ORCID Profile
0000-0002-4565-6607
Current Organisation
University of Adelaide
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Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 09-2006
Publisher: Springer Science and Business Media LLC
Date: 15-12-2012
Publisher: MDPI AG
Date: 07-07-2015
Publisher: Liverpool University Press
Date: 2011
Abstract: This review paper focuses on an important new question: how can climate change affect maritime and other cities of Southeast Asia, and what challenges and possible responses can be identified based on historical and current regional policies and action, especially with regard to air pollution? This review was undertaken as part of the ISDP and ISEAS sponsored initiative: Regional Cooperation in Environmental Protection: Lessons from Two Regions (EU and ASEAN). We examined the cases of the EU and ASEAN policies for the protection of air quality from a scientific practitioner’s point of view. We seek to ascertain if ASEAN can respond to regional human-induced environmental problems given existing problems of national sovereignty and the interest-based character of ASEAN-type associations, since ASEAN’s goal, in contrast to that of the EU, has been regional cooperation rather than regional integration. Both regions are responding differently to climate change and the global economic and environmental realities resulting from, or arising in reaction to, their policies (or lack thereof ). While the EU and ASEAN can and should learn from one another and their relations have been the subject of studies (see for ex le), there are still challenges to be addressed to effectively drive improvement of critical regional (air) pollution issues that may ultimately impact health and productivity. Each regional organization has in its own manner made exemplary efforts towards resolving environmental degradation within its own region and taken efforts to make a positive international impact, but there is still the need for international treaties and more local efforts to empower the regional visions. Our aim is to highlight the status of the respective policy frameworks and exemplify areas in which we can learn from one another in the field of air pollution, given its global relevance for climate change. We conclude by suggesting a strategic summary framework for future action. This paper is not meant to be a history of either EU or ASEAN policy for this, the reader is referred instead to appropriate literature, most notably the EU Environmental Policy Handbook, especially the air quality chapter (3) with excellent background information on European Atmospheric Environment Policy.
Publisher: Springer Science and Business Media LLC
Date: 28-09-2015
Publisher: Copernicus GmbH
Date: 26-07-2007
DOI: 10.5194/ACPD-7-10837-2007
Abstract: Abstract. It was discovered in 1995 that, during the spring time, unexpectedly low concentrations of gaseous elemental mercury (GEM) occurred in the Arctic air. This was surprising for a pollutant known to have a long residence time in the atmosphere however conditions appeared to exist in the Arctic that promoted this depletion of mercury (Hg). This phenomenon is termed atmospheric mercury depletion events (AMDEs) and its discovery has revolutionized our understanding of the cycling of Hg in Polar Regions while stimulating a significant amount of research to understand its impact to this fragile ecosystem. Shortly after the discovery was made in Canada, AMDEs were confirmed to occur throughout the Arctic, sub-Artic and Antarctic coasts. It is now known that, through a series of photochemically initiated reactions involving halogens, GEM is converted to a more reactive species and is subsequently associated to particles in the air and/or deposited to the polar environment. AMDEs are a means by which Hg is transferred from the atmosphere to the environment that was previously unknown. In this article we review the history of Hg in Polar Regions, the methods used to collect Hg in different environmental media, research results of the current understanding of AMDEs from field, laboratory and modeling work, how Hg cycles around the environment after AMDEs, gaps in our current knowledge and the future impacts that AMDEs may have on polar environments. The research presented has shown that while considerable improvements in methodology to measure Hg have been made the main limitation remains knowing the speciation of Hg in the various media. The processes that drive AMDEs and how they occur are discussed. As well, the roles that the snow pack, oceans, fresh water and the sea ice play in the cycling of Hg are presented. It has been found that deposition of Hg from AMDEs occurs at marine coasts and not far inland and that a fraction of the deposited Hg does not remain in the same form in the snow. Kinetic studies undertaken have demonstrated that bromine is the major oxidant depleting Hg in the atmosphere. Modeling results demonstrate that there is a significant deposition of Hg to Polar Regions as a result of AMDEs. Models have also shown that Hg is readily transported to the Arctic from source regions, at times during springtime when this environment is actively transforming Hg from the atmosphere to the snow and ice surfaces. The presence of significant amounts of methyl Hg in snow in the Arctic surrounding AMDEs is important because this species is the link between the environment and impacts to wildlife and humans. Further, much work on methylation and demethylation processes have occurred but are not yet fully understood. Recent changes in the climate and sea ice cover in Polar Regions are likely to have strong effects on the cycling of Hg in this environment however more research is needed to understand Hg processes in order to formulate meaningful predictions of these changes. Mercury, Atmospheric mercury depletion events (AMDE), Polar, Arctic, Antarctic, Ice
Publisher: Elsevier BV
Date: 04-2014
Publisher: Elsevier BV
Date: 06-2022
Publisher: Springer Science and Business Media LLC
Date: 15-11-2014
Publisher: Intellect
Date: 11-2009
Abstract: A new model for environmental and urban sustainability living architecture that connects artifice with the natural world through the use of materials that possess some of the properties of living systems, and can therefore actively exchange energy with the ecosphere, is proposed.
Publisher: Springer Science and Business Media LLC
Date: 08-12-2007
Publisher: Springer Netherlands
Date: 12-08-2013
Publisher: Copernicus GmbH
Date: 12-03-2008
Abstract: Abstract. It was discovered in 1995 that, during the spring time, unexpectedly low concentrations of gaseous elemental mercury (GEM) occurred in the Arctic air. This was surprising for a pollutant known to have a long residence time in the atmosphere however conditions appeared to exist in the Arctic that promoted this depletion of mercury (Hg). This phenomenon is termed atmospheric mercury depletion events (AMDEs) and its discovery has revolutionized our understanding of the cycling of Hg in Polar Regions while stimulating a significant amount of research to understand its impact to this fragile ecosystem. Shortly after the discovery was made in Canada, AMDEs were confirmed to occur throughout the Arctic, sub-Artic and Antarctic coasts. It is now known that, through a series of photochemically initiated reactions involving halogens, GEM is converted to a more reactive species and is subsequently associated to particles in the air and/or deposited to the polar environment. AMDEs are a means by which Hg is transferred from the atmosphere to the environment that was previously unknown. In this article we review Hg research taken place in Polar Regions pertaining to AMDEs, the methods used to collect Hg in different environmental media, research results of the current understanding of AMDEs from field, laboratory and modeling work, how Hg cycles around the environment after AMDEs, gaps in our current knowledge and the future impacts that AMDEs may have on polar environments. The research presented has shown that while considerable improvements in methodology to measure Hg have been made but the main limitation remains knowing the speciation of Hg in the various media. The processes that drive AMDEs and how they occur are discussed. As well, the role that the snow pack and the sea ice play in the cycling of Hg is presented. It has been found that deposition of Hg from AMDEs occurs at marine coasts and not far inland and that a fraction of the deposited Hg does not remain in the same form in the snow. Kinetic studies undertaken have demonstrated that bromine is the major oxidant depleting Hg in the atmosphere. Modeling results demonstrate that there is a significant deposition of Hg to Polar Regions as a result of AMDEs. Models have also shown that Hg is readily transported to the Arctic from source regions, at times during springtime when this environment is actively transforming Hg from the atmosphere to the snow and ice surfaces. The presence of significant amounts of methyl Hg in snow in the Arctic surrounding AMDEs is important because this species is the link between the environment and impacts to wildlife and humans. Further, much work on methylation and demethylation processes has occurred but these processes are not yet fully understood. Recent changes in the climate and sea ice cover in Polar Regions are likely to have strong effects on the cycling of Hg in this environment however more research is needed to understand Hg processes in order to formulate meaningful predictions of these changes.
Publisher: American Chemical Society (ACS)
Date: 30-12-2004
DOI: 10.1021/ES040100V
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2GC02214A
Abstract: Critical minerals have an irreplaceable role in the ongoing revolution in technology and using microfluidic continuous-flow technology for processing these minerals has potential solutions and benefits towards the ESG mining issues.
Publisher: American Chemical Society (ACS)
Date: 09-03-2004
DOI: 10.1021/ES030080H
Abstract: Atmospheric mercury depletion episodes (AMDEs) were studied at Station Nord, Northeast Greenland, 81 degrees 36' N, 16 degrees 40' W, during the Arctic Spring. Gaseous elemental mercury (GEM) and ozone were measured starting from 1998 and 1999, respectively, until August 2002. GEM was measured with a TEKRAN 2735A automatic mercury analyzer based on preconcentration of mercury on a gold trap followed by detection using fluorescence spectroscopy. Ozone was measured by UV absorption. A scatter plot of GEM and ozone concentrations confirmed that also at Station Nord GEM and ozone are linearly correlated during AMDEs. The relationship between ozone and GEM is further investigated in this paper using basic reaction kinetics (i.e., Cl, ClO, Br, and BrO have been suggested as reactants for GEM). The analyses in this paper show that GEM in the Arctic troposphere most probably reacts with Br. On the basis of the experimental results of this paper and results from the literature, a simple parametrization for AMDE was included into the Danish Eulerian Hemispheric Model (DEHM). In the model, GEM is converted linearly to reactive gaseous mercury (RGM) over sea ice with temperature below -4 degrees C with a lifetime of 3 or 10 h. The new AMDE parametrization was used together with the general parametrization of mercury chemistry [Petersen, G. Munthe, J. Pleijel, K. Bloxam, R. Vinod Kumar, A. Atmos. Environ. 1998, 32, 829-843]. The obtained model results were compared with measurements of GEM at Station Nord. There was good agreement between the start and general features periods with AMDEs, although the model could not reproduce the fast concentration changes, and the correlation between modeled and measured values decreased from 2000 to 2001 and further in 2002. The modeled RGM concentrations over the Arctic in 2000 were found to agree well with the temporal and geographical variability of the boundary column of monthly average BrO observed by the GOME satellite. Scenario calculations were performed with and without AMDEs. For the area north of the Polar Circle, the mercury deposition increases from 89 tons/year for calculations without an AMDE to 208 tons/year with the AMDE. The 208 tons/year represent an upper limit for the mercury load to the Artic.
Publisher: Elsevier BV
Date: 02-2014
Publisher: Cambridge University Press (CUP)
Date: 2001
DOI: 10.1017/S0033822200041163
Abstract: Peat deposits in Greenland and Denmark were investigated to show that high-resolution dating of these archives of atmospheric deposition can be provided for the last 50 years by radiocarbon dating using the atmospheric bomb pulse. 14 C was determined in macrofossils from sequential one cm slices using accelerator mass spectrometry (AMS). Values were calibrated with a general-purpose curve derived from annually averaged atmospheric 14 CO 2 values in the northernmost northern hemisphere (NNH, 30°–90°N). We present a thorough review of 14 C bomb-pulse data from the NNH including our own measurements made in tree rings and seeds from Arizona as well as other previously published data. We show that our general-purpose calibration curve is valid for the whole NNH producing accurate dates within 1–2 years. In consequence, 14 C AMS can precisely date in idual points in recent peat deposits within the range of the bomb-pulse (from the mid-1950s on). Comparing the 14 C AMS results with the customary dating method for recent peat profiles by 210 Pb, we show that the use of 137 Cs to validate and correct 210 Pb dates proves to be more problematic than previously supposed. As a unique ex le of our technique, we show how this chronometer can be applied to identify temporal changes in Hg concentrations from Danish and Greenland peat cores.
Publisher: Elsevier BV
Date: 03-2015
Publisher: Wiley
Date: 29-10-2021
Abstract: For the in situ resource utilization (ISRU) of asteroids, the cost-mass conundrum needs to be solved, and technologies may need to be conceptualised from first principals. By using this approach, this Review seeks to illustrate how chemical process intensification can help with the development of disruptive technologies and business matters, how this might influence space-industry start-ups, and even industrial transformations on Earth. The disruptive technology considered is continuous microflow solvent extraction and, as another disruptive element therein, the use of ionic liquids. The space business considered is asteroid mining, as it is probably the most challenging resource site, and the focus is on its last step: the purification of adjacent metals (cobalt versus nickel). The key economic barrier is defined as the reduction in the amount of water used in the asteroid mining process. This Review suggests a pathway toward water savings up to the technological limit of the best Earth-based processes and their physical limits.
Publisher: Elsevier BV
Date: 03-2023
Publisher: Springer Science and Business Media LLC
Date: 24-06-2015
DOI: 10.1038/NCLIMATE2665
Publisher: EDP Sciences
Date: 05-2003
DOI: 10.1051/JP4:20030361
Publisher: Springer US
Date: 24-09-2020
Publisher: Copernicus GmbH
Date: 22-08-2007
Abstract: Abstract. During springtime in the polar regions, unique photochemistry converts inert halide salt ions (e.g. Br−) into reactive halogen species (e.g. Br atoms and BrO) that deplete ozone in the boundary layer to near zero levels. Since their discovery in the late 1980s, research on ozone depletion events (ODEs) has made great advances however many key processes remain poorly understood. In this article we review the history, chemistry, dependence on environmental conditions, and impacts of ODEs. This research has shown the central role of bromine photochemistry, but how salts are transported from the ocean and are oxidized to become reactive halogen species in the air is still not fully understood. Halogens other than bromine (chlorine and iodine) are also activated through incompletely understood mechanisms that are probably coupled to bromine chemistry. The main consequence of halogen activation is chemical destruction of ozone, which removes the primary precursor of atmospheric oxidation, and generation of reactive halogen atoms/oxides that become the primary oxidizing species. The different reactivity of halogens as compared to OH and ozone has broad impacts on atmospheric chemistry, including near complete removal and deposition of mercury, alteration of oxidation fates for organic gases, and export of bromine into the free troposphere. Recent changes in the climate of the Arctic and state of the Arctic sea ice cover are likely to have strong effects on halogen activation and ODEs however, more research is needed to make meaningful predictions of these changes.
Publisher: American Chemical Society (ACS)
Date: 13-04-2012
DOI: 10.1021/ES301201C
Publisher: Elsevier BV
Date: 06-2004
Publisher: Springer Netherlands
Date: 12-08-2013
Publisher: Elsevier BV
Date: 06-2002
DOI: 10.1016/S0048-9697(02)00035-9
Abstract: Traditional peat s le preparation methods such as drying at high temperatures and milling may be unsuitable for Hg concentration determination in peats due to the possible presence of volatile Hg species, which could be lost during drying. Here, the effects of s le preparation and natural variation on measured Hg concentrations are investigated. Slight increases in mercury concentrations were observed in s les dried at room temperature and at 30 degrees C (6.7 and 2.48 ng kg(-1) h(-1), respectively), and slight decreases were observed in s les dried at 60, 90 and 105 degrees C (2.36, 3.12 and 8.52 ng kg(-1) h(-1), respectively). Fertilising the peat slightly increased Hg loss (3.08 ng kg(-1) h(-1) in NPK-fertilised peat compared to 0.28 ng kg(-1) h(-1) in unfertilised peat, when averaged over all temperatures used). Homogenising s les by grinding in a machine also caused a loss of Hg. A comparison of two Hg profiles from an Arctic peat core, measured in frozen s les and in air-dried s les, revealed that no Hg losses occurred upon air-drying. A comparison of Hg concentrations in several plant species that make up peat, showed that some species (Pinus mugo, Sphagnum recurvum and Pseudevernia furfuracea) are particularly efficient Hg retainers. The disproportionally high Hg concentrations in these species can cause considerable variation in Hg concentrations within a peat slice. The variation of water content (1.6% throughout 17-cm core, 0.97% in a 10 x 10 cm slice), bulk density (40% throughout 17-cm core, 15.6% in a 10 x 10 cm slice) and Hg concentration (20% in a 10 x 10 cm slice) in ombrotrophic peat were quantified in order to determine their relative importance as sources of analytical error. Experiments were carried out to determine a suitable peat analysis program using the Leco AMA 254, capable of determining mercury concentrations in solid s les. Finally, an analytical protocol for the determination of Hg concentrations in solid peat s les is proposed. This method allows correction for variation in factors such as vegetation type, bulk density, water content and Hg concentration in in idual peat slices. Several subs les from each peat slice are air dried, combined and measured for Hg using the AMA254, using a program of 30 s (drying), 125 s (decomposition) and 45 s (waiting). Bulk density and water content measurements are performed on every slice using separate subs les.
Publisher: Elsevier BV
Date: 09-2016
Publisher: Elsevier
Date: 2008
Publisher: Springer Netherlands
Date: 2017
Publisher: Research Square Platform LLC
Date: 27-04-2023
DOI: 10.21203/RS.3.RS-2815646/V1
Abstract: Australian residents have the highest solar energy installation rate in the world. However, after experiencing rapid growth, the residential installation rate began to decline sharply starting in 2011. In this study, we examine installation data for small and medium-sized solar photovoltaic (PV) devices across 2,413 Australian postcode areas using regression analysis and coarsened exact matching (CEM). We reevaluate four primary factors influencing the residential solar energy installation rate: natural factors, energy policy factors, rooftop space factors, and socioeconomic factors. Our findings reveal that areas with higher proportions of elderly or low-income residents exhibit greater household solar PV installation rates. Additionally, increased feed-in tariff (FiT) subsidies further motivate these resident groups to install solar PV systems, resulting in higher installation rates within their neighborhoods. The results also suggest that if a subsidy policy with a feed-in tariff average expected return (FiT-AER) of more than 7 cents/kWh persists, elderly and low-income groups in Australia may continue to dominate home solar PV installations. This trend could potentially mitigate energy inequity during the energy transition process.
Publisher: Springer New York
Date: 2012
Publisher: The Arctic Institute of North America
Date: 2004
DOI: 10.14430/ARCTIC501
Publisher: American Chemical Society (ACS)
Date: 28-08-2004
DOI: 10.1021/ES035293L
Abstract: In this paper, we present the first comprehensive long-term record of preanthropogenic rates of atmospheric mercury accumulation in dated peat deposits for the High Arctic of Canada. Geochemical studies of two peat hummocks from Bathurst Island, Nunavut reveal substantial inputs from soil dust (titanium), marine aerosols (bromine), and mineral-water interactions (uranium). Mercury, however, was supplied to these peat mounds exclusively by atmospheric deposition. Mercury concentration measurements and age dating of the peat profiles indicate rather constant natural "background" mercury flux of ca. 1 microgram per square meter per year from 5900 to 800 calibrated years BP. These values are well within the range of the mercury fluxes reported from other Arctic locations, but also by peat cores from southern Canada that provide a record of atmospheric Hg accumulation extending back 8000 years. Thus, preanthropogenic Hg fluxes in the Arctic were not significantly different from atmospheric Hg fluxes in the temperate zone. In preindustrial times, therefore, the High Arctic was no more important as a sink for global atmospheric mercury than was the temperate zone.
Publisher: Springer Netherlands
Date: 2017
Publisher: American Chemical Society (ACS)
Date: 13-02-2002
DOI: 10.1021/ES0111941
Abstract: Gaseous elemental mercury (Hg0) is a globally distributed air toxin with a long atmospheric residence time. Any process that reduces its atmospheric lifetime increases its potential accumulation in the biosphere. Our data from Barrow, AK, at 71 degrees N show that rapid, photochemically driven oxidation of boundary-layer Hg0 after polar sunrise, probably by reactive halogens, creates a rapidly depositing species of oxidized gaseous mercury in the remote Arctic troposphere at concentrations in excess of 900 pg m(-3). This mercury accumulates in the snowpack during polar spring at an accelerated rate in a form that is bioavailable to bacteria and is released with snowmelt during the summer emergence of the Arctic ecosystem. Evidence suggests that this is a recent phenomenon that may be occurring throughout the earth's polar regions.
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B401601G
Abstract: For detailed reconstructions of atmospheric metal deposition using peat cores from bogs, a comprehensive protocol for working with peat cores is proposed. The first step is to locate and determine suitable s ling sites in accordance with the principal goal of the study, the period of time of interest and the precision required. Using the state of the art procedures and field equipment, peat cores are collected in such a way as to provide high quality records for paleoenvironmental study. Pertinent field observations gathered during the fieldwork are recorded in a field report. Cores are kept frozen at -18 degree C until they can be prepared in the laboratory. Frozen peat cores are precisely cut into 1 cm slices using a stainless steel band saw with stainless steel blades. The outside edges of each slice are removed using a titanium knife to avoid any possible contamination which might have occurred during the s ling and handling stage. Each slice is split, with one-half kept frozen for future studies (archived), and the other half further sub ided for physical, chemical, and mineralogical analyses. Physical parameters such as ash and water contents, the bulk density and the degree of decomposition of the peat are determined using established methods. A subs le is dried overnight at 105 degree C in a drying oven and milled in a centrifugal mill with titanium sieve. Prior to any expensive and time consuming chemical procedures and analyses, the resulting powdered s les, after manual homogenisation, are measured for more than twenty-two major and trace elements using non-destructive X-Ray fluorescence (XRF) methods. This approach provides lots of valuable geochemical data which documents the natural geochemical processes which occur in the peat profiles and their possible effect on the trace metal profiles. The development, evaluation and use of peat cores from bogs as archives of high-resolution records of atmospheric deposition of mineral dust and trace elements have led to the development of many analytical procedures which now permit the measurement of a wide range of elements in peat s les such as lead and lead isotope ratios, mercury, arsenic, antimony, silver, molybdenum, thorium, uranium, rare earth elements. Radiometric methods (the carbon bomb pulse of (14)C, (210)Pb and conventional (14)C dating) are combined to allow reliable age-depth models to be reconstructed for each peat profile.
Publisher: American Chemical Society (ACS)
Date: 06-02-2004
DOI: 10.1021/ES034680S
Abstract: The oxidation of elemental mercury (Hg0) to the alent gaseous mercury dibromide (HgBr2) has been proposed to account for the removal of Hg0 during depletion events in the springtime Arctic. The mechanism of this process is explored in this paper by theoretical calculations of the relevant rate coefficients. Rice-Ramsberger-Kassel-Marcus (RRKM) theory, together with ab initio quantum calculations where required, are used to estimate the following: recombination rate coefficients of Hg with Br, I, and O the thermal dissociation rate coefficient of HgBr and the recombination rate coefficients of HgBr with Br, I, OH, and O2. A mechanism based on the initial recombination of Hg with Br, followed by the addition of a second radical (Br, I, or OH) in competition with thermal dissociation of HgBr, is able to account for the observed rate of Hg0 removal, both in Arctic depletion events and at lower latitudes.
Publisher: American Geophysical Union (AGU)
Date: 07-2006
DOI: 10.1029/2005GL025525
Publisher: Elsevier BV
Date: 11-2015
Publisher: American Chemical Society (ACS)
Date: 30-12-2004
DOI: 10.1021/ES040107C
Publisher: Elsevier BV
Date: 10-2014
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.SCITOTENV.2005.11.029
Abstract: Mercury (Hg) has been used for millennia in many applications, primarily in artisanal mining and as an electrode in the chlor-alkali industry. It is anthropogenically emitted as a pollutant from coal fired power plants and naturally emitted, primarily from volcanoes. Its unique chemical characteristics enable global atmospheric transport and it is deposited after various processes, ultimately ending up in one of its final sinks, such as incorporated into deep sediment or bioaccumulated, primarily in the marine environment. All forms of Hg have been established as toxic, and there have been no noted biological benefits from the metal. Throughout time, there have been notable incidents of Hg intoxication documented, and the negative health effects have been documented to those chronically or acutely exposed. Today, exposure to Hg is largely diet or occupationally dependent, however, many are exposed to Hg from their amalgam fillings. This paper puts a tentative monetary value on Hg polluted food sources in the Arctic, where local, significant pollution sources are limited, and relates this to costs for strategies avoiding Hg pollution and to remediation costs of contaminated sites in Sweden and Japan. The case studies are compiled to help policy makers and the public to evaluate whether the benefits to the global environment from banning Hg and limiting its initial emission outweigh the benefits from its continued use or lack of control of Hg emissions. The cases we studied are relevant for point pollution sources globally and their remediation costs ranged between 2,500 and 1.1 million US dollars kg(-1) Hg isolated from the biosphere. Therefore, regulations discontinuing mercury uses combined with extensive flue gas cleaning for all power plants and waste incinerators is cost effective.
Publisher: Springer US
Date: 2009
Publisher: Elsevier BV
Date: 2005
Publisher: Informa UK Limited
Date: 23-06-2017
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.SCITOTENV.2013.02.052
Abstract: This review compares the reconstruction of atmospheric Hg deposition rates and historical trends over recent decades in the Arctic, inferred from Hg profiles in natural archives such as lake and marine sediments, peat bogs and glacial firn (permanent snowpack), against those predicted by three state-of-the-art atmospheric models based on global Hg emission inventories from 1990 onwards. Model veracity was first tested against atmospheric Hg measurements. Most of the natural archive and atmospheric data came from the Canadian-Greenland sectors of the Arctic, whereas spatial coverage was poor in other regions. In general, for the Canadian-Greenland Arctic, models provided good agreement with atmospheric gaseous elemental Hg (GEM) concentrations and trends measured instrumentally. However, there are few instrumented deposition data with which to test the model estimates of Hg deposition, and these data suggest models over-estimated deposition fluxes under Arctic conditions. Reconstructed GEM data from glacial firn on Greenland Summit showed the best agreement with the known decline in global Hg emissions after about 1980, and were corroborated by archived aerosol filter data from Resolute, Nunavut. The relatively stable or slowly declining firn and model GEM trends after 1990 were also corroborated by real-time instrument measurements at Alert, Nunavut, after 1995. However, Hg fluxes and trends in northern Canadian lake sediments and a southern Greenland peat bog did not exhibit good agreement with model predictions of atmospheric deposition since 1990, the Greenland firn GEM record, direct GEM measurements, or trends in global emissions since 1980. Various explanations are proposed to account for these discrepancies between atmosphere and archives, including problems with the accuracy of archive chronologies, climate-driven changes in Hg transfer rates from air to catchments, waters and subsequently into sediments, and post-depositional diagenesis in peat bogs. However, no general consensus in the scientific community has been achieved.
Publisher: Scientific Research Publishing, Inc.
Date: 2015
Publisher: Wiley
Date: 25-10-2013
DOI: 10.1002/TIE.21579
Publisher: CSIRO Publishing
Date: 2007
DOI: 10.1071/EN06082
Abstract: Environmental context. Mercury is of concern to both the public and to the scientific community because it is found at high levels in some marine predators, prompting the US EPA and others to make guidelines restricting the consumption of some species. Most mercury in the environment is emitted to the atmosphere, but it is not known how it is transferred from the atmosphere to the marine environment. Therefore, it is important to study the connection between emission of mercury, its transport and removal from the atmosphere. We have developed a new s ler that is inexpensive, easy to use and with a sufficiently high detection limit that it can be used to measure the low mercury concentrations in the atmosphere at a reasonable time resolution. Abstract. Mercury behaves uniquely in the atmosphere due to its volatility and long lifetime. The existing methods for measuring atmospheric mercury are either expensive or labour intensive. The present paper presents a new measurement technique, the diffusive s ler, that is portable, inexpensive, easy to use, and does not need a power supply. The s ler is sufficiently sensitive that it can measure mercury at low ambient levels with an exposure time of 1 to 3 days. The s ler is based on the Radiello diffusive s ler, which was used to collect volatile organic compounds. In the present paper, the method is validated under controlled laboratory conditions. The uptake rate of the Radiello diffusive s ler is determined using known concentrations of gaseous elemental mercury, and is measured as a function of wind speed, relative humidity and temperature. The Radiello s ler has a detection limit of 0.14 ng m–3 for 1 day of exposure and thus can be used to measure mercury concentrations at the low levels found in ambient air. The Radiello s ler is therefore useful for mapping concentrations close to sources and sinks, in addition to ambient concentrations. For ex le, the s ler can be used to describe the geographical extent of Arctic mercury depletion episodes where gaseous elemental mercury is removed and stays close to 0 ng m–3 for days, and it can be a powerful tool for mapping gradients around point sources and other areas of interest.
Publisher: Springer Science and Business Media LLC
Date: 10-2015
DOI: 10.1038/526323A
Publisher: American Chemical Society (ACS)
Date: 08-07-2011
DOI: 10.1021/ES2014709
Publisher: Elsevier BV
Date: 09-2022
Publisher: Wiley
Date: 25-02-2014
DOI: 10.1002/TIE.21613
Publisher: Elsevier BV
Date: 10-2015
Publisher: Wiley
Date: 29-10-2020
Publisher: The Royal Society of Chemistry
Date: 07-08-2009
DOI: 10.1039/9781847559654-00001
Abstract: The extent of the urban area, the local emission density, and the temporal pattern in the releases govern the local contribution to air pollution levels in urban environments. However, meteorological conditions also heavily affect the actual pollution levels as they govern the dispersion conditions as well as the transport in and out of the city area. The building obstacles play a crucial role in causing generally high pollutant levels in the urban environment, especially inside street canyons where the canyon vortex flow governs the pollution distribution. Of the pollutants dominating urban air pollution climates, particulate pollution in general together with gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) and heavy metals are those where further field measurements, characterization and laboratory studies are urgently needed in order to fully assess the health impact on the urban population and provide the right basis for future urban air pollution management.
Publisher: Elsevier BV
Date: 11-2003
Publisher: The Arctic Institute of North America
Date: 02-09-2016
DOI: 10.14430/ARCTIC4577
Abstract: Seabird guano from large nesting colonies is known to increase trace metal levels in adjacent terrestrial environments today, when global oceans are contaminated with Hg, Cd, and other metals. But the effect of seabird guano in the pre-industrial period has rarely been studied. We used stable C and N isotopic and trace element analyses of a peat core that represents ca. 2000 years of organic matter accumulation to examine the effect on trace elements and nutrients of a seabird colony that existed in northern Baffin Bay during the Holocene Thermal Maximum (ca. 8000–5000 yr BP). Although C and N concentrations were typical of those in other peats, isotopic data identified marine organic matter as the main source of N and a minor source of C in the peat and showed that the unknown seabird was a fish-eating species that was summer-resident for the 2000 yr period. Concentrations of Cd, Br, Sr, and Zn in peat were up to an order of magnitude higher than in ombrotrophic (air-fed) bogs elsewhere, whereas Hg and Cu concentrations were similar to those in other peats, suggesting relatively low levels of Hg and Cu in the guano. This surprising result for Hg contrasts with studies on modern seabirds, in which guano markedly increased environmental Hg concentrations. It could be a consequence of Hg concentrations in Arctic marine food webs in the pre-industrial period that were an order of magnitude lower than those of today.
Publisher: Elsevier
Date: 2008
No related grants have been discovered for Michael Goodsite.