ORCID Profile
0000-0002-8126-4555
Current Organisations
Griffith University
,
SDU
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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)
Inorganic Geochemistry | Analytical Chemistry | Geology | Sensor Technology (Chemical aspects) | Marine Geoscience
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Earth Sciences | Mining Land and Water Management | Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use) |
Related Links
Publications
Planning of Deep Foundation Construction Technical Specifications Using Improved Case-Based Reasoning with Weighted k-Nearest Neighbors
Publisher: American Society of Civil Engineers (ASCE)
Date: 09-2017
Comparing dissolved reactive phosphorus measured by DGT with ferrihydrite and titanium dioxide adsorbents: Anionic interferences, adsorbent capacity and deployment time
Publisher: Elsevier BV
Date: 07-2011
DOI: 10.1016/J.ACA.2011.04.049
Abstract: Two adsorbents (Metsorb and ferrihydrite) used in binding layers with the diffusive gradients in a thin film technique were evaluated for the measurement of dissolved reactive phosphorous (DRP) in synthetic and natural waters. Possible interferences were investigated with Cl(-) (up to 1.35 mol L(-1)) and SO(4)(2-) (up to 0.056 mol L(-1)) having no affect on either DGT binding layer, and HCO(3)(-) (up to 5.7 mmol L(-1)) having no effect on Metsorb-DGT, over 4 days. However, HCO(3)(-) interfered with the ferrihydrite-DGT measurement at concentrations typical of many natural waters (≥0.7 mmol L(-1)) after a deployment period of 1-2 days. The capacity of the Metsorb binding phase for DGT response was ∼37,000 ng P, whereas the capacities of a low-mass (17.8 mg of adsorbent per DGT s ler) and high-mass (29.2mg of adsorbent per DGT s ler) ferrihydrite binding phase were substantially lower (∼15,000 ng P and ∼25,000 ng P, low-mass and high-mass, respectively). Increasing the capacity of the ferrihydrite adsorbent allowed the ferrihydrite-DGT to be utilized for up to 3 days before interference by HCO(3)(-) was observed. Seawater deployments demonstrated that even high-capacity ferrihydrite-DGT devices underestimated the DRP concentration by 37%, whereas Metsorb-DGT measurements were accurate. The Metsorb-DGT is superior to the ferrihydrite-DGT for determining DRP over deployment times greater than 1 day and in waters with ≥0.7 mmol L(-1) HCO(3)(-). Based on the experience obtained from this detailed validation process, the authors propose a number of key requirements that need to be considered when developing new DGT binding layers, with testing the performance over longer deployment times being critical.
Representative measurement of two-dimensional reactive phosphate distributions and co-distributed iron(II) and sulfide in seagrass sediment porewaters
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.CHEMOSPHERE.2011.07.020
Abstract: The high degree of heterogeneity within sediments can make interpreting one-dimensional measurements difficult. The recent development and use of in situ techniques that measure two-dimensional distributions of porewater solutes have facilitated investigation of the role of spatial heterogeneity in sediment biogeochemistry. A colourimetric diffusive equilibration in thin films method has been developed that allows two-dimensional, high-resolution measurement of reactive phosphate in sediment porewaters. A method detection limit of 0.22 μM, an effective upper limit of ~1000 μM and relative standard deviations typically below 5% were achieved. This method was evaluated by deployment in seagrass (Zostera capricorni) colonised sediments, as part of combined probes with similar colourimetric methods for sulfide and iron(II). The two-dimensional, high resolution distributions obtained provide a highly representative measurement of the co-distributions of porewater solutes, allowing heterogeneous features and biogeochemical processes to be observed and interpreted. Microniches of high phosphate concentration >100 μM were observed throughout the distributions and were interpreted to be due to localised zones of rapid organic matter mineralisation, possibly using electron acceptors other than iron(III) oxyhydroxides (e.g. aerobic respiration) as often they did not correspond with microniches of higher Fe(II) concentration.
Titanium dioxide-based DGT for measuring dissolved As(V), V(V), Sb(V), Mo(VI) and W(VI) in water
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.TALANTA.2012.11.070
Abstract: A titanium dioxide-based DGT method (Metsorb-DGT) was evaluated for the measurement of As(V), V(V), Sb(V), Mo(VI), W(VI) and dissolved reactive phosphorus (DRP) in synthetic waters. Mass vs. time DGT deployments at pH 6.06 (0.01 mol L(-1) NaNO3) demonstrated linear uptake of all analytes (R(2) ≥ 0.994). Diffusion coefficients measured using a diffusion cell were in reasonable agreement with diffusion coefficients measured using DGT s lers (DCell/DDGT=0.82-1.10), although a systematic difference was apparent. The Metsorb-DGT method was independent of ionic strength (0.001-0.7 mol L(-1) NaNO3 at pH 7.1) for the measurement of all analytes (CDGT/CSol=0.88-1.11) and, with the exception of V(V), the method was independent of pH (3.98-8.24, 0.01 mol L(-1) NaNO3), indicated by CDGT/CSol values in the range 0.88-1.13 for short-term deployments (up to 10h). For V(V) at pH 3.98, Metsorb-DGT underestimated the solution concentration by 17%, presumably due to weak binding of the VO2(+) species. The Metsorb-DGT and ferrihydrite-DGT (in situ precipitated ferrihydrite) methods were compared by deploying s lers in synthetic freshwater (pH 7.20, conductivity 223 μS cm(-1)) and synthetic seawater (pH 8.3. salinity 34.6) for up to four days. For synthetic freshwater, CDGT/CSol values between 0.87-1.17 were obtained for all analytes measured by the Metsorb-DGT method over the deployment period. For ferrihydrite-DGT, CDGT/CSol values between 0.97-1.23 were obtained for As(V), V(V), W(VI) and DRP. However, Mo and Sb(V) showed reduced uptake and CDGT/CSol values were in the range 0.18-1.14 and 0.39-0.98, respectively. In synthetic seawater deployments, Metsorb-DGT was capable of measuring As(V), V(V), Sb(V), W(VI) and DRP for up to 4 days (CDGT/CSol=0.89-1.26), however, this method was not capable of measuring Mo for deployment times >4h (CDGT=0.27-0.72). For ferrihydrite-DGT, CDGT/CSol values in the range 0.92-1.16 were obtained for As(V), V(V) and DRP, however, Mo(VI), Sb(V) and W(VI) could not be measured to within 15% of the solution concentration (CDGT/CSol 0.02-0.83).
A modified DGT technique for the simultaneous measurement of dissolved inorganic nitrogen and phosphorus in freshwaters
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.ACA.2017.08.024
Abstract: A modified diffusive gradients in thin films (DGT) technique uses both a mixed binding layer (PrCH and A520E resins for NH
Behaviour, development and metal accumulation in striped marsh frog tadpoles (Limnodynastes peronii) exposed to coal mine wastewater
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.AQUATOX.2016.01.014
Abstract: Coal mining generates large quantities of complex effluent, and this often contains high levels of dissolved solids, suspended solids, metals, hydrocarbons, salts and other compounds. Substantial volumes of mine wastewater are periodically discharged into the environment, through both planned and accidental releases, and this raises concerns about the potential for adverse impacts on aquatic wildlife. There have been few attempts to explore sub-lethal effects of coal mine wastewater on hibians compared to other organisms, and this is particularly true for Australian species. To address existing knowledge gaps, we exposed striped marsh frog (Limnodynastes peronii) tadpoles to 25, 50 and 100% coal mine wastewater collected from two holding dams (CMW1 and CMW2) located at an open cut mine in Central Queensland, Australia. The exposure lasted for four weeks, after which survival, growth and development, swimming behaviour, and concentrations of metals and metalloids in tail and liver tissues were assessed. Physico-chemical parameters varied considerably between sites, with higher turbidity, nutrients, total and dissolved organic carbon, alkalinity and arsenic (As) concentrations at CMW1, and higher conductivity, salinity, dissolved solids, hardness and sulfate levels at CMW2. There was no mortality in controls and less than 5% mortality in CMW1 treatments, whereas survival was significantly decreased in tadpoles exposed to CMW2 with 40 and 55% mortality in the 50 and 100% treatments, respectively. Development was significantly delayed in 100% CMW1 wastewater, but tadpole size (growth) was not influenced by the exposure. Hepatosomatic indices were significantly increased in tadpoles exposed to 25 and 50% CMW1 but not the 100% treatment group. Exposed tadpoles (predominantly those exposed to CMW1) exhibited increased activity after very short-term exposure (24h), but this did not persist as animals approached metamorphic climax. At the end of the experiment, tadpoles exposed to both wastewaters had elevated levels of selenium (Se), cobalt (Co) and As in tail and liver tissue compared to controls. Manganese (Mn) levels were also elevated in livers and tails of CMW2 exposed tadpoles. Hepatic tissue accumulated 8-9 times higher concentrations of Co, Mn and Se compared to tail tissue, irrespective of treatments. Future research is warranted to explore possible relationships between metal bioaccumulation, morpho-physiological effects during development, and subsequent higher-level outcomes related to in idual performance and population fitness.
Titanium dioxide-based DGT technique for in situ measurement of dissolved reactive phosphorus in fresh and marine waters
Publisher: American Chemical Society (ACS)
Date: 23-11-2010
DOI: 10.1021/ES1027713
Abstract: A new diffusive gradients in a thin film (DGT) technique for measuring dissolved reactive phosphorus (DRP) in fresh and marine waters is reported. The new method, which uses a commercially available titanium dioxide based adsorbent (Metsorb), was evaluated and compared to the well-established ferrihydrite-DGT method (ferrihydrite cast within the polyacrylamide gel). DGT time-series experiments showed that the mass of DRP accumulated by Metsorb and ferrihydrite was linear with time when deployed in simple solutions. Both DGT methods showed predictable uptake across the pH (4.0-8.3) and ionic strength (0.0001-1 mol L(-1) NaNO(3)) ranges investigated, and the total capacity of the Metsorb binding phase (∼40,000 ng P) was 2.5-5 times higher than the reported total capacity of the ferrihydrite binding phase. The measurement of DRP in synthetic freshwater and synthetic seawater by Metsorb-DGT over a 4 day deployment period showed excellent agreement with the concentration of DRP measured directly in solution, whereas the ferrihydrite-DGT method significantly underestimated (23-30%) the DRP concentration in synthetic seawater for deployment times of two days or more. Field deployments of Metsorb-DGT s lers with various diffusive layer thicknesses allowed accurate measurement of both the diffusive boundary layer thickness and DRP concentration in situ. The Metsorb-DGT method performs similarly to ferrihydrite-DGT for freshwater measurements but is shown to be more accurate than the ferrihydrite method for determining DRP in seawater.
Antimony and arsenic speciation, redox-cycling and contrasting mobility in a mining-impacted river system
Publisher: Elsevier BV
Date: 03-2020
Simultaneous measurement of trace metal and oxyanion concentrations in water using diffusive gradients in thin films with a chelex-metsorb mixed binding layer
Publisher: American Chemical Society (ACS)
Date: 04-12-2014
DOI: 10.1021/AC402247J
Abstract: A new diffusive gradients in thin films (DGT) technique with a mixed binding layer (Chelex-100 and the titanium dioxide based adsorbent Metsorb) is described for the simultaneous measurement of labile trace metal (Mn, Co, Ni, Cu, Cd, and Pb) and oxyanion (V, As, Mo, Sb, W, and P) concentrations in freshwater and seawater. The mixed binding layer (MBL) DGT technique was evaluated against the Chelex-DGT and Metsorb-DGT techniques, and all elution efficiencies and diffusion coefficients have been remeasured for the above analytes. Diffusion coefficients (D) measured using MBL-DGT generally agreed well with those measured by Chelex-DGT (DMBL/DChelex = 0.97-1.05), Metsorb-DGT (DMBL/DMetsorb = 0.97-1.01), and diffusion cell experiments. The measurement of trace metals and oxyanions by MBL-DGT was independent of pH (5.03-8.05) and ionic strength (I = 0.001-0.7 mol L(-1)). MBL-DGT accurately measured the concentration of trace metals and oxyanions in synthetic freshwater (CMBL/CSol = 0.82-1.18) over the 4 day deployment and also agreed well with Metsorb-DGT (CMBL/CMetsorb = 0.84-0.94) and Chelex-DGT (CMBL/CChelex = 0.88-1.11) measurements. In synthetic seawater, MBL-DGT accurately measured the concentration of metals and oxyanions (CMBL/CSol = 0.85-1.12) over 4 days, with the exception of Mo-none of the DGT techniques were capable of measuring Mo in seawater. MBL-DGT measured the Mn concentration accurately over the entire 4 day period, whereas Chelex-DGT only measured Mn accurately up to 2 days. The MBL-DGT method described in this study offers significant advantages over the ferrihydrite-Chelex-DGT method reported previously. These advantages include the commercial availability of both Metsorb and Chelex-100, the higher accuracy of Metsorb for measuring some oxyanions in freshwater and seawater, and the possibility of measuring Fe, which would not be possible using the Chelex-ferrihydrite binding layer.
Redox-sensitive trace metals as paleoredox proxies
Publisher: Elsevier BV
Date: 05-2020
Vanadium Speciation in Ancient Shales Revealed through Synchrotron-Based X-ray Spectroscopy
Publisher: American Chemical Society (ACS)
Date: 26-09-0002
Development and evaluation of the diffusive gradients in thin films technique for measuring nitrate in freshwaters
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.ACA.2016.04.006
Abstract: A new diffusive gradients in thin films (DGT) technique, using Purolite A520E anion exchange resin, was developed and evaluated for the measurement of NO3N in freshwaters. Purolite A520E had a very high uptake efficiency (>98%) and elution efficiency (82.7% with 2 mol L(-1) NaCl as eluent) for NO3N. The 24 h mass vs. time validation experiments had excellent linearity (R(2) ≥ 0.997) and the intrinsic capacity of the binding layer for NO3N was 849 ± 24 μg. NO3N uptake was quantitative over a pH (3.5-8.5) range typical of most natural freshwaters. Several anions competed with NO3N to produce a lower effective binding capacity for NO3N in the following order of selectivity, Cl(-) > HCO3(-) > SO4(2-) > H2PO4(-), although NO3N measurements were quantitative at ionic strengths 0.0001-0.008 mol L(-1) as NaCl. NO2N did not adversely affect determination of NO3N at typical concentrations. Field deployments of DGT s lers with varying diffusive layer thicknesses validated the use of the technique in situ, allowed calculation of the diffusive boundary layer and accurate measurement of NO3N (CDGT/CSOLN 1.03-1.04). Reproducibility of the technique during field deployments was good (relative standard deviation < 3.2%). Limits of detection of A520E-DGT for NO3N were 13.15 μg L(-1) and 7.52 μg L(-1) (equivalent to 0.94 and 0.54 μmol L(-1)) based on 24 h and 48 h deployments, respectively. A520E-DGT determined NO3N concentrations during field deployments were very similar to the average values obtained from 0.45 μm filtered grab s les, which confirmed that the new DGT technique produced highly representative results.
Elemental metabolomics to identify pregnancy risk factors and predict gestational outcomes
Publisher: Elsevier BV
Date: 08-2019
DGT measurement of dissolved aluminum species in waters: Comparing chelex-100 and titanium dioxide-based adsorbents
Publisher: American Chemical Society (ACS)
Date: 06-02-2012
DOI: 10.1021/ES203674N
Abstract: Aluminum is acutely toxic, and elevated concentrations of dissolved Al can have detrimental effects on both terrestrial and aquatic ecosystems. Robust analytical methods that can determine environmentally relevant Al fractions accurately and efficiently are required by the environmental monitoring community. A simple, robust passive s ling method, the diffusive gradients in thin films (DGT) technique, was evaluated for the measurement of dissolved Al species in freshwater and marine water using either Chelex-100 or Metsorb (a titanium dioxide-based binding agent) as the adsorbent. Mass vs time DGT deployments at pH 5.05 (Al(3+) and Al(OH)(2+) dominate) and 8.35 (Al(OH)(4)(-) dominates) demonstrated linear uptake of Al (R(2) = 0.989 and 0.988, respectively) for Metsorb. Similar deployments of Chelex-DGT showed linear uptake at pH 5.05 (R(2) = 0.994) however, at pH 8.35 the mass of Al accumulated was 40-70% lower than predicted, suggesting that Chelex-100 is not suitable for Al measurements at high pH. The Metsorb-DGT measurement was independent of pH (5.0-8.5) and ionic strength (0.001-0.7 mol L(-1) NaNO(3)), whereas the Chelex-DGT measurement was only independent of ionic strength at pH 5.0. At pH 8.4, increasing ionic strength led to considerable underestimation (up to 67%) of Al concentration. Deployments of Metsorb-DGT (up to 4 days) in synthetic freshwater (pH range 5.4-8.1) and synthetic seawater (pH 8.15) resulted in linear mass uptakes, and the concentration measured by DGT agreed well with solution concentrations. Conversely, deployment of Chelex-DGT in synthetic seawater and freshwater (pH ≥7.7 Al(OH)(4)(-) dominant species) resulted in a decrease in accumulated mass with increasing deployment time. In situ field evaluations in fresh, estuarine, and marine waters confirmed that Metsorb-DGT was more accurate than Chelex-DGT for the measurement of dissolved Al in typical environmental waters.
Diffusive Gradients in Thin Films Reveals Differences in Antimony and Arsenic Mobility in a Contaminated Wetland Sediment during an Oxic-Anoxic Transition
Publisher: American Chemical Society (ACS)
Date: 26-01-2018
Abstract: Antimony (Sb) and arsenic (As) are priority environmental contaminants that often co-occur at mining-impacted sites. Despite their chemical similarities, Sb mobility in waterlogged sediments is poorly understood in comparison to As, particularly across the sediment-water interface (SWI) where changes can occur at the millimeter scale. Combined diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques provided a high resolution, in situ comparison between Sb, As, and iron (Fe) speciation and mobility across the SWI in contaminated freshwater wetland sediment mesocosms under an oxic-anoxic-oxic transition. The shift to anoxic conditions released Fe(II), As(III), and As(V) from the sediment to the water column, consistent with As release being coupled to the reductive dissolution of iron(III) (hydr)oxides. Conversely, Sb(III) and Sb(V) effluxed to the water column under oxic conditions and fluxed into the sediment under anoxic conditions. Porewater DGT-DET depth profiles showed apparent decoupling between Fe(II) and Sb release, as Sb was primarily mobilized across the SWI under oxic conditions. Solid-phase X-ray absorption spectroscopy (XAS) revealed the presence of an Sb(III)-S phase in the sediment that increased in proportion with depth and the transition from oxic to anoxic conditions. The results of this study showed that Sb mobilization was decoupled from the Fe cycle and was, therefore, more likely linked to sulfur and/or organic carbon (e.g., most likely authigenic antimony sulfide formation or Sb(III) complexation by reduced organic sulfur functional groups).
Comparing in situ colorimetric DET and DGT techniques with ex situ core slicing and centrifugation for measuring ferrous iron and dissolved sulfide in coastal sediment pore waters
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.CHEMOSPHERE.2017.08.144
Abstract: In productive coastal sediments the separation between different biogeochemical zones (e.g. oxic, iron(III)-reducing and sulfate-reducing) may be on the scale of millimetres. Conventional measurement techniques simply cannot resolve changes in pore water solute concentrations over such small distances. The diffusive equilibration in thin films (DET) and the diffusive gradients in thin films (DGT) techniques allow in situ determination of pore water solute concentration profiles with one-dimensional profiles and/or two-dimensional distributions on the millimetre scale. Here we compare measurements of pore water iron(II) and sulfide using conventional core s ling (slicing and centrifugation) and colorimetric DET-DGT techniques. DET-DGT s lers were deployed within replicate sediment cores from three different sites, which were processed by slicing and centrifugation following retrieval of the s lers, so that the measurements were approximately co-located. Iron(II) concentrations were determined by DET at all three sites (0.3-262 μmol L
Drivers of sulfide intrusion in Zostera muelleri in a moderately affected estuary in south-eastern Australia
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/MF16402
Abstract: The seagrass Zostera muelleri Irmisch ex Asch. is abundant in estuaries in Australia and is under pressure from coastal developments. We studied sulfide intrusion in Z. muelleri along a gradient of anthropogenic impact at five stations in the Wallis Lake estuary, Australia. Results showed differences in sediment biogeochemical conditions, seagrass metrics as well as nutrient content and sulfide intrusion along the gradient from the lower estuary (affected) to the lagoon (unaffected). Sulfide intrusion was driven by complex interactions and related to changes in seagrass morphology and sediment biogeochemistry and was modified by the exposure to wind and wave action. The sediments in the lower estuary had high contributions from phytoplanktonic detritus, whereas the organic pools in the lagoon were dominated by seagrass detritus. Despite high concentrations of organic matter, sulfide intrusion was lower at stations dominated by seagrass detritus, probably because of lower sulfide pressure from the less labile nature of organic matter. Porewater diffusive gradients in thin-film (DGT) sulfide s lers showed efficient sulfide reoxidation in the rhizosphere, with high sulfur incorporation in the plants from sedimentary sulfides being likely due to sulfate uptake from reoxidised sulfide. This is a unique adaptation of Z. muelleri, which allows high productivity in estuarine sediments.
Optimization of colorimetric DET technique for the in situ, two-dimensional measurement of iron(II) distributions in sediment porewaters
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.TALANTA.2011.11.020
Abstract: The recently developed colorimetric diffusive equilibration in thin films (DET) technique for the in situ, high-resolution measurement of iron(II) in marine sediments is optimized to allow measurement of the higher iron concentrations typical of freshwater sediment porewaters. Computer imaging densitometry (CID) is used to analyze the retrieved s lers following exposure to ferrozine, a colorimetric reagent selective for iron(II). The effect of ferrozine concentration, image processing parameters and ionic strength are investigated to improve the applicability of this technique to a wider range of aquatic systems than reported in the first publications of this approach. The technique was optimized to allow detection of up to 2,000 μmol L(-1) iron(II), a four-fold increase on the previous upper detection limit of 500 μ mol L(-1). The CID processing of the scanned color image was also optimized to adjust the sensitivity of the assay as required by processing the image with different color channel filters, the sensitivity of the assay can be optimized for lower concentrations (up to 100 μmol L(-1)) or higher concentrations (up to 2,000 μmol L(-1)) of iron(II), depending on the specific site characteristics. This process does not require separate s ling probes or even separate scans of the DET gels as the color filter and grayscale conversion is done post-image capture. The optimized technique is very simple to use and provides highly representative, high-resolution (1mm) two-dimensional distributions of iron(II) in sediment porewaters. The detection limit of the optimized technique was 4.1±0.3 μmol L(-1) iron(II) and relative standard deviations were less than 6%.
Comparison of DET, DGT and conventional porewater extractions for determining nutrient profiles and cycling in stream sediments
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9EM00312F
Abstract: Passive s lers measurements, especially DET, contributed to understanding of nitrogen transformations and sediment heterogeneity influenced by benthic microalgae, rooted aquatic plants and/or diel light cycles. Measurement capabilities varied considerably, especially for NH 4 –N.
Assisted natural recovery of hypersaline sediments: salinity thresholds for the establishment of a community of bioturbating organisms
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8EM00092A
Abstract: Hypersaline sediments derived from poor land management or the decommissioning of large-scale salt production contribute to the long-term degradation of aquatic environments.
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.
Rapid arsenic(V)-reduction by fire in schwertmannite-rich soil enhances arsenic mobilisation
Publisher: Elsevier BV
Date: 04-2018
A colorimetric DET technique for the high-resolution measurement of two-dimensional alkalinity distributions in sediment porewaters
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.CHEMOSPHERE.2014.07.042
Abstract: Measurements of porewater alkalinity are fundamental to the study of organic matter mineralization in sediments, which plays an essential role in the global cycles of carbon and nutrients. A new colorimetric diffusive equilibration in thin film (DET) technique is described for measuring two-dimensional total alkalinity distributions in sediment porewaters at high resolution (1-2 mm(2)). Thin polyacrylamide hydrogel layers (0.8 mm) equilibrate with the porewater and, after removal, are immediately laid onto another hydrogel containing formic acid, which reacts with alkalinity-generating species, and the pH-indicator bromophenol blue. The resultant color change is quantified using computer-imaging densitometry. The lower limit of detection is 0.2 meq L(-1) and the upper measurement limit is 8 meq L(-1). Deployment in seagrass colonized sediment revealed high levels of spatial heterogeneity in the porewater alkalinity distribution, with concentrations ranging from 2.28 meq L(-1) in the overlying water to 5.13 meq L(-1) in some parts of the sediment. This is the first time that two-dimensional, high-resolution distributions of porewater alkalinity have been measured.
Contrasting effects of bioturbation on metal toxicity of contaminated sediments results in misleading interpretation of the AVS-SEM metal-sulfide paradigm
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8EM00266E
Abstract: The intensity of organism bioturbation complicates the assessment of risk of toxicity when applying the AVS–SEM paradigm. Increased bioturbation in oxidised sediments (SEM AVS) resulted in less toxicity to hipod reproduction and greater toxicity in sulfidic sediments (AVS SEM).
Assessing the uptake of arsenic and antimony from contaminated soil by radish (Raphanus sativus) using DGT and selective extractions
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.ENVPOL.2016.05.027
Abstract: The enrichment of soil arsenic (As) and antimony (Sb) is putting increasing pressure on the environment and human health. The biogeochemical behaviour of Sb and its uptake mechanisms by plants are poorly understood and generally assumed to be similar to that of As. In this study, the lability of As and Sb under agricultural conditions in historically contaminated soils was assessed. Soils were prepared by mixing historically As and Sb-contaminated soil with an uncontaminated soil at different ratios. The lability of As and Sb in the soils was assessed using various approaches: the diffusive gradients in thin films technique (DGT) (as CDGT), soil solution analysis, and sequential extraction procedure (SEP). Lability was compared to the bioaccumulation of As and Sb by various compartments of radish (Raphanus sativus) grown in these soils in a pot experiment. Irrespective of the method, all of the labile fractions showed that both As and Sb were firmly bound to the solid phases, and that Sb was less mobile than As, although total soil Sb concentrations were higher than total soil As. The bioassay demonstrated low bioaccumulation of As and Sb into R. sativus due to their low lability of As and Sb in soils and that there are likely to be differences in their mechanisms of uptake. As accumulated in R. sativus roots was much higher (2.5-21 times) than that of Sb, while the Sb translocated from roots to shoots was approximately 2.5 times higher than that of As. As and Sb in R. sativus tissues were strongly correlated with their labile concentrations measured by DGT, soil solution, and SEP. These techniques are useful measures for predicting bioavailable As and Sb in the historically contaminated soil to R. sativus. This is the first study to demonstrate the suitability of DGT to measure labile Sb in soils.
New diffusive gradients in a thin film technique for measuring inorganic arsenic and selenium(IV) using a titanium dioxide based adsorbent
Publisher: American Chemical Society (ACS)
Date: 09-08-2010
DOI: 10.1021/AC101543P
Abstract: A new diffusive gradients in a thin film (DGT) technique, using a titanium dioxide based adsorbent (Metsorb), has been developed and evaluated for the determination of dissolved inorganic arsenic and selenium. As(III), As(V), and Se(IV) were found to be quantitatively accumulated by the adsorbent (uptake efficiencies of 96.5-100%) and eluted in 1 M NaOH (elution efficiencies of 81.2%, 75.2%, and 88.7%). Se(VI) was not quantitatively accumulated by the adsorbent ( or= 0.998) for As(III), As(V), and Se(IV). Consistent uptake occurred over pH (3.5-8.5) and ionic strength (0.0001-0.75 mol L(-1) NaNO(3)) ranges typical of natural waters, including seawater. Field deployments of DGT probes with various diffusive layer thicknesses confirmed the use of the technique in situ, allowing calculation of the diffusive boundary layers and an accurate measurement of inorganic arsenic. Reproducibility of the technique in field deployments was good (relative standard deviation <8%). Limits of detection (4 day deployments) were 0.01 microg L(-1) for inorganic arsenic and 0.05 microg L(-1) for Se(IV). The results of this study confirmed that DGT with Metsorb was a reliable and robust method for the measurement of inorganic arsenic and the selective measurement of Se(IV) within useful limits of accuracy.
In situ speciation of dissolved inorganic antimony in surface waters and sediment porewaters: Development of a thiol-based diffusive gradients in thin films technique for SbIII
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6EM00189K
Abstract: A new in situ s ling method enables the selective measurement of Sb( iii ) in surface waters and sediment porewaters.
Suspended sediment monitoring in alluvial gullies: A laboratory and field evaluation of available measurement techniques
Publisher: Wiley
Date: 19-06-2020
DOI: 10.1002/HYP.13824
New Training to Meet the Global Phosphorus Challenge.
Publisher: American Chemical Society (ACS)
Date: 08-07-2019
Decomposition of jellyfish carrion in situ: Short-term impacts on infauna, benthic nutrient fluxes and sediment redox conditions
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.SCITOTENV.2016.05.011
Abstract: Jellyfish often form blooms that persist for weeks to months before they collapse en masse, resulting in the sudden release of large amounts of organic matter to the environment. This study investigated the biogeochemical and ecological effects of the decomposition of jellyfish in a shallow coastal lagoon in New South Wales, Australia. Catostylus mosaicus carrion was added to the surface of shallow sub-tidal sediments and biogeochemical parameters and macrofaunal abundance immediately below the jellyfish carrion were measured over three days. Sediment plots without jellyfish served as controls. Sediment oxygen demand and carbon and nitrogen efflux increased by up to 60-fold in the jellyfish plots, compared to control plots, and dissolved organic nutrient fluxes were more sustained than in previous studies due to the use of fresh rather than frozen biomass. The decomposing jellyfish progressively altered sediment redox conditions, indicated by an increase in porewater iron (II) and sulfide concentrations measured by high-resolution in situ diffusive s lers. Abundance of some macrofaunal taxa in the jellyfish plots decreased relative to controls, however, the abundance of a carnivorous gastropod, which was presumably feeding on the carrion, increased in the jellyfish plots. While jellyfish carrion may be a food source for some macrofauna, low oxygen conditions coupled with the accumulation of toxic dissolved sulfides in the near-surface sediments may explain the overall change in the macroinfaunal community.
Development and evaluation of a diffusive gradients in a thin film technique for measuring ammonium in freshwaters
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.ACA.2015.11.022
Abstract: A new diffusive gradients in a thin film (DGT) technique, using Microlite PrCH cation exchange resin, was developed and evaluated for measuring NH4-N in freshwaters. Microlite PrCH had high uptake (>92.5%) and elution efficiencies (87.2% using 2 mol L(-1) NaCl). Mass vs. time validation experiments over 24 h demonstrated excellent linearity (R(2) ≥ 0.996). PrCH-DGT binding layers had an extremely high intrinsic binding capacity for NH4-N (∼3000 μg). NH4-N uptake was quantitative over pH ranges 3.5-8.5 and ionic strength (up to 0.012 mol L(-1) as NaCl) typical of freshwater systems. Several cations (Na(+), K(+), Ca(2+) and Mg(2+)) were found to compete with NH4-N for uptake by PrCH-DGT, but NH4-N uptake was quantitative over concentration ranges typical of freshwater (up to 0.012 mol L(-1) Na(+), 0.006 mol L(-1) K(+), 0.003 mol L(-1) Ca(2+) and 0.004 mol L(-1) Mg(2+)). Effective diffusion coefficients determined from mass vs. time experiments changed non-linearly with electrical conductivity. Field deployments of DGT s lers with varying diffusive layer thicknesses validated the use of the technique in situ, allowed deployment times to be manipulated with respect to NH4-N concentration, and enable the calculation of the diffusive boundary layer thickness. Daily grab s le NH4-N concentrations were observed to vary considerably independent of major rainfall events, but good agreements were obtained between PrCH-DGT values and mean grab s le measurements of NH4-N (CDGT:CSOLN 0.83-1.3). Reproducibility of DGT measurements in the field was good (relative standard deviation < 11%). Limit of detection was 0.63 μg L(-1) (equivalent to 0.045 μmol L(-1)) based on 24 h deployments.
Diel fluctuations in solute distributions and biogeochemical cycling in a hypersaline microbial mat from Shark Bay, WA
Publisher: Elsevier BV
Date: 12-2014
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
Comments on determination of total arsenic using a novel Zn-ferrite binding gel for DGT techniques: Application to the redox speciation of arsenic in river sediments by Gorny et al.
Publisher: Elsevier BV
Date: 03-2016
Characterizing microbial communities and processes in a modern stromatolite (Shark Bay) using lipid biomarkers and two-dimensional distributions of porewater solutes
Publisher: Wiley
Date: 18-02-2014
Abstract: Modern microbial mats are highly complex and dynamic ecosystems. Diffusive equilibration in thin films (DET) and diffusive gradients in thin films (DGT) s lers were deployed in a modern smooth microbial mat from Shark Bay in order to observe, for the first time, two-dimensional distributions of porewater solutes during day and night time. Two-dimensional sulfide and alkalinity distributions revealed a strong spatial heterogeneity and a minor contribution of sulfide to alkalinity. Phosphate distributions were also very heterogeneous, while iron(II) distributions were quite similar during day and night with a few hotspots of mobilization. Lipid biomarkers from the three successive layers of the mat were also analysed in order to characterize the microbial communities regulating analyte distributions. The major hydrocarbon products detected in all layers included n-alkanes and isoprenoids, whilst other important biomarkers included hopanoids. Phospholipid fatty acid profiles revealed a decrease in cyanobacterial markers with depth, whereas sulfate-reducing bacteria markers increased in abundance in accordance with rising sulfide concentrations with depth. Despite the general depth trends in community structure and physiochemical conditions within the mat, two-dimensional solute distributions showed considerable small-scale lateral variability, indicating that the distributions and activities of the microbial communities regulating these solute distributions were equally heterogeneous and complex.
Fate and sublethal effects of metals during amphibian metamorphosis: A systematic review
Publisher: Informa UK Limited
Date: 14-11-2021
Development and evaluation of a new diffusive gradients in thin-films technique for measuring organotin compounds in coastal sediment pore water
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.TALANTA.2017.09.081
Abstract: Organotins present a toxicological risk to biota in the aquatic environment. Understanding the behaviour of these compounds in sediment is challenging, with sophisticated analytical techniques required for their measurement. We investigated the use of silica-bound sorbents for diffusive gradients in thin-films (DGT) adsorption gels to pre-concentrate five organotins (monobutlytin (MBT), dibutyltin (DBT), tributyltin (TBT), diphenyltin (DPhT), triphenyltin (TPhT)) found frequently in coastal sediment. C
Untargeted NMR-based metabolomics for field-scale monitoring: Temporal reproducibility and biomarker discovery in mosquitofish (Gambusia holbrooki) from a metal(loid)-contaminated wetland
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.ENVPOL.2018.09.071
Abstract: There is considerable interest in applying omics techniques, which have proven extremely valuable for laboratory-based toxicology studies, towards field-scale ecotoxicology and environmental monitoring. Concerns that confounding factors in natural ecosystems may exacerbate variability in omics datasets must be addressed to validate the transition from laboratory to field. This study explores how temporal variability related to seasonal and climatic trends influence qualitative and quantitative metabolomics outcomes, in fish from reference and metal(loid)-polluted wetlands in Australia. Female mosquitofish (Gambusia holbrooki) were s led on two separate occasions, from a rehabilitated tailings wetland at the site of historic antimony (Sb) processing and a reference wetland with comparable water quality. The first s ling coincided with greater monthly rainfall and colder water temperature, whereas the second s ling was drier and water was warmer. Despite temporal changes and associated differences in metal(loid) concentrations, site differences in metabolite profiles were qualitatively very similar between s ling events. However, quantitative differences were observed, with a greater number of significantly altered metabolites identified during the second s ling event, which coincided with greater metal(loid) concentrations in both water and fish. The majority of identified metabolites were elevated in fish from the contaminated wetland, but with notable decreases in several metabolites that are known to play a role in various aspects of metal(loid) binding, detoxification and excretion. Specifically, decreased aspartate, histidine, myo-inositol, taurine and choline were observed in fish from the contaminated wetland, and may therefore represent a metabolite suite that is broadly indicative of metal toxicity. Quantitative differences between s ling events are suggestive of a dose-response relationship observable at the cellular level which, if harnessed, may be useful for assigning levels of concern based on the degree of change in a multi-parameter set of metabolite biomarkers.
Antimony measurements in environmental matrices: seven considerations
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7JA00391A
Abstract: A variety of approaches for measuring the content and speciation of Sb in environmental matrices are discussed.
A new colorimetric DET technique for determining mm-resolution sulfide porewater distributions and allowing improved interpretation of iron(II) co-distributions
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.CHEMOSPHERE.2019.125388
Abstract: Measurement of sulfide in pore waters is critical for understanding biogeochemical processes, especially within coastal sediments. Here we report the development of a new colorimetric DET (diffusive equilibration in thin films) technique for determining mm-resolution, two-dimensional sulfide distributions in sediment pore waters. This colorimetric sulfide DET method was based on the standard spectrophotometric methylene blue assay, but modified to allow quantitation of sulfide by computer imaging densitometry. The method detection and effective upper measurement limits of the optimised technique were 3.7 and 1000 μmol L
Evaluation of a titanium dioxide-based DGT technique for measuring inorganic uranium species in fresh and marine waters
Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.TALANTA.2012.05.012
Abstract: A new diffusive gradients in a thin film (DGT) technique for measuring dissolved uranium (U) in freshwater is reported. The new method utilises a previously described binding phase, Metsorb (a titanium dioxide based adsorbent). This binding phase was evaluated and compared to the well-established Chelex-DGT method. Batch experiments showed quantitative uptake (100±3%) of dissolved U by Metsorb and an elution efficiency of 95% was obtained using a mixed eluent of 1 mol L(-1) NaOH/1 mol L(-1) H(2)O(2). The mass of U accumulated by Metsorb was linear (R(2)≥0.98) with time across the pH range 3.0-8.1, validating the DGT measurement. The measured effective diffusion coefficients were highly dependent on pH, ranging from 2.74-4.81×10(-6)cm(2)s(-1), which were in reasonable agreement with values from the literature. Ionic strength showed no effect on the uptake of U, and thereby on diffusion coefficients, at NaNO(3) concentrations ≤0.01 mol L(-1), but caused the U concentration to be underestimated by 18% and 24% at 0.1 mol L(-1) NaNO(3) and 0.7 mol L(-1) NaNO(3), respectively. Deployment of Metsorb-DGT in synthetic freshwater resulted in reliable measurement of the dissolved U concentration (C(DGT)/C(Sol)=1.05), whereas Chelex-DGT significantly underestimated the dissolved U concentration (C(DGT)/C(Sol)=0.76). Metsorb-DGT was found to give reliable results after 8h deployments in synthetic seawater but experienced competition effects with longer deployments. The Chelex-DGT was unable to measure U at all in synthetic seawater. A field deployment in a freshwater stream (Coomera River) confirmed the utility of the Metsorb-DGT method for measuring U in natural freshwaters, but performance of field deployments may require further evaluation due to the possibility of major changes in uranium speciation with pH and water composition. We recommend a filtered s le, of any water in which DGT measurements are to be made, be used to determine the appropriate diffusion coefficient under controlled laboratory conditions.
Inorganic arsenic and iron(II) distributions in sediment porewaters investigated by a combined DGTcolourimetric DET technique
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/EN11074
Abstract: Environmental contextContamination of aquatic ecosystems with inorganic arsenic is a concern for both environmental and human health. Sediments are an important sink for dissolved arsenic, but they may also act as a source of arsenic because of human-induced changes in aquatic systems. This paper describes a new approach for investigating the status of inorganic arsenic in sediments, based on recent developments in diffusion-based sediment s ling techniques. AbstractA new approach for investigating the biogeochemistry of inorganic arsenic and iron(II) in freshwater, estuarine and marine sediments is reported. The recently developed Metsorb diffusive gradients in thin films (DGT) technique for the measurement of total inorganic arsenic and the colourimetric diffusive equilibration in thin films (DET) technique for the measurement of iron(II), were utilised in combination to determine co-located depth profiles of both solutes in sediment porewaters. DGT-measured porewater arsenic concentrations were typically less than 40 nM, whereas iron(II) concentrations reached up to 704 µM. Statistically significant (P 0.0002) correlations between porewater arsenic and iron(II) profiles were observed (R 0.92) in mesocosms of each sediment type. This approach to investigating arsenic and iron geochemistry in sediments allows the in-situ determination of arsenic and iron species at exactly the same location in the sediment at 3-mm resolution for arsenic and 1-mm resolution for iron(II). The technique was capable of detecting very low concentrations of arsenic, with a detection limit of 0.27 nM (0.02 µg L–1) for a 48-h deployment time. Porewater iron(II), which is often present over a wide range of concentrations, was detectable up to 2000 µM. This study shows the application of these recently developed DGT and DET techniques for the in-situ investigation of inorganic arsenic and iron biogeochemistry in sediments. This approach has the potential to enable simple, yet highly representative assessment of the biogeochemical status of arsenic and iron in a variety of natural sediments, including groundwater sediments where mobilised arsenic is responsible for significant human health risks.
DGT and selective extractions reveal differences in arsenic and antimony uptake by the white icicle radish (Raphanus sativus)
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.ENVPOL.2019.113815
Abstract: Increasing soil contamination of arsenic (As) and antimony (Sb) is posing a serious concern to human health. Due to insufficient studies on Sb, the biogeochemical behaviour and plant uptake of Sb are assumed to be similar to that of As. As part of extensive research unravelling As and Sb biogeochemistry and plant uptake, the diffusive gradients in thin films (DGT) technique and sequential extraction procedure (SEP) were applied to evaluate As and Sb uptake by the white icicle radish (Raphanus sativus) cultivated in diluted cattle dip soils contaminated with As only and diluted mining soils contaminated with both As and Sb under agricultural conditions. Labile As and Sb in these soils measured by DGT (C
Synchrotron-Based Imaging Reveals the Fate of Selenium in Striped Marsh Frog Tadpoles
Publisher: American Chemical Society (ACS)
Date: 12-08-2021
In situ evaluation of DGT techniques for measurement of trace metals in estuarine waters: A comparison of four binding layers with open and restricted diffusive layers
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5EM00550G
Abstract: Four different DGT binding layers were used to make selective measurements of trace metals in coastal waters within The Broadwater (Gold Coast, Queensland).
Oxygen loss from seagrass roots coincides with colonisation of sulphide-oxidising cable bacteria and reduces sulphide stress
Publisher: Springer Science and Business Media LLC
Date: 23-10-2019
Elemental Metabolomics for Prediction of Term Gestational Outcomes Utilising 18-Week Maternal Plasma and Urine Samples.
Publisher: Springer Science and Business Media LLC
Date: 04-2020
“Diffusive gradients in thin films” techniques provide representative time-weighted average measurements of inorganic nutrients in dynamic freshwater systems
Publisher: American Chemical Society (ACS)
Date: 02-12-2016
Abstract: Nutrient concentrations in freshwater are highly variable over time, with changes driven by weather events, anthropogenic sources, modifications to catchment hydrology or habitats, and internal biogeochemical processes. Measuring infrequently collected grab s les is unlikely to adequately represent nutrient concentrations in such dynamic systems. In contrast, in situ passive s ling techniques, such as the "diffusive gradients in thin films" (DGT) technique, provide time-weighted average analyte concentrations over the entire deployment time. A pair of recently developed DGT techniques for nitrate (A520E-DGT) and ammonium (PrCH-DGT), as well as the Metsorb-DGT technique for phosphate, were used to monitor inorganic nutrients in different freshwater systems (i.e., streams and wetlands) with a range of environmental values and that were affected by different catchment types. Measurements of grab s les collected frequently (1-2 times daily, 8-10 a.m. and 2-4 p.m.) showed that concentrations of NH
Speciation of dissolved inorganic arsenic by diffusive gradients in thin films: Selective binding of As III by 3-mercaptopropyl-functionalized silica gel
Publisher: American Chemical Society (ACS)
Date: 13-10-2011
DOI: 10.1021/AC202119T
Abstract: A diffusive gradients in thin films (DGT) technique for selectively measuring As(III) utilizes commercially available 3-mercaptopropyl-functionalized silica gel. Deployment of the new technique alongside the Metsorb-DGT for total inorganic arsenic allows the calculation of As(III) directly and As(V) by difference. Uptake of As(III) by mercapto-silica was quantitative and elution with a mixture of 1 mol L(-1) HNO(3) and 0.01 mol L(-1) KIO(3) gave a recovery of 85.6 ± 1.7%. DGT validation experiments showed linear accumulation of As(III) over time (R(2) > 0.998). Accumulation was unaffected by varying ionic strength (0.0001-0.75 mol L(-1) NaNO(3)) and pH (3.5-8.5). Deployment of mercapto-silica DGT and Metsorb DGT in seawater spiked with As(III) and As(V) demonstrated the ability of the combined approach to accurately quantify both species in the presence of potential competing ions. Ferrihydrite DGT, which has been previously reported for the measurement of total inorganic arsenic, was evaluated in seawater and shown to underestimate both As(III) and As(V) at longer deployment times (72 h). Reproducibility of the new mercapto-silica DGT technique was good (relative standard deviations < 9%), and the average method detection limit was sufficiently low to allow quantification of ultratrace concentrations of As(III) (0.03 μg L(-1) 72 h deployment).
Antimony and arsenic exhibit contrasting spatial distributions in the sediment and vegetation of a contaminated wetland
Publisher: Elsevier BV
Date: 08-2017
DOI: 10.1016/J.CHEMOSPHERE.2017.03.142
Abstract: Antimony is a priority environmental contaminant that is relatively poorly studied compared to other trace metal(loid)s. In particular, the behaviour of antimony in wetland sediments, where anaerobic conditions often dominate, has received considerably less attention compared to well-drained terrestrial soil environments. Here we report the results of a spatial assessment of antimony in the sediments and vegetation of a freshwater wetland exposed to stibnite tailings for the past forty years. The concentration of antimony in the sediment decreased rapidly with distance from the tailings deposit, from a maximum of ∼22,000 mg kg
Correction to Vanadium Speciation in Ancient Shales Revealed through Synchrotron-Based X-ray Spectroscopy
Publisher: American Chemical Society (ACS)
Date: 24-02-2023
Coastal bays and coral cays: Multi-element study of Chelonia mydas forage in the Great Barrier Reef (2015–2017)
Publisher: Elsevier BV
Date: 10-2020
Chapter 4 - Binding Layer Properties
Publisher: Cambridge University Press
Date: 31-07-2016
Elemental metabolomics in human cord blood: Method validation and trace element quantification.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.JTEMB.2019.126419
Abstract: Trace elements are an essential requirement for human health and development and changes in trace element status have been associated with pregnancy complications such as gestational diabetes mellitus (GDM), pre-ecl sia (PE), fetal growth restriction (FGR), and preterm birth. Elemental metabolomics, which involves the simultaneous quantification and characterisation of multiple elements, could provide important insights into these gestational disorders. This study used an Agilent 7900 inductively coupled plasma mass spectrometer (ICP-MS) to simultaneously measure 68 elements, in 166 placental cord blood s les collected from women with various pregnancy complications (control, hypertensive, PE, GDM, FGR, pre-term, and post-term birth). There were single element differences across gestational outcomes for elements Mg, P, Cr, Ni, Sr, Mo, I, Au, Pb, and U. Hypertensive and post-term pregnancies were significantly higher in Ni concentrations when compared to controls (control = 2.74 μg/L, hypertensive = 6.72 μg/L, post-term = 7.93 μg/L, p < 0.05), iodine concentration was significantly higher in post-term pregnancies (p < 0.05), and Pb concentrations were the lowest in pre-term pregnancies (pre-term = 2.79 μg/L, control = 4.68 μg/L, PE = 5.32 μg/L, GDM = 8.27 μg/L, p < 0.01). Further analysis was conducted using receiver operating characteristic (ROC) curves for differentiating pregnancy groups. The ratio of Sn/Pb showed the best diagnostic power in discriminating between control and pre-term birth with area under the curve (AUC) 0.86. When comparing control and post-term birth, Mg/Cr (AUC = 0.84), and Cr (AUC = 0.83) had the best diagnostic powers. In pre-term and post-term comparisons Ba was the best single element (81.5%), and P/Cu provided the best ratio (91.7%). This study has shown that analysis of multiple elements can enable differentiation between fetal cord blood s les from control, hypertensive, PE, GDM, FGR, pre and post-term pregnancies. This data highlights the power of elemental metabolomics and provides a basis for future gestational studies.
Reductive sorption of vanadium by green rust in seawater
Publisher: Elsevier BV
Date: 08-2023
Investigating arsenic speciation and mobilization in sediments with DGT and DET: A mesocosm evaluation of oxic-anoxic transitions
Publisher: American Chemical Society (ACS)
Date: 20-03-2012
DOI: 10.1021/ES204484K
Abstract: Mobilization of arsenic from freshwater and estuarine sediments during the transition from oxic to anoxic conditions was investigated using recently developed diffusive s ling techniques. Arsenic speciation and Fe(II) concentrations were measured at high resolution (1-3 mm) with in situ diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques. Water column anoxia induced Fe(II) and As(III) fluxes from the sediment. A correlation between water column Fe(II) and As(III) concentrations was observed in both freshwater (r(s) = 0.896, p < 0.001) and estuarine (r(s) = 0.557, p < 0.001) mesocosms. Porewater s ling by DGT and DET techniques confirmed that arsenic mobilization was associated with the reductive dissolution of Fe(III) (hydr)oxides in the suboxic zone of the sediment a relationship that was visible because of the ability to measure the coincident profiles of these species using combined DGT and DET s lers. The selective measurement of As(III) and total inorganic arsenic by separate DGT s lers indicated that As(III) was the primary species mobilized from the solid phase to the porewater. This measurement approach effectively ruled out substantial As(V) mobilization from the freshwater and estuarine sediments in this experiment. This study demonstrates the capabilities of the DGT and DET techniques for investigating arsenic speciation and mobilization over a range of sediment conditions.
A systematic determination of diffusion coefficients of trace elements in open and restricted diffusive layers used by the diffusive gradients in a thin film technique
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.ACA.2015.07.027
Abstract: A systematic comparison of the diffusion coefficients of cations (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) and oxyanions (Al, As, Mo, Sb, V, W) in open (ODL) and restricted (RDL) diffusive layers used by the DGT technique was undertaken. Diffusion coefficients were measured using both the diffusion cell (Dcell) method at pH 4.00 and the DGT time-series (D(DGT)) method at pH 4.01 and 7.04 (pH 8.30 was used instead of 7.04 for Al) using the Chelex-Metsorb mixed binding layer. The performance of Chelex-Metsorb as a new DGT binding layer for Al uptake was also evaluated for the first time. Reasonable agreement was observed between D(cell) and D(DGT) measurements for both ODL and RDL, except for V and W. The ratios of D(cell)/D(DGT) for V of 0.44 and 0.39, and for W of 0.66 and 0.63 with ODL and RDL respectively, were much lower due to the formation of a high proportion of polyoxometalate species at the higher concentrations required with the D(cell) measurements. This is the first time that D values have been reported for several oxyanions using RDL. Except for Al at pH 8.30 with ODL, all D(DGT) measurements were retarded relative to diffusion coefficients in water (DW) for both diffusive hydrogels. Diffusion in RDL was further retarded compared with ODL, for all elements (0.66-0.78) with both methods. However, the degree of retardation observed changed for cations and anions at each pH. At pH 7.04 cations had a slightly higher D(DGT) and oxyanions had a slightly lower D(DGT) than at pH 4.01 for both ODL and RDL. It is proposed that this is due to partial formation of acrylic acid functional groups (pKa ≈4.5), which would be fully deprotonated at pH 7.04 (negative) and mostly protonated at pH 4.01 (neutral). As Al changes from being cationic at pH 4.01 to anionic at pH 8.30 the results were more complex.
Synchrotron X-ray absorption spectroscopy reveals antimony sequestration by reduced sulfur in a freshwater wetland sediment
Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/EN16198
Abstract: Environmental contextAntimony is an environmental contaminant of increasing concern, due to its growing industrial usage in flame retardants, lead alloys, glass, ceramics and plastics. Here we show, using X-ray absorption spectroscopy, that antimony may be trapped in wetland sediments by reduced sulfur. This finding has implications for the management and remediation of wetlands contaminated with antimony. AbstractThe biogeochemistry of antimony (Sb) in wetland sediments is poorly characterised, despite their importance as contaminant sinks. The organic-rich, reducing nature of wetland sediments may facilitate sequestration mechanisms that are not typically present in oxic soils, where the majority of research to date has taken place. Using X-ray absorption spectroscopy (XAS), we present evidence of antimony speciation being dominated by secondary antimony–sulfur phases in a wetland sediment. Our results demonstrate that, by incorporating a newly developed SbIII–organic sulfur reference standard, linear combination fitting analysis of antimony K-edge XAS spectra and robust statistical assessment of fit quality allows the reliable discrimination of SbIII coordination environments. We found that a contaminated wetland sediment in New South Wales, Australia, contained 57% of the total antimony as SbIII–phases, with 44% present as a highly-disordered antimony phase, likely consisting of SbIII complexed by organic sulfur (e.g. thiols) or an amorphous SbIII sulfide (e.g. SbS3). The methodological approach outlined in this study and our identification of the importance of reduced sulfur in sequestering antimony has implications for future research in the area of antimony biogeochemistry, and for the management of both natural and artificial wetlands contaminated with antimony.
Determining time-weighted average concentrations of nitrate and ammonium in freshwaters using DGT with ion exchange membrane-based binding layers
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6EM00260A
Abstract: Commercially-available AMI-7001 anion exchange and CMI-7000 cation exchange membranes were utilised as binding layers for DGT measurements of NO 3 –N and NH 4 –N in freshwaters.
Evaluation of the DGT technique for selective measurement of aluminium and trace metal concentrations in an acid drainage-impacted coastal waterway
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6EM00276E
Abstract: DGT s lers with different binding layers (Chelex, Metsorb and mixed Chelex–Metsorb) were evaluated for measurement of Al and trace metals in four natural waters with a range of pH.
Passive sampling methods for contaminated sediments: State of the science for metals
Publisher: Wiley
Date: 27-01-2004
DOI: 10.1002/IEAM.1502
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