摘要:

IntroductionOrganic pollutants in soil can change over time by physical, chemical and biological factors. Biological factors include plant roots and soil microbes and their interaction. Understanding adverse effects of pollutants on plants is necessary to predict the changes in food chain linked with plants and consequent flow-on risks to terrestrial and aquatic ecosystems. Polycyclic aromatic hydrocarbons (PAHs) are a group of ubiquitous hazardous organic pollutants derived from crude oil, coal, various combustion sources and pyrolysis of a wide range of plastics.1–3The toxicity of PAHs, which manifest themselves as growth inhibitors, mutagenics or carcinogens, has been reported in animals and microorganisms as well as plants.4,5Because PAHs are persistent toxic compounds in the environment, the compounds should be removed rapidly. Phytoremediation that have been developed in recent times can be used to eliminate these contaminants. Plants have been known to accelerate biodegradation of organic contaminants principally by providing a favorable environment for microbe activities in the rhizosphere.6Plants involved in the biodegradation process of organic contaminants, either directly through phytotransformation7–9or indirectly by raising rhizosphere bacteria, degrade contaminants in soil.10–12This environmentally friendly technology has become a remediation tool for various pollutions.13–15In developing this technology, it is necessary to find plant species which are tolerant to contaminants and grow well in polluted fields, because plants showing extraordinary responses to PAHs can be used for phytomonitoring of PAHs contamination.Phytomonitoring technology is more feasible than phytoremediation because plants can exhibit different responses to a pollutant in their growth and development cycle without changing the concentration of pollutant in the environment. Recent studies have suggested that phytoremediation is an effective method in reducing levels of PAHs in soil.12,16–18Although various physical and chemical factors are included in this process, previous reports indicated that hydrocarbon degradation in rhizosphere enhanced by plant-microbes interaction is the primary mechanism of elimination.10,11With respect to this point, one of the most important factors influencing biological activity and composition of microbial community is the vegetational condition in contaminated soils. Therefore, it is assumed that the degradation of PAHs could be accelerated by vegetation showing high proportion of tolerant species.Typical responses of plants to PAHs are poor germination and growth.19–21Overall vegetational characteristics are usually dependent on species-specific responses to environmental condition. Therefore, it is important to ascertain the adverse effects of PAHs on individual plant species and to evaluate the potential hazard of PAHs to terrestrial ecosystems.The aim of our research was to investigate the responses of plant species that occur dominantly in Korea to PAHs during germination and seedling growth. Identification of plant species that grow dominantly in PAHs-contaminated fields will enable us to select species that accelerate degradation of PAHs with respect to phytoremediation. In addition, responses of wild plants examined in this study may assist the proper selection of species for phytomonitoring or phytoremediation in contaminated fields.

ISSN:1464-0325    

DOI:10.1039/b906560a

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

Environmental impactThe present paper describes a multibiomarker approach used for the first time in the south coast of Portugal with the musselMytilus galloprovincialisto assess the impact of contaminants in this European coastal area. Contrary to the single biomarker approach used commonly in ecotoxicology studies, this work integrates a battery of biomarkers to assess the effect of pollutants (metallic and organic) and environmental physico-chemical parameters. This represents a new tool to evaluate the quality of the coastal environment subjected to the impact of mixtures of contaminants and provides valuable information for environmental risk assessment that allows pollution effects to be distinguished from those induced by natural factors using the mussels as biological indicators.

ISSN:1464-0325    

DOI:10.1039/b909846a

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

IntroductionSydney Olympic Park (SOP) is located in the Homebush Bay area of Sydney, Australia. Prior to the 2000 Sydney Olympic Games, the Homebush Bay area was used as a site for many industrial activities including the state brickworks, an abattoir, a naval armaments depot, and the manufacture of pesticides (i.e.2,4-D, 2,4,5-T, DDT) and other chemicals, paints, plastics and industrial alcohols until the 1990s.1Manufacture of these chemicals produced a variety of waste materials and by-products, including dioxins and chlorinated organic compounds. The SOP site was also used as a site for controlled and uncontrolled dumping of industrial and domestic wastes.2The Homebush Bay area was heavily contaminated with a variety of inorganic and organic chemicals including heavy metals, pesticides and dioxins.3With the awarding of the Olympic Games to Sydney in 1993, remediation of the SOP, including removal, treatment and on-site storage of contaminated sediments and soils, was carried out in the 1990s in preparation for the Olympic Games; however, the sediments of the Homebush Bay itself were not included in the remediation program. Fishing in Homebush Bay is currently banned because of dioxin contamination of the fish.4Wetlands were created in SOP during the remediation process. As a result of the remediation and restoration, SOP is now a home to varied wildlife including the endangered green and golden bell frog (Litoria aurea).5Thus, it was desirable to investigate contaminants in the aquatic environment of the area after remediation to contribute to assessing the effects on the wildlife.Investigations prior to remediation showed that SOP and Homebush Bay sediments were heavily polluted with toxic metals and organic chemicals such as polychlorinated dibenzodioxins and dibenzofurans (PCDDs/Fs), polychlorinated biphenyls (PCBs), various pesticides such as DDT as well as polycyclic aromatic hydrocarbons (PAHs).3,6Contaminants were detected in sediments of Homebush Bay and surrounds at high concentrations, for example up to 316 mg/kg for dioxins/furans, 14 mg/kg for PCBs, 0.7 mg/kg for DDT, and 430 mg/kg for PAHs.7Metals and persistent organic pollutants (POPs) are toxic substances, which may be hazardous to human and environmental health.8,9Some organic substances (DDT, PCBs and PCDDs/Fs as well as PAHs) detected in sediments from the park are among the POPs listed in the 1979 UNECE Convention on Long-Range Transboundary Air Pollution on Persistent Organic Pollutants, adopted in Aarhus in 1998, and the UNEP Stockholm Convention, a global treaty to protect human health and the environment from POPs. Metals and POPs have been investigated in sediments around the world for their distribution and potential toxicity to organisms in aquatic environments.10–12But less research has been conducted for urban wetland contamination of these contaminants.The aim of this study was to assess if the remediation program of SOP was successful in reducing the concentrations of the selected suite of contaminants (i.e.metals, DDT and its metabolites (DDD and DDE), PCBs, dioxins and PAHs) to levels found in urban wetlands of the Sydney Basin. This was done by quantifying each contaminant and comparing the concentrations at SOP and Sydney urban reference sites. Some unremediated sites at the boundary of the SOP were also included in the comparative study.

ISSN:1464-0325    

DOI:10.1039/b910524g

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

IntroductionIn a manuscript published inJ. Environ. Monit.earlier this year, we reported the results from a side-by-side comparison of leaching of nickel from various samples in synthetic lung fluid and other inorganic solutions.1The results from that study suggested that the Zatka leaching method2may greatly overestimate the fraction of “lung-soluble nickel compounds” if nickel subsulfide or nickel carbonate are present in the air. In the case of nickel subsulfide, leaching in ammonium citrate resulted in a 38-fold increase in leached nickel ion compared to that leached in synthetic alveolar lung fluid (after 24 hours at 37 °C). In the case of nickel carbonate, ammonium citrate resulted in 141-fold higher leached nickel ion compared to that leached in synthetic lung fluid.1The Zatka method2has been applied extensively in the nickel industry to estimate the fraction of workplace nickel exposures corresponding to the four main groups of nickel substances (soluble, sulfidic, metallic and oxidic). The first step of the Zatka protocol corresponds to a leaching of the sample in ammonium citrate for 90 minutes at room temperature (20 °C). The nickel measured in this leachate is assumed to correspond to the “water- or lung-soluble” nickel fraction. The preliminary conclusions from our studies indicated that the ammonium citrate solution used in the first step of the Zatka method should be replaced by distilled water to avoid overestimating the fraction of nickel workplace aerosols that is “water- or lung-soluble.” We also suggested that workplace exposure estimates of soluble nickel based primarily on the results of the Zatka method should be re-examined to assess whether nickel subsulfide or carbonate were present and could have skewed the speciation results. The preliminary conclusions from our studies, however, were based on results obtained for one or 24 hours at 37 °C (body temperature) which did not reflect the exact conditions of the Zatka protocol (90 minutes at room temperature).In order to evaluate the effect that the differences in temperature may have on nickel leaching in ammonium citrate (20 °C in Zatka protocolversus37 °C previously tested), we have now applied the first step leaching conditions specified in the Zatka protocol (90 minutes at room temperature) to all samples previously tested. We also extended the previously reported results for leaching of nickel subsulfide and nickel oxide in synthetic alveolar lung fluid and ammonium citrate (24 hours at 37 °C) to include the results corresponding to just one hour at 37 °C.

ISSN:1464-0325    

DOI:10.1039/b909157b

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

LegislationFears grow for Copenhagen dealWith the clock ticking down inexorably, fears are growing that December's climate summit meeting in Copenhagen will fail to deliver an agreement on a post-Kyoto policy framework. UN climate negotiators left the latest round of talks in Bonn in a downbeat mood, noting that little progress had been made.Environmental campaigners are also increasingly concerned. Some believe that so many issues are being thrown into the talks that a meaningful agreement is virtually impossible. Over recent months there have been calls for issues such as water resources and water quality,1,2ocean management,3and ecosystems and biodiversity to be included in any global climate agreement. A recent example was the World Water Week Conference in Stockholm which emphasized a “strong and fair” global climate agreement as “crucial to secure the availability of water resources”.Speaking after the Bonn meeting, UN climate chief Yvo de Boer said: “If we continue at this rate, we are not going to make it”. US climate negotiator Jonathan Pershing was also concerned by the sluggish progress of the talks. “If we don't have more movement and more consensus than we saw here, we won't have an agreement.” Others feared negotiations would lead to a toothless deal in Copenhagen.Prior to the meeting the UN released figures showing pledges made by rich nations would only amount to a 15–21% cut by 2020, rather than the 50% or more that is being sought.UN Secretary-General Ban Ki-moon upped the ante by travelling to the Arctic to highlight the plight of the region widely seen as being in the vanguard of climate change. Standing on rapidly melting polar ice, Mr Ban said: “I feel the power of nature, and at the same time, a sense of vulnerability”. Witnessing the impacts of climate change on icebergs and glaciers first-hand, he said scientists had informed him that global warming is altering the Arctic faster than any other area. “Unless we fight climate change, unless we stop this trend, we'll have devastating consequences for humanity,” the Secretary-General stressed. Mr Ban was set to convene a high-level gathering in New York in late September to shore up political will.Meanwhile, the International Energy Agency (IEA) is urging governments to pay more attention to measures for reducing methane emissions, which it says offers a “particularly effective short-term tactic” for mitigating climate change. Methane's short-term contribution to global warming is particularly significant, due to its relatively high warming potential but short atmospheric lifetime.Methane emissions from the energy sector are expected to increase by 23% by 2020. At present no country has a comprehensive policy framework in place for methane recovery and use as an energy source, the IEA says. The Agency recommends expanding the US-led Methane to Markets initiative which promotes the deployment of methane recovery technologies worldwide. Rich nations should share best practices with developing countries where most of the future growth in emissions is expected to occur, it adds.UNFCCC:http://unfccc.int; IEA:www.iea.org/textbase/Papers/2009/methane_brochure.pdf; World Water Week:www.worldwaterweek.orgEU split on biofuels impactsEuropean countries are divided on how to address the impact of biofuels on land use. A ‘pre-consultation’ on the issue by the European Commission has revealed differing opinions on how to calculate emissions from biofuels, as required under the recent Renewables Directive.4,5Denmark, the Netherlands and the UK favour the inclusion of a measure of ‘indirect land use change’ (ILUC) in the calculation of greenhouse gas emissions from biofuels. Several MEPs also wanted to integrate such impacts in the calculation during the parliamentary debate on the directive.6,7But other countries oppose this, arguing there is insufficient scientific evidence on the ILUC impacts of different types of biofuels. This view is supported by Brazil, a major exporter of ethanol produced from sugar cane.These countries favour other options, primarily the use of international agreements to protect carbon-rich habitats from ILUC impacts. Trade association the European Biodiesel Board (EBB) backs this approach, along with a proposal to give more recognition to biofuels produced on idle land or from non-land sources such as algae. Less controversial is an option to extend possible ILUC restrictions on biofuels used in the EU to non-EU countries and other agricultural commodities.The Commission will use the findings to draft a formal consultation document later this year. It has pledged to finalise its proposals on ILUC impacts by March 2010 so as to allow Member States time to implement them in their renewable energy action plans, which must be adopted in June next year.Across the Atlantic, EPA has released for peer review a lifecycle analysis of renewable fuels. The move was announced in May as part of the Agency's proposed strategy for increasing the supply of biofuels.European Commissionhttp://ec.europa.eu/energy/renewables/consultations/; EBB:www.ebb-eu.org; Renewable Energy Directive:http://eur-lex.europa.eu/(search reference: L:2009:140); EPA:www.epa.gov/otaq/renewablefuels/index.htmNoise standards nothing to shout aboutNew standards for measuring vehicle noise to be introduced in Europe have drawn criticism from environmental campaigners.The standards, set by the UN's Economic Commission for Europe, relate to high accelerations and complement a low speed-based measurement standard. New limit values for noise are expected to follow. Green transport NGO T&E said the new standard will lead to higher noise levels and worsen noise's impact on health. Europe's noise standards should be set by the EU, not by an international body, T&E added.New noise limits for tyres were agreed by the EU in February. European legislation requires EU states to issue action plans for dealing with noise pollution by December 2008, but to date only 14 countries have done so. Earlier this year Europe's road haulage industry called for a more harmonised approach.8Transport and Environment NGO:www.transportenvironment.orgEurope gets new water monitoring rulesNew EU rules on chemical analysis and monitoring of water quality entered into force in August following their publication in the bloc's Official Journal.The new rules set minimum performance criteria for water quality analysis methods. In the absence of methods meeting these criteria, monitoring must be based on the best available techniques “not entailing excessive costs”.The directive is intended to improve the monitoring of water quality across Europe and help the European Commission to assess progress towards meeting the EU's 2015 water quality goal.9Under EU law, member states must adopt river basin management plans by the end of the year, although progress is slow.10European Commission: surface water quality,http://ec.europa.eu/environment/water/water-dangersub/index.htm; Directive:http://eur-lex.europa.eu/(search reference: L2009/201)Agency invests in clean upCleanup efforts at brownfield sites are to receive EPA funding of $55 million. The funds provide so-called revolving loans (i.e.loans with no or low interest) and grants to help communities carry out cleanup activities, redevelop projects, and create jobs.Of the $55 million grant, $42 million is funded through President Obama's American Recovery and Reinvestment Act 2009 and $13 million is funded through the EPA Brownfields funding programme.EPA:www.epa.gov/brownfields/eparecovery/index.htm

ISSN:1464-0325    

DOI:10.1039/b918410b

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

This is the 100th issue of theJournal of Environmental Monitoring. We are using this milestone as an opportunity to highlight the continued development of the environmental sciences over the last 5 years and describe how JEM is adapting to advances in the understanding of our environment.In 2004, theJournal of Environmental Monitoringeditorial board stated that the objective of the journal was “to promote physical, chemical and biological research relating to the measurement pathways …in all environments with a particular emphasis on the interface of these subjects with analytical science”.Journal of Environmental Monitoringhas grown considerably in the last 5 years in tandem with the rapid development and maturation of its original core areas. The boundaries between the compartments of environmental science have become increasingly blurred as advances in one area impact on and promote re-evaluation of others. It is in this new multi-disciplinary arena thatJournal of Environmental Monitoringnow finds itself challenged by how best to interpret and exploit advances in the understanding of our environment with rapid changes in technologies and methodologies. With diversification of our core areas comes the need to establish new goals, new ways of communicating and most importantly new ways of ensuring thatJournal of Environmental Monitoringis at the forefront of reporting environmental impacts. This includes understanding of environmental processes along with appreciating the implications of emerging technologies, climate change, sustainability, land use practices, industrial development and economics. How will these areas impact our ecosystem, our health, our lives, and most importantly, our planet?Journal of Environmental Monitoringbegan as a journal focused more on measurement and monitoring science and has evolved to one focused on understanding environmental processes and impacts. The overarching areas that the Editorial Board has agreed should be the purview of the journal are consistent with and parallel to the basic components of risk evaluation and management, including contaminant sources, transport, and transformation; contaminant fate; contaminant exposure, and effects; and management and policy. The specific categories of interest include scientific research on nanomaterials, contaminant fate and transport, environmental modelling, environmental economics, alternative and renewable energies, ecological processes, environmental and chemical engineering, environmental health, climate change, and geological sciences. Of course these areas overlap to some degree, and we welcome those contributions that provide greater understanding of the interconnectedness of environmental issues. It has been rewarding to see the journal grow in concert with the field, and to see its quality continuing to improve. Our impact factor is now at 2.0 (compared to 1.4 in 2004) and our time from submission to acceptance is under 100 days (128 days in 2004). Our published papers come from authors from around the world, also reflecting the changes in the last five years in the demographics of where environmental research is being conducted.On consideration of the great challenges that now face our environment,Journal of Environmental Monitoringhas taken considerable steps which will lead to a fuller awareness of the consequences of our activities and remediation actions. It is the impacts of environmental research in addressing these great challenges that are now of special concern toJournal of Environmental Monitoringand its readers. With this in mind, in the future we will require all articles submitted toJournal of Environmental Monitoringto provide a statement explaining how the research presented in the paperimpactsthe environmentdirectlyand how the work provides immediate insight into environmentalprocesses. We call this an Environmental Impact statement, and this will replace the justification/novelty statement. This statement should be no more than 120 words long and describe why/how the paper contributes to a multi-level understanding of environmental phenomena (impacts and processes). This is to clarify the appropriateness of the article for a technical but broad environmental audience. It should categorically state how the work contributes to an improved knowledge of the environment and will lead to a better understanding of the subject in question. The environmental impact box is intended to show that the authors have given serious consideration to problems that areenvironmentalin nature rather than analytical.Environmental research is at this point entering a stage where analytical science is playing a supporting role in augmenting decision making and facilitating detailed environmental studies. The future development ofJournal of Environmental Monitoringwill see it move from measurement science to a fuller interpretation of measurement data with serious consideration of what these data really mean, what their implications are, and what they can predict.Our intention is that these changes will increase and further develop the environmental relevance ofJournal of Environmental Monitoringwhich will not only help strengthen the quality of the journal but also increase its value to our readers and subscribers. We hope to challenge researchers into thinking more fully in terms of multi-layered environmental science and the environmental consequences of their work.Finally, we intend to make JEM a catalyst for the discussion and exchange of ideas and information on complex environmental issues. May the next 100 issues of the journal serve to significantly increase and advance our understanding of environmental hazards, processes, and impacts, and offer solutions to today's and future problems.

ISSN:1464-0325    

DOI:10.1039/b916043b

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

The editorial in the inaugural February 1999 issue of JEM stipulated the following goal: “JEM is dedicated to all aspects of the measurement of chemical, physical and biological agents in outdoor, indoor and workplace environments, with a view to assessing exposure in relation to adverse environmental and health effects”. In the context of this broad scope, it is not surprising that environmental monitoring has experienced considerable development in the 10-year interim. Some of the more striking advances reflected in the pages of JEM are highlighted in this perspective.Spatiotemporal monitoring has found extensive application in measurements of the upper atmosphere, in personal air sampling (indoor, outdoor, and the workplace) and in analyses of soil, vegetation, sediments, and water (ground, surface and potable). Clearly, technical developments and global positioning systems (GPS) has constituted a major driving force, which permits one to combine direct-reading exposure and geographic location assessments with activity patterns. Technical developments in improving online-determinations also occurred concomitantly. An important priority is to integrate and coordinate environmental monitoring and research networks on regional, national and international levels. Assessment of nutrient losses from European catchment areas is an example. This facilitates study of entire ecosystems, which will be crucial in climate change impact studies.Nanoparticles (dimensions of 1–100 nm) and nanotechnology burst on the scene during the last decade. They do not constitute new forms of materials, as they exist in nature as biogenic matter or as byproducts of the weathering of rocks. Synthetic nanoparticles consist of inorganic substances, ceramics or carbon. Among their uses is the development of new miniaturized sensors and environmental monitoring devices. Clearly, the focus of nanoparticle research and the related publications is multi-dimensional: new preparation methods and applications; their sampling, measurement and characterization; migration and fate in air, aquatic systems (including drinking water), soils and sediments; as well as their routes of entry, absorption by and toxicity to organisms (including humans). Not surprisingly, these developments require new micro-analytical techniques and instrumentation.Elemental speciation/fractionation of airborne particulates, especially with a focus on workplace samples, has been a topic in JEM articles throughout its publication history. Newer techniques such as X-ray absorption fine structure (XFAS) and absorption near-edge structure (XANES) spectroscopy have been helpful. Speciation/fractionation studies have been extended to urban and landfill air, soils, plants, surface water and tissues (including human).Advances in polymerase chain reaction (PCR) technology have made available sensitive, accurate, rapid and quantitative identification of micro-organisms. The primary development is referred to as real-time PCR. A fluorescent reporter molecule is employed to monitor the progress of a PCR reaction and circumvents the need to use gel electrophoresis at the end-point of the PCR reaction. Typical applications are for the detection and characterization of toxigenic fungi (moulds) in house and building dust (airborne and on surfaces) and bacteria in air and in drinking and recreational water. By contrast, bioluminescence generated by bacteria, algae, or transfected cells, are useful in quantifying dioxin-like chemicals in sample extracts. Biosensors for determining toxic chemicals and measuring genotoxicity have also been developed.Until recently, a suite of persistent organic substances has been measured in conventional media (i.e., air, sediments, soil, and water and foods). The majority of these substances were organochlorines including polychlorinated biphenyls (PCBs), dioxins and pesticides. Contaminants which have received less attention are referred to as ‘emerging organic pollutants’ and include as major players brominated flame retardants [of which the polybrominated diphenylethers (PBDEs), polybrominated biphenyls (PBBs) and tetrabromobisphenol A constitute major classes], as well as perfluorooctane sulfonate (PFOS) and other per- and polyfluorinated alkyl substances. Additional emerging substances are: airborne allergenic proteins (e.g., in grain dust), enzymes (e.g., in industrial settings), and endotoxins (e.g., microbial lipopolysaccharides); and pharmaceuticals in aquatic environments such as common drugs and synthetic fragrances from household personal care products. Levels of the contaminants referred to above are extensively measured in tissues of sentinel organisms and receptors in the context of exposure and toxicity assessments. The tissue-residue approach is considered to reflect the target dose better than concentrations in the exposure media.This snapshot of the topics covered in the first 100 issues of JEM clearly illustrate that it has achieved its initial goal. The multiple exposure media, agents and receptors that are being studied and monitored, along with new developments in technology and modelling, all ensure that the field of environmental monitoring will continue to expand. No doubt, this will be spurred on by the increasing level of anthropogenic activity and the expected consequences of global climate change.

ISSN:1464-0325    

DOI:10.1039/b918031c

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

Cold fusion historyAt a press conference on March 23, 1989, organized by the University of Utah, electrochemists Dr Martin Fleischmann and Dr Stanley Pons announced a new room-temperature fusion process (Fig. 1). The University of Utah press release announced the discovery as “Sustained n-fusion at room temperature,” but within hours, the media—confused about another field called muon-catalyzed fusion—assigned the term “cold fusion” to the Fleischmann–Pons discoveryB. Stanley Pons and Martin Fleischmann (1989) (Image copyright University of Utah).For lack of a better understanding for many years following the discovery, the term “cold fusion” remained as a common reference to this work. The historic controversy will always be remembered by the term “cold fusion”; however, scientifically speaking, there are good reasons to leave the term “cold fusion” in the past. We will get to those later.The field was recognized in 1989 from the work of Fleischmann and Pons: electrolysis experiments using the heavy metal palladium and the hydrogen isotope deuterium. They had begun experimenting at the University of Utah in 1984.Fleischmann and Pons claimed an electrochemical method of generating nuclear energy, in a way that was previously unrecognized by nuclear physicists.Their suggestion of creating room-temperature deuterium–deuterium fusion triggered an uproar in the scientific community, particularly among physicists who understood nuclear fusion well.

ISSN:1464-0325    

DOI:10.1039/b915458m

出版商:RSC    

年代:2009

数据来源: RSC

摘要:

IntroductionRegardless of the cause of the enrichment of any given trace element in a natural water, it is sometimes desirable and often useful to be able to determine the “baseline” or “background” value for that parameter, for comparison, to be able to quantify and better understand any changes which may have taken place as the water evolves. In the case of many trace elements, this means being able to reliably undertake determinations at the part per trillion (ng/L) concentration level: accurate and precise measurements in this range requires limits of detection (LOD) at least a factor of ten lower. Because the concentrations of many trace metals in natural freshwaters are extremely low, both sensitive analytical methods combined with clean lab methods and procedures are of paramount importance.A precedent was established for measuring Pb at extremely low concentrations in ancient layers of polar ice by Claire Patterson who documented in excruciating detail the extraordinary precautions that are needed to measure Pb reliably at the ng/L (part per trillion) concentration range.1Subsequently, laboratories dedicated to studies of metals in polar ice have incorporated many of these pioneering discoveries and developments.2Using metal-free “clean lab” methods combined with ICP-SMS allows the simultaneous determination of a broad range of trace elements, as well as Pb isotope ratios (206Pb,207Pb,208Pb) to be measured reliably in ancient layers of polar ice.3–5The snow and ice which has accumulated since the Industrial Revolution, even in the most remote regions of the Arctic, is profoundly contaminated by such potentially toxic elements as Pb6and Sb7and therefore would provide a misleading starting point for any discussion of trace elements in “natural” freshwaters. In contrast, ancient layers of polar ice widely are considered to be the “cleanest water on earth”. To put trace element concentrations into perspective, it is helpful to use this material as a reference point, to provide a baseline against which other waters may be compared. In this commentary, we use ancient layers (ca.3.3 to 7.9 K years old) of ice from Devon Island, Nunavut, Canada, as a starting point for the discussion. A detailed description of the purpose built Ti corer, and mechanical decontamination of the outer layers of the ice core samples, is given elsewhere.8

ISSN:1464-0325    

DOI:10.1039/b917090c

出版商:RSC    

年代:2009

数据来源: RSC

ISSN:1464-0325    

DOI:10.1039/b915456f

出版商:RSC    

年代:2009

数据来源: RSC