摘要:

What future for dioxins? As the United Nations Environment Programme targets dioxins under its new POP agreement and the EPA issues a major reassessment of dioxin health risks JEM takes a look at current research on one of the most controversial environmental contaminants. Dioxins have long been a focus for scientiÆc public and regulatory concern. They Ærst hit the headlines in the 1960s through their use in some forms of the herbicide Agent Orange during the Vietnam War.1 They also achieved notoriety as a result of the accidental release of 2,3,7,8-TCDD the most toxic form of dioxin at Seveso in 1976 an incident that left a large area contaminated. More recent cases have focused on food contamination. In the southern United States in 1997 chickens eggs and catÆsh were found to be contaminated with dioxins as a result of contaminated ingredients in animal feed.And in a high proÆle case in Belgium last year dioxin Box 1 Assessing dioxin exposures PCDD/PCDF exhibit biological effects commonly associated with chlorinated organic chemicals. Dioxin exposures are associated with an increased risk of severe skin lesions altered liver function and lipid metabolism. They can cause general weakness associated with dramatic weight loss changes in activity of various liver enzymes and depression of the immune system. They are also suspected of causing abnormalities of the endocrine and nervous systems. TCDD has been designated carcinogenic by the US EPA and the International Agency for Research on Cancer.For the risk assessment of complex mixtures of PCDD/PCDF concentrations of dioxin and furan congeners are presented in terms of toxicity equivalents (TEQs) of TCDD the best studied compound within the dioxin family. In this approach the toxicity of the 17 individual 2,3,7,8-substituted congeners is ranked in relation to the toxicity of 2,3,7,8-TCDD based on evidence that there is a common receptor-mediated mechanism of action for these compounds (see main text). The toxic equivalency factors (TEFs) allow analytical data for individual PCDD/PCDF congeners to be converted into a single TEQ and thus a single order of magnitude estimate of toxicity. While the TEQ approach has some limitations it is widely accepted in the international scientiÆc community and is fundamental to the evaluation of dioxins which always exist in nature as complex mixtures.In Bilthoven in 1990 experts from the World Health Organisation established a tolerable daily intake (TDI) for dioxins of 10 pg TCDD per kg21 body weight (bw). This was subsequently re-evaluated in the light of new epidemiological evidence especially on neurotoxicological development and the endocrine system. In May 1998 WHO established a new TDI of 1± 4 pg kg21 (bw) day21 which is now the recognised international standard for human exposure. Adapted from Dioxins and their effects on human health Factsheet 225 World Health Organisation This journal is # The Royal Society of Chemistry 2000 contamination also linked to animal feed was found to have affected a variety of foodstuffs including eggs meat and milk products.The resulting scandal over how the incident was investigated led to the downfall of the Belgian government.2 Dioxin is the collective term for the class of compounds made up of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF). They are highly persistent organic pollutants (POPs) found in all environmental compartments and being fat soluble tend to accumulate in higher mammals and humans. Their resistance to degradation and semi-volatility means that they may be transported over long distances and because of their persistence dioxins released into the environment many years ago continue to contribute to current-day exposure. At their meeting in South Africa from 4th to 9th December 2000 parties to the United Nations Environment Programme (UNEP) POPs Convention Focus are expected to agree controls on dioxins and furans as part of a major new agreement to reduce and eventually eliminate toxic chemical releases.3 It includes a new Ænancial instrument the POPs Fund to help developing countries address the problems of dioxins and other POPs.This landmark agreement represents the Ærst stage towards global action against one of the most problematic environmental contaminants. New perspectives Dioxins and dioxin-like compounds that may have similar effects have been studied extensively over many years possibly more so than any other organic pollutant.The sheer volume of research Ændings is overwhelming. For instance a 1995 study of dioxin emissions from waste incineration ran to 500 pages,4 a recent analysis by EU the European Dioxin Inventory runs to 900 pages,5 and the EPA's latest review to be 89N J. Environ. Monit. 2000 2 Focus published shortly (see below) occupies a mammoth 2200 pages.6 Research has focused in particular on origins and sources environmental pathways and toxicity to human health (see Box 1). Recent scientiÆc advances have come in three main areas which together have provided important new insights on the dioxin issue. Firstly a series of national and international inventories have served to bettercharacteriseenvironmentalemissions and pathways.While showing large reductions in the overall volume of dioxin emissions these studies have also highlightedmajor changes in the signiÆcance of point versus non-point sources.Secondly the health risks of dioxins have been re-evaluated by agencies such as the World Health Organisation and the US Environmental Protection Agency (EPA) in the light of new evidence from epidemiological studies and laboratory investigations. These reviews suggest rather worryingly that dioxins are potentially more harmful than previously thought with signiÆcant health risks occurring close to currently observed background levels. Thirdly in addition to cancer and other health effects dioxins are nowsuspected of beingwithin the class of compounds known as endocrine disrupting chemicals (EDCs) responsible for affecting the hormone systems of humans and animals.In terms of riskassessment,thisaddsanewdimensionto an already complicated picture. A wealth of data Formost industrialised countries the sources and scale of dioxin releases to the environment are now fairly well characterised as a result of recent efforts to establish national inventories. These highlightÆvemainsources:combustionand incineration;metals smelting reÆning and processing; chemicalmanufacturing and processing; reservoir sources (such as old electrical equipment); and biological and photochemical sources.Of these combustion sources are by far themost signiÆcant.According toUNEP waste incineration and small-scale combustors (industrial and domestic boilers etc.) together account for around 60% of global releases to air.7 Environmentalists have singled out waste incineration for criticism claiming that the burning of plastics wastes containing chlorine contributes directly to airborne emissions.However a major evaluation undertaken in 1995 found no clear relationship between fuel chlorine 90N J. Environ. Monit. 2000 2 content and dioxin concentrations in Øue gases.4 The review concluded that the variabilityobservedindioxin emissionswas more likely to be explained by factors such as combustor design operating practices andmeasurement errors rather than by fuel chlorine input.While refuting these Ændings environmentalists have openedup asecond front,attacking waste incineration for concentrating dioxins in incinerator ashes.8 One consequence of the work on inventories has been to reveal wide discrepancies in national emissions and reduction efforts.In France for example Ægures from the Environment Ministry published earlier this year estimated an overall reduction in emissions of 65% since 1995.9 Stricter rules are set to cut incinerator emissions even further from 200 g in 1995 to an estimated 10 g by 2007. Greece on the other hand has been rather less successful in curbing emissions. While ofÆcial Ægures are unavailable Greenpeace claimed recently that the uncontrolled burning of waste either by individuals or on unregulated local landÆlls was releasing around 920 g of dioxins per year into the environment – more than the whole of France.9 In Norway estimated annual emissions have fallen by 96% over the last 15 years.9 According to the latest estimates from the Pollution Control Authority total emissions for 1999 were 22 g compared to 600 g in 1985.The Agency attributes much of this fall to the introduction of pollution control equipment at a single installation–a magnesium works near Olso. More stringent regulations the phasing out of chlorinated compounds and industrial closures also contributed. According to the EPA's latest estimates in the US dioxin releases to air water and land decreased by around 80% between 1987 and 1995 due primarily to reductions in air emissions from municipal and medical waste incinerators.6 Eventual reductions of greater than 95% are expected once existing regulations for municipal waste incinerators and medical waste incinerators take effect.Canada issued its Ærst national inventory in January 1999 which has subsequently been updated.10 Highlights included a 43% reduction in atmospheric releases compared to the base year of 1990 mainly as a result of the upgrading or closure of industrial facilities. Releases to water have been reduced by an estimated 99% through the implementation of new regulations in the paper and pulp industry. Another recent study from Canada highlighted the long-range transport of emissions.11 Analysing dioxin concentrations in Nunavut in the Canadian arctic scientists from the City University of New York estimated that between 74 and 85% of the measured pollution originated in the United States and a further 4±9% from even further away in Mexico.Only around 8±21% was contributed by Canadian sources. A changing picture These and other emission inventories show that the distribution of releases is changing fundamentally. As controls on point sources such as waste incineration and the metals industry take effect so other sources account for a greater proportion of overall emissions. In the French study for example dioxins from sources other than waste incineration and metallurgical facilities were estimated to account for around 30% of total emissions.Household wood burning industrial boilers and the illicit burning of PVC cables were highlighted as particularly signiÆcant.9 With emissions from waste incineration declining as a result of new technology and legislation data for other sources needs to be improved. For example only limited information is available for the iron and steel sector in some countries including Canada and the US. Emissions to water tend to be characterised only in terms of wastewaters from the pulp and paper industries ignoring other potential routes such as sewage sludge. Reviewing the current situation in the reporting of dioxin data UNEP noted recently that the number of national emission inventories is still limited with coverage in fewer than 20 countries.7 Furthermore current inventories focus almost exclusively on emissions to air and largely ignore emissions to water and land a point also emphasised in the EU's latest inventory of national sources.12,13 The EU report stresses the need to Ænd a balance between sources with a high potential emission (such as MSW incineration and pesticide production) and sources that are important in terms of environmental impact or exposure (such as pesticide use and sludge disposal).Reservoir sources are also potentially signiÆcant such as the ``old'' chemicals{ contained in {The main chemicals concerned are polychlorinated biphenyls used in transformers and capacitors 2,4,5-trichlorophenoxy acetic acid (2,4,5-T) and pentachlorophenol (PCP) used for wood treatment.transformers and capacitors together with landÆlls contaminated soils and sediments. Other shortcomings in data collection procedures also need to be overcome. At present for example there are no harmonised methods for generating and evaluating data for national dioxin inventories and coverage varies from country to country.7 Some countries provide estimates in terms of ranges whereas others use mean or median values to calculate annual emissions for a given source. Greater harmonisation of protocols for sampling and analysing stack emission water and soils is needed. Dioxins reassessed EPA is due to publish a comprehensive scientiÆc reassessment of dioxin exposure and human health effects by the end of the year.6 Begun in 1991 the EPA exercise represents probably the most thorough investigation ever into the environmental and health risks of a speciÆc pollutant.Drafts of the health effects and exposure documents were released in 1994 and reviewed by the EPA's Science Advisory Board (SAB) the following year. While responding favourably to most of the reassessment the SAB recommended that two chapters on dose±response modelling and risk characterisation be amended and that an additional document on toxic equivalency factors (TEFs) be developed. These three revised documents were issued for consultation in June 2000 and will be incorporated into the Ænal reassessment. EPA is also expected to publish a new dioxins strategy in response to the Ændings of the reassessment exercise.The review Ænds that the weight of evidence from epidemiological studies laboratory animals and ancillary experimental data suggests that exposure to dioxins and related Box 2 Measuring elimination The principle of Level of QuantiÆcation has been suggested as a baseline to assist in establishing a virtual elimination target. The Level of QuantiÆcation is deÆned as the lowest concentration that can be accurately measured using sensitive but routine sampling and analytical methods. Any measurement below the LoQ may not be reliably quantiÆable. LoQ is deÆned as LoQ~10s where s is estimated as s the standard deviation of replicate measurements of an analyte at a concentration near the detection limit.For a measurement at the LoQ the uncertainty is °30% (10s°3s) at the 99% conÆdence level. The 10s is to ensure that a measurement greater than this value will certainly be greater than 3s the level of detection. A region between 3s and 10s represents an area of less-certain quantiÆcation and a level above 10s is in the region of quantiÆcation. Adapted from ``Level of QuantiÆcation Determination PCDD/PCDF and Hexachlorobenzene'' Environmental Technology Centre Environment Canada 1999 compounds may result in a broad spectrum of health effects. In particular recent research has highlighted signiÆcant biological effects for TCDD in experimental systems. SpeciÆc data for other TCDD-like congeners and for human populations is largely lacking however.The report notes that a series of common biological steps are known to be necessary for most if not all of the observed effects of dioxin and related compounds in vertebrates including humans. These steps include the binding of dioxin-like compounds to a cellular protein called the ``Ah receptor'' as a precursor to biochemical cellular and tissue-level changes in normal biological processes. This binding is not sufÆcient in itself however and exposure to chemicals with a similar structure to TCDD will result in similar effects. The report concludes therefore that biological responses are related to cumulative exposures to all dioxin-like chemicals rather than to exposure to any single dioxin-like compound.ConÆrming that the major route of human exposure is through ingestion of foods the report estimates that TDI's have decreased signiÆcantly since the 1970s and that as of the mid-1990s adult TDIs for dioxins and dioxin-like PCBs averaged 70 pg TEQ day21. Average background exposure (exposure not readily identiÆable with point sources) led to body burdens in the late 1980s in the range 30±80 pg TEQ g21 lipid with a mid-point of approximately 55 pg TEQ g21 lipid. The average tissue level appears to be declining and the best estimate of current (late 1990s) average body burden for the US population is 25 pg TEQ g21 lipid. One of the report's most important Ændings is on how these general exposures relate to human health.``Given the assumption that TEQ intake values represent a valid comparison with TCDD exposure'' EPA says ``some of Focus these adverse impacts may be occurring at or within one order of magnitude of average background TEQ intake or body burden levels. As body burdens increase within and above this range the probability of occurrence as well as the spectrum of human noncancer response most likely increases''. As a result the ``margin of exposure between body burdens associated with background levels of exposure and levels where effects detectable in humans in terms of body burden TEQs is considerably smaller than previously estimated and in some cases may be 1 or even less''. Overall the report concludes that while dioxins have the potential to produce a spectrum of health effects there is currently no clear indication of increased disease in the general population attributable to dioxin-like compounds.This lack of evidence is symptomatic of the shortcomings of current scientiÆc data and tools rather than conclusive proof of no exposure effects. Factors such as the apparently low margin-of-exposure for non-cancer effects and the potential for signiÆcant cancer risks through incremental exposures suggest a need for further research into the impacts of these chemicals at or near current background levels. Towards zero Regulatory authorities in the US Canada and the EU as well as the UNEP POP Convention have set targets of virtual elimination of dioxins (and other toxic substances) from the environment.As environmental concentrations of these compounds become ever smaller this prompts the question of what actually constitutes ``elimination''. How should elimination be deÆned? How can such a target be measured? And how will we know when it has been achieved? The concept of Level of QuantiÆcation 91N J. Environ. Monit. 2000 2 Focus (LoQ) can be used as a baseline to assist in setting a virtual elimination target (see Box 2). LoQ is determined by assessing the variability (standard deviation) of repeated measurements of analytes at a concentration near the detection limit. The approach is well deÆned in environmental analysis but has only recently been applied to dioxins because of the lack of high quality low level datasets on emission sources.One analysis estimated the LoQ for PCDD/ PCDF to be 32 pg m23 TEQ (based on existing data) and 16 pg m23 TEQ (based on measurements in spiked blank trains and in Øy ashes).14 Another recent analytical advance has been the development of sampling protocols for the mono- through triisomers. 15 Typically concentrations of PCDDs/PCDFs are reported only in terms of the tetra- through octa-CDD/ CDF isomers. This is because the toxic isomers of interest are subsets of the tetra- through octa-isomers and hence commercial tests using the isotope dilution technique are only available for these isomers. However the monothrough tri-CDD/CDF isomers are important for understanding formation mechanisms and source±receptor relationships.New tests for these lower level isomers have recently been reported. Charting paths In terms of future research environmental agencies continue to place a high priority on improving our understanding of environmental pathways and exposure routes. EPA's reassessment hypothesises that the primary mechanism by which dioxinlike compounds enter ecological food chains and human diet is via atmospheric deposition.6 At present it is unclear whether this deposition represents primarily current contributions of dioxin and related compounds from all media 92N J. Environ. Monit. 2000 2 or is the result of past emissions that persist and recycle in the environment.Understanding the relationship between these two scenarios will be particularly important in assessing the relative contributions from individual point sources and the effectiveness of current or future control strategies. In the light of earlier incidents animal feedstuffs are also a major concern. Both the EPA and the EU are currently investigating the potential public health risks from animal feed. Other areas being investigated in the US include a national milk sampling network to measure the concentrations of dioxins and other POPs in milk and a national air monitoring network to periodically measure dioxins in ambient air.16 Our understanding of dioxins has come a long way in the nine years since EPA started its scientiÆc reassessment.Despite the plethora of inventories reviews and studies there is still much that we do not know however and dioxins seem set to be a feature of the research landscape for some time to come. At 2000z pages EPA's latest offering might look like the deÆnitive report on the subject but it will surely not be the last word. References 1 Dioxins and their effects on human health Factsheet 225 World Health Organisation June 1999. See www.who.int/inf-fs/en/fact225.html 2 J. Environ. Monit. 1999 1 63N. 3 For background documents on the POP Convention and latest news on the negotiations see www.chem.unep.ch/ pops/ 4 Relationship Between Chlorine inWaste Streams and Dioxin Emissions From Combustors ASME Research Committee on Industrial andMunicipalWastes American Society for Mechanical Engineers New York 1995.Available at www.ping.be/ƒ ping5859/Eng/ ChlorineASME.html 5 The European Dioxin Inventory DG Environment European Commission 1997. See http://europa.eu.int/comm/ environment/dioxin/download.htm 6 Exposure and Human Health Reassessment of 2,3,7,8- Tetrachlorodibenzo-p-dioxin (TCDD) and Related Compounds Environmental Protection Agency 2000 forthcoming. Drafts of the full report are available at www.epa.gov/ncea/pdfs/dioxin/ dioxreass.htm 7 Dioxin and Furan Inventories National and Regional Emissions of PCDD/PCDF UNEP Chemical Programme May 1999. 8 J. Environ. Monit.2000 2 12N. See also ``Greenpeace attacks PVC-dioxin study'' in ENDS Daily 22nd April 1997 www.ends.co.uk 9 J. Environ. Monit. 2000 5 79N. 10 Dioxins and Furans and Hexachlorobenzene Inventory of releases (second edition) Environment Canada September 2000. 11 Long-range Air Transport of Dioxin from North American Sources to Ecologically Vulnerable Receptors in Nunavut Arctic Canada B. Commoner et al. Center for the Biology of Natural Systems City University of New York October 2000. 12 Compilation of EU Dioxin Exposure and Health Data Summary Report DG Environment European Commission October 1999. Available at http://europa. eu.int/comm/environment/dioxin/ download.htm 13 Releases of Dioxins and Furans to Land and Water in Europe DG Environment European Commission 1999. Available at http://europa.eu.int/comm/ environment/dioxin/download.htm 14 Level of QuantiÆcation Determination PCDD/PCDF and Hexachlorobenzene Analysis & Air Quality Division Environmental Technology Centre Environment Canada 1999. 15 Extension of US EPA methods 0023A/ 8290 to include C12-labelled mono- diand tri-chlorinated dibenzo-p-dioxin and dibenzofuran standards B.K. Gullett J.V Ryan and D.Tabor EPA. 16 For details of current EPA research see www.epa.gov/ncea/projects.htm and for the latest EU research Ændings see http:// europa.eu.int/comm/environment/ dioxin/download.htm. Mike Sharpe

ISSN:0960-7919    

DOI:10.1039/b008834j

出版商:RSC    

年代:2000

数据来源: RSC

摘要:

Legislation Canada and US Ænalise ozone agreement The long-running talks between Canada and the United States on reductions of transboundary ozone pollution have entered their Ænal phase with the publication of a draft agreement. The text in the form of an Ozone Annex to the Canada±US Air Quality Agreement lays the foundations for signiÆcant reductions in smog-causing pollutants on both sides of the border. Under the draft Annex the US will reduce NOx emissions by 35% by 2007. This represents a 70% reduction in US emissions from power plants and major industrial sources during the summer months when smog creates the greatest health risk. Transboundary smog accounts for 30±70% of air pollution along the eastern seaboard. In Canada the Ænal draft puts an annual cap of 44 kilotonnes of NOx emissions from fossil fuel power plants a 50% reduction from present levels.Canada will also revise emission standards for cars and light duty trucks. Progress in implementing the new agreement will be reviewed in 2004 and in the meantime both countries have agreed to look at further options to reduce emissions from signiÆcant sources such as transportation manufacturing and electricity. Environment Canada ``US±Canada Ozone Annex Negotiations ± Negotiators' Joint Statement'' www.ec.gc.ca/minister/ speeches/001013_s_e.htm Major EU legislation Ænalised A series of new environmental directives have been Ænalised by the EU after completing all legislative hurdles.These include the controversial Water Framework Directive one of the most This journal is # The Royal Society of Chemistry 2000 complex pieces of legislation to have been negotiated at EU level (see separate item below). The Marine Pollution Directive will set a framework for co-operation between EU member states and accession countries in the event of accidental pollution incidents at sea. It includes provision for a seven year e7 m action programme to help maintain mutual assistance networks and to develop joint databases. Agreement on a revision of the EU's waste incineration directive has also been formally announced. The new directive covers both hazardous and non-hazardous waste and for the Ærst time sets limits on the co-incineration of waste for example in cement kilns.Other legislation to complete the EU's protracted negotiation process are a directive on end-of-life vehicles (ELVs) and port waste facilities for ships. EU tackles new water law The full implications of the new EU Water Framework Directive are becoming apparent following the presentation of proposals by the European Commission to move beyond an existing list of chemicals identiÆed for eventual phase out. The new directive requires member states to adopt strict controls to progressively reduce emissions of priority substances 32 of which have already been identiÆed by the European Commission. Last minute changes to the directive now also require a subsidiary list of priority hazardous substances (PHS) to be selected from the Ærst list which are to be phased out within 20 years.In a report issued in September the European Parliament's Environment Committee said that the priority list needed to be extended to include a wider range of substances. The initial list was News drawn up in response to requirements in the new directive to reduce emissions posing a ``signiÆcant risk to or via the aquatic environment''. The late addition of the PHS provision makes the initial list redundant the Committee says. It proposes adding seven substances decylphenol dicofol hexamethyldisiloxane hexachlorocyclopentadiene methoxychlor p-tert-butyltoluene and tetrabromobisphenol A (TBBA). In response to pressure from the Parliament and elsewhere for clariÆcation of the PHS approach the Commission has issued speciÆc proposals.These involve placing each of the 32 priority substances into one of Æve groups according to criteria such as whether they have been banned under international legislation or have undergone EU risk analysis. Group one containing the most dangerous chemicals will deÆnitely be added to the PHS list; those in group Æve will deÆnitely not. The remaining groups will take account of additional factors such as presence of endocrine-disrupting properties and the economic implications of phase out. European Commission ``Working Document on Priority Hazardous Substances'' http://europa.eu.int/comm/ environment/; European Parliament Environment Committee www.europarl.eu.int/dg2/envi/en/ default.htm US introduces consolidated regs The EPA has introduced the Ærst consolidated air pollution regulation as part of moves to streamline environmental management legislation.The innovative rule combines 16 existing federal air rules applying to synthetic organic chemical manufacturers signiÆcantly reducing monitoring 93N J. Environ. Monit. 2000 2 News record-keeping and reporting burdens for industry. The regulation is voluntary manufacturers can either continue as at present complying with 16 separate regulations or choose to comply with the new rule. Like the original regulations the consolidated rule continues to require stringent reductions in emissions of volatile organic compounds (VOCs) and air toxics.The full regulations are published in the Federal Register and are accessible online at www.epa.gov/ttn/oarpg/ramain.html New options needed for transport emissions Regulatory controls on fuel quality and vehicle emission standards will be of decreasing importance in the future in controlling air pollution according to the initial Ændings from a major EU research programme into road transport Environmental quality North American pollution controls take effect Pollution controls in North America are starting to work according to a scientiÆc report released by the North American Research Strategy For Tropospheric Ozone (NARSTO). The controls established over the last 30 years to reduce the amount of ground level ozone have demonstrated positive results especially in some large urban areas.While efforts to reduce ground level ozone have produced some notable successes much of the potential for real air quality improvement has been offset by expanding populations and human activity. Despite this the report emphasises that air quality would be considerably worse if the pollution controls were not in place. In addition NARSTO recognises that ozone science is much better understood than it was a decade ago. The report recommends that the scientiÆc and policy communities continue to work together in the areas of research monitoring and coordination to secure substantial improvements in North American air quality.NARSTO is a partnership of government utilities industry and academe in the United States Canada and Mexico which seeks to improve the 94N J. Environ. Monit. 2000 2 emissions. Launched in May the Auto/ Oil II programme follows on from Auto/ Oil I which is already set to yield substantial improvements in air quality by 2010. A legislative package on fuel quality and vehicle emission standards was agreed under the Auto/Oil I programme in 1998. Analysing the expected impacts of this the report predicts signiÆcant impacts for common pollutants such as benzene carbon monoxide nitrogen dioxide Æne particulates and ozone. Overall these should be cut by around 80% from 1995 to 2010.The net result according to the Commission will be ``a signiÆcant decoupling of conventional emissions from trafÆc/economic growth''. Problem areas remain however particularly in PM10 ozone and local exceedances of nitrogen dioxide standards. Potential measures include new EU-wide controls on PM10 atmospheric and related sciences used to support air quality management policies. The report is the Ærst comprehensive assessment of the status of ozone reduction efforts since a US National Research Council review in 1991. Environment Canada ``An Assessment Of Atmospheric Ozone Pollution A North American Perspective'' available at www.cgenv.com/Narsto Living with the greenhouse effect Grass and shrubs will replace alpine plants and lichens on mountain moors.Insect attacks on mountain birch forests will increase and thawing permafrost areas will be covered with landslides and rock debris. These are some of the potential consequences of the greenhouse effect according to researchers in Sweden. Based on investigations in the area around Tornetra» sk a mountainous area in northern Sweden during 1992±1998 scientists from the Swedish EPA claim that evidence of climate change is already apparent. For example a series of extremely early springs led to a sudden mass death of Diaspensia lapponica a slow-growing species hampered by together with more targeted measures on nitrogen dioxide. These might also address expected exceedances of benzene standards.While further EU-wide controls on fuels and vehicles are likely Auto/Oil II suggests that their relative importance will decrease as existing measures come on stream. As a result future air quality policy will need to look at non-road transport sources. Non-technical measures for policy-makers suggested by the report include promotion of alternative fuels Æscal instruments enhanced vehicle scrapping schemes and road pricing. European Commission ``Review of the Auto/Oil II Programme'' http:// europa.eu.int/eur-lex/en/com/pdf/2000/ com2000_0626en01.pdf; Auto/Oil II Programme //europa.eu.int/comm/environment/ autooil/index.htm increased nutrients supply. Other more fast-growing grass species were favoured. The greenhouse effect is expected to lead to temperature increases of 1±3.5 �C per century.The winter climate in northern latitudes is expected to becomemore varied with earlier springs and risk of weather setbacks. As temperatures rise nutrients (mainly nitrogen) increase and fertilise the ground.Mountain soils are usually nitrogen-poor so an increase in temperature can dramatically change conditions for plant life. How long the effect will last is uncertain. Some of the experiments showed a signiÆcant increase in nitrogen supply for a few years but after Æve years no effects remained. Apermanent increase of nutrientswould lead toan increase in grasses andsedges the researchers predict whereas slow-growing species would decline. Themost signiÆcant effectswillmost probably be above the tree line where conditions allow new species to become established.Species growing on and belowthe tree line will spread and become more vigorous while lichens and mosses will decline seriously affecting reindeer pastures. It is likely that forests currently protected by low winter temperatures will be ravaged by pest insects in a warmer climate. Researchers propose a new monitoring programme to focus on changes in climate vegetation and water run-off. Swedish EPA ``Mountain Ecosystems in a Changed Climate'' Report No 5085 www.internat.environ.se Indicators show mixed results for the Great Lakes The health of the Great Lakes is showing signs of improvement but some areas remain cause for concern according to the State of the Lakes Ecosystem Conference (SOLEC).SOLEC's recent biennial meeting in Hamilton Ontario brought together policy-makers industrialists academics and environmental groups to review the status of the Great Lakes Basin. It is the only forum where research and monitoring efforts from throughout the Basin are used to build an overall picture of Great Lakes health through simple scientiÆc indicators. Dozens of organisations and thousands of individuals routinely collect and analyse data and report on parts of the Great Lakes Basin ecosystem. SOLEC organises this data into an integrated and comprehensive package. Scientists have found that while contaminant levels in Æsh and wildlife continue to decline Æsh consumption advisories remain in effect on all the Great Lakes.Atmospheric deposition is now one of the most important sources of pollution for all the Lakes representing some 90% of the total load of some chemicals. Many of these come from sources outside the Great Lakes Basin and even outside North America. While the last SOLEC meeting in 1998 emphasised the development of core indicators to represent the state of major ecosystem components for the Great Lakes SOLEC 2000 focused on approximately 30 of the 18 proposed indicators. These cover not only issues such as excess nutrients toxic contaminants and habitat destruction but also less recognisable problems such as the Chemical hazards EU divided over phthalate leaching tests The prospect of regulations for phthalate plasticisers is again back on the agenda after an EU committee broadly supported a plan for migration-based leaching tests.introduction of non-native species and atmospheric deposition of toxic chemicals. Information gathered at SOLEC coupled with other environmental information will help measure progress towards the objectives of the Canada±US Great Lakes Water Quality Agreement (GLWQA). The agreement commits Canada and the United States to maintain the chemical physical and biological integrity of the Great Lakes ecosystem. Environment Canada SOLEC 2000 press release www.on.ec.gc.ca/press/ solce2000_e.html UK water quality could do better A crop of reports on water quality in the UK suggests that rivers are getting cleaner but that there is still roomfor improvement in terms of non-point sources.Figures fromthe latest annual riverwater quality survey plus earlier Ændings for Scotland and Northern Ireland show that 95% of UK rivers can now support Æsh. Since 1990 urban areas in northern England and the EnglishMidlands have shown the strongest improvement a result that theEnvironmentAgencyattributes toa combination of tighter regulation and the water companies' investment in better sewage treatment. The survey only covers chemical pollution the results of a more detailed survey of biological water quality are due early next year. A rather different picture of UK water quality emerges from another survey prepared by independent experts.Focusing on ``diffuse'' sources such as agriculture urbanisation and deposition of transport emissions the report concludes that nonpoint sources and their impacts are increasing both in absolute terms and relative to point sources. The costs for the UK water industry run into ``hundeds of millions of pounds'' through more sophisticated treatments for drinking water and wastewater. Key cost factors for drinking water treatment include the In a recent opinion the ScientiÆc Committee on Toxicity Ecotoxicity and the Environment endorsed plans by the EU's Joint Research Centre (JRC) to develop a validated method for testing phthalate migration into saliva for toys sucked by children.News impact of organic wastes faecal pathogens nitrogen phosphorous and chemicals. These together with oils and hydrocarbons also push up wastewater treatment costs. Other important issues according to the report include new pollution problems from the proliferation of small industrial estates and recreational activities and increases in levels of trace chemicals such as zinc from pharmaceuticals and other products. Environment Agency www.environmentagency. gov.uk; ``Diffuse Pollution Impacts'' Chartered Institution of Water and Environmental Management www.ciwem.org.uk Experts assess PaciÆc pollution Long-range transport of air pollutants such as smog precursors sulfur dioxide DDT mercury and radionuclides is a major issue in the North PaciÆc a recent report has concluded.Over 100 scientists from the US Russia China Japan Canada and South Korea met in Seattle in Julfor the First International Conference onTrans-PaciÆcTransportofAtmospheric Contaminants. The Conference aimed to identify research needs in addressing the long-range transport problem and to help establish a network of individuals and organisations across the region. The report of the meeting issued recently by EPA shows the participants achieved consensus in many areas. They also recognised important gaps and uncertainties in present knowledge and called for a co-operative PaciÆc Environmental Research Strategy to promote a common scientiÆc understanding of long-range transport.EPA OfÆce of International Activities ``Consensus Statement of the First International Conference on Trans-PaciÆc Transport of Atmospheric Contaminants'' available at www.epa.gov/oia The JRC is working with a number of other laboratories including the two centres in the Netherlands and the UK which Ærst proposed phthalate test methods last year [JEM 1999 1 111N]. Reviewing the JRC's proposal the committee noted that ``the validation 95N J. Environ. Monit. 2000 2 News protocol is to a great extent in accordance with the guidelines recommended by CSTEE''. While calling for a number of further improvements it concluded that ``these recommendations should not postpone the proposed validation programme of in-vitro methods for migration testing''.The move is likely to reopen sharp divisions within the EU over the regulation of phthalates which are used as softeners in children's toys and other products made of PVC. The European Commission initially resisted a ban on phthalates preferring instead a regulatory approach based on migration limits. In the absence of viable tests however and under pressure from several member states the Commission introduced an ``emergency'' ban at the end of last year [JEM 2000 2 8N]. This has been renewed several times since most recently in September. With member states increasingly divided on the issue no decision on the Commission's proposal for a permanent ban is expected until early next year.One group led by the UK and the Netherlands and apparently also Spain France and Italy favours a system of product labelling combined with maximum phthalate migration levels based on agreed test methods. But the EU's environmental ``hawks'' comprising Germany Sweden Denmark Finland and Austria say the labelling option is too weak and want the current ban extended. CSTEE ``Opinion on Phthalate Migration Test Method Validation'' available at www.europa.eu.int/comm/ food/fs/sc/sct/out68_en.html Public and occupational health Study demonstrates phthalate exposure For the Ærst time scientists in the US have conÆrmed the presence of metabolites of phthalates in humans. Researchers from the Centre for Disease Control and Prevention (CDC) of the National Center for Environmental Health analysed urine samples from nearly 300 adults aged 20±60 for seven 96N J.Environ. Monit. 2000 2 Scientists criticise EDC list A priority list of endocrine-disrupting chemicals (EDCs) has been heavily criticised by EU scientists because it could lead to some dangerous chemicals slipping through the regulatory net. The preliminary list of EDCs was requested by the European Commission earlier this year from consultants in the UK and the Netherlands as a basis for further evaluation and possible regulation. Reviewing the consultants' initial assessment the EU's ScientiÆc Committee on Toxicology Ecotoxicology and the Environment (CSTEE) found shortcomings in the methodology and selection criteria used to develop the list.CSTEE was especially critical of the ``total omission'' of selection criteria which take account of either the potency of the chemicals or dose±response data. These it said were imperative as a satisfactory starting point for further hazard and risk assessment. The consultants' approach to Æltering a longer list of candidate EDCs was also questioned by CSTEE. Over 200 substances were excluded from the list on the basis of their environmental persistence and industrial production volumes. Warning that this approach was ``simplistic'' and ``too restrictive'' the committee recommended that further consideration be given to how these data gaps could be Ælled and ``how these substances should be brought back into the prioritisation process''.CSTEE ``Opinion on Endocrine Disrupting Chemicals List'' http:// europa.eu.int/comm/food/fs/sc/sct/ out73_en.html metabolites associated with exposure to various phthalates chemicals used in plastics solvents detergents and many other products. Because phthalates are found throughout the environment measuring the chemicals after they have actually been processed in the body yields important information about actual human exposure levels. By looking at metabolites the scientists are looking at human exposures rather than simply Regulators close in on wood chemicals Norway has moved to outlaw the use of preservatives containing copper chrome and arsenic (CCA) on wood and timber products due to concerns over the environmental and health risks.Norway's Pollution Control Authority (SFT) says that the burning of CCA-impregnated timber is a major source of atmospheric releases of these chemicals which also persist in ash. If timber is landÆlled then leaching can be a problem requiring special controls. CCA-based treatment products came on to the market in the 1960s and are widely used to keep wood from rotting. However SFT points out that many wooden structures in Norway have stood for nearly one thousand years without CCA so it can hardly be considered an essential technical requirement. Meanwhile in Denmark the EPA has published a report which it claims to be the most comprehensive documentation to date on environmentally friendly techniques for protecting wood.These include reviving many traditional methods which have fallen into disuse such as ensuring that the tougher heartwood side of a plank faces outwards and ensuring timber is not exposed to moisture unnecessarily. SFT; www.sft.no; ``Documentation of Wood Protection by Design'' Danish EPA www.mst.dk measuring chemicals in the environment. However the level of exposure that causes illness is still unknown. Commenting on the results CDC Director Richard Jackson said ``This is important. For the Ærst time phthalate metabolites have been measured in human samples and we can see which phthalates show the highest level of exposure in people.This study is an example of how we should assess environmental exposures in the future.'' Kenneth Olden Director of NIEHS added that in gathering real exposure data the study offered a way forward in terms of ``the missing data we need for scientiÆcally sound conclusions regarding human environmental healthrisks''. Of the seven metabolites measured in the human samples four were found in more than 75% of the samples analysed. The phthalate levels measured ranged from below detection to as high as 15 ppm. Those found in the highest quantities were diethyl phthalate (DEP) dibutyl phthalate (DBP) and benzylbutyl phthalate (BzBP) which are found in a wide variety of products including detergents lubricating oils solvents cosmetics and wood Ænishes.Di-(2- ethylhexyl) phthalate (DEHP) is used in much higher volumes as a plasticiser in PVC products and packaging but did not show as high a level of metabolite. The sources of exposure are still being investigated. NIEHS has also made available for public comment reports on the possible human reproductive effects of phthalates produced by its expert panel details of which were released earlier this year [JEM 2000 2 78N]. National Centre for Environmental Health ``Levels of Seven Urinary Phthalate Metabolites in a Human Reference Population'' in Environmental Health Perspectives October 2000; Center for the Evaluation of Risks to Human Reproduction http:// cerhr.niehs.nih.gov Air pollution linked to children's health Common air pollutants slow children's lung development over time according to a research team led by the University of Southern California.The 10 year research programme is one of the most comprehensive studies ever undertaken Research activities Arctic nations to assess climate change Scientists are launching an urgent assessment of the potential impacts of climate change on the arctic environment following a request from countries within the region. Meeting in Alaska in October of the long-term effects of smog on children's health. Writing in the October issue of the American Journal of Respiratory and Critical Care Medicine the researchers report that growth of lung function in children exposed to polluted air tends to lag behind those who grow up breathing cleaner air.Children with decreased lung function may be more susceptible to respiratory disease and may be more likely to have chronic respiratory problems as adults. On average the lung function growth rate of children in the most polluted community was about 10% lower compared to children in the least polluted community and was most evident in the 10±14 age range. Commenting on the results study leader John Peters of USC said ``This is the best evidence yet of a chronic effect of air pollution in children''. Noting that the association was strongest for those children who spend more time outdoors his colleague W. James Gauderman added that the results were ``consistent with what we would expect from a detrimental effect of outdoor air pollution''.A further Ænding was that the observed effects appear to be associated with nitrogen dioxide and particulate matter rather than with ozone. Another recent research report from the Health Effects Institute conÆrms earlier Ændings that ambient particulate pollution poses an increased mortality risk for people with certain pre-existing cardiac or respiratory conditions [JEM 2000 2 71N]. University of Southern California ``Children's Health Study'' www.usc.edu/ medicine/scehsc; HEI Research Report 97 Health Effects Institute available at www.healtheffects.org Advances in EDC testing Two major contributions on endocrine disrupting chemicals (EDCs) by US membersof the Arctic Council called for the assessment as a priority action inthe light of mounting concern over climate change.The Council was created in 1996 to represent the concerns of the arctic region with the chairmanship this year passing from the US to Finland. At its News agencies should help strengthen the link between science and the regulatory decision process. Looking at reproductive and developmental toxicity EPA and the NIEHS have published a scientiÆc peer review of low-dose effects and dose±response relationships for EDCs. EPA has also released the annual report of its Endocrine Disruptor Screening Program which is undertaking systematic screening of chemicals to investigate potential hormonal effects.In the peer review a panel examined data from 38 studies (excluding dioxin and dioxin-like compounds) on low-dose effects in laboratory animals that could be relevant for human health assessments. The nature of the dose± response curve for EDCs in the low dose region was also investigated. The panel concluded that low-dose effects have been clearly demonstrated for estradiol and some estrogenic compounds such as nonylphenol and the phytoestrogen genistein. Results for other compounds are inconclusive however partly due to differences in study design. Areas for additional research are identiÆed that would clarify uncertainties about low-dose effects and better characterise observed effects.These include the use of new technologies such as cDNA microarrays and proteomics and additional or more sensitive response biomarkers for evaluating low-dose effects. Special consideration should be given to study design the panel says and to biological and environmental factors that might affect experimental outcomes. In selecting animal models for study the use of species and strains that are highly responsive to EDCs is advocated. Finally in terms of the dose±response relationship the panel says that this will depend on numerous factors including the endpoint being evaluated the chemical being studied the dosing regime and the biological characteristics of the target tissue. latest meeting the Council agreed to develop projects under its newly established action plan to eliminate arctic pollution.It also called on the UN Environment Programme to initiate a global environmental impact assessment of mercury emissions. 97N J. Environ. Monit. 2000 2 News Arctic Council http://arcticcouncil. usgs.gov European networks reviewed Big changes are likely in European environmental science networks following a review by the European Environment Agency. The overhaul of the network of European Topic Centres (ETCs) aims to improve their efÆciency Publications Watersheds at risk As ecological risk assessment evolves it is moving beyond a focus on single species toward addressing multiple species and their interactions and from assessing effects of simple chemical toxicity to the cumulative impacts of interacting chemical physical and biological stresses.This report presents the proceedings of a workshop on an assessment framework for characterising risks at the watershed scale. Thirty-Æve experts from various disciplines considered how such aspects should account for numerous stresses interconnected pathways and multiple end-points. ``Workshop Report on Characterising Ecological Risk at the Watershed Scale'' National Center for Environmental Assessment www.epa.gov.ncea/ ecorisk.htm Guidelines for ecological indicators This document describes a process for the technical evaluation of ecological indicators. It was developed by members of the EPA's OfÆce of Research and Development (ORD) primarily to assist 98N J.Environ. Monit. 2000 2 and effectiveness and provide a more policy-relevant focus. ETCs are collaborative cross-country partnerships of scientiÆc experts who provide support for the EEA on speciÆc projects. The number of networks is to be reduced from eight to Æve with the new centres having broader remits. This will include for the Ærst time an explicit focus on material Øows biodiversity and climate change. The new system should the indicator component of ORD's Environmental Monitoring and Assessment Program (EMAP). The guidelines are intended to direct ORD scientists and others during the course of indicator development and to provide a consistent framework for indicator review.Evaluation Guidelines for Ecological Indicators'' EPA/620/R-99/005 available at www.epa.gov/emap/html/ pubs/docs/resdocs/ecoind.htm Information on pesticide use EPA has issued a paper on the role of use-related information in pesticide risk assessment and risk management. The paper describes in terms accessible to the layman how the data is obtained and how the Agency employs these data. It includes sections on the role of use-related information in human health risk assessments and ecological assessments and in risk management decisions. Future steps for improving pesticide data and for strengthening the Agency's analytical approaches are also discussed. The paper is part of EPA's efforts for earlier participation by stakeholders in decision-making on the use of pesticides. enable much better support for the EU legislative processes in areas such as the new water framework directive (see separate item this issue). Bids for the new centres were recently received and the successful applicants will be announced early next year. European Environment Agency www.eea.eu.int ``The Role Of Use-Related Information In Pesticide Risk Assessment And Risk Management'' EPA OfÆce of Pesticide Programs August 2000 www.epa.gov/ pesticides Pesticide risk assessments EPA's OfÆce of Pesticide Programs has issued Standard Operating Procedures for incorporating screening-level estimates of drinking water exposure into health risk assessments. The document provides the detailed procedures for implementing OPP's overall policy as articulated in ``Estimating the Drinking Water Component of a Dietary Exposure Assessment'' issued in November 1999. It contains terms deÆnitions and calculations examples of speciÆc language that may be used in presenting results and an appendix containing example scenarios and calculations. ``StandardOperating Procedure (SOP) For Incorporating Screening-Level EstimatesOfDrinkingWater Exposure Into Aggregate RiskAssessments'' EPA OfÆce of Pesticide Programs September 2000 www.epa.gov/pesticides

ISSN:0960-7919    

DOI:10.1039/b008835h

出版商:RSC    

年代:2000

数据来源: RSC

摘要:

Monitoring of platinum in the environment Since the introduction of catalytic converters for the control of vehicle emission a controversial discussion has begun on platinum emission and its eventual consequences for the environment. This brief overview covers the main aspects of anthropogenic emission of platinum and its bioavailability. Modern analytical methods for Pt determination in different environmental samples are also presented. Introduction Discussion concerning the exposure of the environment to toxic metals such as lead cadmium or mercury from several sources have been carried out for a long time. Platinum because of its inertness was considered harmless for a long time. It belongs to the group of elements that are the least abundant in the Earth's crust with a mean concentration1 of 5 mg kg21.Due to its speciÆc physical and chemical properties platinum Ænds application in various technological processes (chemical electrical petrochemical) and in jewellery. Between 1986 and 1995 the industrial demand for Pt increased by 66%. In 1994 42% of platinum production was used in catalytic converters 39% in the jewellery industry 4% in chemistry 4% in the glass industry 5% in electronics and 6% in the oil industry and others.2 So far more than 50% of the platinum produced has been used in environmentally relevant spheres. Platinum determined3 in snow samples from Greenland Antarctic and the Alps (in order to assess the past natural background) was in the concentration range 0.008±2.7 pg g21.The lowest value was measured in ancient ice from Greenland dating back 7000 years. Platinum has been included in the investigations into potential toxic substrates to human health since the widespread introduction of catalytic converters for automobile exhaust gases. These catalysts which contain platinum This Chemistry of Society Royal The journal This journal is is # The Royal Society of Chemistry 2000 2000 along with palladium and rhodium remove 90% of the carbon monoxide unburned hydrocarbons and nitrogen oxide present three major gaseous environmental pollutants. Catalytic converters used in cars or in industrial processes are the most important source of the environmental impact of platinum.While the beneÆts from their use are obvious recent studies have shown increasing Pt content in different environmental samples. Although emission in the form of airborne particulate material or dust from the abrasion and deterioration of the catalyst is considerable lower than for example Pb emission from leaded fuels it is nevertheless relevant with respect to the low natural background. Platinum concentrations in road sediments collected in Sweden4 increased from 3.0 ng g21 in 1984 to 8.9 ng g21 in 1991. Measurements along roads in the USA5 and Germany6 also showed elevated platinum concentrations in dust samples. In contrast to the large body of information concerning the toxicity of mercury or lead and their environmental effects the corresponding information on platinum has not yet been fully obtained.Recently hospital efØuents have been considered as a source for Pt emission into waste water and sewage sludge.7,8 These efØuents contain platinum from excreted antineoplastic drugs which have been widely used in cancer chemotherapy for some years. Other possible Pt sources in the environment such as metallurgical plants fertilisers or pesticides are also being determined.9 Pt emission from trafÆc A converter designed for an average family car contains about 1.8 g of platinum group metals.10 The amount of platinum emitted from catalytic converters has up to now been the subject of controversial discussion. In engine test stand experiments11 it was Viewpoint found that under conditions simulating city trafÆc Pt emission is in the range 2± 78 ng km21.The particles emitted (metal in a highly dispersed form together with aluminium oxide) were mainly greater than 10 mm. The highest platinum concentrations were measured in this fraction. However recent calculations,9 under more realistic street conditions showed that platinum emission attributed to the trafÆc reaches 0.8 mg km21. The most likely reason for the difference between this and the test stand experiments is the relation between the emission rate and the speed of an individual car. Moreover laboratory experiments are normally performed under excellent technical conditions with respect to the engine employed.Taking into consideration the results from the test stand experiments and also the amount of platinum determined in the soil and grass samples a Pt emission rate of 0.5±0.8 mg Pt km21 should serve as a realistic basis for Øux calculations.9 The Pt species emitted from the catalytic converters are attached to particles of alumina mainly in the form of nanocrystal platinum. However Xray photoelectron spectroscopy studies12 showed small amounts of ionic forms on the surface resembling that of a pure metal exposed to a stream of oxygen. Such oxidic species of platinum could easily be mobilised by complexation.13,14 Experiments using platinum chloride complexes have already demonstrated the availability of water-soluble Pt compounds to plants.15 Several percent of the total platinum content in airborne dust was determined as being species that are soluble in 0.07 mol dm23 HCl.16 Wei and Morrison4 concluded from sequential extraction of road sediments that transformation of Pt from inorganic to organic bound species occurs especially on organic-rich materials.SigniÆcant concentrations of trafÆcemitted platinum have been detected in a variety of environmental samples (Table 1). Several studies have shown a 99N 99N J. Environ. Monit. 2000 J. Environ. Monit. 2000 2 Viewpoint Table 1 Platinum content in different environmental samples Place of sampling (data) Sample Dortmund Germany (1992) Munich Germany (1993±1994) Munich Germany (1994) Frankfurt Germany (1995) Gent Belgium (1995) Hanau Germany (1995) Richmond UK (1996) Ken UK (1996) Siegen Germany (1996) Karlsruhe Germany (1997) Airborne dust Airborne dust in local buses Tunnel dust Road dust Grass near motorway Soil near motorway Road dust Soil from botanic garden Grass near motorway Road dust apg mg21 of air.decrease of platinum concentration with greater distances from the motorway.4,23 Almost all the platinum was deposited within a distance of 2±5 m from the road and at w20 m no platinum pollution could be detected. Only the uppermost soil layer down to 20 cm contained traceable concentrations. Helmers and Klu»mmerer calculated24 that 2100 kg of platinum will be emitted in Germany by cars with Pt/Rh catalytic converters up to the year 2018.In these calculations it was taken into consideration that since the early 1990's new cars have been equipped with advanced types of converters mainly based on palladium. Platinum deposited on the roads can be washed out during rain and transported to urban rivers by means of stormwater outfalls. This metal has been found to be toxic to aquatic life.25,26 In Bavarian rivers Pt concentrations of between 0.05 and 8.5 ng dm23 were measured and this metal is generally enriched in sediments and aquatic plants.20 Platinum concentrations in the range 0.04±12.4 mg g±1 were determined27 in the freshwater isopod Asellus aquaticus which lives on sediments. The uptake mechanism depends on the form of platinum present in the environment; Pt(II) was accumulated at a lower rate than Pt(IV).Pt emission from industrial processes Very little is known about the industrial impact of platinum on the environment. The metallurgical industries especially copper±nickel processing plants seem to be the most important contributor to its emission. Moreover the loss of Pt from the catalyst gauze used in the chemical industry should be considered. For example the loss of platinum from Pt/ Rh alloy gauze used for oxidation of 100N 100N J. Environ. J. Environ. Monit. Monit. 2000 2000 2 Concentration range/ng g21 0.6±130 3.0±33a 170 51 1.4±1.7 23±112 0.42±29.8 0.8±1.6 17.0±95.6 112±169 ammonia in the manufacture of nitric acid is 0.061 g of Pt per tonne of HNO3 produced.28 In sediment samples collected from Kelly Lake in Canada (situated about 4 km from the high stack of a nickel smelter) abnormally high Pt concentrations (1000±2800 mg g21) were detected.29 These concentrations were elevated by a factor of 100±1000 when compared to the geogenic background values.The dust taken directly from the stack's interior (as the presumed source) contained 11 000 mg g21 of platinum. High concentrations of platinum (max. 466 mg g21) have also been detected in the upper layer of soil in the vicinity of major metallurgical plants in the Monchegorsk area on the Kola Peninsula Russia.30 Even at a distance of 2.5 km from the plants a mean value of 50 mg g21 was found.The study of anthropogenic platinum emission (also Pd Rh and Au) into snow during one winter season (1995/96) was reported by Gregurek et al.31 The samples were collected from the surroundings of the industrial plants Zapoljarnyj Nikel and Monchegorsk on the Kola Peninsula. Values of up to 650 ng dm23 were found and the concentrations increased with the proximity to the industrial sources. The prevailing wind direction plays an important role in the metal distribution. Platinum group element contents in particulate matter deposited in snow reØect their distribution in primary ores. This fact can be used as a simple method for Ængerprinting and tracing of different industrial sources.Generally elevated platinum values due to automotive catalysts are restricted to a narrow range along roadside soil whereas those due to emission from processing plants display a large-area dispersion and are preferentially transported by the wind.21 Both sources Reference 16 17 18 19 20 21 22 22 20 6 have different interelement ratios especially the Pt :Rh ratio. The emission of platinum during the production processes either into the atmosphere or into waste water was calculated as being up to 98 kg year21 for Germany alone.24 Pollution from medical application Platinum complexes based on cisdichlorodiamineplatinum( II) (cisplatin) have been widely used in the therapy of some cancer forms.A new generation of Ptbased drugs carboplatin and lobaplatin show increased activity together with reduced toxicity.32 However only a small part of these anti-cancer drugs are absorbed by the body. After administration only 10±20% of the carboplatin becomes bound to protein 50±75% is excreted in the urine in the Ærst 24 h and for cisplatin 31±85% of the dose is excreted during the Ærst 51 days.7 A study by Schierl et al.33 showed that the platinum concentration in the urine can be higher than a factor of 40 as compared with the normal level 8 years after a patient's last cisplatin therapy. As neither hospital sewage nor urine and excretions from patients treated with Ptbased drugs are specially treated platinum is emitted in hospital sewage.Usually the efØuents from hospitals are simply treated together with household sewage in municipal sewage treatment plants. From the efØuent of Freiburg University Hospital one of the largest hospitals in Germany a platinum concentration of 1±2 ng dm23 in the communal sewage is the result.3 The Pt levels detected in the sewage of various hospitals and hospital departments in Germany were approximately 110± 176 ng dm23 during the day and 38 ng dm23 at night. A total Pt emission for all German hospitals of Fig. 1 Platinum and palladium content in sewage sludge ashes from the municipal puriÆcation plant of Stuttgart. 28.6 kg year21 was calculated on the basis of the annual amounts of Pt drugs used in the treatment of patients.7 Comparable values were observed on a European scale.8 Compared with platinum emissions from other sources the efØuents of hospitals are not the most signiÆcant ones but they should not be disregarded.In archived samples of sewage sludge ashed from the puriÆcation plant of Stuttgart a signiÆcant increase of Pt has been observed (Fig. 1).18 This is consistent with the data of Scha» fer et al.6 who observed that from 1993 to 1997 the platinum concentration in sewage sludge incineration ashes from the municipal sewage plant at Karlsruhe doubled from 64 to 138 mg kg21. The Pt :Rh ratio of about 20 in the sludge differed markedly from the ratio of 6 typically found in environmental samples that are mainly inØuenced by trafÆc emission.This indicates that urban sludges not only receive and concentrate emissions from trafÆc but also from hospital and medical efØuents or industrial sources.6,34 For example extraordinarily high concentrations of Pt (1.1 mg kg21) were found in the sludges of the city of Pforzheim; these levels were caused by the concentration of jewellery producers in the city.18 Bioavailability of Pt species With regard to the increase of platinum emissions and allergic and cytotoxic potential of its compounds,35,36 several research groups mainly located in Europe are dealing with the mobility and bioavailability of this metal in the environment. The highest mobility of platinum in soil is observed at a pH of close to 1; in neutral solutions (pH 6±7) mobility is much lower while the presence of NaCl increases the mobility.19 Animal tests with rats (using as a model substance Pt(0) with a solubility of 10% in NaCl solution) were carried out to prove platinum bioavailability.37 After intratracheal instillations the highest concentrations of Pt were found in the lungs and the lung macrophages.Smaller amounts were detected in the blood kidneys spleen stomach and liver showing the bioavailability of platinum particles. After oral administration 97% of the platinum dose was excreted via the faeces and 0.09% via the urinary tract (where 100% is denoted as the total Pt content excreted in the faeces and urine over 8 days) during the Ærst 2 days.Platinum can enter the food chain either through deposition of Ptcontaining particles or by uptake from water and from waste water sludges used as fertilisers for plants. Some work has been undertaken on plants exposed to dissolved platinum salts.15,38±41 The uptake into different parts of the plants decreases in the order rootwstemwleaf. The evaluation of Pt content in different plants grown on contaminated soils (collected from areas adjacent to a German highway) shows a measurable transfer of metal from soil to plants. The transfer coefÆcients (deÆned as the concentration ratio between the levels in the plant and the soil) for Pt were similar to copper.42 It is noteworthy that analysis of common grass collected in the vicinity of a motorway near Stuttgart (Germany)43 also showed increasing amounts of Al Ce La Nd and Zr in parallel with platinum between 1992 and 1994.Two cultivation experiments were carried out in order to check to what extent platinum can enter the food chain by accumulation in plants.38 The grass Viewpoint grown on a sandy loam soil spiked with a water-soluble Pt compound [Pt(NH3)4](NO3)2 hardly accumulated the metal (accumulation factors were in the range 0.004±0.016). Cucumber plants which were grown hydroponically in nutrient solutions containing the same Pt compound strongly enriched platinum; accumulation factors were 11±42 in the green plant fraction and 1700±2100 in the roots. This indicates the important role of soil in the immobilisation of Pt compounds.From the grass cultures not treated with tetraammineplatinum(II) nitrate only one Pt species (molecular weight 160±200 kDa) was isolated while in the treated grass samples (uptake exclusively by the roots) up to seven different species were detected (molecular weight 19±1000 kDa).40 The platinum binding ligands in this fraction were characterised as Æxed to phytochelatins or to polygalacturonic acid behaving as an ion exchanger.40,43,44 However 90% of the absorbed platinum was bound to the low molecular species such as methionine or peptide glutathione. Wine samples served as an example for following the path growth continuing with the fermentation process of grape juice and resulting in the Ænal product.Fermentation experiments with grape must with a ``natural'' Pt content of 0.4 ng dm23 proved that added and co-fermented platinum was 70±90% adsorbed and thereby was almost completely enriched in the yeast.39 Only a small amount of the Pt passed into the wine. Vineyard locations near roads with high trafÆc showed noticeably higher mean values for platinum content (Table 2). Although platinum is emitted mainly in the form of Pt metal or metal oxide particulates there is evidence that at least part of this is soluble and can undergo transformations in the environment. Platinum allergy is conÆrmed as being due to a group of charged compounds that contain reactive ligand systems; the most effective of which are chloride ligands and the allergic response increases with an increasing number of chlorine atoms.45 The exposure±effect relationship for a platinum salt allergy in workers in catalyst production plants was conÆrmed.46 The platinum levels in the urine and blood of these employees could be up to 100 times higher than non-exposed control individuals.47 Chronic exposure to soluble platinum 101N 101N J.Environ. J. Environ. Monit. Monit. 2000 2000 2 Viewpoint Table 2 Content of platinum in different parts of grapes and soil (year of vegetation 1991)39 Content of Pt/ng g21 Near high trafÆc roads Sample 0.84 0.33 0.13 0.009 0.0004 Soil Leaf Stalk Berry Wine compounds may lead to toxic effects which are collectively known as a syndrome called platinosis.Increased platinum blood levels (3.8±4.0 ng ml21) were also found48 in medical staff occupied in the administration of Ptbased drugs in comparison with unexposed subjects (0.69±1.2 ng ml21). Analytical methods Analytical methods for the determination of platinum in environmental samples have been signiÆcantly improved during recent years.10,49,50 Adsorptive cathodic stripping voltammetry graphite furnace atomic absorption spectrometry (GFAAS) and inductively coupled plasma-mass spectrometry (ICP-MS) are the most sensitive methods of detection. Voltammetric methods use the adsorption of the platinum formazone complex formed in situ on a hanging mercury drop electrode.This complex catalyses the production of hydrogen and the reduction current associated with this reaction is related to the platinum concentration. However this method is negatively affected by even very low residual levels of organic matrix in the solution. The accuracy of GFAAS for low platinum levels strongly depends on the background absorption correction.49 For environmental samples it also requires a preconcentration step.49±51 Platinum in dust samples was enriched by electrodeposition into a graphite tube packed with reticulated vitreous carbon and determined by atomic absorption directly from the packed tube used for preconcentration.52 Some efforts have been made using solid sampling techniques after preconcentration on an ion exchange resin.49 ICP-MS offers the best sensitivity and convenience for simultaneous determination of other platinum group metals.A variety of sample introduction modes into the ICP such as ultrasonic or 102N 102N J. Environ. J. Environ. Monit. Monit. 2000 2000 2 TrafÆc free Æeld-paths 0.30 0.10 0.05 0.002 0.0001 thermospray nebulisation electrothermal vaporisation slurry techniques or direct injection have been used.53±56 Flow injection and isotope dilution are included in some procedures. Problems with ICP-MS occurred due to strong interferences by spectral overlap of HfOz ions with isotopes of Pt.53 The values obtained by several laboratories for platinum concentrations in environmental samples as measured by GFAAS and ICP-MS were tested with respect to the rules of quality assurance and quality control including sampling and sample decomposition.Considerable differences have been observed among the results.57 The reactivity bioavailability and toxicity of platinum are not necessary correlated with the total content but also depend on its chemical form oxidation state the chemical bonds in which it is involved and possible associations with other components of a given matrix. The different platinum species have to be separated before analysis this can be performed by chromatographic40,43,44 or electrophoretic58,59 techniques. Methods such as HPLC-ICP-MS and CE-ICPMS are able to generate information concerning the transformation behaviour of platinum in soils and plants.Conclusions The importance of platinum has increased enormously as a result of technological developments in catalytic converters for automobiles and chemical industries. For a long time Pt compounds have been considered harmless and they have had little impact on the environment. In the last twenty years however increasing platinum concentrations in soil dust contaminated grass and sewage sludge have been detected. The main pathways by which platinum can enter the food chain have to be taken into account aerosol deposition caused by Pt emission from motor vehicles and industrial sources transport by hospital efØuents via contaminated waste water and direct entry into soils via artiÆcial fertilisers.The primary sources from which platinum can be incorporated into the human body are therefore plants or agricultural products. However many problems are not solved yet and many questions are currently under discussion; the most important among them is the bioavailability and toxicity of platinum species. According to its chemical relationship with nickel and palladium Pt possesses a relatively high allergic potential. Therefore long-term monitoring studies are necessary to control the impact of platinum emission into the environment. Similarly more information concerning the exposure of the human population to Pt in water air and foodstuffs and the health effects of such exposure is needed.The author thanks Prof. A. Hulanicki for comments on the manuscript. Preparation of this paper was supported by grant No. 3TO9A 083 17 from the Polish State Committee for Research. References 1 R. Hartley Chemistry of the platinum group metals Elsevier Amsterdam 1991. 2 H. Renner in Metals and their compounds in the environment ed. E. Merian VCH Weinheim 1991. 3 C. Barbante G. Cozzi G. Capodaglio K. Van de Veide C. Ferrari A. Veysseyra C. F. Boutron G. Scarponi and P. Cescon Anal. Chem. 1999 71 4125. 4 C.Wei and G. M. Morrison Anal. Chim. Acta 1994 284 587. 5 V. Hodge and M. O. Stallard Environ. Sci. Technol. 1986 20 1058. 6 J. Scha» fer J. D. Eckhardt Z. A. Berner and D. Stu» ben Environ.Sci. Technol. 1999 33 3166. 7 K.Ku»mmerer and E. Helmers Sci. Total Environ. 1997 193 179. 8 K.Ku»mmerer E. Helmers P. Hubner G. Mascart M. Milandri F. Reinthaler and M. Zwakenberg Sci. Total Environ. 1999 225 155. 9 E. Helmers Environ. Sci. Pollut. Res. 1997 4 100. 10 R. R. Barefoot Environ. Sci. Technol. 1997 31 309. 11 H. P. Ko» ning R. F. Hertel W. Koch and G. Rosner Atmos. Environ. Part A 1992 26A 741. 12 R. Schlo» gl G. Indlekofer and P. Oelhafen Angew. Chem. 1987 99 312. 13 D. Nachtigall H. Koch S. Artell, K. Lewsen G. Wu» nsch T. Ru» hle and R. Schlo» gl Fresenius' J. Anal. Chem. 1996 354 742. 14 S. Artelt H. Koch D. Nachtigall and U. Heinrich Toxicol. Lett. 1998 96±97 163. 15 H. J. Ballach and R.Witting Environ. Sci. Pollut. Res. 1996 3 1. 16 F. Alt A. Bambauer K. Hoppstoch B. Mergel and G. To» lg Fresenius' J. Anal. Chem. 1993 346 693. 17 R. Schierl and G. Fruhmann Sci. Total Environ. 1996 182 21. 18 E. Helmers H. Schwarzer and M. Schuster Environ. Sci. Pollut. Res. 1998 5 44. 19 F. Zerini B. Skerstupp F. Alt E. Helmers and H. Urban Sci. Total Environ. 1997 206 137. 20 T. Hees B. Wenclawiak S. Lustig P. Schramel M. Schwarzer M. Schuster D. Verstrache R. Dams and E. Helmers Environ. Sci. Pollut. Res. 1998 5 105. 21 F. Zerini F. Dirksen B. Skerstrupp and H. Urban Environ. Sci. Pollut. Res. 1998 5 223. 22 M. L. Farago B. Kavqanagh R. Blanks J. Kelly G. Kazanatzis I. Thornton P. R. Simon J. M. Cook S.Parry and G. M. Hall Fresenius' J. Anal. Chem. 1996 354 660. 23 E. Helmers and N. Mergel Fresenius' J. Anal. Chem. 1998 362 522. 24 E. Helmers and K. Klu»mmerer Environ. Sci. Pollut. Res. 1999 6 29. 25 C. Wei and G. M. Morrison Hydrobiology 1992 235 597. 26 I. Veltz F. Arsac S. Biaganti-Risbourg F. Habets H. Lechenault and G. Vernet Arch. Environ. Contam. Toxicol. 1996 31 63. 27 S. Rauch an G. M. Morrison Sci. Total Environ. 1999 235 261. 28 N. Yuantao and Y. Zhengfen Platinum Metals Rev. 1999 43 62. 29 J. H. Crocket and Y. Terruta Can. Mineral. 1976 14 58. 30 V. Pavlov M. Often and C. Reimann J. Geochem. Explor. 1997 58 283. 31 D. Gregurek F. Meleher H. Niskavaara V. Pavlov C. Reimann and E. F. StrumpØ Atmos. Environ.1999 33 3281. 32 H. J. Gauchelaar D. R. Uges P. Aulenbacher E. G. de Vries and N. H. Mulder Pharm. Res. 1993 9 808. 33 R. Schierl B. Rohrew and J. Hohnloser Cancer Chemother. Pharmacol. 1995 36 75. 34 D. Laschka and M. Nachtwey Chemosphere 1997 34 1803. 35 M. Niezborala and R. Garnier Occup. Environ. Med. 1996 53 252. 36 P. J. Linnett and E. G. Hughes Occup. Environ. Med. 1999 56 191. 37 S. Artelt O. Creutzenberg H. Koch K. Lewsen D. Nachtigall U. Heinrich T. Ru» hle and R. Schlo» gl Sci. Total Environ. 1999 228 219. 38 D. Verstaete J. Riondato J. Vercanteren F. Vanhaecke L. Moens R. Dams and M. Verloo Sci. Total Environ. 1998 218 153. 39 F. Alt H. R. Eschauer B. Mergel J. Messerschmidt and G. To» lg Fresenius' J.Anal. Chem. 1997 357 1013. 40 F. Alt J. Messerschmidt and G. Weber Anal. Chim. Acta 1998 359 65. 41 J. Scha» fer D. Hannker J. D. Eckhardt and D. Stu»ben Sci. Total Environ. 1998 215 59. 42 E. Helmers Chemosphere 1996 33 405. 43 G. Weber F. Alt and J. Messerschmidt Fresenius' J. Anal. Chem. 1998 362 209. 44 N. Jakubowski C. Thomas D. Klueppel and D. Stuewer Analusis 1998 26 M37. 45 M. E. Farago P. Kavanagh R. Blanks G. Kazatzis I. Thornton P. R. Simpson J. M. Cook H. T. Delves and G. E. M. Hall Analyst 1998 123 451. 46 R. Merget R. Kulzer A. Dierkes- Globisch R. Breitstadt A. Gelber A. Kniffka S. Artelt H. P. Koening Viewpoint F. Alt R. Vormberg X. Baur and G. Schultze-Werninghaus J. Allerg. Clin. Immun. 2000 105 364. 47 F. Alt A. Bambauer K. Hoppstoch B. Mergler and G. To» lg Fresenius' J. Anal. Chem. 1993 346 693. 48 O. Nygren and L. Lundgren Int. Arch. Occup. Environ. Healtth 1997 70 209. 49 I. V. Kubrakova T. F. Kudinova N. M. Kuzmin I. A. Kovalev G. I. Tsysin and Y. A. Zolotov Anal. Chim. Acta 1996 334 167. 50 K. Pyrzyn� ska Talanta 1998 47 841. 51 B. Godlewska-Z « y�kiewicz B. Les�niewska J. Micha�owski and A. Hulanicki Int. J. Environ. Anal. Chem. 1999 75 71. 52 E. Beinrohr M. L. Lee P. Tscho» pel and G. To» lg Fresenius' J. Anal. Chem. 1993 346 689. 53 M. Parent H. Vanhoe L. Moens and R. Dams Fresenius' J. Anal. Chem. 1996 354 664. 54 M. Totland I. Jarvis and R. E. Jarvis Chem. Geol. 1993 104 175. 55 R. Vlasœa�nkova V. Otruba J. Bendl M. Fisœera and V. Kanicky Talanta 1999 48 839. 56 D. Klueppel N. Jakubowski J. Messerschmidt D. Stuewer and D. Klockow J. Anal. At. Spectrom. 1998 13 255. 57 W. Wegschneider and M. Zischka Fresenius' J. Anal. Chem. 1993 174 49. 58 S. Lusting J. De Kimpe R. Cornelis P. Schramel and B. Michalke Electrophoresis 1999 20 1627. 59 B. Michalke and P. Schramel Fresenius' J. Anal.Chem. 1997 357 594. Krystyna Pyrzyn�ska Department of Chemistry University of Warsaw 02±093 Warsaw Pasteura 1 Poland 103N 103N J. Environ. J. Environ. Monit. Monit.

ISSN:0960-7919    

DOI:10.1039/b007368g

出版商:RSC    

年代:2000

数据来源: RSC

摘要:

Pesticides in Perspective Introduction Although consumers Ærst interest in connection with pesticides is the safety of the food that they eat they are increasingly becoming aware of and concerned about the effects pesticides may have on the environment. The previous article in this column described the measures the UK government takes to monitor the environment for such effects. A signiÆcant number of other world governments undertake similar monitoring to a greater or lesser extent. However a signiÆcant amount of experimental and modelling work has to be conducted by industry before compounds are registered for use to prove that such pesticide use does not result in harmful side effects on nontarget organisms in the environment Ecological Risk Assessment for Agricultural Pesticides{ Introduction Pesticides are designed to control target pest disease and weed organisms.In agriculture these chemicals are used to protect crops from competition from weeds and attack by plant pathogens insects and other pests. They have the potential to impact on non-target organisms both within the target area and through movement of the chemical or treated organisms off-target. Furthermore the control of pest species may impact indirectly on other species which rely on the pests as a food source. Ever since Rachel Carson's book Silent Spring the potential effects of pesticides on our environment has often had a high proÆle in the media and is discussed in very emotive terms witness the last line of a previous article in this series ``The environmental impact of pesticides is a far sharper nail {The opinions expressed in the following article are entirely those of the author and do not necessarily represent the views of either The Royal Society of Chemistry the Editor or Editorial Board of JEM Zeneca Agrochemicals or those of the Column Editor.104N J. Environ. Monit. 2000 2 This journal is # The Royal Society of Chemistry 2000 such as birds bees and aquatic organisms. The current article gives an overview of the ecological risk assessment that is required for pesticides globally prior to approval being granted. The author of this article is Mick Hamer who has worked for Zeneca Agrochemicals for 22 years since joining with a degree in Zoology from Oxford University in 1978.His practical research experience covers the fate and effects of pesticides in aquatic ecosystems and includes aquatic ecotoxicology (laboratory and Æeld) bioconcentration and bioavailability in sediments. His current role is as Technical Advocate within the Ecological Risk Assessment Section preparing and presenting risk assessments and technical positions for for the pesticides cofÆn than residues in food''.1 Another article in the series ``Monitoring of Pesticides in the UK Environment''2 described the various schemes that through a combination of chemical and biological monitoring together with incident reporting ensure compliance with regulatory standards and identify potential adverse effects.Of course monitoring for adverse effects and taking subsequent regulatory action whilst a very important tool can be seen as `shutting the stable door after the horse has bolted' as these monitoring programmes are only possible post-registration. As adverse effects are by deÆnition undesirable it is vital that the registration process has the ability to identify potential risks screening out unacceptable chemicals and/or use patterns and allowing for risk mitigation such that risks are reduced to an acceptable level. This article looks at such schemes and how recent developments in ecotoxicity testing and exposure modelling are being incorporated into them. It will also highlight areas where risk assessment Pesticides discussions with regulators pesticide distributors users and any other interested parties.He has been involved in many technical workshops on aquatic and sediment ecotoxicology and risk assessment mostly through SETAC (Society of Environmental Toxicology and Chemistry) of which he is a European Council member. He has presented at many ecotoxicological and risk assessment courses including shortcourses on probabilistic risk assessment for agrochemicals at SETAC US and World conferences. Dr Terry Clark Column Editor Zeneca Agrochemicals UK E-mail Terry.Clark@aguk.zeneca.com procedures are still under development and anywhere it might be considered that deÆciencies exist within such schemes.Before discussing different approaches to ecological risk assessment it is customary to clarify what is meant by risk assessment and a working deÆnition is below. Also given is a deÆnition of risk management which highlights the distinction between the two.3 Risk assessment is a science based process that consists of hazard identiÆcation and exposure assessment and that ultimately integrates hazard and exposure to characterise risk. Risk management is a policy-based activity that deÆnes risk assessment questions and endpoints to protect human health and the environment. It takes the scientiÆc risk assessment and incorporates social economic political and legal factors that impinge or inØuence the Ænal decision and selects regulatory actions.Risk assessment should therefore be a scientiÆc process and not some sort of black art. Risk management has a much wider brief of which science is only one part. However as a risk assessor I have to admit that we frequently have trouble seeing beyond the science and therefore of appreciating the difÆculties faced by the risk manager. Risk can be considered as the probability of an adverse event occurring. Of course deÆning an adverse event is a difÆcult thing to do and it is all too easy to default to the easy option of any effect being looked upon being unacceptable. However this can remove much of the science from the process and should be strongly resisted particularly when we are discussing effects in agriculture which in itself will bring changes to the environment whether chemicals are used or not.Pesticide risk assessment schemes and registration Pesticide risk assessment schemes have been established for some time in the USA under FIFRA (Federal Insecticide Fungicide and Rodenticide Act) and Europe under the EU Pesticide Directive 91/414/EEC. These in common with other procedures for assessing the risk of toxicants adopt a tiered approach. Tier 1 is essentially a screen there to identify low risk uses or those groups of organisms at low risk. It is important to realise that it is not the ``pesticide'' which is being assessed and registered but the use which includes the chemical and its use pattern (application method rate and timing) together with any relevant environmental fate data.So for example a chemical may present an unacceptable ecological risk if applied by air-blast in hops or citrus at rates required to give effective pest control and yet be perfectly acceptable applied by tractor-mounted sprayer for use to control cereal pests. Tier 1 also focuses the assessment on the organisms that might be at risk for example it might identify low risk to terrestrial organisms whilst indicating potential risks to aquatic invertebrates and Æsh. Failure to ``pass'' at tier 1 does not mean that the pesticide use presents a risk rather that there is insufÆcient information to reach a conclusion. The options exist therefore to (i) remove the issue by not allowing registration; (ii) reduce the risk to acceptable levels by reducing exposure through limiting application rates numbers of applications or the use of no-spray zones; (iii) reÆne the risk assessment.The Ærst two options above can be seen as risk management tools. The Ærst option however may deny the obvious beneÆts social and/or economic that the pesticide might bring. Equally an industry which has already invested hugely in the development of a chemical is likely to look for an alternative solution. It is of course in industry's interests to develop chemicals which can be registered and given the importance of having pesticides with acceptable environmental proÆles assessing environmental proÆles is now part of the decision making process during selection of potential pesticides.Given this it should therefore be unlikely that registration of a new active ingredient is totally refused on ecological risk grounds although risk mitigation measures may be necessary. However regulatory requirements evolve rapidly and sometimes unpredictably. One problem therefore can be the time-lag of 5±10 years between pesticide invention development and registration making it is necessary to look into the future and anticipate future regulatory concerns. The process is somewhat different for chemicals already registered however it is important to ensure that chemicals are re-evaluated to ensure they reach current environmental standards.Mitigation measures that result in reducing non-target exposure are an approach that can be adopted although limiting application rates for a speciÆc use is often not a viable option as rates tend to be optimised on efÆcacy. More likely is that certain uses which require higher application rates or result in higher non-target exposures may not be registered. The use of no-spray zones is a useful tool in reducing exposure to nontarget organisms outside the target area for example in aquatic environments or hedgerows. When considering exposure of organisms within the target area which can include birds mammals and other wildlife together with earthworms and beneÆcial arthropods no sprayzones are not an effective mitigation measure.Therefore it is necessary to include in registration schemes the potential for risk assessment reÆnement. This involves further work to remove some of the uncertainties that are inherent in initial risk characterisation to obtain a more realistic estimate of the risk. This work can involve (i) further interrogation of the data already available; (ii) further ecotoxicity testing; (iii) better characterisation of exposure/effects of the chemical. As stated above failure to do any further work will result in regulatory action to mitigate the risk ranging from not registering the use or restricting the Pesticides use such that trigger values are not exceeded. Representative groups of organisms are assessed for risk to pesticides including from the terrestrial environment birds and mammals bees and beneÆcial arthropods earthworms soil micro-organisms non-target plants and from the aquatic environment Æsh aquatic invertebrates and plants.All these organisms are assessed in Europe under 91/414/EEC whereas the US EPA concentrates on birds and mammals bees non-target plants and aquatic organisms. Tier 1 Screening out low risk uses The quotient approach. Tier 1 screens out low risk uses/organisms and most commonly uses the quotient approach. This involves comparing an estimate of toxicity derived from a standard test under laboratory conditions with a worst-case estimate of exposure a predicted environmental concentration (PEC) based on proposed label uses.For aquatic organisms it is assumed exposure is through the water phase and PECs (w/v) in water for example in mg l21 are compared to a toxicity value (LC50 NOEC) expressed in the same units. For birds and mammals it is assumed that exposure is through eating treated food items and residue concentrations (w/w) in mg kg21 are compared to toxicity data (dietary LC50 NOEC) again in the same units. The estimate of exposure at tier 1 is generally a maximum modelled residue concentration regardless of how long the exposure in the toxicity tests which could be up to 2 years in some of the longer term chronic tests. The US EPA derives a risk quotient (RQ) as RQ~ exposure toxicity and the EU derives a toxicity/exposure ratio (TER) as TER~ toxicity exposure For toxicity to bees a similar situation exists whereby the exposure (Æeld application rate) is divided by the toxicity (mg bee21) to derive a hazard quotient.If the resulting RQ is less than a certain value the level of concern (LOC) the risk is characterised as low and no further action is required. The same is true if the TER exceeds a trigger value. Effectively in common with many 105N J. Environ. Monit. 2000 2 Pesticides other risk assessment schemes a safety factor is being applied to cover uncertainty. In ecological risk assessment for pesticides the factor applied can vary between 1 and 100 depending on the organisms being assessed and whether the toxicity endpoint is acute based on short-term lethal or immobility effects (LD/LC/ EC50) or chronic based on no observed effect generally from longer term tests and based on both lethal and relevant sub-lethal (growth reproduction) parameters.How conservative or worstcase the exposure assessment is can also affect the safety factor applied. It is reasonable to assume that these safety factors have a sound scientiÆc basis however this is not always the case. Safety factors are supposed to cover all the uncertainty in the initial risk assessment including inter- and intra-species sensitivities inter- and intra-laboratory variation and laboratory-to-Æeld extrapolations. These factors will vary according to the mechanism of toxicity of a chemical together with its physico-chemical properties and environmental fate.Thus tier 1 safety factors are generic whereas the parameters to do with the uncertainty are mostly chemical speciÆc. A good discussion of safety factors including the precautionary principle is presented by Chapman et al. `A critical evaluation of safety (uncertainty) factors for ecological risk assessment'.4 Safety factors have been chosen to be protective they have worked in the past and consequently are required to be large enough to ensure that those uses classiÆed as low risk at tier 1 indeed are and that there is only a low probability of incorrectly concluding that there will be no signiÆcant effects in the environment.At the risk of being repetitive it is not a requirement to achieve a toxicity/ exposure or an exposure/toxicity ratio such that these safety factors are achieved or triggers not exceeded although that can be an option through reÆning the exposure estimates. All too often papers are published which state that residue levels have exceeded ``safe'' levels or that acute/chronic effects may be expected based on some residue monitoring programme with reference to ``maximum permissible concentrations'' (MPC) or ``environmental quality standards'' (EQS) derived from the lowest toxicity value together with a generic safety factor. Often for pesticides additional information will be available to reÆne the risk assessment and whilst residue 106N J.Environ. Monit. 2000 2 levels should not be declared to be ``safe'' they might present a perfectly acceptable level of risk whilst exceeding MPC or EQS values. Alternative tier 1 approaches. With birds mammals bees earthworms and aquatic organisms the tier 1 procedures are relatively well established with both the standard tests and the tier 1 assessments well characterised and understood. The beneÆcial arthropod area is less well deÆned however tier 1 procedures are under review by an expert group5 and it is likely that some hazard quotient approach will be included at tier 1 in the near future.6 For assessing risk to beneÆcial arthropods at tier 1 the current procedure under 91/414/EEC requires indicator species to be tested in the laboratory with the results expressed as % effect at the Æeld rate.If the effect on these indicator species is less than a trigger value the chemical is deemed to be harmless to beneÆcials at the proposed rate the risk is acceptable and no further work is required. In this scheme the safety factor is built into the sensitivity of the tier 1 tests and the fact that they overestimate toxic effects in the Æeld. This is due to the acknowledged sensitivity of some of the tier 1 test species and the extreme exposure. For example tests may be done with direct application at Æeld rates onto glass plates or bare soil there is no crop interception for foliar applied products and no allowance for dilution in a three-dimensional environment.Another area where the risk assessment procedures are under development include the potential risk to non-target plants. Assessment for effects on plants at the Æeld rate and multiples or fractions of the Æeld rate can indicate the potential for effects on non-target plants. However a number of risk assessment questions remain. For example particularly for a herbicide what is a non-target plant? If any non-crop plants in the target area are considered pests and therefore legitimate targets what about those off-crop? What effect and exposure level is it appropriate for use at tier 1? What constitutes a signiÆcant effect on a plant? Whilst it is perhaps easy to see the signiÆcance of effects on seedling germination or emergence it is more difÆcult to interpret effects when the endpoint is a qualitative or quantitative effect on growth or vigour.ReÆning the risk assessment Tier 2 and beyond A tier 1 risk assessment clearly identiÆes uses and organisms that are low risk and provides a focus for further assessments. Given the type of chemicals being used their bio-efÆcacy and the wide range of non-target organisms studied tier 1 ecological risk assessments rarely result in an absence of areas requiring further consideration. Some applications do so on the basis of there being no or limited exposure of the chemical to non-target organisms through the registered use such as stored grain products or seed treatments.If tier 1 criteria are not met registration can be denied unless the risk assessment can be reÆned to demonstrate that the risk is acceptable. Under Directive 91/414/EEC Annex VI states that for aquatic organisms if tier 1 triggers are not met ``ºno authorisation shall be granted ººunless it is clearly established through an appropriate risk assessment that under Æeld conditions no unacceptable impact on the viability of exposed species occurs.'' Similar statements albeit with different trigger values are included for other organisms. Unacceptable impacts should not occur and from this it can be concluded that there is such a thing as an acceptable impact. It is unrealistic to expect that the use of pesticides would result in no impact and indeed against the background of the impact of agriculture and other environmental impacts natural and anthropogenic it is unrealistic to require this.Unlike the initial risk characterisation in many instances there are no standard procedures available at tier 2 and risk reÆnement is conducted very much on a case-by-case basis. Lately however there has been a lot of activity in this higher tier area. This has involved groups of academics regulators and industry getting together to share both their experience and their opinions of these higher tier assessments. The outputs from such groups range from guidance documents in study design and interpretation to tools such as exposure models which can be used conduct these assessments.These include (i) ECOFRAM Ecological Committee on FIFRA Risk Assessment Methods;7 (ii) FOCUS Forum for the Coordination of Pesticide Models and Their Use; (iii) HARAP Higher Tier Aquatic Risk Assessment for Pesticides;8 (iv) ESCORT2 European Standard Characteristics of Non-target Arthropod Regulatory Testing;5 (v) CLASSIC Community Level Aquatic System Studies±Interpretation Criteria.9 The above list is not meant to be comprehensive rather to give an indication of the amount of interest and effort in this area. ECOFRAM covers the entire area of terrestrial (using avian as an example but using principles which would be transferable to other vertebrates) and aquatic exposure and effects using four different subgroups.The other groups are more focused on the different areas described in their titles. Given the toxicity/exposure quotients used it seems obvious to split the discussion of how to reÆne the risk assessment into these two areas. I would like to discuss brieØy the approaches to reÆning the risk assessment starting with time a parameter which is relevant to both exposure and effects. The importance of time Although the studies conducted for the initial risk assessment clearly have a time component for example ``96 h LC50 to rainbow trout'' ``5 day dietary LC50 to bobwhite quail'' or ``21 day Daphnia magna life-cycle study'' the LC50/NOEC endpoint is used in the tier 1 assessment without reference to time.Generally it is not just exposure to a particular residue concentration that produces an effect the time of exposure is equally important in determining the dose to an organism. A combination of the level of exposure and the time of exposure is generally what produces the observed effect and effects manifest themselves after a particular time. Although not normally expressed an LT or ET50 (the time taken to kill or affect 50% of the test population) at a speciÆed concentration is a valid alternative endpoint to an LC or EC50 at a speciÆed time. The exposure value used at tier 1 is usually a peak concentration from a worst-case modelled scenario regardless of how long this level is maintained. From this maximum level of exposure the only way the exposure level is going to change is for it to reduce which will affect the potential dose an organism will receive and may modify the potential effects.Thus one of the Ærst considerations in reÆning the ecological risk assessment can be establishing the relationship between exposure/effect/time. Standard laboratory studies are designed to determine hazard and generally use maintained exposures. The difference between laboratory and Æeld exposures particularly for compounds that dissipate rapidly in the environment can mean that complex long-term studies have little or no value in risk assessment. A valuable initial source of information on the link between time of exposure and effects can be the simple tier 1 studies which will often contain more information than simply the data used to generate the reported endpoint.For example in a 96 h LC50 study assessments would normally be made after 24 48 and 72 h and these observations together with knowledge of the mechanism of toxicity or toxicokinetics can help establish the relationship between time of exposure and effects. Alternatively simple studies can be designed to deÆne the relationship between time of exposure and effect. Any number of PEC values can be developed for a compound in the environment maximum values time weighted average concentrations over any period of time or even annualised means. Establishing the relationship between time of exposure and time to effect can indicate which PEC is the most appropriate.ReÆning exposure Where possible reÆnements of exposure estimates are commonly used at higher tiers in risk assessment. There is a tendency to jump straight from tier 1 to chemical monitoring in the environment and generate ``real world'' data. This is sometimes because of the mistrust of computer models and a feeling that measuring real world concentrations will determine real world exposures. However this approach has its limitations. Care must be taken when trying to extrapolate from any monitored situation to other similar situations and there is always the problem with establishing where the monitored chemical came from. Monitoring is only a snapshot in time and monitoring programmes rarely give sufÆcient information about concentrations over time which is often necessary to determine exposure.These problems can be overcome with the use of higher tier modelling. However modelling has its own problems most notably that of model validation. These modelling procedures are best developed and validated within the US by the EPA for exposure in aquatic environments and in Europe the FOCUS Pesticides surface water group is working on similar approaches. The US EPA use an established generic tier 1 exposure model (GENEEC generic estimated environmental concentration) into which chemical speciÆc parameters and application data are entered. Entry into a non-target water body through run-off and spray drift produces a single worstcase entry rate concentration together with concentrations in the water over time.From this it is possible to move to tier 2 modelling (PRZM/EXAMS pesticide root zone model/experimental analysis modelling systems) which is speciÆc to a particular crop and region. This uses historic weather data and is able to produce concentrations over time typically 36 years allowing distributions of concentrations to be developed and probabilistic estimates of exposure to be made. ECOFRAM discusses this fully and the further developments at tiers 3 and 4 of modelling. At the highest tiers of exposure modelling the real world starts to be addressed. Earlier modelling makes assumptions about the proximity of water bodies to crops normally that they are adjacent.Using satellite imagery and geographic information systems (GIS) a picture can be built up of the area in which a chemical is or may be used. The proximity of water bodies to crops the different types of water bodies soil types slopes and other features can all be added in to determine where in relation to the chemical application are the water bodies we are trying to protect and what is the probability of exposure. The above procedures are relevant to aquatic environments but similar procedures can be used for terrestrial environments where exposure is often via residues on crops or potential food items. Tier 1 would assume a bird or mammal would consume food containing maximum residues throughout its lifetime.Data on the decline of residues on crops can be used to better characterise exposure and the assumption that 100% of an animals diet consists of treated food can begin to be challenged. ReÆning toxicity/effects There are a number of approaches available for reÆning the toxicity input into the risk assessment. Some of these simply use the quotient approach from tier 1 modifying toxicity values through generating toxicity data under more realistic conditions. For example instead of maintaining concentrations 107N J. Environ. Monit. 2000 2 Pesticides throughout a test the chemical could be introduced at the start of the study and allowed to dissipate and behave in a similar way to how it would in the environment.Calculating the toxicity based on the initial exposure will give a value which can be compared to modelled peak exposure concentrations giving a better estimate of the relationship between environmental exposures and effects. This approach is an alternative to reÆning exposure estimates according to time and calculating PECs other than initial maximum levels. ReÆning risk is all about reducing uncertainties and often the biggest uncertainty in ecological risk assessment is with regard to inter-species sensitivity. How representative of the organisms we are trying to protect in the Æeld are those individuals/species tested in the laboratory? We are usually not trying to protect individual organisms but populations and communities of different species.If we really wish to understand the potential risks from a chemical it is important to understand the sensitivities of different groups of organisms. Tier 1 safety factors are generic and if the laboratory species are particularly sensitive to a pesticide then they could be overprotective and any possible beneÆts from the chemical could be lost in needless mitigation. Indeed sensitivity in response to chemicals is one of the criteria used in selecting test organisms as surrogates both the life stage and the species. For a relatively small investment by testing the toxicity of a wide range of species much of the uncertainty can be removed from the assessment.What should be done with species sensitivity data and how should it be incorporated into the risk assessment? One approach is simply to acknowledge the reduction in the uncertainty and reduce the safety factor applied in the assessment. Without this there is no incentive to generate data beyond the limited base-set requirements to understand the potential risks. There are other ways of using these data. Understanding inter-species sensitivity is a major part of the aquatic risk assessment process being developed in ECOFRAM. This proposes the use of species sensitivity distributions in a probabilistic effects assessment. The principle behind this is the same as for other probabilistic assessments in that it assumes that the species tested are from a distribution of sensitivities in a universe of species.The available data are Ætted to a model to describe the 108N J. Environ. Monit. 2000 2 distribution of sensitivities that would be expected to occur. From this distribution exposure levels that would protect 90 95 99% or indeed any percentage of the species can be determined. Of course there are a number of concerns such as what level if any of species affected might be acceptable which species might be affected how might they be affected and are they economically ecologically or otherwise important. It is important to establish that the species are from the same sensitivity distribution and what is an appropriate model to Æt to that distribution.Despite these and other questions this approach has been used for many years in some form. Indeed it is an attractive idea that with this approach probabilistic estimates of effects can be combined with those of exposure to give joint probabilities. All of the effects assessments discussed so far have involved laboratory studies when our stated goal is protection of species and communities in the Æeld. Field studies still have a place in effects assessments although for the same reason as for chemical monitoring biological monitoring in the Æeld should not be undertaken lightly. Establishing cause and effect provision of adequate controls and applicability to other situations are always problematic.Controlled Æeld or semi-Æeld studies are however a very useful tool and may be the only tool currently available to assess recovery in affected systems. Recovery particularly time to recovery plays an important part in determining whether an effect is acceptable. Another tool under development is population modelling to determine whether populations are affected given certain input parameters (for example the sensitivity of different life stages to the chemical) and assumptions. These models allow the running of different scenarios however they are often limited by the availability of certain basic life-history data. Limitations of ecological risk assessments for agrochemicals and do they work? There are a number of areas in which the current risk assessment schemes are commonly considered deÆcient in certain areas.Some of these will be discussed albeit brieØy below. One criticism is that some groups of organisms are not represented. Quite clearly this is going to be the case at tier 1 where currently only 2 bird species honey bees 2 Æsh an aquatic invertebrate and a freshwater green alga together with some 10 non-target plant species might be studied for US registration. Risk to wild mammals uses data generated for the toxicology assessment. In addition for registration in Europe data are also required for non-target arthropods earthworms and the effects on soil micro-organisms. Protection of the environment and any exposed species is the goal and so it is easy to think of organisms that are not represented.Most commonly mentioned are reptiles and amphibians. There is particular concern over amphibians as there has undoubtedly been a decline in populations globally and pesticides have been cited as one of the contributing factors. It could be argued that vertebrates as a sub-phylum are actually fairly well represented with 3 classes being tested and there should perhaps be more legitimate concerns over invertebrates particularly aquatic invertebrates where the tier 1 requirement is a single freshwater crustacean zooplankton species (Daphnia). Whilst perhaps not so vocal as those advocating more protection for reptiles and amphibians there are people championing various different aquatic invertebrates.It would not seem unreasonable to add aquatic insects to the list of species tested at tier 1 if testing an insecticide; for example in the same way as herbicides trigger additional testing on plants. What is important is not ensuring that organisms are represented in the battery of tests rather that the battery of tests is protective of all the organisms of concern. For example there is little value in testing an amphibian or an aquatic protozoan if they are already protected by those surrogate species tested together with the applied safety factors at tier 1. Whether this is the case it is probably not possible to say currently and there is perhaps some basic research and information gathering required in this area.An ecological risk assessment for pesticides concentrates on direct impacts on exposed species and it would ideally demonstrate low risk of any effect. If direct effects are anticipated the potential for indirect effects does need to be considered and should be addressed by community level studies. One area not covered is the potential for indirect effects on wildlife as a result of the intended effect of the chemical such as removal of unwanted pests. A previous article cited the example of the decline in farmland birds associated with intensive farming as an indirect effect of pesticides.2 This is perhaps a good example which shows the importance of not just looking at ecological risk assessment in isolation but the importance of an integrated crop management (ICM) approach towards sustainable agriculture.Ecological risk assessment for pesticides concentrates on single chemicals whereas in the environment organisms exposure might be exposed to more than one pesticide or other chemical mixtures including natural toxins and a variety of other stressors. Concern is often expressed for the effects of complex mixtures on exposed organisms and that this is not considered in the standard ecological risk assessment procedures. It would be impossible to consider the potential range of mixtures that occur in the environment and therefore in risk assessment the pragmatic approach is to evaluate chemicals individually.Pesticides are tested in mixtures to representative organisms when formulated together in a product and so therefore a relatively large database exists on mixtures. Chemical mixtures may act in different ways they may act independently (in which there is no interaction) and this might be expected if the chemicals have differentmechanisms of toxicity. Additive effects might be expected if the chemicals have the same mode of action. Greatest concern is expressed that there could be a synergistic effect that is the effect of the chemicals together is greater than that predicted from the parts the converse of this is an antagonistic effect,which is not likely to be of concern in a risk assessment.Whilst it is easy to talk about these different possible effects of mixtures detecting them or differentiating between them in standard ecotoxicity tests is extremely difÆcult.Databases of toxicity tests with mixtures show independence or additivity to be the most common mechanism. Independence of action might be expected frommixtures of pesticides as formulations because chemicals with different modes of action and mechanisms of toxicity are generally mixed to produce different effects or hit different targets. It is less likely that chemicals with the same mode of action would be sprayed together and so whilst chemicals with similar modes of action might be found together in areas remote from the target (for example in a river estuary) it is less likely in the worst-case inÆeld or edge-of-Æeld scenarios (for example in a small headwater stream) straight after application which are those situations which drive the risk assessment.There have been reports of synergy from mixtures of pesticides. Perhaps the best example is the interactive effects between the ergosterol-biosynthesis inhibiting (EBI) fungicides and organophosphorus and pyrethroid insecticides in birds10 and bees.11 The biochemical basis for this is well established and it is readily demonstrated in the laboratory with controlled doses and the correct timing of the dose of the chemicals. It is unlikely that these laboratory effects would translate into effects in the Æeld nevertheless the possibility of synergism exists and whilst it is impossible to test for all situations consideration should be given to the possibility for such effects through the known biochemical modes of action.As a cautionary note a synergistic effect between fungicides used in bananas was initially publicised as the cause of Taura Syndrome a disease of cultured shrimps most common in Ecuador. Fungicides are used extensively in bananas and can be found in some water monitoring samples. A claim had been made that Taura Syndrome was generated in the laboratory from exposure to mixtures of chemicals. However these laboratory claims could not be substantiated and eventually a viral agent was identiÆed as the cause.12 If the process of ecological risk assessment for pesticides works why is there such concern for the environmental risks? There are a number of reasons for this.Perhaps the most important is that there are still a number of older compounds being used some of which (for example some organochlorine insecticides) are of environmental concern. This is particularly true in less developed countries where these chemicals are readily made cheap and because of this risk management decisions might be different than in some developed nations. Some compounds are not being supported through reregistration procedures in the US and the EU. It is important that the newer compounds with a better environmental proÆle are allowed to come through the registration process to replace older compounds registered when requirements were less comprehensive if they do not meet current standards.Programmes such as the US EPA Reduced Risk Registration Scheme explained by Rick Tinsworth13 will be valuable in ensuring this is the case. Requirements for registration are now extensive and whilst it is not possible to state that any pesticide use presents no risk it is possible to conclude that the use of compounds which have recently been through a regulatory ecological risk assessment are of low or negligible risk to the environment when used according to label recommendations. That is not to say Pesticides that we can be complacent and this where the incident reporting and monitoring discussed by Pepper and Carter2 in their earlier article are important.If it is true that current pesticides are of low risk to the environment why is it that Professor Ian Shaw can state ``The environmental impact of pesticides is a far sharper nail for the pesticides cofÆn than residues in food''?1 This statement might be true for some pesticides although perhaps not for the majority of those currently registered. What we have is a similar situation to that of the relevance of pesticide residues in our diet presented in excellent discussions by Ian Shaw and Naresh Atreya.14 There is a gap between public perception of risks and reality. A gap due to ineffective risk communication a gap which will not be easy to bridge but one which the industry together with other stakeholders will have to address as part of the progress towards a sustainable agricultural system. References 1 I. Shaw J. Environ. Monit. 2000 2 34N. 2 T. Pepper and A. Carter J. Environ. Monit. 2000 2 83N. 3 SETAC Pesticide Risk and Mitigation Final report of the Aquatic Risk Assessment and Mitigation Dialogue Group SETAC Foundation for Environmental Education Pensacola FL 1994. 4 P. M. Chapman et al. Environ. Toxicol. Chem. 1998 17 99. 5 M. P. CandolÆ et al. Guidance document on regulatory testing and risk assessment procedures for plant protection products with non-target arthropods SETAC Europe Brussels 2nd ed. in preparation. 6 P. J. Campbell et al. J. Pest. Sci. 2000 in press. 7 ECOFRAM US EPA http:// www.epa.gov/oppefed1/ecorisk/ 8 P. J. Campbell et al. Guidance document on higher-tier aquatic risk assessment for pesticides (HARAP) SETAC-Europe Brussels 1999. 9 W. Heger et al. Proceedings of the CLASSIC workshop (Community Level Aquatic System Studies - Interpretation Criteria) SETAC-Europe Brussels in preparation. 10 G. Johnston et al. Environ. Toxicol. Chem. 1994 4 621. 11 E. D. Pilling Aspects Appl. Biol. 1992 31 43. 12 K. W. Hasson et al. Diseases of Aquatic Organisms 1995 23 115. 13 R. Tinsworth J. Environ. Monit. 2000 2 63N. 14 N. Atreya J. Environ. Monit. 2000 2 53N Mick Hamer Ecological Risk Assessment Section Zeneca Agrochemicals Bracknell UK 109N J. Environ. Monit. 2000 2

ISSN:0960-7919    

DOI:10.1039/b008962l

出版商:RSC    

年代:2000

数据来源: RSC