits are used to provide a direct link between bulk and imaging XANES spectroscopy. The results indicate that both the speciation and distribution of Cu species are significantly affected by ageing. The majority of heterogeneously distributed micrometre-sized Cu sulfide particles present in fresh biosolids disappear during the oxidative stockpiling process. In aged biosolids most of the Cu is homogeneously redistributed on organic matter suggesting that Cu mobility is temporarily increased during this redistribution process. This manuscript demonstrates how large XANES imaging datasets could be analysed and used to gain a deep understanding of metal speciation in environmental s les.
In situ analysis of metal(loid)s in plants: State of the art and artefacts
Publisher: Elsevier BV
Date: 08-2011
Pyrophosphate and orthophosphate addition to soils: sorption, cation concentrations, and dissolved organic carbon
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/SR07014
Abstract: Liquid polyphosphate fertilisers contain both orthophosphate and pyrophosphate, and have shown significant yield increases compared to granular orthophosphate fertiliser on highly phosphorus (P) fixing soils. The P sorption chemistry of the dominant P species in a polyphosphate fertiliser (pyrophosphate and orthophosphate) was compared on a range of Australian soils, and the effect of these P species on equilibrium solution chemistry was also examined. Phosphorus supplied as pyrophosphate had a stronger sorption affinity than orthophosphate in all soils. The greater efficiency of pyrophosphate-based fertiliser on some soil types is therefore not due to reduced sorption of this P supplied as pyrophosphate compared to P supplied as orthophosphate fertiliser. In general, the addition of pyrophosphate to soil resulted in a larger decrease in calcium concentration in solution compared to orthophosphate. In contrast, there was an increase in iron concentration in solution with pyrophosphate addition, indicating sequestration reactions associated with the dissolution of dissolved organic carbon into soil solution. The pyrophosphate ion generally mobilised more Fe into solution than orthophosphate in several soils, likely through complexation reactions leading to Fe desorption/dissolution from the soil solid phase. These findings highlight the differences in soil chemical reactions that occur with the addition of polyphosphate fertilisers, which may contribute to their yield advantage in some soil types.
In vivo synchrotron study of thallium speciation and compartmentation in lberis intermedia
Publisher: American Chemical Society (ACS)
Date: 03-09-2004
DOI: 10.1021/ES049569G
Abstract: Thallium (TI) is a metal of great toxicological concern and its prevalence in the natural environment has steadily increased as a result of manufacturing and combustion practices. Due to its low natural abundance and increasing demand, TI is the fourth most expensive metal, thus, recovery and reuse could be a profitable endeavor. The hyperaccumulator Iberis intermedia was examined via in vivo micro-X-ray absorption near edge (micro-XANES) and micro-X-ray fluorescence (micro-XRF) spectroscopies to determine the speciation and distribution of TI within leaves of the plant. I. intermedia plants were cultivated under controlled conditions in 0, 10, and 20 mg TI kg(-1) soil leading to a shoot concentration of up to 13 430 mg TI kg(-1) dry weight plant mass during 10 weeks of growth. Live plant leaves were examined by micro-XANES and micro-XRF which determined aqueous TI(I) to be the model species distributed primarily throughout the vascular network. A direct relationship of vein size to TI concentration was observed. The high uptake of TI and high potential biomass of I. intermedia, combined with knowledge of TI speciation and compartmentation within the plant, are discussed in terms of accumulation/tolerance mechanisms, consequences for potential food chain contamination, and phytomining strategies to reclaim TI-contaminated soils, sediments, and waters.
Arsenic distribution and speciation in the fronds of the hyperaccumulator Pteris vittata
Publisher: Wiley
Date: 21-10-2002
In Situ Fixation of Metal(loid)s in Contaminated Soils: A Comparison of Conventional, Opportunistic, and Engineered Soil Amendments
Publisher: American Chemical Society (ACS)
Date: 28-10-2015
Abstract: This study aimed to assess and compare the in vitro and in vivo bioaccessibility/bioavailability of As and Pb in a mining contaminated soil (As, 2267 mg kg(-1) Pb, 1126 mg kg(-1)), after the addition of conventional (phosphoric acid), opportunistic [water treatment residues (WTRs)], and engineered [nano- and microscale zero valent iron (ZVI)] amendments. Phosphoric acid was the only amendment that could significantly decrease Pb bioaccessibility with respect to untreated soil (41 and 47% in the gastric phase and 2.1 and 8.1% in the intestinal phases, respectively), giving treatment effect ratios (TERs, the bioaccessibility in the amended soil ided by the bioaccessibility in the untreated soil) of 0.25 and 0.87 in the gastric and intestinal phase, respectively. The in vivo bioavailability of Pb decreased in the phosphate treatment relative to the untreated soil (6 and 24%, respectively), and also in the Fe WTR 2% (12%) and nZVI-2 (13%) treatments. The ZVI amendments caused a decrease in As bioaccessibility, with the greatest decrease in the nZVI2-treated soil (TERs of 0.59 and 0.64 in the gastric and intestinal phases, respectively). Arsenic X-ray absorption near-edge spectroscopy analysis indicated that most of the As in the untreated soil was present as As(V) associated with Fe mineral phases, whereas in the treated soil, the proportion of arsenosiderite increased. Arsenite was present only as a minor species (3-5%) in the treated soils, with the exception of an nZVI treatment [∼14% of As(III)], suggesting a partial reduction of As(V) to As(III) caused by nZVI oxidation.
Chemical Speciation and Distribution of Cadmium in Rice Grain and Implications for Bioavailability to Humans
Publisher: American Chemical Society (ACS)
Date: 10-09-2020
Microelemental characterisation of Aboriginal Australian natural Fe oxide pigments
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5AY01547B
Abstract: This manuscript presents the first comprehensive microcharacterisation of Fe oxide minerals used in Aboriginal Australian mineral pigments.
Foliar application of zinc sulphate and zinc EDTA to wheat leaves: differences in mobility, distribution, and speciation
Publisher: Oxford University Press (OUP)
Date: 21-06-2018
DOI: 10.1093/JXB/ERY236
Critical review perspective: elemental speciation analysis methods in environmental chemistry - moving towards methodological integration
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/EN09018
Abstract: Environmental context. Elemental speciation defines mobility, accumulation behaviour and toxicity of elements in the environment. Environmental processes are then modelled using species information. Hence, it is important for environmental chemists to rely on unequivocal, precise and accurate analytical data for the identification and quantification of elemental species. Abstract. We review the application of speciation analysis used in environmental chemistry studies to gain information about the molecular ersity of elements in various environmental compartments. The review focuses on three major analytical methodologies: electrochemical, X-ray absorption spectroscopy, and methods that couple chromatography with mass spectrometric detection. In particular, the review aims to highlight the advantages and disadvantages of the three methods, and to demonstrate that both the chemistry of the element and the nature of the environmental compartment determine the choice of the preferred analytical technique. We demonstrate that these two factors can lead to technique-dependent shortcomings that contribute to the current gaps in knowledge of elemental speciation in the environment. In order to fill those gaps, multi-method approaches are urgently needed. Finally, we present a selection of recent studies that exhibit the potential to use complementary techniques to overcome method-dependent limitations in order to reduce ambiguities and to gain more confidence in the assignment of the molecular structure of elements in environmental s les.
Aging of nickel added to soils as predicted by soil pH and time
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.CHEMOSPHERE.2013.03.013
Abstract: Although aging processes are important in risk assessment for metals in soils, the aging of Ni added to soils has not been studied in detail. In this study, after addition of water soluble Ni to soils, the changes over time in isotopic exchangeability, total concentrations and free Ni(2+) activity in soil pore water, were investigated in 16 European soils incubated outdoors for 18 months. The results showed that after Ni addition, concentrations of Ni in soil pore water and isotopic exchangeability of Ni in soils initially decreased rapidly. This phase was followed by further decreases in the parameters measured but these occurred at slower rates. Increasing soil pH increased the rate and extent of aging reactions. Semi-mechanistic models, based on Ni precipitation/nucleation on soil surfaces and micropore diffusion, were developed and calibrated. The initial fast processes, which were attributed to precipitation/nucleation, occurred over a short time (e.g. 1h), afterwards the slow processes were most likely controlled by micropore diffusion processes. The models were validated by comparing predicted and measured Ni aging in three additional, widely differing soils aged outdoors for periods up to 15 months in different conditions. These models could be used to scale ecotoxicological data generated in short-term studies to longer aging times.
Hydrolysis of Pyrophosphate in a Highly Calcareous Soil
Publisher: Wiley
Date: 05-2006
Repeated applications of fipronil, propyzamide and flutriafol affect soil microbial functions and community composition: A laboratory-to-field assessment
Publisher: Elsevier BV
Date: 08-2023
Assessing the lability and environmental mobility of organically bound copper by stable isotope dilution
Publisher: American Chemical Society (ACS)
Date: 19-04-2022
Abstract: The environmental mobility of Cu and therefore its potential toxicity are closely linked to its attachment to natural organic matter (NOM). Geochemical models assume full lability of metals bound to NOM, especially under strong oxidizing conditions, which often leads to an overestimation of the lability of soil metals. Stable isotope dilution (SID) has been successfully applied to estimate the labile (isotopically exchangeable) pool of soil metals. However, its application to study the lability of NOM-Cu required development of a robust separation and detection approach so that free Cu ions can be discriminated from (the also soluble) NOM-Cu. We developed a SID protocol (with enriched
Cellular binding, uptake and biotransformation of silver nanoparticles in human T lymphocytes
Publisher: Springer Science and Business Media LLC
Date: 13-05-2021
DOI: 10.1038/S41565-021-00914-3
Abstract: Our knowledge of uptake, toxicity and detoxification mechanisms as related to nanoparticles' (NPs') characteristics remains incomplete. Here we combine the analytical power of three advanced techniques to study the cellular binding and uptake and the intracellular transformation of silver nanoparticles (AgNPs): single-particle inductively coupled mass spectrometry, mass cytometry and synchrotron X-ray absorption spectrometry. Our results show that although intracellular and extracellularly bound AgNPs undergo major transformation depending on their primary size and surface coating, intracellular Ag in 24 h AgNP-exposed human lymphocytes exists in nanoparticulate form. Biotransformation of AgNPs is dominated by sulfidation, which can be viewed as one of the cellular detoxification pathways for Ag. These results also show that the toxicity of AgNPs is primarily driven by internalized Ag. In fact, when toxicity thresholds are expressed as the intracellular mass of Ag per cell, differences in toxicity between NPs of different coatings and sizes are minimized. The analytical approach developed here has broad applicability in different systems where the aim is to understand and quantify cell-NP interactions and biotransformation.
Applicability of Diffusive Gradients in Thin Films for Measuring Mn in Soils and Freshwater Sediments
Publisher: American Chemical Society (ACS)
Date: 09-11-2011
DOI: 10.1021/AC201780F
Abstract: Manganese (Mn) is an essential plant nutrient, receiving increased attention due to significant deficiency problems in modern crop production. In aquatic sediments, Mn plays an important role in controlling the mobility of other elements due to its high redox sensitivity. Diffusive gradients in thin films (DGT) is recognized as one of the most promising techniques to assess plant availability of nutrients in soils and mobility in sediments. However, the appropriate conditions where DGT can be used to measure Mn in soils and sediments have not been thoroughly investigated. We deployed DGTs in soil, sediment, and solution to investigate the effect of pH and competition from Ca and Fe ions. We found that by using DGT it is possible to accurately measure Mn in soils at pH levels and Ca and Fe concentrations resembling those of normal and fertile agricultural soils. However, in acid soils at pH below 5.5, Mn measurements might be biased due to potential competition effects caused by Ca. Soil deployments showed that changes in soil redox conditions were closely reflected by the DGT based Mn measurements. This might enable a novel approach of using DGT to predict Mn mobility and plant availability in soils. In reducing aquatic sediments, high concentrations of ferrous ions can displace Mn from the resin-gel of the DGT device. We found this to be a significant problem with longer deployment times.
Evidence for Different Reaction Pathways for Liquid and Granular Micronutrients in a Calcareous Soil
Publisher: Wiley
Date: 2008
Synchroton X-ray absorption-edge computed microtograpy imaging of thallium compartmentalization in Iberis intermedia
Publisher: Springer Science and Business Media LLC
Date: 24-04-2007
Zinc Speciation in Organic Waste Drives Its Fate in Amended Soils
Publisher: American Chemical Society (ACS)
Date: 27-08-2020
Effects of changes in leaf properties mediated by methyl jasmonate (MeJA) on foliar absorption of Zn, Mn and Fe
Publisher: Oxford University Press (OUP)
Date: 21-06-2017
DOI: 10.1093/AOB/MCX063
Determination of mobile heavy metal fraction in soil: Results of a pot experiment with sewage sludge
Publisher: Informa UK Limited
Date: 10-1998
Comparison of toxicity of zinc for soil microbial processes between laboratory‐contamined and polluted field soils
Publisher: Wiley
Date: 11-2003
DOI: 10.1897/02-503
Abstract: Soil microbial processes are readily disturbed by added zinc (Zn) in laboratory ecotoxicity tests. This study compares Zn toxicity between freshly spiked soils and soils that have been contaminated with Zn in the field. Soils were s led in three transects ( 0.05) or increased significantly with soil Zn concentrations in the transect soils. These increases could not be explained by soil pH or % soil organic carbon. Leaching soils after spiking significantly lowered the toxic effects of Zn on nitrification or on substrate-induced respiration. The soil solution Zn concentrations of field soils were always smaller than in spiked soils at equivalent total Zn. Highest soil solution Zn concentrations were always lower than the soil-solution EC50s of spiked soils. It is concluded that there is a large discrepancy in microbial responses to elevated Zn between spiked soils (unleached) and field-contaminated soils and there is a need to explain this discrepancy in terms of Zn availability, adaptation processes, and additional soil factors controlling the microbial processes.
Metabolic engineering of bread wheat improves grain iron concentration and bioavailability
Publisher: Wiley
Date: 25-01-2019
DOI: 10.1111/PBI.13074
Imaging element distribution and speciation in plant cells
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.TPLANTS.2013.12.001
Abstract: To maintain cellular homeostasis, concentrations, chemical speciation, and localization of mineral nutrients and toxic trace elements need to be regulated. Imaging the cellular and subcellular localization of elements and measuring their in situ chemical speciation are challenging tasks that can be undertaken using synchrotron-based techniques, such as X-ray fluorescence and X-ray absorption spectrometry, and mass spectrometry-based techniques, such as secondary ion mass spectrometry and laser-ablation inductively coupled plasma mass spectrometry. We review the advantages and limitations of these techniques, and discuss ex les of their applications, which have revealed highly heterogeneous distribution patterns of elements in different cell types, often varying in chemical speciation. Combining these techniques with molecular genetic approaches can unravel functions of genes involved in element homeostasis.
Silver toxicity thresholds for multiple soil microbial biomarkers
Publisher: American Chemical Society (ACS)
Date: 27-06-2018
Abstract: Material flow analysis shows that soil is a key repository for silver (Ag) from (nano)silver-functionalized consumer products, but the potential effects of Ag toxicity, via Ag
Complementary Imaging of Silver Nanoparticle Interactions with Green Algae: Dark-Field Microscopy, Electron Microscopy, and Nanoscale Secondary Ion Mass Spectrometry
Publisher: American Chemical Society (ACS)
Date: 13-11-2017
Abstract: Increasing consumer use of engineered nanomaterials has led to significantly increased efforts to understand their potential impact on the environment and living organisms. Currently, no in idual technique can provide all the necessary information such as their size, distribution, and chemistry in complex biological systems. Consequently, there is a need to develop complementary instrumental imaging approaches that provide enhanced understanding of these "bio-nano" interactions to overcome the limitations of in idual techniques. Here we used a multimodal imaging approach incorporating dark-field light microscopy, high-resolution electron microscopy, and nanoscale secondary ion mass spectrometry (NanoSIMS). The aim was to gain insight into the bio-nano interactions of surface-functionalized silver nanoparticles (Ag-NPs) with the green algae Raphidocelis subcapitata, by combining the fidelity, spatial resolution, and elemental identification offered by the three techniques, respectively. Each technique revealed that Ag-NPs interact with the green algae with a dependence on the size (10 nm vs 60 nm) and surface functionality (tannic acid vs branched polyethylenimine, bPEI) of the NPs. Dark-field light microscopy revealed the presence of strong light scatterers on the algal cell surface, and SEM imaging confirmed their nanoparticulate nature and localization at nanoscale resolution. NanoSIMS imaging confirmed their chemical identity as Ag, with the majority of signal concentrated at the cell surface. Furthermore, SEM and NanoSIMS provided evidence of 10 nm bPEI Ag-NP internalization at higher concentrations (40 μg/L), correlating with the highest toxicity observed from these NPs. This multimodal approach thus demonstrated an effective approach to complement dose-response studies in nano-(eco)-toxicological investigations.
Mechanistic insights of 2,4-D sorption onto biochar: Influence of feedstock materials and biochar properties
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.BIORTECH.2017.07.073
Abstract: Objective of this study was to investigate the mechanisms of 2,4-Dichlorophynoxy acetic acid (2,4-D) sorption on biochar in aqueous solutions. Sorption isotherm, kinetics, and desorption experiments were performed to identify the role of biochars' feedstock and production conditions on 2,4-D sorption. Biochars were prepared from various green wastes (tea, burcucumber, and hardwood) at two pyrolytic temperatures (400 and 700°C). The tea waste biochar produced at 700°C was further activated with steam under a controlled flow. The sorption of 2,4-D was strongly dependent on the biochar properties such as specific surface area, surface functional groups, and microporosity. The steam activated biochar produced from tea waste showed the highest (58.8mgg
Evaluating the mobility of polymer-stabilised zero-valent iron nanoparticles and their potential to co-transport contaminants in intact soil cores
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.ENVPOL.2016.06.025
Abstract: The use of zero-valent iron nanoparticles (nZVI) has been advocated for the remediation of both soils and groundwater. A key parameter affecting nZVI remediation efficacy is the mobility of the particles as this influences the reaction zone where remediation can occur. However, by engineering nZVI particles with increased stability and mobility we may also inadvertently facilitate nZVI-mediated contaminant transport away from the zone of treatment. Previous nZVI mobility studies have often been limited to model systems as the presence of background Fe makes detection and tracking of nZVI in real systems difficult. We overcame this problem by synthesising Fe-59 radiolabelled nZVI. This enabled us to detect and quantify the leaching of nZVI-derived Fe-59 in intact soil cores, including a soil contaminated by Chromated-Copper-Arsenate. Mobility of a commercially available nZVI was also tested. The results showed limited mobility of both nanomaterials <1% of the injected mass was eluted from the columns and most of the radiolabelled nZVI remained in the surface soil layers (the primary treatment zone in this contaminated soil). Nevertheless, the observed breakthrough of contaminants and nZVI occurred simultaneously, indicating that although the quantity transported was low in this case, nZVI does have the potential to co-transport contaminants. These results show that direct injection of nZVI into the surface layers of contaminated soils may be a viable remediation option for soils such as this one, in which the mobility of nZVI below the injection/remediation zone was very limited. This Fe-59 experimental approach can be further extended to test nZVI transport in a wider range of contaminated soil types and textures and using different application methods and rates. The resulting database could then be used to develop and validate modelling of nZVI-facilitated contaminant transport on an in idual soil basis suitable for site specific risk assessment prior to nZVI remediation.
The use of DGT for prediction of plant available copper, zinc and phosphorus in agricultural soils
Publisher: Springer Science and Business Media LLC
Date: 13-05-2011
Model development for simulating the bioavailability of Ni to the hyperaccumulator Thlaspi goesingense
Publisher: Elsevier
Date: 2005
Nanoparticle Size and Coating Chemistry Control Foliar Uptake Pathways, Translocation, and Leaf-to-Rhizosphere Transport in Wheat
Publisher: American Chemical Society (ACS)
Date: 10-05-2019
Abstract: Nanoenabled foliar-applied agrochemicals can potentially be safer and more efficient than conventional products. However, limited understanding about how nanoparticle properties influence their interactions with plant leaves, uptake, translocation through the mesophyll to the vasculature, and transport to the rest of the plant prevents rational design. This study used a combination of Au quantification and spatial analysis to investigate how size (3, 10, or 50 nm) and coating chemistry (PVP versus citrate) of gold nanoparticles (AuNPs) influence these processes. Following wheat foliar exposure to AuNPs suspensions (∼280 ng per plant), adhesion on the leaf surface was increased for smaller sizes, and PVP-AuNPs compared to citrate-AuNPs. After 2 weeks, there was incomplete uptake of citrate-AuNPs with some AuNPs remaining on the outside of the cuticle layer. However, the fraction of citrate-AuNPs that had entered the leaf was translocated efficiently to the plant vasculature. In contrast, for similar sizes, virtually all of the PVP-AuNPs crossed the cuticle layer after 2 weeks, but its transport through the mesophyll cells was lower. As a consequence of PVP-AuNP accumulation in the leaf mesophyll, wheat photosynthesis was impaired. Regardless of their coating and sizes, the majority of the transported AuNPs accumulated in younger shoots (10-30%) and in roots (10-25%), and 5-15% of the NPs <50 nm were exuded into the rhizosphere soil. A greater fraction of larger sizes AuNPs (presenting lower ζ potentials) was transported to the roots. The key hypotheses about the NPs physical-chemical and plant physiology parameters that may matter to predict leaf-to-rhizosphere transport are also discussed.
Remediation of Site Contamination
Publisher: Springer Science and Business Media LLC
Date: 15-11-2013
Phytoremediation of metals, metalloids, and radionuclides
Publisher: Elsevier
Date: 2002
Grain Unloading of Arsenic Species in Rice
Publisher: Oxford University Press (OUP)
Date: 30-10-2009
Abstract: Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a ± stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols.
Absorption of foliar-applied Zn in sunflower (Helianthus annuus)
Publisher: Oxford University Press (OUP)
Date: 17-07-2019
DOI: 10.1093/AOB/MCY135
Cobalamin Concentrations in Fetal Liver Show Gender Differences: A Result from Using a High-Pressure Liquid Chromatography–Inductively Coupled Plasma Mass Spectrometry as an Ultratrace Cobalt Speciati
Publisher: American Chemical Society (ACS)
Date: 06-12-2016
DOI: 10.1021/ACS.ANALCHEM.6B03730
Abstract: Maternal diet and lifestyle choices may affect placental transfer of cobalamin (Cbl) to the fetus. Fetal liver concentration of Cbl reflects nutritional status with regards to vitamin B12, but at these low concentration current Cbl measurement methods lack robustness. An analytical method based on enzymatic extraction with subsequent reversed-phase-high-pressure liquid chromatography (RP-HPLC) separation and parallel ICPMS and electrospray ionization (ESI)-Orbitrap-MS to determine specifically Cbl species in liver s les of only 10-50 mg was developed using 14 pig livers. Subsequently 55 human fetal livers were analyzed. HPLC-ICPMS analysis for cobalt (Co) and Cbl gave detection limits of 0.18 ng/g and 0.88 ng/g d.m. in liver s les, respectively, with a recovery of >95%. Total Co (Co
In Situ Distribution and Speciation of Toxic Copper, Nickel, and Zinc in Hydrated Roots of Cowpea
Publisher: Oxford University Press (OUP)
Date: 27-04-2011
Abstract: The phytotoxicity of trace metals is of global concern due to contamination of the landscape by human activities. Using synchrotron-based x-ray fluorescence microscopy and x-ray absorption spectroscopy, the distribution and speciation of copper (Cu), nickel (Ni), and zinc (Zn) was examined in situ using hydrated roots of cowpea (Vigna unguiculata) exposed to 1.5 μm Cu, 5 μm Ni, or 40 μm Zn for 1 to 24 h. After 24 h of exposure, most Cu was bound to polygalacturonic acid of the rhizodermis and outer cortex, suggesting that binding of Cu to walls of cells in the rhizodermis possibly contributes to the toxic effects of Cu. When exposed to Zn, cortical concentrations remained comparatively low with much of the Zn accumulating in the meristematic region and moving into the stele approximately 60% to 85% of the total Zn stored as Zn phytate within 3 h of exposure. While Ni concentrations were high in both the cortex and meristem, concentrations in the stele were comparatively low. To our knowledge, this is the first report of the in situ distribution and speciation of Cu, Ni, and Zn in hydrated (and fresh) plant tissues, providing valuable information on the potential mechanisms by which they are toxic.
Correction to Vanadium Speciation in Ancient Shales Revealed through Synchrotron-Based X-ray Spectroscopy
Publisher: American Chemical Society (ACS)
Date: 24-02-2023
Chapter 6 Advances in Isotopic Dilution Techniques in Trace Element Research
Publisher: Elsevier
Date: 2008
In Situ Speciation and Distribution of Toxic Selenium in Hydrated Roots of Cowpea
Publisher: Oxford University Press (OUP)
Date: 08-07-2013
Reductive sorption of vanadium by green rust in seawater
Publisher: Elsevier BV
Date: 08-2023
Trends in hard X-ray fluorescence mapping: Environmental applications in the age of fast detectors
Publisher: Springer Science and Business Media LLC
Date: 11-03-2011
DOI: 10.1007/S00216-011-4829-2
Abstract: Environmental s les are extremely erse but share a tendency for heterogeneity and complexity. This heterogeneity poses methodological challenges when investigating biogeochemical processes. In recent years, the development of analytical tools capable of probing element distribution and speciation at the microscale have allowed this challenge to be addressed. Of these available tools, laterally resolved synchrotron techniques such as X-ray fluorescence mapping are key methods for the in situ investigation of micronutrients and inorganic contaminants in environmental s les. This article demonstrates how recent advances in X-ray fluorescence detector technology are bringing new possibilities to environmental research. Fast detectors are helping to circumvent major issues such as X-ray beam damage of hydrated s les, as dwell times during scanning are reduced. They are also helping to reduce temporal beamtime requirements, making particularly time-consuming techniques such as micro X-ray fluorescence (μXRF) tomography increasingly feasible. This article focuses on μXRF mapping of nutrients and metalloids in environmental s les, and suggests that the current ide between mapping and speciation techniques will be increasingly blurred by the development of combined approaches.
Metalloids, Soil Chemistry and the Environment
Publisher: Springer New York
Date: 2010
DOI: 10.1007/978-1-4419-6315-4_3
Abstract: This chapter reviews physical chemical properties, origin and use ofmetalloids and their relevance in the environment. The elements boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At) are considered metalloids. Metalloids conduct heat and electricity intermediate between nonmetals and metals and they generally form oxides. The natural abundance ofmetalloids varies from Si being the second most common element in the Earth's crust to At as the rarest of natural elements on Earth. The metalloid elements Ge, Te, Po and At are normally present in trace or ultratrace levels in the environment and as such are not considered of relevance in terms of environmental health. The environmental geochemical processes, factors and parameters controlling the partitioning and the speciation of B, Si, As and Sb are reviewed in relation to the bioavailability of these metalloids. Approaches based on the hypothesis that metal toxicity is related to both the metal-ligand complexation processes and the metal interactions with competing cations at the cell surface (biotic ligand) have so far not been successful for assessing metalloid bioavailability. The chapter concludes that our understanding of metalloids toxicity will improve in the future if, in addition to the points discussed above, surface membrane potentials are considered. This should represent a robust approach to the prediction of metalloid toxicity.
Insights into the fate of antimony (Sb) in contaminated soils: Ageing influence on Sb mobility, bioavailability, bioaccessibility and speciation
Publisher: Elsevier BV
Date: 05-2021
Understanding the interaction of gold and silver nanoparticles with natural organic matter using affinity capillary electrophoresis
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9EN00014C
Abstract: Nanoparticles (NPs) undergo a number of changes in environmental systems which are often influenced by their interaction with natural organic matter (NOM).
The effect of biochar feedstock, pyrolysis temperature, and application rate on the reduction of ammonia volatilisation from biochar-amended soil
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.SCITOTENV.2018.01.312
Abstract: Ammonia (NH
Evaluation of the diffusive gradients in thin-films (DGT) technique for measuring nitrate and ammonium in soil
Publisher: CSIRO Publishing
Date: 20-02-2023
DOI: 10.1071/EN22107
Abstract: Environmental context Nitrate (NO3−) and ammonium (NH4+) are the most important soil nitrogen forms for plant growth. However, conventional extraction techniques may introduce artefacts affecting the measurement of plant-available N concentrations following s ling and s le preparation processes. This is the first study of the DGT technique being used to measure NO3-N and NH4-N in a wide range of soils, compared with conventional KCl extraction, and examined different factors that contribute to the plant-availability of these ions in soils. The knowledge would help to optimise soil nitrogen management practices, increase economic benefits and reduce environmental impacts. Rationale The availability of soil nitrogen for plant uptake can be affected by numerous soil factors such as soil texture, moisture and organic matter content, temperature and microbial activity. Conventional extraction techniques may affect the measurement of plant-available N concentrations following s ling and s le preparation processes, including drying, sieving, homogenising, freezing and thawing. The diffusive gradients in thin-films (DGT) technique can overcome some limitations of the conventional extraction techniques and has been used to successfully estimate the plant-available fractions of nutrients, such as P, K, Zn, Cu and Mn in soils. Therefore, it is important to evaluate the use of DGT for measuring NO3− and NH4+ in a wide variety of soils and examine the factors that contribute to the plant-availability of these ions in soils. Methodology The experiment evaluated the ability of the DGT technique to measure NO3-N and NH4-N in soils using binding layers containing A520E anion exchange resin or Microlite® PrCH cation exchange resin, respectively. The DGT results were compared to those from conventional KCl extraction. Results The A520E- and PrCH-DGTs showed good detection limits for NO3-N (6.90 µg L−1) and NH4-N (6.23 µg L−1) and were able to measure potentially available NO3-N and NH4-N in unfertilised soils. The mass of NO3-N and NH4-N that accumulated on the DGT device increased linearly across soil concentrations ranging from 5 to 300 mg kg−1 NO3-N (depending on soil type) and 5–300 mg kg−1 NH4-N which is equivalent to fertiliser rates of 75–450 kg ha−1 N. DGTs were used to measure potentially available NO3-N and NH4-N in ten soils with various physical and chemical properties. The DGT results were compared with conventional KCl extraction used to determine soil mineral N. DGT and KCl extraction measured values were significantly correlated with each other for NO3-N (R2 = 0.53 P-value 0.001), but the relationship between the two measurements was weaker for NH4-N (R2 = 0.20, P-value = 0.045). Discussion The results suggest that the two methods s le different N pools in the soils, with DGT targeting the NO3-N and NH4-N that are available in soil pore water and attached to labile solid phases.
Foliar and soil uptake of 134Cs and 85Sr by grape vines
Publisher: Elsevier BV
Date: 11-1997
DOI: 10.1016/S0048-9697(97)00261-1
Abstract: The foliar and soil uptake of 134Cs and 85Sr by grape vines and their subsequent translocation to fruits and to the other plant compartments is described. Grape vine plants growing in pots and kept in an open field were contaminated with 134Cs and 85Sr in ionic form by sprinkling on the aerial part, or by addition to the soil. Sprinkling was effected at the stage of ripening of the grapes. Interception, determined by analysing all the leaves picked from three plants after the sprinkling, was approx. 50% of the sprayed activity. Soil contamination was effected after the fruit setting, 1 month earlier than sprinkling. At ripening, the whole plant was picked. Berries, leaves, shoots, stems, roots and soil were analysed by gamma spectrometry. Activities of the different parts of the plant were expressed as: (a) translocation factors of intercepted activity for foliar treatment (b) transfer factors of activity applied to the soil for soil treatment. Both factors were calculated per unit of fresh weight, or referred to the total biomass of the plant compartment. Leaf-to-fruit translocation factors per unit of weight are of the order of magnitude of 10(-1) for 134Cs and of 10(-2) for 85Sr. One/two order of magnitude lower are soil-to-fruit transfer factors: 10(-3) both for 134Cs and for 85Sr. Radiocesium behaves quite differently from radiostrontium, but the behaviour of both radionuclides within the grape vine is independent of the path of absorption, by leaves or by roots. 134Cs is absorbed more easily than 85Sr by plant foliage, but is absorbed with more difficulty than 85Sr by roots. After absorption by either route, radiocesium concentrates mainly in the fruit compartment of the plant, whereas radiostrontium concentrates in the foliar compartment. Loss from the aerial part of the plant is higher for 85Sr than for 134Cs. 85Sr remains more available in soil than 134Cs, is more absorbed by roots and is more leached downward. After foliar contamination, the dominant pathway of radionuclides to reach the soil is by dislodging of non-absorbed radionuclides or senescent cells from the aerial part of the plant by action of wind and rain.
Immobilization of heavy metals in soils using inorganic amendments in a greenhouse study
Publisher: Wiley
Date: 04-2003
Sequentially extracted arsenic from different size fractions of contaminated soils
Publisher: Springer Science and Business Media LLC
Date: 2000
Sulfur-Containing Chitin and Chitosan Derivatives as Trace Metal Adsorbents: A Review
Publisher: Informa UK Limited
Date: 2013
“A Terrible Beauty”: Iris Murdoch’s Irish Novel, The Red and the Green
Publisher: Informa UK Limited
Date: 17-11-2019
Characterization of Leached Phosphorus from Soil, Manure, and Manure-Amended Soil by Physical and Chemical Fractionation and Diffusive Gradients in Thin Films (DGT)
Publisher: American Chemical Society (ACS)
Date: 12-09-2012
DOI: 10.1021/ES301861A
Abstract: We are challenged to date to fully understand mechanisms controlling phosphorus (P) mobilization in soil. In this study we evaluated physical properties, chemical reactivity, and potential bioavailability of P mobilized in soil during a leaching event and examined how the amounts and properties of leached P were influenced by surface application of cattle manure. Leaching experiments on manure itself, and on intact soil columns (14.1 cm inner dia., 25 cm height) before and after manure application, were carried out at an irrigation rate of 1 mm h(-1) for 48 h. High concentrations of dissolved reactive P (DRP) were found in manure leachates (up to 32 mg L(-1)), whereas concentrations of P in soil leachates were low both before and after manure application (around 0.04 mg L(-1) before application and up to 0.4 mg L(-1) afterward). This result indicates that the soil retained most of the P added with manure. Manure particles themselves were also largely retained by the soil. Combined physical (centrifugation) and chemical (molybdate reactiveness) fractionation of leached P showed that leachates in the manure treated soils were dominated by dissolved unreactive P (DUP), mainly originating from manure. However, centrifugation only removed a small fraction of total particles from the leachates, indicating that the so-called dissolved fraction may be associated with low density particulate matter. Deployment of Diffusive Gradients in Thin films (DGT) devices in the leachates proved to be a good approach for measuring reactive P in soil leachates. The results indicated that total reactive P (TRP) gave a better estimate of potentially bioavailable P than both total P (TP) and DRP in these experiments.
Long-term changes in land use influence phosphorus concentrations, speciation, and cycling within subtropical soils
Publisher: Elsevier BV
Date: 07-2021
Isotopic Exchangeability, Hydrolysis and Mobilization Reactions of Pyrophosphate in Soil
Publisher: Wiley
Date: 09-2008
Cellular compartmentation of nickel in the hyperaccumulators Alyssum lesbiacum, Alyssum bertolonii and Thlaspi goesingense
Publisher: Oxford University Press (OUP)
Date: 12-2001
DOI: 10.1093/JEXBOT/52.365.2291
Abstract: Nickel uptake and cellular compartmentation were investigated in three Ni hyperaccumulators: Alyssum bertolonii (Desv), Alyssum lesbiacum (Candargy) and Thlaspi goesingense (Hálácsy). The three species showed similar hyperaccumulation of Ni, but T. goesingense was less tolerant to Ni than the two Alyssum species. An addition of 500 mg Ni kg(-1) to a nutrient-rich growth medium significantly increased shoot biomass of all three species, suggesting that the Ni hyperaccumulators have a higher requirement for Ni than normal plants. Energy-dispersive X-ray microanalysis (EDXA) was performed on frozen-hydrated tissues of leaves (all species) and stems (Alyssum only). In all species analysed, Ni was distributed preferentially in the epidermal cells, most likely in the vacuoles, of the leaves and stems. In stems, there was a second peak of Ni in the boundary cells between the cortical parenchyma and the vascular cylinder. The non-glandular trichomes on the leaf surfaces of the two Alyssum species were highly enriched with Ca, but contained little Ni except in the base. In the leaves of T. goesingense, the large elongated epidermal cells contained more Ni than the cells of the stomatal complexes. The role of cellular compartmentation in Ni hyperaccumulation is discussed.
Identification of the Primary Lesion of Toxic Aluminum in Plant Roots
Publisher: Oxford University Press (OUP)
Date: 10-02-2015
Abstract: Despite the rhizotoxicity of aluminum (Al) being identified over 100 years ago, there is still no consensus regarding the mechanisms whereby root elongation rate is initially reduced in the approximately 40% of arable soils worldwide that are acidic. We used high-resolution kinematic analyses, molecular biology, rheology, and advanced imaging techniques to examine soybean (Glycine max) roots exposed to Al. Using this multidisciplinary approach, we have conclusively shown that the primary lesion of Al is apoplastic. In particular, it was found that 75 µm Al reduced root growth after only 5 min (or 30 min at 30 µm Al), with Al being toxic by binding to the walls of outer cells, which directly inhibited their loosening in the elongation zone. An alteration in the biosynthesis and distribution of ethylene and auxin was a second, slower effect, causing both a transient decrease in the rate of cell elongation after 1.5 h but also a longer term gradual reduction in the length of the elongation zone. These findings show the importance of focusing on traits related to cell wall composition as well as mechanisms involved in wall loosening to overcome the deleterious effects of soluble Al.
Microfluidic Cell Microarray Platform for High Throughput Analysis of Particle–Cell Interactions
Publisher: American Chemical Society (ACS)
Date: 02-03-2018
Multiparameter toxicity screening on a chip: Effects of UV radiation and titanium dioxide nanoparticles on HaCaT cells
Publisher: AIP Publishing
Date: 07-2019
DOI: 10.1063/1.5113729
Abstract: Microfluidic screening is gaining attention as an efficient method for evaluating nanomaterial toxicity. Here, we consider a multiparameter treatment where nanomaterials interact with cells in the presence of a secondary exposure (UV radiation). The microfluidic device contains channels that permit immobilization of HaCaT cells (human skin cell line), delivery of titanium dioxide nanoparticles (TNPs), and exposure to a known dose of UV radiation. The effect of single-parameter exposures (UV or TNP) was first studied as a benchmark, and then multiparameter toxicity (UV and TNP) at different concentrations was explored. The results demonstrate a concentration-dependent protective effect of TNP when exposed to UV irradiation.
Aging of dissolved copper and copper-based nanoparticles in five different soils: Short-term kinetics vs. long-term fate
Publisher: Wiley
Date: 11-2017
Phloem transport of arsenic species from flag leaf to grain during grain filling
Publisher: Wiley
Date: 10-06-2011
Surface immobilization of engineered nanomaterials for in situ study of their environmental transformations and fate
Publisher: American Chemical Society (ACS)
Date: 02-08-2013
DOI: 10.1021/ES400839H
Abstract: The transformation and environmental fate of engineered nanomaterials (ENMs) is the focus of intense research due to concerns about their potential impacts in the environment as a result of their uniquely engineered properties. Many approaches are being applied to investigate the complex interactions and transformation processes ENMs may undergo in aqueous and terrestrial environments. However, major challenges remain due to the difficulties in detecting, separating, and analyzing ENMs from environmental matrices. In this work, a novel technique capable of in situ study of ENMs is presented. By exploiting the functional interactions between surface modified silver nanoparticles (AgNPs) and plasma-deposited polymer films, AgNPs were immobilized on to solid supports that can be deployed in the field and retrieved for analysis. Either negatively charged citrate or polyethylene glycol, or positively charged polyethyleneimine were used to cap the AgNPs, which were deployed in two field sites (lake and marina), two standard ecotoxicity media, and in primary sewage sludge for a period of up to 48 h. The chemical and physical transformations of AgNPs after exposure to different environments were analyzed by a combination of XAS and SEM/EDX, taken directly from the substrates. Cystine- or glutathione-bound Ag were found to be the dominant forms of Ag in transformed ENMs, but different extents of transformation were observed across different exposure conditions and surface charges. These results successfully demonstrate the feasibility of using immobilized ENMs to examine their likely transformations in situ in real environments and provide further insight into the short-term fate of AgNPs in the environment. Both the advantages and the limitations of this approach are discussed.
Neutral electrolyzed oxidizing water is effective for pre-harvest decontamination of fresh produce
Publisher: Elsevier BV
Date: 02-2021
Responsiveness of wheat (Triticum aestivum) to liquid and granular phosphorus fertilisers in southern Australian soils
Publisher: CSIRO Publishing
Date: 2005
DOI: 10.1071/SR04066
Abstract: Recent field trials on alkaline soils in southern Australia showed significant grain yield responses to liquid compared with traditional granular forms of P fertiliser. However the advantages of liquid over granular P forms of fertiliser has not been consistent on all soil types. In order to better predict the soil types on which liquid P fertilisers are likely to have potential, a glasshouse trial was conducted to compare the responsiveness of wheat to both liquid and granular forms of P on a wide range of Australian soils. A granular P fertiliser (triple superphosphate) and 2 liquid fertilisers (phosphoric acid and ammonium polyphosphate) were compared at a rate equivalent to 12 kg P/ha in 29 soils representing many of the soil types used for grain production in Victoria and South Australia. Wheat biomass was enhanced by P application in 86% of the soils tested. In 62% of the P-responsive soils, wheat dry matter was significantly greater when liquid P fertilisers were used compared with the granular form. Chemical analysis of the soils tested showed that the better performance of liquid P forms was not correlated to total P concentration in soil, P buffer capacity, or P availability as measured by Colwell-P. However, there was a significant positive relationship between calcium carbonate (CaCO3) content of soil and wheat responsiveness to liquid P fertiliser.
In Vitro, in Vivo, and Spectroscopic Assessment of Lead Exposure Reduction via Ingestion and Inhalation Pathways Using Phosphate and Iron Amendments
Publisher: American Chemical Society (ACS)
Date: 29-07-2019
Crossed flow microfluidics for high throughput screening of bioactive chemical-cell interactions
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6LC01261B
Abstract: A crossed flow microfluidic device was used for generation of cell-based arrays aiming for high throughput screening of applied bioactive chemicals to captured cells.
Assessing the plant availability of manganese in soils using Diffusive Gradients in Thin films (DGT)
Publisher: Elsevier BV
Date: 08-2012
Localization of iron in rice grain using synchrotron X-ray fluorescence microscopy and high resolution secondary ion mass spectrometry
Publisher: Elsevier BV
Date: 03-2014
Maia X-ray fluorescence imaging: Capturing detail in complex natural samples
Publisher: IOP Publishing
Date: 03-04-2014
Megapixel imaging of (micro)nutrients in mature barley grains
Publisher: Oxford University Press (OUP)
Date: 05-09-2010
DOI: 10.1093/JXB/ERQ270
Stable isotope techniques for assessing labile Cu in soils: Development of an L-value procedure, its application, and reconciliation with E values
Publisher: American Chemical Society (ACS)
Date: 06-04-2006
DOI: 10.1021/ES051845J
Abstract: Isotopic techniques have become a valuable tool for assessing the lability or potential availability of elements in soil. Until now, work on soil Cu has been limited to E-value methods where soil solution extracts are obtained by physical means due to the very short (12.4 h) half-life of the radio isotope 64Cu. However, a stable isotope method has recently been developed for determining soil Cu E values that utilizes enhancement of the 65Cu isotope in soil and measurement of the subsequent ratio with 63Cu. We have developed an L-value technique for soil Cu, where plants are used to s le the soil solution and therefore give a direct measure of the plant available Cu. The L-value technique developed was then compared, and found to be equivalent, with E values using equilibration periods up to and including the growth period of plants in the L-value method.
Unraveling the Complexity in the Aging of Nanoenhanced Textiles: A Comprehensive Sequential Study on the Effects of Sunlight and Washing on Silver Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 17-05-2016
Abstract: The scientific understanding of nanoparticle (NP) release and transformations they undergo during the product life cycle is h ered by the narrow scope of many research endeavors in terms of both breadth of variables and completeness of analytical characterization. We conducted a comprehensive suite of studies to reveal overarching mechanisms and parameters for nanosilver transformations either still adhered to the fabric or when released after washing. Laboratory prepared nanoenhanced fabrics were investigated: three Ag variants and one Au used as an unreactive reference to separate mechanical from chemical releases. Sequential combinations of sunlight irradiation and/or washing in seven different detergent formulations was followed by NP characterization ided into two groups: (1) dissolved and particulate matter in the wash solutions and (2) the fraction that remained on the fabric. Analytical techniques included spICP-MS, XANES, TEM, SEM, and total metals analysis of fabric digests and wash water filtrates. Sunlight irradiation stabilizes metallic Ag upon washing. Detergents containing oxidizing agents assisted with Ag particle release but not Au NPs, inferring additional chemical mechanisms. While particle size played some role, the NP capping agent/fabric binder combination was a key factor in release. When particles were released, little alteration in size was observed. The use of well-controlled fabrics, unreactive reference materials, and a life-cycle based experimental regime are paramount to understanding changes in Ag speciation and release upon use of nanoenhanced textiles.
Soil and the intensification of agriculture for global food security
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.ENVINT.2019.105078
Abstract: Soils are the most complex and erse ecosystem in the world. In addition to providing humanity with 98.8% of its food, soils provide a broad range of other services, from carbon storage and greenhouse gas regulation, to flood mitigation and providing support for our sprawling cities. But soil is a finite resource, and rapid human population growth coupled with increasing consumption is placing unprecedented pressure on soils through the intensification of agricultural production - the increasing of crop yield per unit area of soil. Indeed, the human population has increased from ca. 250 million in the year 1000, to 6.1 billion in the year 2000, and is projected to reach 9.8 billion by the year 2050. The current intensification of agricultural practices is already resulting in the unsustainable degradation of soils. Major forms of this degradation include the loss of organic matter and the release of greenhouse gases, the over-application of fertilizers, erosion, contamination, acidification, salinization, and loss of genetic ersity. This ongoing soil degradation is decreasing the long-term ability of soils to provide humans with services, including future food production, and is causing environmental harm. It is imperative that the global society is not shortsighted by focusing solely on the near-immediate benefits of soils, such as food supply. A failure to identify the importance of soil within increasingly intensive agricultural systems will undoubtedly have serious consequences for humanity and represents a failure to consider intergenerational equity. Of utmost importance is the need to unequivocally recognize that the degradation of soils leads to a clear economic cost through the loss of services, with such principles needing to be explicitly considered in economic frameworks and decision-making processes at all levels of governance. We contend that the concept of the Water-Food-Energy nexus must be expanded, forming the Water-Soil-Food-Energy nexus.
Analytical characterisation of nanoscale zero-valent iron: A methodological review
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.ACA.2015.10.040
Abstract: Zero-valent iron nanoparticles (nZVI) have been widely tested as they are showing significant promise for environmental remediation. However, many recent studies have demonstrated that their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Both the mobility and reactivity of nZVI mainly depends on properties such as particle size, surface chemistry and bulk composition. In order to ensure efficient remediation, it is crucial to accurately assess and understand the implications of these properties before deploying these materials into contaminated environments. Many analytical techniques are now available to determine these parameters and this paper provides a critical review of their usefulness and limitations for nZVI characterisation. These analytical techniques include microscopy and light scattering techniques for the determination of particle size, size distribution and aggregation state, and X-ray techniques for the characterisation of surface chemistry and bulk composition. Ex le characterisation data derived from commercial nZVI materials is used to further illustrate method strengths and limitations. Finally, some important challenges with respect to the characterisation of nZVI in groundwater s les are discussed.
Vanadium Speciation in Ancient Shales Revealed through Synchrotron-Based X-ray Spectroscopy
Publisher: American Chemical Society (ACS)
Date: 26-09-0002
Methodologies and approaches for the analysis of cell–nanoparticle interactions
Publisher: Wiley
Date: 21-07-2017
DOI: 10.1002/WNAN.1486
Abstract: How to study nanoparticle–cell interactions is the key question that puzzles researchers in the fields of nanomedicine as well as in nanotoxicology. In nanotoxicology, the amount of nanoparticles internalized by the cells or bound to the external surfaces of cells determines the toxic profile of those particles. In medical applications, cellular uptake and binding of medically effective nanoparticles decides their efficacy. Despite the importance of understanding the extent and mode of nanoparticle–cell interactions, these processes are underinvestigated, mainly due to the lack of suitable user‐friendly methodologies. Here we discuss the advantages and limitations of currently available (and most advanced) microscopic, spectroscopic, and other bioanalytical methods that could be used to assess cell‐nanoparticle interactions either qualitatively or quantitatively. Special emphasis is given to the methods that enable analysis and identification of nanoparticles at single‐cell level, and allow intracellular localization and speciation analysis of nanoparticles. This article is categorized under: Nanotechnology Approaches to Biology Cells at the Nanoscale Toxicology and Regulatory Issues in Nanomedicine Toxicology of Nanomaterials
Laterally resolved speciation of arsenic in roots of wheat and rice using fluorescence‐XANES imaging
Publisher: Wiley
Date: 11-11-2013
DOI: 10.1111/NPH.12595
Abstract: Accumulation of arsenic (As) within plant tissues represents a human health risk, but there remains much to learn regarding the speciation of As within plants. We developed synchrotron‐based fluorescence‐X‐ray absorption near‐edge spectroscopy (fluorescence‐ XANES ) imaging in hydrated and fresh plant tissues to provide laterally resolved data on the in situ speciation of As in roots of wheat ( Triticum aestivum ) and rice ( Oryza sativa ) exposed to 2 μM As(V) or As( III ). When exposed to As(V), the As was rapidly reduced to As( III ) within the root, with As(V) calculated to be present only in the rhizodermis. However, no uncomplexed As( III ) was detected in any root tissues, because of the efficient formation of the As( III )–thiol complex – this As species was calculated to account for all of the As in the cortex and stele. The observation that uncomplexed As( III ) was below the detection limit in all root tissues explains why the transport of As to the shoots is low, given that uncomplexed As( III ) is the major As species transported within the xylem and phloem. Using fluorescence‐ XANES imaging, we have provided in situ data showing the accumulation and transformation of As within hydrated and fresh root tissues.
Zinc from foliar-applied nanoparticle fertiliser is translocated to wheat grain: A 65Zn radiolabelled translocation study comparing conventional and novel foliar fertilisers
Publisher: Elsevier BV
Date: 12-2020
X-ray Absorption and Micro X-ray Fluorescence Spectroscopy Investigation of Copper and Zinc Speciation in Biosolids
Publisher: American Chemical Society (ACS)
Date: 15-08-2011
DOI: 10.1021/ES201710Z
Abstract: Despite its pivotal role in determining the risks and time frames associated with contaminant release, metal speciation remains a poorly understood aspect of biosolids chemistry. The work reported here used synchrotron-based spectroscopy techniques to investigate the speciation of copper and zinc in a range of Australian biosolids. High resolution element mapping of biosolids s les using micro X-ray fluorescence spectroscopy revealed considerable heterogeneity in key element associations, and a combination of both organic and inorganic copper and zinc binding environments. Linear combination fitting of K-edge X-ray absorption spectra indicated consistent differences in metal speciation between freshly produced and stockpiled biosolids. While sulfide minerals play a dominant role in metal binding in freshly dewatered biosolids, they are of lesser importance in dried biosolids that have been stockpiled. A degree of metal binding with iron oxide minerals was apparent but the results did not support the hypothesis that biosolids metals are chiefly associated with iron minerals. This work has potential implications for the long-term stability of metals in biosolids and their eventual fate following land application.
Engineered silver nanoparticles in terrestrial environments: a meta-analysis shows that the overall environmental risk is small
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8EN00486B
Abstract: The risk of engineered silver nanoparticles to terrestrial plants and fauna (including humans through trophic transfer) is small.
Translocation of Foliar Absorbed Zn in Sunflower (Helianthus annuus) Leaves
Publisher: Frontiers Media SA
Date: 02-03-2022
Abstract: Foliar zinc (Zn) fertilization is an important approach for overcoming crop Zn deficiency, yet little is known regarding the subsequent translocation of this foliar-applied Zn. Using synchrotron-based X-ray fluorescence microscopy (XFM) and transcriptome analysis, the present study examined the translocation of foliar absorbed Zn in sunflower ( Helianthus annuus ) leaves. Although bulk analyses showed that there had been minimal translocation of the absorbed Zn out of the leaf within 7 days, in situ analyses showed that the distribution of Zn in the leaf had changed with time. Specifically, when Zn was applied to the leaf for 0.5 h and then removed, Zn primarily accumulated within the upper and lower epidermal layers (when examined after 3 h), but when examined after 24 h, the Zn had moved to the vascular tissues. Transcriptome analyses identified a range of genes involved in stress response, cell wall reinforcement, and binding that were initially upregulated following foliar Zn application, whereas they were downregulated after 24 h. These observations suggest that foliar Zn application caused rapid stress to the leaf, with the initial Zn accumulation in the epidermis as a detoxification strategy, but once this stress decreased, Zn was then moved to the vascular tissues. Overall, this study has shown that despite foliar Zn application causing rapid stress to the leaf and that most of the Zn stayed within the leaf over 7 days, the distribution of Zn in the leaf had changed, with Zn mostly located in the vascular tissues 24 h after the Zn had been applied. Not only do the data presented herein provide new insight for improving the efficiency of foliar Zn fertilizers, but our approach of combining XFM with a transcriptome methodological system provides a novel approach for the study of element translocation in plants.
Synchrotron X-ray spectroscopy for investigating vanadium speciation in marine sediment: limitations and opportunities
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8JA00231B
Abstract: Synchrotron-based X-ray spectroscopy is a powerful technique for investigating vanadium speciation in marine sediment.
Synchrotron-based X-Ray approaches for examining toxic trace metal(loid)s in soil-plant systems
Publisher: Wiley
Date: 11-2017
Abstract: Elevated levels of trace metal(loid)s reduce plant growth, both in soils contaminated by industrial activities and in acid agricultural soils. Although the adverse effects of trace metal(loid)s have long been recognized, there remains much unknown both about their behavior in soils, their toxicity to plants, and the mechanisms that plants use to tolerate elevated concentrations. Synchrotron-based approaches are being utilized increasingly in soil-plant systems to examine toxic metal(loid)s. In the present review, brief consideration is given to the theory of synchrotron radiation. Thereafter, we review the use of synchrotron-based approaches for the examination of various trace metal(loid)s in soil-plant systems, including aluminum, chromium, manganese, cobalt, nickel, copper, zinc, arsenic, selenium, and cadmium. Within the context of this review, X-ray absorption spectroscopy (XAS) and X-ray fluorescence microscopy (μ-XRF) are of particular interest. These techniques can provide in situ analyses of the distribution and speciation of metal(loid)s in soil-plant systems. The information presented here serves not only to understand the behavior of trace metals in soil-plant systems, but also to provide ex les of the potential applications of synchrotron radiation that can be used to advantage in other studies.
Speciation of metal(loid)s in environmental samples by X-ray absorption spectroscopy: A critical review
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.ACA.2014.02.044
Abstract: Element specificity is one of the key factors underlying the widespread use and acceptance of X-ray absorption spectroscopy (XAS) as a research tool in the environmental and geo-sciences. Independent of physical state (solid, liquid, gas), XAS analyses of metal(loid)s in complex environmental matrices over the past two decades have provided important information about speciation at environmentally relevant interfaces (e.g. solid-liquid) as well as in different media: plant tissues, rhizosphere, soils, sediments, ores, mineral process tailings, etc. Limited s le preparation requirements, the concomitant ability to preserve original physical and chemical states, and independence from crystallinity add to the advantages of using XAS in environmental investigations. Interpretations of XAS data are founded on sound physical and statistical models that can be applied to spectra of reference materials and mixed phases, respectively. For spectra collected directly from environmental matrices, abstract factor analysis and linear combination fitting provide the means to ascertain chemical, bonding, and crystalline states, and to extract quantitative information about their distribution within the data set. Through advances in optics, detectors, and data processing, X-ray fluorescence microprobes capable of focusing X-rays to micro- and nano-meter size have become competitive research venues for resolving the complexity of environmental s les at their inherent scale. The application of μ-XANES imaging, a new combinatorial approach of X-ray fluorescence spectrometry and XANES spectroscopy at the micron scale, is one of the latest technological advances allowing for lateral resolution of chemical states over wide areas due to vastly improved data processing and detector technology.
Assessing the potential for zinc and cadmium phytoremediation with the hyperaccumulator Thlaspi caerulescens
Publisher: Springer Science and Business Media LLC
Date: 2003
Optimising the foliar uptake of zinc oxide nanoparticles: Do leaf surface properties and particle coating affect absorption?
Publisher: Wiley
Date: 09-09-2020
DOI: 10.1111/PPL.13167
The Use of Microfluidics in Cytotoxicity and Nanotoxicity Experiments
Publisher: MDPI AG
Date: 12-04-2017
DOI: 10.3390/MI8040124
Measurement of Inorganic Arsenic Species in Rice after Nitric Acid Extraction by HPLC-ICPMS: Verification Using XANES
Publisher: American Chemical Society (ACS)
Date: 13-05-2013
DOI: 10.1021/ES304299V
Abstract: The measurement of As species in rice is normally accomplished by extraction followed by HPLC-ICPMS analysis. This method, however, has not been comprehensively validated by comparing these speciation results with XANES, which does not require s le extraction, due to the challenge of conducting XANES analysis at very low As concentrations. In this study As speciation data using nitric acid extraction/HPLC-ICPMS and XANES are compared to verify the efficacy of using 2% v/v nitric acid extraction and HPLC-ICPMS to measure inorganic As, DMA, and MA in reference rice materials and common rice varieties obtainable in Australia. Total As and As species (As(III), As(V), DMA, and MA) concentrations measured in 8 reference materials were in agreement with published values. XANES analysis was performed on 5 s les having total As concentrations ranging from 0.198 to 0.335 μg g(-1). XANES results gave similar proportions of total As(III), As(V), and DMA to HPLC-ICPMS. XANES was able to distinguish two forms of As(III): As(III) and As(III)GSH. Total As concentrations in rice s les varied from 0.006 to 0.45 μg g(-1) As (n = 47) with a mean ± std of 0.127 ± 0.112 μg g(-1) As with most As present as inorganic species (63 ± 26%). DMA was found in nearly all the rice s les with the majority of s les containing concentrations below 0.05 μg g(-1) As while MA concentrations were negligible (<0.003 μg g(-1) As). Six rice varieties produced in Australia, China, and Spain all had elevated DMA concentrations (0.170-0.399 μg g(-1) As) that were correlated with total As concentrations (r(2) = 0.7518). In conclusion, comparison of As speciation by HPLC-ICPMS and XANES showed that similar As species were detected indicating the appropriateness of using 2% v/v nitric acid for extraction of rice prior to speciation. Common rice varieties obtainable in Australia generally have low As concentrations with most As present as inorganic As.
Measurement of labile Cu in soil using stable isotope dilution and isotope ratio analysis by ICP-MS
Publisher: Springer Science and Business Media LLC
Date: 26-10-2004
DOI: 10.1007/S00216-004-2816-6
Abstract: Isotope dilution is a useful technique to measure the labile metal pool, which is the amount of metal in soil in rapid equilibrium (<7 days) with the soil solution. This is normally performed by equilibrating soil with a metal isotope, and s ling the labile metal pool by using an extraction (E value), or by growing plants (L value). For Cu, this procedure is problematic for E values, and impossible for L values, due to the short half-life of the 64Cu radioisotope (12.4 h), which makes access and handling very difficult. We therefore developed a technique using enriched 65Cu stable isotope and measurement of 63Cu/65Cu ratios by quadrupole inductively coupled plasma mass spectrometry (ICP-MS) to measure labile pools of Cu in soils using E value techniques. Mass spectral interferences in detection of 63Cu/65Cu ratios in soil extracts were found to be minimal. Isotope ratios determined by quadrupole ICP-MS compared well to those determined by high-resolution (magnetic sector) ICP-MS. E values determined using the stable isotope technique compared well to those determined using the radioisotope for both uncontaminated and Cu-contaminated soils.
Effect of water treatment residuals on soil phosphorus, copper and aluminium availability and toxicity
Publisher: Elsevier BV
Date: 06-2010
DOI: 10.1016/J.ENVPOL.2010.03.006
Abstract: Water treatment residuals (WTRs) are produced by the treatment of potable water with coagulating agents. Beneficial recycling in agriculture is h ered by the fact that WTRs contain potentially toxic contaminants (e.g. copper and aluminium) and they bind phosphorus strongly. These issues were investigated using a plant bioassay (Lactuca sativa), chemical extractions and an isotopic dilution technique. Two WTRs were applied to an acidic and a neutral pH soil at six rates. Reductions in plant growth in amended soils were due to WTR-induced P deficiency, rather than Al or Cu toxicity. The release of potentially toxic Al from WTRs was found to be mitigated by their alkaline nature and pH buffering capacity. However, acidification of WTRs was shown to release more soluble Al than soil naturally high in Al. Copper availability was relatively low in all treatments. However, the lability of WTR-Cu increased when the WTR was applied to the soil.
Synthesis and Characterization of Thiolated Chitosan Beads for Removal of Cu(II) and Cd(II) from Wastewater
Publisher: Springer Science and Business Media LLC
Date: 20-11-2013
Grain Accumulation of Selenium Species in Rice (Oryza sativa L.)
Publisher: American Chemical Society (ACS)
Date: 23-04-2012
DOI: 10.1021/ES203871J
Abstract: Efficient Se biofortification programs require a thorough understanding of the accumulation and distribution of Se species within the rice grain. Therefore, the translocation of Se species to the filling grain and their spatial unloading were investigated. Se species were supplied via cut flag leaves of intact plants and excised panicle stems subjected to a ± stem-girdling treatment during grain fill. Total Se concentrations in the flag leaves and grain were quantified by inductively coupled plasma mass spectrometry. Spatial accumulation was investigated using synchrotron X-ray fluorescence microtomography. Selenomethionine (SeMet) and selenomethylcysteine (SeMeSeCys) were transported to the grain more efficiently than selenite and selenate. SeMet and SeMeSeCys were translocated exclusively via the phloem, while inorganic Se was transported via both the phloem and xylem. For SeMet- and SeMeSeCys-fed grain, Se dispersed throughout the external grain layers and into the endosperm and, for SeMeSeCys, into the embryo. Selenite was retained at the point of grain entry. These results demonstrate that the organic Se species SeMet and SeMeSeCys are rapidly loaded into the phloem and transported to the grain far more efficiently than inorganic species. Organic Se species are distributed more readily, and extensively, throughout the grain than selenite.
Application of MicroResp™ for soil ecotoxicology
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.ENVPOL.2013.04.010
Abstract: MicroResp™ is a miniaturised method for measuring substrate induced respiration (SIR) in soil. We modified the MicroResp™ method to develop a rapid tool for quantifying the ecotoxicological impact of contaminants. The method is based on reduction in SIR across a gradient of contaminant, allowing for determination of dose-response curves EC-values. Contaminants are mixed into soil s les at a range of concentrations each s le is then dispensed into a column of eight wells in 96 well format (deep) plates. Moisture and glucose are added to the s les at levels to provide maximum response. Released CO₂ from the soils is then measured using colorimetric gel-traps, following the standard MicroResp™ methodology. Examination revealed that this method works over a range of soil types and is insensitive to minor variations in assay length (2-7 h), alteration of moisture content (±20 μL from optimum), and soil storage conditions (4 °C versus fresh).
Hard X-ray synchrotron biogeochemistry: Piecing together the increasingly detailed puzzle
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/EN13209
Speciation and lability of Ag-, AgCl-, and Ag2 S-nanoparticles in soil determined by X-ray absorption spectroscopy and diffusive gradients in thin films
Publisher: American Chemical Society (ACS)
Date: 29-12-2015
DOI: 10.1021/ES504229H
Abstract: Long-term speciation and lability of silver (Ag-), silver chloride (AgCl-), and silver sulfide nanoparticles (Ag2S-NPs) in soil were studied by X-ray absorption spectroscopy (XAS), and newly developed “nano” Diffusive Gradients in Thin Films (DGT) devices. These nano-DGT devices were designed specifically to avoid confounding effects when measuring element lability in the presence of nanoparticles. The aging profile and stabilities of the three nanoparticles and AgNO3 (ionic Ag) in soil were examined at three different soil pH values over a period of up to 7 months. Transformation of ionic Ag, Ag-NP and AgCl-NPs were dependent on pH. AgCl formation and persistence was observed under acidic conditions, whereas sulfur-bound forms of Ag dominated in neutral to alkaline soils. Ag2S-NPs were found to be very stable under all conditions tested and remained sulfur bound after 7 months of incubation. Ag lability was characteristically low in soils containing Ag2S-NPs. Other forms of Ag were linked to higher DGT-determined lability, and this varied as a function of aging and related speciation changes as determined by XAS. These results clearly indicate that Ag2S-NPs, which are the most environmentally relevant form of Ag that enter soils, are chemically stable and have profoundly low Ag lability over extended periods. This may minimize the long-term risks of Ag toxicity in the soil environment.
Effect of toxic cations on copper rhizotoxicity in wheat seedlings
Publisher: Wiley
Date: 02-2005
DOI: 10.1897/03-069R.1
Abstract: Copper pollution may occur in acidic soils where the low pH leads to release of Al and Mn in soil solution, which could interact with Cu toxicity. Very little information exists regarding the influence of toxic cations on the phytotoxicity of Cu. In this study, we tested the hypothesis that phytotoxicity of Cu2+ may be overestimated in acidic soils due to synergism between Al or Mn and Cu toxicity. Rhizotoxicity of Al, Mn, and Cu to wheat seedlings was studied in well-defined nutrient solutions, with these elements present singly or in combination. Toxicity was expressed on a solution metal-activity basis, with metal activities calculated using GEOCHEM-PC and verified using Donnan dialysis. Of the three ions, Cu2+ was the most rhizotoxic, with activities of Cu2+, Al3+, and Mn2+ resulting in a 25% reduction in root elongation of 0.12, 1.26, and 211 microM, respectively. Although there was no interaction between Mn2+ and Cu2+ toxicity, Cu2+ was significantly less toxic on a relative basis in the presence of Al3+. Thus, critical thresholds for soil solution Cu2+ activity determined in acidic soils will be underprotective compared to soils that contain low concentrations of soluble Al (e.g., limed or nonacidic soils).
Advanced in situ Spectroscopic Techniques and their Applications in Environmental Biogeochemistry: Introduction to the Special Section
Publisher: Wiley
Date: 05-2011
DOI: 10.2134/JEQ2010.0542
Abstract: Understanding the molecular-scale complexities and interplay of chemical and biological processes of contaminants at solid, liquid, and gas interfaces is a fundamental and crucial element to enhance our understanding of anthropogenic environmental impacts. The ability to describe the complexity of environmental biogeochemical reaction mechanisms relies on our analytical ability through the application and developmemnt of advanced spectroscopic techniques. Accompanying this introductory article are nine papers that either review advanced in situ spectroscopic methods or present original research utilizing these techniques. This collection of articles summarizes the challenges facing environmental biogeochemistry, highlights the recent advances and scientific gaps, and provides an outlook into future research that may benefit from the use of in situ spectroscopic approaches. The use of synchrotron-based techniques and other methods are discussed in detail, as is the importance to integrate multiple analytical approaches to confirm results of complementary procedures or to fill data gaps. We also argue that future direction in research will be driven, in addition to recent analytical developments, by emerging factors such as the need for risk assessment of new materials (i.e., nanotechnologies) and the realization that biogeochemical processes need to be investigated in situ under environmentally relevant conditions.
Chemical characterisation, antibacterial activity, and (nano)silver transformation of commercial personal care products exposed to household greywater
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9EN00738E
Abstract: The objective of this study was to test the original speciation of silver (Ag) in eight different commercially available personal care products and investigate the chemical transformation of Ag during exposure to two types of synthetic greywater.
Effects of chemical amendments on the lability and speciation of metals in anaerobically digested biosolids
Publisher: American Chemical Society (ACS)
Date: 17-09-2013
DOI: 10.1021/ES400805J
Abstract: The interaction of inorganic contaminants present in biosolids with iron, aluminum, and manganese oxy/hydroxides has been advocated as a key mechanism limiting their bioavailability. In this study, we investigated whether this is indeed the case, and further, whether it can be exploited to produce optimized biosolids products through the addition of chemical additives during sewage sludge processing. Experiments were conducted to investigate whether the addition of iron- and aluminum-based amendments (at 5 different rates) during the anaerobic digestion phase of wastewater treatment can effectively change the speciation or lability of contaminant metals (copper, zinc and cadmium) in biosolids destined for use in agriculture. The performance of the bioreactors was monitored throughout and the speciation and lability were determined in both fresh and 3-month aged biosolids using X-ray absorption spectroscopy (Cu, Zn) and isotopic dilution ((65)Cu, (65)Zn, (109)Cd). The tested amendments (FeCl3, Al2(SO4)3, and Al-rich water treatment residual) did not cause significant changes in metal speciation and were of limited use for reducing the lability of contaminant metals in good quality biosolids (suitable for use in agriculture), suggesting that high affinity binding sites were already in excess in these materials. However, the use of chemical amendments may offer advantages in terms of treatment process optimization and may also be beneficial when biosolids are used for contaminated site remediation.
Phosphorus speciation in the fertosphere of highly concentrated fertilizer bands
Publisher: Elsevier BV
Date: 12-2021
Impact of Surface Charge on Cerium Oxide Nanoparticle Uptake and Translocation by Wheat (Triticum aestivum)
Publisher: American Chemical Society (ACS)
Date: 16-06-2017
Abstract: Nanoparticle (NP) physiochemical properties, including surface charge, affect cellular uptake, translocation, and tissue localization. To evaluate the influence of surface charge on NP uptake by plants, wheat seedlings were hydroponically exposed to 20 mg/L of ∼4 nm CeO
Synchrotron-Based Imaging Reveals the Fate of Selenium in Striped Marsh Frog Tadpoles
Publisher: American Chemical Society (ACS)
Date: 12-08-2021
Synchrotron-Based X-Ray Fluorescence Microscopy as a Technique for Imaging of Elements in Plants
Publisher: Oxford University Press (OUP)
Date: 14-08-2018
DOI: 10.1104/PP.18.00759
A multi-technique investigation of copper and zinc distribution, speciation and potential bioavailability in biosolids
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.ENVPOL.2012.02.012
Abstract: The use of biosolids in agriculture continues to be debated, largely in relation to their metal contents. Our knowledge regarding the speciation and bioavailability of biosolids metals is still far from complete. In this study, a multi-technique approach was used to investigate copper and zinc speciation and partitioning in one contemporary and two historical biosolids used extensively in previous research and field trials. Using wet chemistry and synchrotron spectroscopy techniques it was shown that copper/zinc speciation in the biosolids was largely equivalent despite the biosolids being derived from different countries over a 50 year period. Furthermore, copper speciation was consistently dominated by sorption to organic matter whereas Zn partitioned mainly to iron oxides. These data suggest that the results of historical field trials are still relevant for modern biosolids and that further risk assessment studies should concentrate particularly on Cu as this metal is associated with the mineralisable biosolids fraction.
Coupling Speciation and Isotope Dilution Techniques To Study Arsenic Mobilization in the Environment
Publisher: American Chemical Society (ACS)
Date: 14-02-2004
DOI: 10.1021/ES034931X
Abstract: We have developed an approach to isolate mechanisms controlling mobility and speciation of As in soil-water systems. The approach uses a combination of isotopic exchange and chromatographic/mass spectrometric As speciation techniques. We used this approach to identify mechanisms responsible for changes in the concentration of soluble As in two contaminated soils (Eaglehawk and Tavistock) subjected to different redox conditions and microbial activity. A high proportion of the total As in both soils was present in a nonlabile form. Incubation of the soils under anaerobic conditions led to changes in the concentration of soluble As in each soil but did not change the As speciation or the proportion of total As in labile forms in the soils. Hence, a decrease in soluble As in the Eaglehawk soil was the result of an Eh-induced pH decrease, enhancing the solid-phase sorption of As(V). An increase in soluble As in the Tavistock soil was due to an Eh-induced pH increase, decreasing solid-phase sorption of As(V). Incubation of the soils under aerobic conditions with microbial activity stimulated by addition of glucose resulted in no change in the solution concentration or speciation of As in the Eaglehawk soil, but led to a large increase in the concentration of soluble As in the Tavistock soil. This increase was due to conversion of exchangeable forms of As(V) into less strongly sorbed As(III) species. Incubation under anaerobic conditions in the presence of glucose resulted in a large increase in the concentration of soluble As in both soils however, different mechanisms were found to be responsible for the increase in each soil. In the Eaglehawk soil higher concentrations of As were again due to conversion of exchangeable forms of As(V) into less strongly sorbed As(III) species. In contrast in the Tavistock soil, the increased As in solution was the result of release of As(V) from the large reservoir of nonlabile soil As.
Plant-Available Phosphorus in Highly Concentrated Fertilizer Bands: Effects of Soil Type, Phosphorus Form, and Coapplied Potassium
Publisher: American Chemical Society (ACS)
Date: 13-07-2020
Selenium Characterization in the Global Rice Supply Chain
Publisher: American Chemical Society (ACS)
Date: 08-06-2009
DOI: 10.1021/ES900671M
Abstract: For up to 1 billion people worldwide, insufficient dietary intake of selenium (Se) is a serious health constraint. Cereals are the dominant Se source for those on low protein diets, as typified by the global malnourished population. With crop Se content constrained largely by underlying geology, regional soil Se variations are often mirrored by their locally grown staples. Despite this, the Se concentrations of much of the world's rice, the mainstay of so many, is poorly characterized, for both total Se content and Se speciation. In this study, 1092 s les of market sourced polished rice were obtained. The s led rice encompassed dominant rice producing and exporting countries. Rice from the U.S. and India were found to be the most enriched, while mean average levels were lowest in Egyptian rice: approximately 32-fold less than their North American equivalents. By weighting country averages by contribution to either global production or export, modeled baseline values for both were produced. Based on a daily rice consumption of 300 g day(-1), around 75% of the grains from the production and export pools would fail to provide 70% of daily recommended Se intakes. Furthermore, Se localization and speciation characterization using X-ray fluorescence (micro-XRF) and X-ray absorption near edge structure (micro-XANES) techniques were investigated in a Se-rich s le. The results revealed that the large majority of Se in the endosperm was present in organic forms.
Fate of ZnO Nanoparticles in Soils and Cowpea (Vigna unguiculata)
Publisher: American Chemical Society (ACS)
Date: 14-11-2013
DOI: 10.1021/ES403466P
Abstract: The increasing use of zinc oxide nanoparticles (ZnO-NPs) in various commercial products is prompting detailed investigation regarding the fate of these materials in the environment. There is, however, a lack of information comparing the transformation of ZnO-NPs with soluble Zn(2+) in both soils and plants. Synchrotron-based techniques were used to examine the uptake and transformation of Zn in various tissues of cowpea ( Vigna unguiculata (L.) Walp.) exposed to ZnO-NPs or ZnCl2 following growth in either solution or soil culture. In solution culture, soluble Zn (ZnCl2) was more toxic than the ZnO-NPs, although there was substantial accumulation of ZnO-NPs on the root surface. When grown in soil, however, there was no significant difference in plant growth and accumulation or speciation of Zn between soluble Zn and ZnO-NP treatments, indicating that the added ZnO-NPs underwent rapid dissolution following their entry into the soil. This was confirmed by an incubation experiment with two soils, in which ZnO-NPs could not be detected after incubation for 1 h. The speciation of Zn was similar in shoot tissues for both soluble Zn and ZnO-NPs treatments and no upward translocation of ZnO-NPs from roots to shoots was observed in either solution or soil culture. Under the current experimental conditions, the similarity in uptake and toxicity of Zn from ZnO-NPs and soluble Zn in soils indicates that the ZnO-NPs used in this study did not constitute nanospecific risks.
Transformation of Calcium Phosphates in Alkaline Vertisols by Acidified Incubation
Publisher: American Chemical Society (ACS)
Date: 16-08-2019
Abstract: Acid-soluble soil phosphorus (P) is a potential resource in P-limited agricultural systems that may become critical as global P sources decrease in the future. The fate of P in three alkaline Vertisols, a major agricultural soil type, after acidic incubation was investigated using synchrotron-based K-edge X-ray absorption near-edge structure (XANES) spectroscopy, geochemical modeling, wet chemistry soil extraction, and a P sorption index. Increases in labile P generally coincided with decreased stability and dissolution of calcium phosphate (CaP) minerals. However, only a minor proportion of the CaP dissolved in each soil was labile. In two moderate-P soils (800 mg P kg
Bridging the divide between human and environmental nanotoxicology
Publisher: Springer Science and Business Media LLC
Date: 10-2015
Abstract: The need to assess the human and environmental risks of nanoscale materials has prompted the development of new metrological tools for their detection, quantification and characterization. Some of these methods have tremendous potential for use in various scenarios of nanotoxicology. However, in some cases, the limited dialogue between environmental scientists and human toxicologists has h ered the full exploitation of these resources. Here we review recent progress in the development of methods for nanomaterial analysis and discuss the use of these methods in environmental and human toxicology. We highlight the opportunities for collaboration between these two research areas.
Challenges of polymer‐based pH sensing in soil
Publisher: Wiley
Date: 29-09-2023
DOI: 10.1002/POL.20230481
Exchangeability of orthophosphate and pyrophosphate in soils: a double isotopic labelling study
Publisher: Springer Science and Business Media LLC
Date: 23-07-2008
Functional characterisation of metal(loid) processes in planta through the integration of synchrotron techniques and plant molecular biology
Publisher: Springer Science and Business Media LLC
Date: 27-12-2012
Hair analysis as a biomonitor for toxicology, disease and health status
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CS15021A
Abstract: Hair analysis receives a large amount of academic and commercial interest for wide-ranging applications. However, in many instances, especially for elemental or 'mineral' analysis, the degree of success of analytical interpretation has been quite minimal with respect to the extent of such endeavors. In this critical review we address the questions surrounding hair analysis with specific intent of discovering what hair concentrations can actually relate to in a biogenic sense. This is done from a chemistry perspective to explain why and how elements are incorporated into hair and their meaning. This includes an overview of variables attributed to altering hair concentrations, such as age, gender, melanin content, and other less reported factors. Hair elemental concentrations are reviewed with regard to morbidity, with specific ex les of disease related effects summarized. The application of hair analysis for epidemiology and etiology studies is enforced. A section is dedicated specifically to the area of population studies with regards to mercury, which highlights how endogenous and exogenous incorporation relies on species dependant metabolism and metabolic products. Many of the considerations are relevant to other areas of interest in hair analysis, such as for drug and isotopic analysis. Inclusion of a table of elemental concentrations in hair should act as a valuable reference (298 references).
Erratum to: A review of recent developments in the speciation and location of arsenic and selenium in rice grain
Publisher: Springer Science and Business Media LLC
Date: 04-02-2012
Pesticide effects on nitrogen cycle related microbial functions and community composition
Publisher: Elsevier BV
Date: 02-2022
DOI: 10.1016/J.SCITOTENV.2021.150734
Abstract: The extensive application of pesticides in agriculture raises concerns about their potential negative impact on soil microorganisms, being the key drivers of nutrient cycling. Most studies have investigated the effect of a single pesticide on a nutrient cycling in single soil type. We, for the first time, investigated the effect of 20 commercial pesticides with different mode of actions, applied at their recommended dose and five times their recommended dose, on nitrogen (N) microbial cycling in three different agricultural soils from southern Australian. Functional effects were determined by measuring soil enzymatic activities of β-1,4-N-acetyliglucosaminidase (NAG) and l-leucine aminopeptidase (LAP), potential nitrification (PN), and the abundance of functional genes involved in N cycling (amoA and nifH). Effects on nitrifiers ersity were determined with licon sequencing. Overall, the pesticides effect on N microbial cycling was dose-independent and soil specific. The fungicides flutriafol and azoxystrobin, the herbicide chlorsulfuron and the insecticide fipronil induced a significant reduction in PN and β-1,4-N-acetylglucosaminidase activity (P < 0.05) (NAG) in the alkaline loam soil with low organic carbon content i.e. a soil with properties which typically favors pesticide bioavailability and therefore potential toxicity. For the nitrifier community, the greatest pesticide effects were on the most dominant Nitrososphaeraceae (ammonia-oxidizing archaea AOA) whose abundance increased significantly compared to the less dominant AOA and other nitrifiers. The inhibiting effects were more evident in the soil s les treated with fungicides. By testing multiple pesticides in a single study, our findings provide crucial information that can be used for pesticide hazard assessment.
Characterizing the uptake, accumulation and toxicity of silver sulfide nanoparticles in plants
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6EN00489J
Abstract: Plants take up Ag 2 S-NPs without a marked selectivity in regard to particle size and without substantial transformation during upward translocation.
The rhizotoxicity of metal cations is related to their strength of binding to hard ligands
Publisher: Wiley
Date: 02-01-2014
DOI: 10.1002/ETC.2435
Abstract: Mechanisms whereby metal cations are toxic to plant roots remain largely unknown. Aluminum, for ex le, has been recognized as rhizotoxic for approximately 100 yr, but there is no consensus on its mode of action. The authors contend that the primary mechanism of rhizotoxicity of many metal cations is nonspecific and that the magnitude of toxic effects is positively related to the strength with which they bind to hard ligands, especially carboxylate ligands of the cell-wall pectic matrix. Specifically, the authors propose that metal cations have a common toxic mechanism through inhibiting the controlled relaxation of the cell wall as required for elongation. Metal cations such as Al(3+) and Hg(2+), which bind strongly to hard ligands, are toxic at relatively low concentrations because they bind strongly to the walls of cells in the rhizodermis and outer cortex of the root elongation zone with little movement into the inner tissues. In contrast, metal cations such as Ca(2+), Na(+), Mn(2+), and Zn(2+) , which bind weakly to hard ligands, bind only weakly to the cell wall and move farther into the root cylinder. Only at high concentrations is their weak binding sufficient to inhibit the relaxation of the cell wall. Finally, different mechanisms would explain why certain metal cations (for ex le, Tl(+), Ag(+), Cs(+), and Cu(2+)) are sometimes more toxic than expected through binding to hard ligands. The data presented in the present study demonstrate the importance of strength of binding to hard ligands in influencing a range of important physiological processes within roots through nonspecific mechanisms.
Sorption of silver nanoparticles to laboratory plastic during (eco)toxicological testing
Publisher: Informa UK Limited
Date: 15-10-2015
DOI: 10.3109/17435390.2015.1084059
Abstract: Here, we evaluate the extent of sorption of silver nanoparticles (AgNPs) with different primary sizes (30 and 70 nm) and surface properties (branched polyethylene imine, "bPEI" and citrate coating) to laboratory plastic during (eco)toxicological testing. Under conditions of algal growth inhibition assay, up to 97% of the added AgNPs were sorbed onto the test vessels whereas under conditions of in vitro toxicological assay with mammalian cells, the maximum loss of AgNPs was 15%. We propose that the high concentration of proteins and biomolecules in the in vitro toxicological assay originating from serum-containing cell culture medium prevented NP sorption due to steric stabilisation. The sorption of AgNPs to test vessels was clearly concentration dependent. In the conditions of algal growth inhibition assay at 10 ng AgNPs/mL, up to 97% of AgNPs were lost from the test while at higher concentrations (1000 ng AgNPs/mL), the loss of AgNPs was remarkably smaller, up to 64%. Sorption of positively charged bPEI-coated AgNPs was more extensive than the sorption of negatively charged citrate-coated AgNPs and, when calculated on a mass basis, more 70 nm-sized Ag than 30 nm Ag sorbed to plastic surfaces. In summary, this study demonstrates that the loss of AgNPs during (eco)toxicological tests due to sorption on test vessel surfaces is significant, especially in diluted media (e.g. in algal growth medium) and at low NP concentrations. Thus, to ensure the accurate interpretation of (eco)toxicological results, the loss of AgNPs due to adsorption to test vessels should not be overlooked and considered for each specific case.
Cadmium accumulation in populations of Thlaspi caerulescens and Thlaspi goesingense
Publisher: Wiley
Date: 2000
Arsenic adsorption by soils and iron-oxide-coated sand: kinetics and reversibility
Publisher: Wiley
Date: 08-1999
DOI: 10.1002/(SICI)1522-2624(199908)162:4<451::AID-JPLN451>3.0.CO;2-B
Fate and lability of silver in soils: Effect of ageing
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.ENVPOL.2014.04.030
Abstract: The fate and lability of added soluble Ag in soils over time was examined by measurement of labile metal (E-value) by isotopic dilution using the (110m)Ag radioactive isotope and the solid-phase speciation of Ag by X-ray absorption near edge structure (XANES) spectroscopy. After two weeks of ageing the E-values for Ag decreased by 20-90% with a further decrease of 10-40% after six months. The overall decrease in labile Ag for all soils after the 6 month ageing period was 50-100%. The ageing was more rapid and pronounced in the alkaline soils. XANES results for Ag in soils indicated that for the majority of soils the added Ag(+) was reduced to metallic Ag over time, and associations with Fe-oxohydroxides and reduced S groups in organic matter also decreased Ag lability. Strong positive correlations were found between metallic Ag and non-labile Ag and between organic carbon and Ag bonded with S species.
Risk assessment on-a-chip: a cell-based microfluidic device for immunotoxicity screening
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0NA00857E
Abstract: This study presents the development of a microfluidic device to assess the cytotoxicity of nanoparticles on human immune cells.
Assessing the aggregation behaviour of iron oxide nanoparticles under relevant environmental conditions using a multi-method approach
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.WATRES.2013.04.029
Abstract: Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe2O3NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach. Under some soil conditions (i.e. pH 7, 10 mM NaCl and 2 mM CaCl2) and increasing particle concentration, Fe2O3NPs underwent extensive aggregation to form large aggregates (>1 μm). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative "green" solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe2O3NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe2O3NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl2, however, even at low concentrations, induced the aggregation of DOM-coated Fe2O3NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment.
Mobility, solubility and lability of fluid and granular forms of P fertiliser in calcareous and non-calcareous soils under laboratory conditions
Publisher: Springer Science and Business Media LLC
Date: 02-2005
Effect of soil amendments on molybdenum availability in mine affected agricultural soils
Publisher: Elsevier BV
Date: 2021
Polyphosphate speciation for soil and fertilizer analysis
Publisher: Informa UK Limited
Date: 10-2007
Manganese Toxicity in Barley is Controlled by Solution Manganese and Soil Manganese Speciation
Publisher: Wiley
Date: 03-2012
Fast X-ray fluorescence microscopy provides high-throughput phenotyping of element distribution in seeds
Publisher: Oxford University Press (OUP)
Date: 24-11-2022
Abstract: The concentration, chemical speciation, and spatial distribution of essential and toxic mineral elements in cereal seeds have important implications for human health. To identify genes responsible for element uptake, translocation, and storage, high-throughput phenotyping methods are needed to visualize element distribution and concentration in seeds. Here, we used X-ray fluorescence microscopy (μ-XRF) as a method for rapid and high-throughput phenotyping of seed libraries and developed an ImageJ-based pipeline to analyze the spatial distribution of elements. Using this method, we nondestructively scanned 4,190 ethyl methanesulfonate (EMS)-mutagenized M1 rice (Oryza sativa) seeds and 533 erse rice accessions in a genome-wide association study (GWAS) panel to simultaneously measure concentrations and spatial distribution of elements in the embryo, endosperm, and aleurone layer. A total of 692 putative mutants and 65 loci associated with the spatial distribution of elements in rice seed were identified. This powerful method provides a basis for investigating the genetics and molecular mechanisms controlling the accumulation and spatial variations of mineral elements in plant seeds.
Determination of Tl-(I) and Tl-(III) by IC-ICP-MS and application to Tl speciation analysis in the Tl hyperaccumulator plant Iberis intermedia
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B312603J
In situ chemical transformations of silver nanoparticles along the water-sediment continuum
Publisher: American Chemical Society (ACS)
Date: 09-12-2015
DOI: 10.1021/ES504395M
Abstract: In order to accurately assess the potential environmental risk posed by silver nanoparticles (Ag-NPs), their transformation and fate must be investigated in natural systems. This has proven to be very challenging due to the difficulties encountered in retrieving/analyzing NPs dispersed in complex and heterogeneous environmental matrices at relevant (i.e., low) concentrations. In this study, we overcame this challenge by immobilizing functionalized Ag-NPs onto plasma polymerized solid substrates to form "nano in situ deployment devices" (nIDDs). This method allowed us to retrieve and analyze the Ag-NPs after 48 h of direct exposure in freshwater-sediment and saltwater-sediment environments. The type and extent of Ag-NPs transformation was expected to vary along the water-sediment continuum as sediments typically contain steep gradients in solute concentrations and redox potential. To trace the distribution of redox sensitive elements (e.g., Fe, Mn), Diffusive Equilibration in Thin-films (DET) devices were inserted into the sediments alongside the nIDDs. Chemical transformation of the immobilized Ag-NPs across the water-sediment continuum was investigated after retrieval by synchrotron radiation X-ray Absorption Spectroscopy. Linear combination fitting of Ag K-edge X-ray absorption spectra indicated that the chemical transformations of Ag-NPs in both freshwater and saltwater sediments were strongly affected by the redox conditions over the investigated range. Silver bound to reduced sulfur was the principal product of Ag-NP transformations but different extents of transformation were observed for Ag-NPs exposed to different depths in the sediment. These field results add important insights about the transformation of Ag-NPs in heterogeneous environments.
Novel application of X-ray fluorescence microscopy (XFM) for the non-destructive micro-elemental analysis of natural mineral pigments on Aboriginal Australian objects
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5AN02065D
Abstract: This manuscript presents the first comprehensive non-destructive micro elemental characterisation of mineral pigments used on Aboriginal Australian objects.
Mapping element distributions in plant tissues using synchrotron X-ray fluorescence techniques
Publisher: Humana Press
Date: 10-2013
DOI: 10.1007/978-1-62703-152-3_9
Abstract: Synchrotron-based X-ray fluorescence (XRF) is allowing substantial advances in several disciplines of plant science by allowing the in situ examination of elements within plant tissues. Continual improvements in detector speed, sensitivity, and resolution are increasing the ersity of questions that can be addressed using this technique, including the in situ analysis of elements (such as nutrients or toxicants) within fresh and hydrated tissues. Here, we describe the general principles for designing and conducting experiments for the examination of elemental distributions in plant material using micro-XRF.
Metal bioaccumulation and toxicity in soils - Why bother with speciation?
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/CH02226
Abstract: This review assesses metal speciation in soils, including analytical techniques used for measurement and the advantages and disadvantages of using chemical speciation information, in both the solid and aqueous phase, to predict adverse effects of metal contamination in soils and for use in soil protection policies. Other techniques used to assess metal lability and bioavailability in soil are also discussed.
In situ fixation of metals in soils using bauxite residue: chemical assessment
Publisher: Elsevier BV
Date: 08-2002
DOI: 10.1016/S0269-7491(01)00294-9
Abstract: Contamination of soils with heavy metals and metalloids is a widespread problem all over the world. Low cost, non-invasive, in situ technologies are required for remediation processes. We investigated the efficiency of a bauxite residue (red mud) to fix heavy metals in two soils, one contaminated by industrial activities (French soil), and one by sewage sludge applications (UK soil). This Fe-oxide rich material was compared with lime, or beringite, a modified aluminosilicate that has been used for in situ fixation processes. Four different crop species were successively grown in pots. Metal concentrations in the soil pore waters were analyzed during the growing cycles. At the end of the experiment fluxes of heavy metals were measured using a diffusive gradient in thin film technique (DGT). Furthermore, a sequential extraction procedure (SEP) and an acidification test were performed to investigate the mechanisms of metal fixation by different soil amendments. In both soils, the concentrations of metals in the soil pore water and metal fluxes were greatly decreased by the amendments. An application of 2% red mud performed as well as beringite applied at 5%. Increasing soil pH was a common mechanism of action for all the amendments. However, the red mud amendment shifted metals from the exchangeable to the Fe-oxide fraction, and decreased acid extractability of metals. The results suggest that specific chemisorption, and possibly metal diffusion into oxide particles could also be the mechanisms responsible for the fixation of metals by red mud.
Polyphosphate-fertilizer solution stability with time, temperature, and pH
Publisher: Wiley
Date: 29-05-2007
Single Cell Level Quantification of Nanoparticle–Cell Interactions Using Mass Cytometry
Publisher: American Chemical Society (ACS)
Date: 24-07-2017
DOI: 10.1021/ACS.ANALCHEM.7B01006
Abstract: Quantification of cell-associated nanoparticles (NPs) is a paramount question in both nanomedicine and nanotoxicology. Inductively coupled plasma mass spectrometry is a well-established method to resolve cell-associated (metal) NPs in bulk cell populations, however, such analysis at single cell level remains a challenge. Here we used mass cytometry, a technique that combines single cell analysis and time-of-flight mass spectrometry, to quantitatively analyze extra- and intracellular silver (Ag) in in idual Ag NP exposed human T-lymphocytes. The results revealed significant population heterogeneity: for ex le, in lymphocytes exposed to 3 μg of 30 nm branched polyethylene imine coated Ag NPs/mL the extracellularly bound Ag varied from 79 to 560 fg and cellular uptake from 17 to 121 fg. Similar litude of heterogeneity was observed in cells exposed to various doses of Ag NPs with other sizes and surface coatings, demonstrating the importance of single cell analysis when studying NP-cell interactions. Although mass cytometry has some shortcomings such as inability to analyze potential transformation or dissolution of NPs in cells, we consider this method as the most promising for quantitative assessment of cell-NP interaction at single cell level.
The role of soil in defining planetary boundaries and the safe operating space for humanity
Publisher: Elsevier BV
Date: 2021
Element distribution and iron speciation in mature wheat grains (Triticum aestivum L.) using synchrotron X-ray fluorescence microscopy mapping and X-ray absorption near-edge structure (XANES) imaging
Publisher: Wiley
Date: 04-06-2016
DOI: 10.1111/PCE.12749
Abstract: Several studies have suggested that the majority of iron (Fe) and zinc (Zn) in wheat grains are associated with phytate, but a nuanced approach to unravel important tissue-level variation in element speciation within the grain is lacking. Here, we present spatially resolved Fe-speciation data obtained directly from different grain tissues using the newly developed synchrotron-based technique of X-ray absorption near-edge spectroscopy imaging, coupling this with high-definition μ-X-ray fluorescence microscopy to map the co-localization of essential elements. In the aleurone, phosphorus (P) is co-localized with Fe and Zn, and X-ray absorption near-edge structure imaging confirmed that Fe is chelated by phytate in this tissue layer. In the crease tissues, Zn is also positively related to P distribution, albeit less so than in the aleurone. Speciation analysis suggests that Fe is bound to nicotianamine rather than phytate in the nucellar projection, and that more complex Fe structures may also be present. In the embryo, high Zn concentrations are present in the root and shoot primordium, co-occurring with sulfur and presumably bound to thiol groups. Overall, Fe is mainly concentrated in the scutellum and co-localized with P. This high resolution imaging and speciation analysis reveals the complexity of the physiological processes responsible for element accumulation and bioaccessibility.
Selenopeptides and elemental selenium in Thunbergia alata after exposure to selenite: quantification method for elemental selenium
Publisher: Oxford University Press (OUP)
Date: 26-02-2015
DOI: 10.1039/C5MT00025D
Abstract: Three month old Thunbergia alata were exposed for 13 days to 10 μM selenite to determine the biotransformation of selenite in their roots. Selenium in formic acid extracts (80 ± 3%) was present as selenopeptides with Se–S bonds and selenium–PC complexes (selenocysteinyl-2-3-dihydroxypropionyl-glutathione, seleno-phytochelatin2, seleno-di-glutathione). An analytical method using HPLC-ICPMS to detect and quantify elemental selenium in roots of T. alata plants using sodium sulfite to quantitatively transform elemental selenium to selenosulfate was also developed. Elemental selenium was determined as 18 ± 4% of the total selenium in the roots which was equivalent to the selenium not extracted using formic acid extraction. The results are in an agreement with the XAS measurements of the exposed roots which showed no occurrence of selenite or selenate but a mixture of selenocysteine and elemental selenium.
Synchrotron X-ray absorption-edge computed microtomography imaging of thallium compartmentalization in Iberis intermedia
Publisher: Springer Science and Business Media LLC
Date: 06-01-2007
Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples
Publisher: Public Library of Science (PLoS)
Date: 02-06-2011
Long-term aging of copper added to soils
Publisher: American Chemical Society (ACS)
Date: 14-09-2006
DOI: 10.1021/ES060306R
Abstract: Aging refers to the processes by which the mobility and bioavailability/toxicity of metals added to soil decline with time. Although long-term aging is a key process that needs to be considered in the risk assessment of metals in field soils, the long-term aging of Cu added to soils has not been studied in detail. In this study, the effects of aging on Cu isotopic exchangeability, total Cu in soil pore water, pore water free Cu2+ activity, and "available" Cu measured by the technique of diffusive gradient in thin film (DGT-Cu) were investigated in 19 European soils at two total Cu concentrations shown to inhibit plant (tomato) growth by 10 and 90%. After addition of Cu, the soils were leached, incubated outdoors, and s led regularly over a 2-year period. The results showed that when water soluble Cu was added to soils, concentrations of Cu determined by each of the techniques tended to decrease rapidly initially, followed by further decreases at slow rates. Soil pH was a vital factor affecting the aging rate of Cu added to soils. The relatively low solubility products and low isotopic exchangeabilities of Cu in calcareous soils immediately after addition of soluble Cu2+ suggested Cu2+ probably precipitated in these soils as Cu2(OH)2CO3 (malachite) and Cu(OH)2. Isotopic dilution was found to be a robust technique for measuring rates of long-term aging reactions. A semi-mechanistic model was developed to describe the rate and extent of Cu aging across soils as affected by soil pH and other physicochemical parameters. Although not measured directly, it is inferred from soil physicochemical controls on Cu aging that processes of precipitation/nucleation of Cu in soils and hydrolysis of Cu2+ followed by a diffusion process controlled the decrease in Cu availability with time. The model was validated by testing it against field soils with different contamination histories and was found to successfully predict the isotopic exchangeability of Cu added to soils based on two parameters: soil pH and time.
Synchrotron-based X-ray absorption near-edge spectroscopy imaging for laterally resolved speciation of selenium in fresh roots and leaves of wheat and rice
Publisher: Oxford University Press (OUP)
Date: 26-05-2015
DOI: 10.1093/JXB/ERV254
Lead, antimony and arsenic in dissolved and colloidal fractions from an amended shooting-range soil as characterised by multi-stage tangential ultrafiltration and centrifugation
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/EN12010
Abstract: Environmental context The size of soil colloids is – among other characteristics – crucial for the mobility of associated contaminants. We analysed the effect of liming on the size of colloids mobilised from strongly contaminated shooting-range soils using multi-stage tangential ultrafiltration (MTUF) for the size fractionation of dispersed soil colloids. Our results indicate the high analytical potential of MTUF and show that liming induces the aggregation of colloids, thereby decreasing the mobilisation of colloid-bound Sb and As, but increasing colloidal Pb. Abstract The size and composition of colloids are important factors controlling their relevance as carriers of metal(loid)s in soils. Liming, which is often used to reduce the effect of heavy metal contamination in soil, can alter concentrations and characteristics of colloids in soil suspension. In batch studies, we compared the influence of changing pH and cation valency on the size distribution and composition of dispersed colloids and on the concentrations of Pb, As and Sb associated with colloids and in solution following the addition of Ca(OH)2 and KOH to soil s les from a contaminated-shooting range site. Multi-stage tangential ultrafiltration (MTUF) and centrifugation were used for the size fractionation of colloids in aqueous suspension. An increase in soil pH resulted in an increase in colloid-associated Pb, with much higher concentrations in the KOH than in the Ca(OH)2 treated s les. In contrast colloid-associated Sb and As increased only in the KOH treated s les. Addition of the monovalent K-ion induced the dispersion of small (~9–220 nm) organo(-mineral) colloids, whereas the alent Ca-ion suppressed their dispersion and led to the formation of larger colloids (220–1200 nm). Whereas centrifugation underestimated contaminants (i.e. Pb) associated with organic colloids (density .6 g cm–3) MTUF gave a distorted distribution of inorganic colloids (i.e. needle-shaped sesquioxides).
Foliar‐applied manganese and phosphorus in deficient barley: Linking absorption pathways and leaf nutrient status
Publisher: Wiley
Date: 07-2022
DOI: 10.1111/PPL.13761
Abstract: Foliar fertilization delivers essential nutrients directly to plant tissues, reducing excessive soil fertilizer applications that can lead to eutrophication following nutrient leaching. Foliar nutrient absorption is a dynamic process affected by leaf surface structure and composition, plant nutrient status, and ion physicochemical properties. We applied multiple methods to study the foliar absorption behaviors of manganese (Mn) and phosphorus (P) in nutrient‐deficient spring barley ( Hordeum vulgare ) at two growth stages. Nutrient‐specific chlorophyll a fluorescence assays were used to visualize leaf nutrient status, while laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) was used to visualize foliar absorption pathways for P and Mn ions. Rapid Mn absorption was facilitated by a relatively thin cuticle with a low abundance of waxes and a higher stomatal density in Mn‐deficient plants. Following absorption, Mn accumulated in epidermal cells and in the photosynthetically active mesophyll, enabling a fast (6 h) restoration of Mn‐dependent photosynthetic processes. Conversely, P‐deficient plants developed thicker cuticles and epidermal cell walls, which reduced the penetration of P across the leaf surface. Foliar‐applied P accumulated in trichomes and fiber cells above leaf veins without reaching the mesophyll and, as a consequence, no restoration of P‐dependent photosynthetic processes was observed. This study reveals new links between leaf surface morphology, foliar‐applied ion absorption pathways, and the restoration of affected physiological processes in nutrient‐deficient leaves. Understanding that ions may have different absorption pathways across the leaf surface is critical for the future development of efficient fertilization strategies for crops in nutrient‐limited soils.
Chemical behavior of fluid and granular Mn and Zn fertilisers in alkaline soils
Publisher: CSIRO Publishing
Date: 2010
DOI: 10.1071/SR09051
Abstract: The grain yield benefits of applying micronutrient fluid fertilisers over conventional granular products in calcareous sandy loam soils have been agronomically demonstrated. An understanding of the fundamental mechanisms and reactions occurring following application of these products to soils is critical to improve fertiliser management. We therefore examined the diffusion, solubility, and potential availability of manganese (Mn) and zinc (Zn) from both granular and fluid forms of Mn and Zn fertiliser in an alkaline calcareous and alkaline non-calcareous soil using laboratory incubation experiments in conjunction with an isotopic dilution technique with 54Mn and 65Zn. Enhanced mobility, solubility, and/or potential availability of Mn and Zn from fluid fertilisers were observed in comparison to Mn or Zn from granular fertilisers in both soils after 5 weeks of incubation. Differential behaviour of fluid and granular fertilisers for Mn and Zn appeared to be independent of their effects on soil pH. Most (~90%) of the Mn in granular fertiliser dissolved and diffused out of the granule but was retained within 4 mm of the point of granular placement, whereas most (~85%) of the Zn in the granular Zn fertiliser source remained in the granule. Our data suggest that the superior agronomic effectiveness of fluid Mn and Zn fertilisers observed in calcareous soils under field conditions may have resulted from the enhanced diffusion (Mn) and/or solubility/availability (Mn, Zn) of these micronutrients in soil when applied in fluid form.
Changes of Ni biogeochemistry in the rhizosphere of the hyperaccumulator Thlaspi goesingense
Publisher: Springer Science and Business Media LLC
Date: 04-2005
Zinc Accumulates in the Nodes of Wheat Following the Foliar Application of 65Zn Oxide Nano- and Microparticles
Publisher: American Chemical Society (ACS)
Date: 26-05-2021
Leachability, bioaccessibility and plant availability of trace elements in contaminated soils treated with industrial by-products and subjected to oxidative/reductive conditions
Publisher: Elsevier BV
Date: 02-2014
Chemical Bioavailability in the Terrestrial Environment – recent advances
Publisher: Elsevier BV
Date: 10-2013
Characteristics of cadmium uptake in two contrasting ecotypes of the hyperaccumulator Thlaspi caerulescens
Publisher: Oxford University Press (OUP)
Date: 03-2002
DOI: 10.1093/JEXBOT/53.368.535
Abstract: Uptake of Cd and Zn by intact seedlings of two contrasting ecotypes of the hyperaccumulator Thlaspi caerulescens was characterized using radioactive tracers. Uptake of Cd and Zn at 2 degrees C was assumed to represent mainly apoplastic binding in the roots, whereas the difference in uptake between 22 degrees C and 2 degrees C represented metabolically dependent influx. There was no significant difference between the two ecotypes in the apoplastic binding of Cd or Zn. Metabolically dependent uptake of Cd was 4.5-fold higher in the high Cd-accumulating ecotype, Ganges, than in the low Cd-accumulating ecotype, Prayon. By contrast, there was only a 1.5-fold difference in the Zn uptake between the two ecotypes. For the Ganges ecotype, Cd uptake could be described by Michaelis-Menten kinetics with a V(max) of 143 nmol g(-1) root FW h(-1) and a K(m) of 0.45 microM. Uptake of Cd by the Ganges ecotype was not inhibited by La, Zn, Cu, Co, Mn, Ni or Fe(II), and neither by increasing the Ca concentration. By contrast, addition of La, Zn or Mn, or increasing the Ca concentration in the uptake solution decreased Cd uptake by Prayon. Uptake of Ca was larger in Prayon than in Ganges. The results suggest that Cd uptake by the low Cd-accumulating ecotype (Prayon) may be mediated partly via Ca channels or transporters for Zn and Mn. By contrast, there may exist a highly selective Cd transport system in the root cell membranes of the high Cd-accumulating ecotype (Ganges) of T. caerulescens.
Absorption of foliar-applied Zn fertilizers by trichomes in soybean and tomato
Publisher: Oxford University Press (OUP)
Date: 03-03-2018
DOI: 10.1093/JXB/ERY085
Effects of methyl jasmonate on plant growth and leaf properties
Publisher: Wiley
Date: 14-04-2018
Silver Nanoparticles Entering Soils via the Wastewater–Sludge–Soil Pathway Pose Low Risk to Plants but Elevated Cl Concentrations Increase Ag Bioavailability
Publisher: American Chemical Society (ACS)
Date: 15-07-2016
Abstract: The widespread use of silver nanoparticles (Ag-NPs) results in their movement into wastewater treatment facilities and subsequently to agricultural soils via application of contaminated sludge. On-route, the chemical properties of Ag may change, and further alterations are possible upon entry to soil. In the present study, we examined the long-term stability and (bio)availability of Ag along the "wastewater-sludge-soil" pathway. Synchrotron-based X-ray absorption spectroscopy (XAS) revealed that ca. 99% of Ag added to the sludge reactors as either Ag-NPs or AgNO3 was retained in sludge, with ≥79% of this being transformed to Ag2S, with the majority (≥87%) remaining in this form even after introduction to soils at various pH values and Cl concentrations for up to 400 days. Diffusive gradients in thin films (DGT), chemical extraction, and plant uptake experiments indicated that the potential (bio)availability of Ag in soil was low but increased markedly in soils with elevated Cl, likely due to the formation of soluble AgClx complexes in the soil solution. Although high Cl concentrations increased the bioavailability of Ag markedly, plant growth was not reduced in any treatment. Our results indicate that Ag-NPs entering soils through the wastewater-sludge-soil pathway pose low risk to plants due to their conversion to Ag2S in the wastewater treatment process, although bioavailability may increase in saline soils or when irrigated with high-Cl water.
Chapter 7 Frontiers in assessing the role of chemical speciation and natural attenuation on the Bioavailability of Contaminants in the Terrestrial Environment
Publisher: Elsevier
Date: 2008
In situ fixation of metals in soils using bauxite residue: biological effects
Publisher: Elsevier BV
Date: 08-2002
DOI: 10.1016/S0269-7491(01)00295-0
Abstract: Soils polluted with heavy metals can cause phytotoxicity and exhibit impared microbial activities. In this paper we evaluate the responses of different biological endpoints to in situ remediation processes. Three soil amendments (red mud, beringite and lime) were applied to two soils polluted by heavy metals. Oilseed rape, wheat, pea and lettuce were grown successively in pots on the untreated and amended soils and their yield and metal uptake were determined. A suite of microbial tests (lux-marked biosensors, Biolog and soil microbial biomass) were performed to determine the effect of the soil amendments on the functionality and size of the soil microbial community. In both soils all three amendments reduced phytotoxicity of heavy metals, enhanced plant yields and decreased the metal concentrations in plants. The red mud treatment also increased soil microbial biomass significantly. The microbial biosensors responded positively to the remediation treatments in the industrially-contaminated soil used in the experiment. Red mud applied at 2% of soil weight was as effective as beringite applied at 5%. The results also showed that since the biological systems tested respond differently to the alleviation of metal toxicity, a suite of biological assays should be used to assess soil remediation processes.
Nanotechnology: A New Opportunity in Plant Sciences
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.TPLANTS.2016.04.005
Abstract: The agronomic application of nanotechnology in plants (phytonanotechnology) has the potential to alter conventional plant production systems, allowing for the controlled release of agrochemicals (e.g., fertilizers, pesticides, and herbicides) and target-specific delivery of biomolecules (e.g., nucleotides, proteins, and activators). An improved understanding of the interactions between nanoparticles (NPs) and plant responses, including their uptake, localization, and activity, could revolutionize crop production through increased disease resistance, nutrient utilization, and crop yield. Herewith, we review potential applications of phytonanotechnology and the key processes involved in the delivery of NPs to plants. To ensure both the safe use and social acceptance of phytonanotechnology, the adverse effects, including the risks associated with the transfer of NPs through the food chain, are discussed.
Fate of Zinc Oxide Nanoparticles during Anaerobic Digestion of Wastewater and Post-Treatment Processing of Sewage Sludge
Publisher: American Chemical Society (ACS)
Date: 30-07-2012
DOI: 10.1021/ES301487S
Abstract: The rapid development and commercialization of nanomaterials will inevitably result in the release of nanoparticles (NPs) to the environment. As NPs often exhibit physical and chemical properties significantly different from those of their molecular or macrosize analogs, concern has been growing regarding their fate and toxicity in environmental compartments. The wastewater-sewage sludge pathway has been identified as a key release pathway leading to environmental exposure to NPs. In this study, we investigated the chemical transformation of two ZnO-NPs and one hydrophobic ZnO-NP commercial formulation (used in personal care products), during anaerobic digestion of wastewater. Changes in Zn speciation as a result of postprocessing of the sewage sludge, mimicking composting/stockpiling, were also assessed. The results indicated that "native" Zn and Zn added either as a soluble salt or as NPs was rapidly converted to sulfides in all treatments. The hydrophobicity of the commercial formulation retarded the conversion of ZnO-NP. However, at the end of the anaerobic digestion process and after postprocessing of the sewage sludge (which caused a significant change in Zn speciation), the speciation of Zn was similar across all treatments. This indicates that, at least for the material tested, the risk assessment of ZnO-NP through this exposure pathway can rely on the significant knowledge already available in regard to other "conventional" forms of Zn present in sewage sludge.
Methods for assessing laterally-resolved distribution, speciation and bioavailability of phosphorus in soils
Publisher: Springer Science and Business Media LLC
Date: 08-01-2022
Assessing the contributions of lateral roots to element uptake in rice using an auxin-related lateral root mutant
Publisher: Springer Science and Business Media LLC
Date: 12-01-2013
Coating Fe2O3 with graphene oxide for high-performance sodium-ion battery anode
Publisher: Elsevier BV
Date: 10-2016
A new method for determination of potassium in soils using diffusive gradients in thin films (DGT)
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/EN11070
Abstract: Environmental contextPotassium is an essential plant nutrient and farmers need to be able to predict how much soil K is plant available in order to optimise fertiliser applications and crop production. Traditional methods such as chemical extraction are generally poor predictors. A DGT based methodology that could enhance the assessment of plant available K is developed, which will assist plant growers to determine the correct fertiliser application, thereby avoiding crop deficiencies and limiting the misuse of K as a precious natural resource. AbstractPotassium is an essential plant nutrient often limiting plant productivity. Ammonium acetate extraction is often used to predict the potassium status of soils. However, correlation between extracted K and plant uptake is often poor, especially over a range of different soil textures. Diffusive gradients in thin films (DGT), which determines the diffusive supply of elements, has been shown to accurately measure plant available elements in several cases. Up until now, however, the DGT devices available have not been suitable for measuring K. We set out to develop a DGT device suitable for the measurement of K in soil and test its ability to predict plant available K. The DGT device contained a binding layer based on Amberlite IRP-69 cation exchange resin. It proved suitable for the measurement of K under conditions similar to those usually found in soil if a 2-h deployment time was used and the labile K concentration was limited to 400 µM. Prediction of plant K concentrations with DGT were similar to those with ammonium acetate extractions over a range of typical agricultural soils with sandy and sandy loam textures. The results indicate that this new type of DGT has the potential to improve the accuracy of predictions of the K status of soils, although more tests using a wider range of plant species and soils are necessary.
Silver speciation and release in commercial antimicrobial textiles as influenced by washing
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.CHEMOSPHERE.2014.03.116
Abstract: The use of nanoscale Ag in textiles is one the most often mentioned uses of nano-Ag. It has previously been shown that significant amounts of the Ag in the textiles are released upon washing. However, the form of Ag present in the textiles remains largely unknown as product labelling is insufficient. The aim of this study was therefore to investigate the solid phase speciation of Ag in original and washed silver textiles using XANES. The original Ag speciation in the textiles was found to vary greatly between different materials with Ag(0), AgCl, Ag2S, Ag-phosphate, ionic Ag and other species identified. Furthermore, within the same textile a number of different species were found to coexist. This is likely due to a combination of factors such as the synthesis processes at industrial scale and the possible reaction of Ag with atmospheric gases. Washing with two different detergents resulted in marked changes in Ag-speciation. For some textiles the two detergents induced similar transformation, in other textiles they resulted in very different Ag species. This study demonstrates that in functional Ag textiles a variety of different Ag species coexist before and after washing. These results have important implications for the risk assessment of Ag textiles because they show that the metallic Ag is only one of the many silver species that need to be considered.
Lability of Cd, Cu, and Zn in polluted soils treated with lime, beringite, and red mud and identification of a non-labile colloidal fraction of metals using isotopic techniques
Publisher: American Chemical Society (ACS)
Date: 04-02-2003
DOI: 10.1021/ES026083W
Abstract: The use of soil amendments has been proposed as a low input alternative for the remediation of metal polluted soils. However, little information is available concerning the stability, and therefore the longevity, of the remediation treatments when important soil parameters change. In this paper we investigate the effect of pH changes on the lability of heavy metals in soils treated with lime, beringite, and red mud using a modified isotopic dilution technique in combination with a stepwise acidification procedure. Significant amounts of nonlabile (fixed) Cu and Zn were found to be associated with colloids <0.2 microm in the solution phase. The results obtained indicated that the mobility of fixed colloidal metals is significant and increases with soil pH. This must be considered because most of the soil amendments are alkaline and increase soil pH. All the soil amendments significantly decreased the lability of Cd, Zn, and Cu in the soils as a whole. However, when the soils were re-acidified, the labile pool of metals increased sharply and in the case of lime and beringite, the lability of the metals was similar, at equal pH, to the untreated soil. In contrast the lability of metals in the red mud treated soils was always smaller than that in the untreated soils across the range of pH values tested. These results suggest that the mechanism of action of lime and beringite is similar and probably related to increased metal adsorption and precipitation of metal hydroxides and carbonates at high pH. In the case of red mud, a combination of pH dependent and independent mechanisms (possibly solid-phase diffusion or migration into micropores) may be responsible for the metal fixation observed.
Use of X-ray tomography for examining root architecture in soils
Publisher: Elsevier BV
Date: 2022
Quantitative determination of metal and metalloid spatial distribution in hydrated and fresh roots of cowpea using synchrotron-based X-ray fluorescence microscopy
Publisher: Elsevier BV
Date: 10-2013
DOI: 10.1016/J.SCITOTENV.2013.05.091
Abstract: Many metals and metalloids, jointly termed metal(loid)s, are toxic to plants even at low levels. This has limited the study of their uptake, distribution, and modes of action in plant roots grown at physiologically relevant concentrations. Synchrotron-based X-ray fluorescence microscopy was used to examine metal(loid)s in hydrated cowpea (Vigna unguiculata L.) roots exposed to Zn(II), Ni(II), Mn(II), Cu(II), Hg(II), Se(IV), Se(VI), As(III), or As(V). Development of a mathematical model enabled in situ quantitative determination of their distribution in root tissues. The binding strength of metals influenced the extent of their movement through the root cylinder, which influenced the toxic effects exerted-metals (e.g. Cu, Hg) that bind more strongly to hard ligands had high concentrations in the rhizodermis and caused this tissue to rupture, while other metals (e.g. Ni, Zn) moved further into the root cylinder and did not cause ruptures. When longitudinal distributions were examined, the highest Se concentration in roots exposed to Se(VI) was in the more proximal root tissues, suggesting that Se(VI) is readily loaded into the stele. This contrasted with other metal(loid)s (e.g. Mn, As), which accumulated in the apex. These differences in metal(loid) spatial distribution provide valuable quantitative data on metal(loid) physiology, including uptake, transport, and toxicity in plant roots.
Anticancer Thiosemicarbazones: Chemical Properties, Interaction with Iron Metabolism, and Resistance Development
Publisher: Mary Ann Liebert Inc
Date: 10-03-2019
Abstract: During the past decades, thiosemicarbazones were clinically developed for a variety of diseases, including tuberculosis, viral infections, malaria, and cancer. With regard to malignant diseases, the class of α-N-heterocyclic thiosemicarbazones, and here especially 3-aminopyridine-2-carboxaldehyde thiosemicarbazone (Triapine), was intensively developed in multiple clinical phase I/II trials. Recent Advances: Very recently, two new derivatives, namely COTI-2 and di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) have entered phase I evaluation. Based on the strong metal-chelating/metal-interacting properties of thiosemicarbazones, interference with the cellular iron (and copper) homeostasis is assumed to play an important role in their biological activity. In this review, we summarize and analyze the data on the interaction of (α-N-heterocyclic) thiosemicarbazones with iron, with the special aim of bridging the current knowledge on their mode of action from chemistry to (cell) biology. In addition, we highlight the difference to classical iron(III) chelators such as desferrioxamine (DFO), which are used for the treatment of iron overload. We want to emphasize that thiosemicarbazones are not solely removing iron from the cells/organism. In contrast, they should be considered as iron-interacting drugs influencing erse biological pathways in a complex and multi-faceted mode of action. Consequently, in addition to the discussion of physicochemical properties (e.g., complex stability, redox activity), this review contains an overview on the ersity of cellular thiosemicarbazone targets and drug resistance mechanisms.
Unraveling the Complex Behavior of AgNPs Driving NP-Cell Interactions and Toxicity to Algal Cells
Publisher: American Chemical Society (ACS)
Date: 26-10-2016
Abstract: While the importance of nanoparticle (NP) characterization under relevant test conditions is widely recognized in nanotoxicology, few studies monitor NPs behavior in the presence of exposed organisms. Here we studied the behavior of nine types of silver nanoparticles (AgNPs) during the 48 h algal toxicity test. In particular, we investigated NP aggregation and dissolution by time-resolved inductively coupled plasma mass spectrometry and ultrafiltration and performed mass balance measurements to study the distribution of Ag in the test system. We also determined the amount of extra- and intracellular Ag by chemically etching AgNPs on the surface of algal cells and used dark field microscopy for their imaging. We observed that positively charged branched polyethilenimine (bPEI)-coated AgNPs tend to aggregate in the presence of algae and interact with test vessels and algal cells, while citrate-coated AgNPs have a tendency to dissolve. On the other hand, with large variation of half-maximum effective concentration (EC50) across tested NPs (5.4 to 300 ngAg mL
Development and evaluation of a new colorimetric DGT technique for the 2D visualisation of labile phosphate in soils
Publisher: Elsevier BV
Date: 04-2021
Agglomeration behaviour of titanium dioxide nanoparticles in river waters: A multi-method approach combining light scattering and field-flow fractionation techniques
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.JENVMAN.2015.05.011
Abstract: Titanium dioxide nanoparticles (TiO2 NPs) are currently one of the most prolifically used nanomaterials, resulting in an increasing likelihood of release to the environment. This is of concern as the potential toxicity of TiO2 NPs has been investigated in several recent studies. Research into their fate and behaviour once entering the environment is urgently needed to support risk assessment and policy development. In this study, we used a multi-method approach combining light scattering and field-flow fractionation techniques to assess both the aggregation behaviour and aggregate structure of TiO2 NPs in different river waters. Results showed that both the aggregate size and surface-adsorbed dissolved organic matter (DOM) were strongly related to the initial DOM concentration of the tested waters (i.e. R(2) > 0.90) suggesting that aggregation of TiO2 NPs is controlled by the presence and concentration of DOM. The conformation of the formed aggregates was also found to be strongly related to the surface-adsorbed DOM (i.e. R(2) > 0.95) with increasing surface-adsorbed DOM leading to more compact structures. Finally, the concentration of TiO2 NPs remaining in the supernatant after sedimentation of the larger aggregates was found to decrease proportionally with both increasing IS and decreasing DOM concentration, resulting in more than 95% sedimentation in the highest IS s le.
Biofortified indica rice attains iron and zinc nutrition dietary targets in the field
Publisher: Springer Science and Business Media LLC
Date: 25-01-2016
DOI: 10.1038/SREP19792
Abstract: More than two billion people are micronutrient deficient. Polished grains of popular rice varieties have concentration of approximately 2 μg g −1 iron (Fe) and 16 μg g −1 zinc (Zn). The HarvestPlus breeding programs for biofortified rice target 13 μg g −1 Fe and 28 μg g −1 Zn to reach approximately 30% of the estimated average requirement (EAR). Reports on engineering Fe content in rice have shown an increase up to 18 μg g −1 in glasshouse settings in contrast, under field conditions, 4 μg g −1 was the highest reported concentration. Here, we report on selected transgenic events, field evaluated in two countries, showing 15 μg g −1 Fe and 45.7 μg g −1 Zn in polished grain. Rigorous selection was applied to 1,689 IR64 transgenic events for insert cleanliness and, trait and agronomic performances. Event NASFer-274 containing rice nicotianamine synthase ( OsNAS2 ) and soybean ferritin ( SferH-1 ) genes showed a single locus insertion without a yield penalty or altered grain quality. Endosperm Fe and Zn enrichment was visualized by X-ray fluorescence imaging. The Caco-2 cell assay indicated that Fe is bioavailable. No harmful heavy metals were detected in the grain. The trait remained stable in different genotype backgrounds.
Speciation and Distribution of Phosphorus in a Fertilized Soil
Publisher: Wiley
Date: 11-2006
Cellular compartmentation of cadmium and zinc in relation to other elements in the hyperaccumulator Arabidopsis halleri
Publisher: Springer Science and Business Media LLC
Date: 12-12-2000
Abstract: The cellular compartmentation of elements was analysed in the Zn hyperaccumulator Arabidopsis halleri (L.) O'Kane & Al-Shehbaz (=Cardaminopsis halleri) using energy-dispersive X-ray microanalysis of frozen-hydrated tissues. Quantitative data were obtained using oxygen as an internal standard in the analyses of vacuoles, whereas a peak/background ratio method was used for quantification of elements in pollen and dehydrated trichomes. Arabidopsis halleri was found to hyperaccumulate not only Zn but also Cd in the shoot biomass. While large concentrations of Zn and Cd were found in the leaves and roots, flowers contained very little. In roots grown hydroponically, Zn and Cd accumulated in the cell wall of the rhizodermis (root epidermis), mainly due to precipitation of Zn/Cd phosphates. In leaves, the trichomes had by far the largest concentrations of Zn and Cd. Inside the trichomes there was a striking sub-cellular compartmentation, with almost all the Zn and Cd being accumulated in a narrow ring in the trichome base. This distribution pattern was very different from that for Ca and P. The epidermal cells other than trichomes were very small and contained lower concentrations of Zn and Cd than mesophyll cells. In particular, the concentrations of Cd and Zn in the mesophyll cells increased markedly in response to increasing Zn and Cd concentrations in the nutrient solution. This indicates that the mesophyll cells in the leaves of A. halleri are the major storage site for Zn and Cd, and play an important role in their hyperaccumulation.
Phosphorus availability of sewage sludge‐based fertilizers determined by the diffusive gradients in thin films (DGT) technique
Publisher: Wiley
Date: 23-08-2017
A One Health approach to managing the applications and implications of nanotechnologies in agriculture
Publisher: Springer Science and Business Media LLC
Date: 06-2019
DOI: 10.1038/S41565-019-0460-8
Abstract: The need for appropriate science and regulation to underpin nanosafety is greater than ever as ongoing advances in nanotechnology are rapidly translated into new industrial applications and nano-enabled commercial products. Nevertheless, a disconnect persists between those examining risks to human and environmental health from nanomaterials. This disconnect is not atypical in research and risk assessment and has been perpetuated in the case of engineered nanomaterials by the relatively limited overlap in human and environmental exposure pathways. The advent of agri-nanotechnologies brings both increased need and opportunity to change this status quo as it introduces significant issues of intersectionality that cannot adequately be addressed by current discipline-specific approaches alone. Here, focusing on the specific case of nanoparticles, we propose that a transdisciplinary approach, underpinned by the One Health concept, is needed to support the sustainable development of these technologies.
Impact of twenty pesticides on soil carbon microbial functions and community composition
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.CHEMOSPHERE.2022.135820
Abstract: Pesticides are known to affect non-targeted soil microorganisms. Still, studies comparing the effect of multiple pesticides on a wide range of microbial endpoints associated with carbon cycling are scarce. Here, we employed fluorescence enzymatic assay and real-time PCR to evaluate the effect of 20 commercial pesticides, applied at their recommended dose and five times their recommended dose, on soil carbon cycling related enzymatic activities (α-1,4-glucosidase, β-1,4-glucosidase, β-d-cellobiohydrolase and β-xylosidase), and on the absolute abundance of functional genes (cbhl and chiA), in three different South Australian agricultural soils. The effects on cellulolytic and chitinolytic microorganisms, and the total microbial community composition were determined using shotgun metagenomic sequencing in selected pesticide-treated and untreated s les. The application of insecticides significantly increased the cbhl and chiA genes absolute abundance in the acidic soil. At the community level, insecticide fipronil had the greatest stimulating effect on cellulolytic and chitinolytic microorganisms, followed by fungicide metalaxyl-M and insecticide imidacloprid. A shift towards a fungal dominated microbial community was observed in metalaxyl-M treated soil. Overall, our results suggest that the application of pesticides might affect the soil carbon cycle and may disrupt the formation of soil organic matter and structure stabilisation.
Short‐term natural attenuation of copper in soils: Effects of time, temperature, and soil characteristics
Publisher: Wiley
Date: 03-2006
DOI: 10.1897/04-601R.1
Abstract: Natural attenuation of metals added to soils refers to the processes by which the mobility and bioavailability/toxicity of the added metals decline with time. In this paper, we used isotopic dilution techniques to investigate the short-term (30 d) natural attenuation of Cu added to 19 European soils at two effective concentrations shown to inhibit plant (tomato) growth by 10 and 90%. The results showed that the lability of Cu added to soils rapidly decreased after addition, especially in the soils with pH > 6.0, followed by a slow decrease in Cu lability. The lability of Cu added to soils also decreased with increasing incubation temperature. The activation energies and the apparent diffusion rate coefficients for the attenuation processes were 33 to 36 kJ/mol and 0.66 to 20.9 x 10(-10)/s at 20 degrees C, respectively, and were consistent with Cu diffusion in meso- and micropores. The attenuation of Cu lability was modeled on the basis of three processes: precipitation/nucleation of Cu on soil surfaces, Cu occlusion within organic matter, and diffusion of Cu into micropores. The soil and environmental factors governing attenuation rates were soil pH, organic matter content, incubation time, and temperature. Soil pH is the key factor for natural attenuation of Cu added to soils. The model can be used to scale ecotoxicological data generated from different soils and under different incubation times and temperatures.
Physiological evidence for a high‐affinity cadmium transporter highly expressed in a Thlaspi caerulescens ecotype
Publisher: Wiley
Date: 2001
DOI: 10.1046/J.1469-8137.2001.00003.X
Abstract: • Uptake kinetics and translocation characteristics of cadmium and zinc are presented for two contrasting ecotypes of the Cd/Zn hyperaccumulator Thlaspi caerulescens , Ganges (southern France) and Prayon (Belgium). • Experiments using radioactive isotopes were designed to investigate the physiology of Cd and Zn uptake, and a pressure‐chamber system was employed to collect xylem sap. • In contrast to similar Zn uptake and translocation, measurements of concentration‐dependent influx of Cd revealed marked differences between ecotypes. Ganges alone showed a clear saturable component in the low Cd concentration range maximum influx V max for Cd was fivefold higher in Ganges and there was a fivefold difference in the Cd concentration in xylem sap. Addition of Zn to the uptake solution at equimolar concentration to Cd did not decrease Cd uptake by Ganges, but caused a 35% decrease in Prayon. • There is strong physiological evidence for a high‐affinity, highly expressed Cd transporter in the root cell plasma membranes of the Ganges ecotype of T. caerulescens . This raises evolutionary questions about specific transporters for non‐essential metals. The results also show the considerable scope for selecting hyperaccumulator ecotypes to achieve higher phytoextraction efficiencies.
Mobility and lability of phosphorus from highly concentrated fertiliser bands
Publisher: Elsevier BV
Date: 2023
Temporal Evolution of Copper Distribution and Speciation in Roots of Triticum aestivum Exposed to CuO, Cu(OH)2, and CuS Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 05-08-2018
Abstract: Utilization of nanoparticles (NP) in agriculture as fertilizers or pesticides requires an understanding of the NP properties influencing their interactions with plant roots. To evaluate the influence of the solubility of Cu-based NP on Cu uptake and NP association with plant roots, wheat seedlings were hydroponically exposed to 1 mg/L of Cu NPs with different solubilities [CuO, CuS, and Cu(OH)
Arsenic fractionation in soils using an improved sequential extraction procedure
Publisher: Elsevier BV
Date: 06-2001
Bioimaging Techniques Reveal Foliar Phosphate Uptake Pathways and Leaf Phosphorus Status
Publisher: Oxford University Press (OUP)
Date: 15-06-2020
DOI: 10.1104/PP.20.00484
Accumulation and distribution of aluminium and other elements in tea (Camellia sinensis) leaves
Publisher: EDP Sciences
Date: 12-2003
DOI: 10.1051/AGRO:2003045
Evidence for effects of manufactured nanomaterials on crops is inconclusive
Publisher: Proceedings of the National Academy of Sciences
Date: 02-11-2012
Comparative antibacterial activities of neutral electrolyzed oxidizing water and other chlorine-based sanitizers
Publisher: Springer Science and Business Media LLC
Date: 27-12-2019
DOI: 10.1038/S41598-019-56248-7
Abstract: There is increasing demand for safe and effective sanitizers for irrigation water disinfection to prevent transmission of foodborne pathogens to fresh produce. Here we compared the efficacy of pH-neutral electrolyzed oxidizing water (EOW), sodium hypochlorite (NaClO) and chlorine dioxide (ClO 2 ) against single and mixed populations of E. coli , Listeria and Salmonella under a range of pH and organic matter content. EOW treatment of the mixed bacterial suspension resulted in a dose-dependent ( mg/L free chlorine), rapid ( min) and effective (4–6 Log 10 ) reduction of the microbial load in water devoid of organic matter under the range of pH conditions tested (pH, 6.0, 7.0, 8.4 and 9.2). The efficacy of EOW containing 5 mg/L free chlorine was unaffected by increasing organic matter, and compared favourably with equivalent concentrations of NaClO and ClO 2 . EOW at 20 mg/L free chlorine was more effective than NaClO and ClO 2 in reducing bacterial populations in the presence of high (20–100 mg/L) dissolved organic carbon, and no regrowth or metabolic activity was observed for EOW-treated bacteria at this concentration upon reculturing in rich media. Thus, EOW is as effective or more effective than other common chlorine-based sanitizers for pathogen reduction in contaminated water. EOW’s other characteristics, such as neutral pH and ease of handling, indicate its suitability for fresh produce sanitation.
Constitutive overexpression of the OsNAS gene family reveals single-gene strategies for effective iron- and zinc-biofortification of rice endosperm
Publisher: Public Library of Science (PLoS)
Date: 06-09-2011
Reactive gaseous mercury is generated from chloralkali factories resulting in extreme concentrations of mercury in hair of workers
Publisher: Springer Science and Business Media LLC
Date: 27-02-2018
DOI: 10.1038/S41598-018-20544-5
Abstract: Occupational exposure of chloralkali workers to highly concentrated mercury (Hg) vapour has been linked to an increased risk of renal dysfunction and behavioural changes. It is generally believed that these workers are exposed to elemental Hg, which is used in abundance during the production process however, the lack in analytical techniques that would allow for identification of gaseous Hg species poses a challenge, which needs to be addressed in order to reach a consensus. Here, we present the results from simulated exposure studies, which provide sound evidence of higher adsorption rate of HgCl 2 than Hg 0 and its irreversible bonding on the surface of hair. We found that chloralkali workers were exposed to HgCl 2 , which accumulated in extremely high concentrations on the hair surface, more than 1,000 times higher than expected from unexposed subjects and was positively correlated with Hg levels in the finger- and toenails.
Examination of the Distribution of Arsenic in Hydrated and Fresh Cowpea Roots Using Two- and Three-Dimensional Techniques
Publisher: Oxford University Press (OUP)
Date: 25-05-2012
Abstract: Arsenic (As) is considered to be the environmental contaminant of greatest concern due to its potential accumulation in the food chain and in humans. Using novel synchrotron-based x-ray fluorescence techniques (including sequential computed tomography), short-term solution culture studies were used to examine the spatial distribution of As in hydrated and fresh roots of cowpea (Vigna unguiculata ‘Red Caloona’) seedlings exposed to 4 or 20 µm arsenate [As(V)] or 4 or 20 µm arsenite. For plants exposed to As(V), the highest concentrations were observed internally at the root apex (meristem), with As also accumulating in the root border cells and at the endodermis. When exposed to arsenite, the endodermis was again a site of accumulation, although no As was observed in border cells. For As(V), subsequent transfer of seedlings to an As-free solution resulted in a decrease in tissue As concentrations, but growth did not improve. These data suggest that, under our experimental conditions, the accumulation of As causes permanent damage to the meristem. In addition, we suggest that root border cells possibly contribute to the plant’s ability to tolerate excess As(V) by accumulating high levels of As and limiting its movement into the root.
Unraveling microbiomes and functions associated with strategic tillage, stubble, and fertilizer management
Publisher: Elsevier BV
Date: 2008
Plant and rhizosphere processes involved in phytoremediation of metal-contaminated soils
Publisher: Springer Science and Business Media LLC
Date: 2001
Aggregation behaviour of engineered nanoparticles in natural waters: Characterising aggregate structure using on-line laser light scattering
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.JHAZMAT.2014.11.003
Abstract: Adsorption of natural organic matter, aggregation and disaggregation have been identified as three of the main processes affecting the fate and behaviour of engineered nanoparticles (ENPs) in aquatic environments. However, although several methods have been developed to study the aggregation behaviour of ENPs in natural waters, there are only a few studies focusing on the fate of such aggregates and their potential disaggregation behaviour. In this study, we proposed and demonstrated a simple method for characterising the aggregation behaviour and aggregate structure of ENPs in different natural waters. Both the aggregate size of ENPs and their adsorption capacity for dissolved organic matter (DOM) were strongly related (R(2)>0.97, p 0.95, p<.05) to the amount of DOM adsorbed by the ENPs during the aggregation process. Under high ionic strength conditions, aggregation is mainly governed by diffusion and the aggregates formed under these conditions showed the lowest stability and fractal dimension, forming linear, chain-like aggregates. In contrast, under low ionic strength conditions, the aggregate structure was more compact, most likely due to strong chemical binding with DOM and bridging mechanisms involving alent cations formed during reaction-limited aggregation.
Heavy metal content and mutagenic activity, evaluated by Vicia faba micronucleus test, of Tiber river sediments
Publisher: Elsevier BV
Date: 09-1997
DOI: 10.1016/S1383-5718(97)00093-4
Abstract: Tiber river sediment s les, collected in October 1995, were tested for mutagenicity by the micronucleus test in Vicia faba root tips. Four stations were studied within the urban area of Rome: (1) Castel Giubileo, at the entry of the urban area (2) Ponte Tor di Quinto, immediately after the confluence of the tributary river Aniene (3) Ponte Sublicio, in the middle of the city and (4) Ponte della Magliana, immediately outside Rome, 20 km from the sea. Since no significant increase in micronucleus frequency was observed in any of the tested stations compared to control (while in previous c aigns mutagenic activity was observed in some of the same stations), it can be assumed an interesting recovery from mutagenic pollution in the 2 last years. The s les were analysed for pH value, nitrogen, organic matter and carbonate content, and the concentration of some potentially mutagenic heavy metal ions (Zn, Cd, Ni, V, Cu) was assessed. In all s les, a concentration of heavy metals higher than unpolluted areas was observed. However, the alkaline pH measured should keep them as non-bioavailable elements.
XANES Demonstrates the Release of Calcium Phosphates from Alkaline Vertisols to Moderately Acidified Solution
Publisher: American Chemical Society (ACS)
Date: 31-03-2016
Abstract: Calcium phosphate (CaP) minerals may comprise the main phosphorus (P) reserve in alkaline soils, with solubility dependent on pH and the concentration of Ca and/or P in solution. Combining several techniques in a novel way, we studied these phenomena by progressively depleting P from suspensions of two soils (low P) using an anion-exchange membrane (AEM) and from a third soil (high P) with AEM together with a cation-exchange membrane. Depletions commenced on untreated soil, then continued as pH was manipulated and maintained at three constant pH levels: the initial pH (pHi) and pH 6.5 and 5.5. Bulk P K-edge X-ray absorption near-edge structure (XANES) spectroscopy revealed that the main forms of inorganic P in each soil were apatite, a second more soluble CaP mineral, and smectite-sorbed P. With moderate depletion of P at pHi or pH 6.5, CaP minerals became more prominent in the spectra compared to sorbed species. The more soluble CaP minerals were depleted at pH 6.5, and all CaP minerals were exhausted at pH 5.5, showing that the CaP species present in these alkaline soils are soluble with decreases of pH in the range achievable by rhizosphere acidification.
Zinc hyperaccumulation and cellular distribution in Arabidopsis halleri
Publisher: Wiley
Date: 05-2000
Probabilistic modelling of engineered nanomaterial emissions to the environment: A spatio-temporal approach
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5EN00004A
Abstract: For the environmental risk assessment of engineered nanomaterials (ENM) knowledge about environmental concentrations is crucial.
The effect of different pyrolysis temperatures on the speciation and availability in soil of P in biochar produced from the solid fraction of manure
Publisher: Elsevier BV
Date: 02-2017
DOI: 10.1016/J.CHEMOSPHERE.2016.11.058
Abstract: Biochar application to agricultural land has been proposed as a means for improving phosphorus (P) availability in soil. The purpose of the current study was to understand how pyrolysis temperature affects P speciation in biochar and how this affects availability of P in the amended soil. Biochar was produced at different temperatures from digestate solids. The primary species of P in digestate solids were simple calcium phosphates. However, a high co-occurrence of magnesium (Mg) and P, indicated that struvite or other magnesium phosphates may also be important species. At low temperatures, pyrolysis had little effect on P speciation however, as the temperature increased above 600 °C, the P gradually became more thermodynamically stable in species such as apatite. At very high temperatures above 1000 °C, there were indications of reduced forms of P. Biochar production decreased the immediate availability of P in comparison with the original digestate solids. However, for biochar produced at low temperatures, availability quickly increased to the same levels as in the digestate solids. For biochar produced at higher temperatures, availability remained depressed for much longer. The low availability of P in the biochar produced at high temperatures can probably be explained by the formation of less soluble P species in the biochar. In contrast, the transient decrease of availability of the P in the biochar produced at low temperatures can be explained by mechanisms, such as sorption on biochar, which gradually decreases because of oxidation of the biochar surfaces or changes in pH around the biochar particles.
Speciation and Isotopic Exchangeability of Nickel in Soil Solution
Publisher: Wiley
Date: 03-2009
DOI: 10.2134/JEQ2006.0275
Abstract: Knowledge of trace metal speciation in soil pore waters is important in addressing metal bioavailability and risk assessment of contaminated soils. In this study, free Ni(2+) activities were determined in pore waters of long-term Ni-contaminated soils using a Donnan dialysis membrane technique. The pore water free Ni(2+) concentration as a percentage of total soluble Ni ranged from 21 to 80% (average 53%), and the average amount of Ni bound to dissolved organic matter estimated by Windermere Humic Aqueous Model VI was < or = 17%. These data indicate that complexed forms of Ni can constitute a significant fraction of total Ni in solution. Windermere Humic Aqueous Model VI provided reasonable estimates of free Ni(2+) fractions in comparison to the measured fractions (R(2) = 0.83 with a slope of 1.0). Also, the isotopically exchangeable pools (E value) of soil Ni were measured by an isotope dilution technique using water extraction, with and without resin purification, and 0.1 mol L(-1) CaCl(2) extraction, and the isotopic exchangeability of Ni species in soil water extracts was investigated. The concentrations of isotopically non-exchangeable Ni in water extracts were <9% of total water soluble Ni concentrations for all soils. The resin E values expressed as a percentage of the total Ni concentrations in soil showed that the labile Ni pool ranged from 0.9 to 32.4% (average 12.4%) of total soil Ni. Therefore the labile Ni pool in these well-equilibrated contaminated soils appears to be relatively small in relation to total Ni concentrations.
Changes in soil bacterial communities and diversity in response to long-term silver exposure
Publisher: Oxford University Press (OUP)
Date: 20-09-0010
Abstract: Silver-induced selective pressure is becoming increasingly important due to the growing use of silver (Ag) as an antimicrobial agent in biomedical and commercial products. With demonstrated links between environmental resistomes and clinical pathogens, it is important to identify microbial profiles related to silver tolerance/resistance. We investigated the effects of ionic Ag stress on soil bacterial communities and identified resistant ersistent bacterial populations. Silver treatments of 50-400 mg Ag kg(-1) soil were established in five soils. Chemical lability measurements using diffusive gradients in thin-film devices confirmed that significant (albeit decreasing) labile Ag concentrations were present throughout the 9-month incubation period. Synchrotron X-ray absorption near edge structure spectroscopy demonstrated that this decreasing lability was due to changes in the Ag speciation to less soluble forms such as Ag(0) and Ag2S. Real-time PCR and Illumina MiSeq screening of 16S rRNA bacterial genes showed β- ersity changes, increasing α- ersity in response to Ag pressure, and immediate and significant reductions in 16S rRNA gene counts with varying degrees of recovery. These effects were more strongly influenced by exposure time than by Ag dose at these rates. Ag-selected dominant OTUs principally resided in known persister taxa (mainly Gram positive), including metal-tolerant bacteria and slow-growing Mycobacteria.
Use of municipal solid wastes for chemical and microbiological recovery of soils contaminated with metal(loid)s
Publisher: Elsevier BV
Date: 08-2017
Characterising the exchangeability of phenanthrene associated with naturally occurring soil colloids using an isotopic dilution technique
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.ENVPOL.2015.01.031
Abstract: The association of polycyclic aromatic hydrocarbons (PAHs) with inorganic and organic colloids is an important factor influencing their bioavailability, mobility and degradation in the environment. Despite this, our understanding of the exchangeability and potential bioavailability of PAHs associated with colloids is limited. The objective of this study was to use phenanthrene as a model PAH compound and develop a technique using (14)C phenanthrene to quantify the isotopically exchangeable and non-exchangeable forms of phenanthrene in filtered soil water or sodium tetraborate extracts. The study was also designed to investigate the exchangeability of colloidal phenanthrene as a function of particle size. Our findings suggest that the exchangeability of phenanthrene in sodium tetraborate is controlled by both inorganic and organic colloids, while in aqueous solutions inorganic colloids play the dominant role (even though coating of these by organic matter cannot be excluded). Filter pore size did not have a significant effect on phenanthrene exchangeability.
Leaching of heavy metals from contaminated soils using EDTA
Publisher: Elsevier BV
Date: 07-2001
DOI: 10.1016/S0269-7491(00)00176-7
Abstract: Ethylenediaminetetraacetic acid (EDTA) extraction of Zn, Cd, Cu and Pb from four contaminated soils was studied using batch and column leaching experiments. In the batch experiment, the heavy metals extracted were virtually all as 1:1 metal-EDTA complexes. The ratios of Zn, Cd, Cu and Pb of the extracted were similar to those in the soils, suggesting that EDTA extracted the four heavy metals with similar efficiency. In contrast, different elution patterns were obtained for Zn, Cd, Cu and Pb in the column leaching experiment using 0.01 M EDTA. Cu was either the most mobile or among the most mobile of the four heavy metals, and its peak concentration corresponded with the arrival of full strength EDTA in the leachate. The mobility of Zn and Cd was usually slightly lower than that of Cu. Pb was the least mobile, and its elution increased after the peaks of Cu and Zn. Sequential fractionations of leached and un-leached soils showed that heavy metals in various operationally defined fractions contributed to the removal by EDTA. Considerable mobilisation of Fe occurred in two of the four soils during EDTA leaching. Decreases in the Fe and Mn oxide fraction of heavy metals after EDTA leaching occurred in both soils, as well as in a third soil that showed little Fe mobilisation. The results suggest that the lability of metals in soil, the kinetics of metal desorption/dissolution and the mode of EDTA addition were the main factors controlling the behaviour of metal leaching with EDTA.
Kinetics of Zn Release in Soils and Prediction of Zn Concentration in Plants Using Diffusive Gradients in Thin Films
Publisher: American Chemical Society (ACS)
Date: 25-05-2004
DOI: 10.1021/ES0352597
Abstract: Effective concentrations (CE) of Zn measured by the technique of DGT (diffusive gradients in thin films) were compared, along with total concentrations of Zn and the concentrations of Zn in soil solutions, to Zn concentrations in plants. Soils variously contaminated with Zn were collected in the vicinity of two galvanized electrical transmission towers (pylons) and two motorway crash barriers. Lepidium sativum was grown in each soil and in corresponding control soils amended with ZnCl2 to similar total Zn concentrations. CE, concentrations in soil solution, and total Zn were measured in all soils, and total Zn was measured in the plant shoots. The CE values, soil solution Zn, and shoot Zn concentrations were all larger in ZnCl2 amended soils than in field contaminated soils at corresponding total Zn. Correlations between the concentration of Zn in the plants and the measured soil parameter followed the order CE > soil solution > total Zn. The low scatter in the plot of log plant concentration versus log CE revealed a relationship with two distinct features. Plant Zn was between 100 and 300 mg/kg up to an effective Zn concentration of about 2 mg/L, above which plant Zn increased steadily with increasing CE. Use of a dynamic model to interpret the DGT measurement suggests that the intrinsic rate of release of Zn from solid phase to solution, expressed as a rate constant, is much higher for soils that receive fresh supplies of Zn. This finding provides a mechanistic basis for reconciling laboratory experiments, where metal is freshly amended, to data obtained in the field. The potential of DGT as a surrogate for metal availability to plants is further confirmed by this work.
The Availability of Copper in Soils Historically Amended with Sewage Sludge, Manure, and Compost
Publisher: Wiley
Date: 03-2012
DOI: 10.2134/JEQ2011.0317
Abstract: Metals in soils amended with sewage sludge are typically less available compared with those in soils spiked with soluble metal salts. However, it is unclear if this difference remains in the long term. A survey of copper (Cu) availability was made in soils amended with sewage sludge, manure, and compost, collectively named organic amendments. Paired sets of amended and control soils were collected from 22 field trials where the organic amendments had aged up to 112 yr. Amended soils had higher total Cu concentrations (range, 2-220 mg Cu kg median, 15 mg Cu kg) and organic C (range, 1-16 g kg median, 4 g kg) than control soils. All s les were freshly spiked with CuCl, and the toxicity of added Cu to barley was compared between amended and control soils. The toxicity of added Cu was significantly lower in amended soils than in control soil in 15 sets by, on average, a factor of 1.4, suggesting that aged amendments do not largely increase Cu binding sites. The fraction of added Cu that is isotopic exchangeable Cu (labile Cu) was compared between control soils freshly spiked with CuCl and amended soils with both soils at identical total Cu concentrations. Copper derived from amendments was significantly less labile (on average 5.9-fold) than freshly added Cu in 18 sets of soils. This study shows that Cu availability after long-term applications of organic amendments is lower than that of freshly added Cu salts, mainly because of its lower availability in the original matrix and ageing reactions than because of increased metal binding sites in soil.
Disinfection options for irrigation water: Reducing the risk of fresh produce contamination with human pathogens
Publisher: Informa UK Limited
Date: 19-12-2020
Distribution of minerals in wheat grains (Triticum aestivum L.) and in roller milling fractions affected by pearling
Publisher: American Chemical Society (ACS)
Date: 20-01-2015
DOI: 10.1021/JF5055485
Abstract: The distribution of minerals in (pearled) wheat grains was measured by synchrotron X-ray fluorescence, and the impact of pearling (0, 3, 6, 9, and 12% by weight) on the mineral composition of flour, shorts, and bran was identified by ICP-MS. The xylem mobile elements (Mn, Si, Ca, and Sr) dominated in the outermost bran layers, while the phloem mobile elements (K, Mg, P, Fe, Zn, and Cu) were more concentrated in the aleurone. Pearling lowered the concentrations of xylem mobile elements and increased the concentrations of most phloem mobile elements in the pearled grains. Molybdenum, Cd, and especially Se were more evenly distributed, and pearling affected their concentrations in milling products less. Pearling (3%) increased the concentration of several nutrients (P, Zn, Cu) in the flour because the bran fractions reaching the flour are enriched in aleurone. The correlations of concentrations of Mg, Fe, Zn, and Cu with that of P suggested their association with phytate.
Dynamics of Lead Bioavailability and Speciation in Indoor Dust and X-ray Spectroscopic Investigation of the Link between Ingestion and Inhalation Pathways
Publisher: American Chemical Society (ACS)
Date: 28-08-2019
Probing the nature of soil organic matter
Publisher: Informa UK Limited
Date: 26-09-2021
A radio-isotopic dilution technique for functional characterisation of the associations between inorganic contaminants and water-dispersible naturally occurring soil colloids
Publisher: CSIRO Publishing
Date: 2013
DOI: 10.1071/EN13020
Abstract: Environmental context The fate and behaviour of inorganic contaminants are dominated by soluble complex formation and interactions with naturally occurring colloids. Although the importance of these interactions has long been debated, our understanding of the mobility and bioavailability of contaminant–colloid associations has been h ered by the limitations of common operationally defined analytical techniques. The method developed in this study facilitates a step forward from operationally defined characterisation of the association between contaminants and colloids to a functional characterisation in terms of their exchangeability and potential bioavailability. Abstract Despite evidence that the fate and behaviour of inorganic contaminants are influenced by their interactions with water-dispersible naturally occurring soil colloids, our understanding of the mobility and bioavailability of contaminant–colloid associations has been h ered by the limitations of common operationally defined analytical techniques. In this paper, an isotopic dilution method was developed to quantify the isotopically exchangeable and non-exchangeable forms of zinc and phosphorus in filtered soil-water extracts. In addition, the effect of filter size on the determination of Zn and P exchangeability was investigated. The results showed that the isotopically non-exchangeable Zn and P in filtered soil-water extracts respectively ranged between 5 and 60% and 10 and 50% and was associated with water-dispersible colloids. Filter pore size had a significant effect on Zn and P exchangeability. Whereas the .1-µm filtrates contained isotopically exchangeable Zn and P fractions equal to the total Zn and P concentrations (i.e. 100% isotopically exchangeable Zn and P), the filtrates obtained from larger filter sizes (0.22, 0.45 and 0.7µm) contained increasing proportions of non-exchangeable Zn and P.
Mobility and potential bioavailability of antimony in contaminated soils: Short-term impact on microbial community and soil biochemical functioning
Publisher: Elsevier BV
Date: 06-2020
Sulfur crosslinks from thermal degradation of chitosan dithiocarbamate derivatives and thermodynamic study for sorption of copper and cadmium from aqueous system
Publisher: Springer Science and Business Media LLC
Date: 04-11-2016
DOI: 10.1007/S11356-015-5654-5
Abstract: Pristine chitosan beads were modified with sulfur (S)-containing functional groups to produce thiolated chitosan beads (ETB), thereby increasing S donor ligands and crosslinks. The effect of temperature, heating time, carbon disulfide (CS2)/chitosan ratio, and pH on total S content of ETB was examined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The total S content of ETB increased with increasing CS2/chitosan ratio and decreased with decreasing pH and increasing temperature (>60 °C) and heating time (at 60 °C). Spectroscopic analyses revealed the presence of thiol (-SH)/thione, disulfide (-S-S-), and sulfonate groups in ETB. The thiolation mechanism involves decomposition of dithiocarbamate groups, thereby forming thiourea crosslinks and trithiocarbonate, resulting in -SH oxidation to produce -S-S- crosslinks. The partially formed ETB crosslinks contribute to its acid stability and are thermodynamically feasible in adsorbing Cd and Cu. The S-containing functional groups added to chitinous wastes act as sorbents for metal remediation from acidic environments.
Phytoextraction of heavy metal contaminated soils withThlaspi goesingense and Amaranthus hybridus: Rhizosphere manipulation using EDTA and ammonium sulfate
Publisher: Wiley
Date: 12-2001
DOI: 10.1002/1522-2624(200112)164:6<615::AID-JPLN615>3.0.CO;2-6
In vivo formation of natural HgSe nanoparticles in the liver and brain of pilot whales
Publisher: Springer Science and Business Media LLC
Date: 28-09-2016
DOI: 10.1038/SREP34361
Abstract: To understand the biochemistry of methylmercury (MeHg) that leads to the formation of mercury-selenium (Hg-Se) clusters is a long outstanding challenge that promises to deepen our knowledge of MeHg detoxification and the role Se plays in this process. Here, we show that mercury selenide (HgSe) nanoparticles in the liver and brain of long-finned pilot whales are attached to Se-rich structures and possibly act as a nucleation point for the formation of large Se-Hg clusters, which can grow with age to over 5 μm in size. The detoxification mechanism is fully developed from the early age of the animals, with particulate Hg found already in juvenile tissues. As a consequence of MeHg detoxification, Se-methionine, the selenium pool in the system is depleted in the efforts to maintain essential levels of Se-cysteine. This study provides evidence of so far unreported depletion of the bioavailable Se pool, a plausible driving mechanism of demonstrated neurotoxic effects of MeHg in the organism affected by its high dietary intake.
Tolerance of nitrifying bacteria to copper and nickel
Publisher: Wiley
Date: 08-2006
DOI: 10.1897/05-517R.1
Abstract: Evidence is mounting that soil microorganisms can become increasingly tolerant to metals on exposure. However, in situ investigations regarding the effects of metals, particularly Cu and Ni, on specific soil functions/communities are still limited in number. Here, we investigated whether preexposure of nitrifying bacteria to Cu or Ni can induce increased tolerance to these metals. We also investigated whether changes in the tolerance of populations exposed to Cu under field conditions (long term) or in a laboratory-spiked soil (short term) occur. The method used was specifically designed to avoid possible confounding factors because of aging of metals in soil. Sterilized soils were enriched with different concentrations of Ni or Cu and were inoculated with the same soil that was either uncontaminated or had been contaminated previously with metals. Nitrification was measured after 28 d. In the laboratory-spiked soil, the exposed nitrifier community showed an increased tolerance to Ni but not to Cu. However, we found an increased tolerance to Cu in the case of a nitrifying community exposed to Cu for nearly 80 years under field conditions. These results indicate that the capacity of nitrifying bacteria to adapt to at least some metals is a widespread phenomenon. However, acquisition of tolerance to Cu may be more difficult, or require more time, compared with tolerance to Ni.
Molybdenum Sequestration in BrassicaSpecies. A Role for Anthocyanins?
Publisher: Oxford University Press (OUP)
Date: 08-2001
Abstract: To elucidate plant mechanisms involved in molybdenum (Mo) sequestration and tolerance, Brassica spp. seedlings were supplied with molybdate, and the effects on plant physiology, morphology, and biochemistry were analyzed. When supplied with (colorless) molybdate Indian mustard (Brassica juncea) seedlings accumulated water-soluble blue crystals in their peripheral cell layers. Energy dispersive x-ray analysis showed that Mo accumulated predominantly in the vacuoles of the epidermal cells. Therefore, the blue crystals are likely to be a Mo compound. The x-ray absorption spectrum of the plant-accumulated Mo was different than that for molybdate, indicating complexation with a plant molecule. Because the blue compound was water soluble and showed a pH-dependent color change, possible involvement of anthocyanins was investigated. An anthocyanin-less mutant of Brassica rapa (“fast plants”) was compared with varieties containing normal or high anthocyanin levels. The anthocyanin-less mutant did not show accumulation of a blue compound when supplied with molybdate. In the anthocyanin-containing varieties, the blue compound colocalized with anthocyanins in the peripheral cell layers. Mo accumulation by the three B. rapa varieties was positively correlated with anthocyanin content. Addition of molybdate to purified B. rapa anthocyanin resulted in an in vitro color change from pink to blue. Therefore, Mo appears to be sequestered in vacuoles of the peripheral cell layers of Brassica spp. as a blue compound, probably a Mo-anthocyanin complex.
Distribution and speciation of Mn in hydrated roots of cowpea at levels inhibiting root growth
Publisher: Wiley
Date: 13-09-2012
DOI: 10.1111/J.1399-3054.2012.01674.X
Abstract: The phytotoxicity of Mn is important globally due to its increased solubility in acid or waterlogged soils. Short-term (≤24 h) solution culture studies with 150 µM Mn were conducted to investigate the in situ distribution and speciation of Mn in apical tissues of hydrated roots of cowpea [Vigna unguiculata (L.) Walp. cv. Red Caloona] using synchrotron-based techniques. Accumulation of Mn was rapid exposure to 150 µM Mn for only 5 min resulting in substantial Mn accumulation in the root cap and associated mucigel. The highest tissue concentrations of Mn were in the root cap, with linear combination fitting of the data suggesting that ≥80% of this Mn(II) was associated with citrate. Interestingly, although the primary site of Mn toxicity is typically the shoots, concentrations of Mn in the stele of the root were not noticeably higher than in the surrounding cortical tissues in the short-term (≤24 h). The data provided here from the in situ analyses of hydrated roots exposed to excess Mn are, to our knowledge, the first of this type to be reported for Mn and provide important information regarding plant responses to high Mn in the rooting environment.
Quantifying the adsorption of ionic silver and functionalized nanoparticles during ecotoxicity testing: Test container effects and recommendations
Publisher: Informa UK Limited
Date: 10-09-2015
DOI: 10.3109/17435390.2014.994570
Abstract: Silver nanoparticles (Ag-NPs) are used in a wide variety of products, prompting concerns regarding their potential environmental impacts. To accurately determine the toxicity of Ag-NPs it is necessary to differentiate between the toxicity of the nanoparticles themselves and the toxicity of ionic silver (Ag) released from them. This is not a trivial task given the reactive nature of Ag in solution, and its propensity for both adsorption and photoreduction. In the experiments reported here, we quantified the loss of silver from test solutions during standard ecotoxicity testing conducted using a variety of different test container materials and geometries. This sensitive (110m)Ag isotope tracing method revealed a substantial underestimation of the toxicity of dissolved Ag to the green algae Pseudokirchneriella subcapitata when calculated only on the basis of the initial test concentrations. Furthermore, experiments with surface-functionalized Ag-NPs under standard algal growth inhibition test conditions also demonstrated extensive losses of Ag-NPs from the solution due to adsorption to the container walls, and the extent of loss was dependent on Ag-NP surface-functionality. These results hold important messages for researchers engaged in both environmental and human nanotoxicology testing, not only for Ag-NPs but also for other NPs with various tailored surface chemistries, where these phenomena are recognized but are also frequently disregarded in the experimental design and reporting.
Can earthworm-secreted calcium carbonate immobilise Zn in contaminated soils?
Publisher: Elsevier BV
Date: 07-2014
Transformation of four silver/silver chloride nanoparticles during anaerobic treatment of wastewater and post-processing of sewage sludge
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.ENVPOL.2013.01.029
Abstract: The increasing use of silver (Ag) nanoparticles [containing either elemental Ag (Ag-NPs) or AgCl (AgCl-NPs)] in commercial products such as textiles will most likely result in these materials reaching wastewater treatment plants. Previous studies indicate that a conversion of Ag-NPs to Ag2S is to be expected during wastewater transport/treatment. However, the influence of surface functionality, the nature of the core structure and the effect of post-processing on Ag speciation in sewage sludge/biosolids has not been investigated. This study aims at closing these knowledge gaps using bench scale anaerobic digesters spiked with Ag nitrate, three different types of Ag-NPs, and AgCl-NPs at environmentally realistic concentrations. The results indicate that neither surface functionality nor the different compositions of the NP prevented the formation of Ag2S. Silver sulfides, unlike the sulfides of other metals present in sewage sludge, were stable over a six month period simulating composting/stockpiling.
Methods to Visualize Elements in Plants
Publisher: Oxford University Press (OUP)
Date: 23-01-2020
DOI: 10.1104/PP.19.01306
Losses of essential mineral nutrients by polishing of rice differ among genotypes due to contrasting grain hardness and mineral distribution
Publisher: Elsevier BV
Date: 09-2012
A review of recent developments in the speciation and location of arsenic and selenium in rice grain
Publisher: Springer Science and Business Media LLC
Date: 08-12-2011
Speciation and distribution of arsenic and localization of nutrients in rice grains
Publisher: Wiley
Date: 22-06-2009
DOI: 10.1111/J.1469-8137.2009.02912.X
Abstract: Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (micro-XANES, micro-X-ray fluorescence (micro-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.
Assessing plant-available glyphosate in contrasting soils by diffusive gradient in thin-films technique (DGT)
Publisher: Elsevier BV
Date: 2019
DOI: 10.1016/J.SCITOTENV.2018.07.221
Abstract: Glyphosate represents one quarter of global herbicide sales, with growing interest in both its fate in soils and potential to cause non-target phytotoxicity to plants. However, assessing glyphosate bioavailability to plants from soil residues remains challenging. Here we demonstrate that the diffusive gradient in thin-films technique (DGT) can effectively measure available glyphosate across boundary conditions typical of the soil environment: pH 4-9, P concentrations of 20-300 μg P L
Synchrotron-based techniques for plant and soil science: opportunities, challenges and future perspectives
Publisher: Springer Science and Business Media LLC
Date: 17-01-2009
Complete transformation of ZnO and CuO nanoparticles in culture medium and lymphocyte cells during toxicity testing
Publisher: Informa UK Limited
Date: 06-02-2017
Mobility of heavy metals in soil and their uptake by sunflowers grown at different contamination levels
Publisher: EDP Sciences
Date: 1998
Synchrotron-based Techniques Shed Light on Mechanisms of Plant Sensitivity and Tolerance to High Manganese in the Root Environment
Publisher: Oxford University Press (OUP)
Date: 22-09-2015
DOI: 10.1104/PP.15.00726
Optimization of binding B-lymphocytes in a microfluidic channel: surface modification, stasis time and shear response
Publisher: IOP Publishing
Date: 30-11-2017
Quantitative multimodal analyses of silver nanoparticle-cell interactions: Implications for cytotoxicity
Publisher: Elsevier BV
Date: 2016
Salinity induced differences in growth, ion distribution and partitioning in barley between the cultivar Maythorpe and its derived mutant Golden Promise
Publisher: Springer Science and Business Media LLC
Date: 2003
Non-labile silver species in biosolids remain stable throughout 50 years of weathering and ageing
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.ENVPOL.2015.05.017
Abstract: Increasing commercial use of nanosilver has focussed attention on the fate of silver (Ag) in the wastewater release pathway. This paper reports the speciation and lability of Ag in archived, stockpiled, and contemporary biosolids from the UK, USA and Australia, and indicates that biosolids Ag concentrations have decreased significantly over recent decades. XANES revealed the importance of reduced-sulfur binding environments for Ag speciation in materials ranging from freshly produced sludge to biosolids weathered under ambient environmental conditions for more than 50 years. Isotopic dilution with (110 m)Ag showed that Ag was predominantly non-labile in both fresh and aged biosolids (13.7% mean lability), with E-values ranging from 0.3 to 60 mg/kg and 5 mM CaNO3 extractable Ag from 1.2 to 609 μg/kg (0.002-3.4% of the total Ag). This study indicates that at the time of soil application, biosolids Ag will be predominantly Ag-sulfides and characterised by low isotopic lability.
Arsenic in field-collected soil solutions and extracts of contaminated soils and its implication to soil standards
Publisher: Wiley
Date: 04-2002
DOI: 10.1002/1522-2624(200204)165:2<221::AID-JPLN221>3.0.CO;2-0
Investigating the foliar uptake of zinc from conventional and nano-formulations: a methodological study
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/EN19019
Abstract: Environmental contextZinc, an essential micronutrient often applied to crops as a fertiliser, can be difficult to analyse in plants due to limitations of conventional techniques. Here, we use radiotracers and a non-destructive imaging technique to visualise how zinc applied as a nanofertiliser moves within wheat plants over time. This is an important step towards developing cost-effective fertilisers to help solve one of the world’s most widespread plant deficiencies. AbstractZinc (Zn) deficiency affects half of the world’s arable soil and one-third of the world’s human population. Application of Zn foliar fertilisers to cereal crops can be an effective way to increase grain Zn content however, commonly used formulations can scorch the leaf (e.g. soluble Zn salts) or are prohibitively expensive (e.g. chelated Zn, ZnEDTA). Zinc oxide nanoparticles (ZnO-NPs) may offer an efficient and cost-effective alternative, but little is known regarding the mechanisms of Zn uptake and translocation within the plant. Foliar-applied Zn is analytically challenging to detect, locate and quantify, as it is omnipresent. Furthermore, any single analytical technique does not have the detection limit or spatial resolution required. In this study, the uptake and mobility of foliar-applied ZnEDTA, ZnO-NPs and ZnO microparticles (ZnO-MPs) to wheat (Triticum aestivum L.) were investigated using inductively coupled plasma mass spectroscopy (ICP-MS), synchrotron-based X-ray fluorescence microscopy (XFM) and radiotracing techniques using 65Zn-labelled formulations. The three techniques were compared to highlight limitations and advantages of each. We also report, for the first time, a novel time-resolved invivo autoradiography imaging technique that can be used to visualise 65Zn in live plants treated with foliar applications of 65ZnO-NPs and MPs. The images were supplemented by gamma spectroscopy analysis for quantification. The results of this study provide important insights into the analytical challenges faced when investigating foliar-applied Zn nanofertilisers in plants. Potential solutions using nuclear techniques are also discussed, which in turn may ultimately lead to the development of more efficient foliar fertilisers.
Determination of labile Cu in soils and isotopic exchangeability of colloidal Cu complexes
Publisher: Wiley
Date: 11-04-2006
Nanomaterials as fertilizers for improving plant mineral nutrition and environmental outcomes
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9EN00971J
Abstract: Nanomaterials can potentially be used as fertilizers to improve both plant nutrition and environmental outcomes.
An inter-laboratory study to test the ability of amendments to reduce the availability of Cd, Pb, and Zn in situ
Publisher: Elsevier BV
Date: 11-2005
DOI: 10.1016/J.ENVPOL.2005.02.020
Abstract: An international inter-laboratory research program investigated the effectiveness of in situ remediation of soils contaminated by cadmium, lead and zinc, measuring changes in soil and soil solution chemistry, plants and soil microbiota. A common soil, from mine wastes in Jasper County MO, was used. The soil was pH 5.9, had low organic matter (1.2 g kg(-1) C) and total Cd, Pb, and Zn concentrations of 92, 5022, and 18 532 mg kg(-1), respectively. Amendments included lime, phosphorus (P), red mud (RM), cyclonic ashes (CA), biosolids (BIO), and water treatment residuals (WTR). Both soil solution and NH4NO3 extractable metals were decreased by all treatments. Phytotoxicity of metals was reduced, with plants grown in P treatments having the highest yields and lowest metal concentration (0.5, 7.2 and 406 mg kg(-1) Cd, Pb, and Zn). Response of soil micro-organisms was similar to plant responses. Phosphorus addition reduced the physiologically based extraction test Pb from 84% of total Pb extracted in the untreated soil to 34.1%.
Tandem Probe Analysis Mode for Synchrotron XFM: Doubling Throughput Capacity
Publisher: American Chemical Society (ACS)
Date: 11-03-2022
What’s new about cadmium hyperaccumulation?
Publisher: Wiley
Date: 2001
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