MODELKEY. Models for assessing and forecasting the impact of environmental key pollutants on freshwater and marine ecosystems and biodiversity (5 pp)

BACKGROUND: Triggered by the requirement of Water Framework Directive for a good ecological status for European river systems till 2015 and by still existing lacks in tools for cause identification of insufficient ecological status MODELKEY (http:// www.modelkey.org), an Integrated Project with 26 partners from 14 European countries, was started in 2005. MODELKEY is the acronym for 'Models for assessing and forecasting the impact of environmental key pollutants on freshwater and marine ecosystems and biodiversity'. The project is funded by the European Commission within the Sixth Framework Programme. OBJECTIVES: MODELKEY comprises a multidisciplinary approach aiming at developing interlinked tools for an enhanced understanding of cause-effect-relationships between insufficient ecological status and environmental pollution as causative factor and for the assessment and forecasting of the risks of key pollutants on fresh water and marine ecosystems at a river basin and adjacent marine environment scale. New modelling tools for risk assessment including generic exposure assessment models, mechanistic models of toxic effects in simplified food chains, integrated diagnostic effect models based on community patterns, predictive component effect models applying artificial neural networks and GIS-based analysis of integrated risk indexes will be developed and linked to a user-friendly decision support system for the prioritisation of risks, contamination sources and contaminated sites. APPROACH: Modelling will be closely interlinked with extensive laboratory and field investigations. Early warning strategies on the basis of sub-lethal effects in vitro and in vivo are provided and combined with fractionation and analytical tools for effect-directed analysis of key toxicants. Integrated assessment of exposure and effects on biofilms, invertebrate and fish communities linking chemical analysis in water, sediment and biota with in vitro, in vivo and community level effect analysis is designed to provide data and conceptual understanding for risk arising from key toxicants in aquatic ecosystems and will be used for verification of various modelling approaches. CONCLUSION AND PERSPECTIVE: The developed tools will be verified in case studies representing European key areas including Mediterranean, Western and Central European river basins. An end-user-directed decision support system will be provided for cost-effective tool selection and appropriate risk and site prioritisation.     

Towards a renewed research agenda in ecotoxicology

New concerns about biodiversity, ecosystem services and human health triggered several new regulations increasing the need for sound ecotoxicological risk assessment. The PEER network aims to share its view on the research issues that this challenges. PEER scientists call for an improved biologically relevant exposure assessment. They promote comprehensive effect assessment at several biological levels. Biological traits should be used for Environmental risk assessment (ERA) as promising tools to better understand relationships between structure and functioning of ecosystems. The use of modern high throughput methods could also enhance the amount of data for a better risk assessment. Improved models coping with multiple stressors or biological levels are necessary to answer for a more scientifically based risk assessment. Those methods must be embedded within life cycle analysis or economical models for efficient regulations. Joint research programmes involving humanities with ecological sciences should be developed for a sound risk management.     

Predictive modeling of effects under global change

The status of computer simulation models from around the world for evaluating the possible ecological, environmental, and societal consequences of global change is presented in this paper. In addition, a brief synopsis of the state of the science of these impacts is included. Issues considered include future changes in climate and patterns of land use for societal needs. Models discussed relate to vegetation (e.g. crop), soil, bio-geochemistry, water, and wildlife responses to conventional, forecasted changes in temperature and precipitation. Also described are models of these responses, alone and interactively, to increased CO(2), other air pollutants and UV-B radiation, as the state of the science allows. Further, models of land-use change are included. Additionally, global multiple sector models of environment, natural resources, human population dynamics, economics, energy, and political relations are reviewed for integrated impact assessment. To the extent available, information on computer software and hardware requirements is presented for the various models. The paper concludes with comments about using these technologies as they relate to ecological risk assessment for policy decision analysis. Such an effort is hampered by considerable uncertainties with the output of existing models, because of the uncertainties associated with input data and the definitions of their dose-response relationships. The concluding suggestions point the direction for new developments in modeling and analyses that are needed for the 21st century.     

Aquatic predicted no-effect concentration for three polycyclic aromatic hydrocarbons and probabilistic ecological risk assessment in Liaodong Bay of the Bohai Sea, China

Predicted no-effect concentration (PNEC) is often used in ecological risk assessment to determine low-risk concentrations for chemicals. In the present study, native marine species were selected for toxicity testing. The PNECs for three polycyclic aromatic hydrocarbons (PAHs), specifically phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP), were derived from chronic and acute toxicity data with log-normal statistical methods. The achieved PNECs for Phe, Pyr, and BaP were 2.33, 1.09, and 0.011 μg/L, respectively. In Jinzhou Bay and the Shuangtaizi River Estuary of Liaodong Bay in the Bohai Sea, China, the surface water concentrations of the three PAHs were analyzed by gas chromatography–mass spectrometry. Based on two probabilistic ecological risk assessment (PERA) methods, namely probabilistic risk quotient and joint probability curve, the potential risk of Phe, Pyr, and BaP in Jinzhou Bay and Shuangtaizi River Estuary was assessed. The same order of ecological risk (BaP > Phe > Pyr) was found by both models. Our study considered regional characteristics of marine biota during the calculation of PNECs, and the PERA methods provided probabilities of potential ecological risks of chemicals. Within the study area, further research on BaP is required due to its high potential ecological risk.     

新疆某矿冶区周边土壤重金属生物有效性与生态风险评价

矿业活动对土壤系统良性运转带来较大的环境负荷,矿区周边土壤重金属污染风险评估是土壤污染防治和资源可持续开发的关键。在应用单因子污染指数法、潜在生态风险指数法、风险评价编码法(RAC),并结合空间分析和冗余分析手段的基础上,对新疆某矿冶区周边土壤重金属生物有效性和生态风险进行了系统研究。结果表明：研究区土壤As、Cu、Mn和Cd超标率分别为88%、38%、49%和24%;土壤Mn、Zn、As和Cd弱酸可溶态高值区主要集中在尾砂库和收砷房的附近区域。单因子污染指数评价揭示As和Cu污染累积较为严重。潜在生态风险评价显示,As、Cd和Cu生态风险较高,Mn为低生态风险。风险编码法(RAC)评价结果进一步揭示Mn和Cd具有显著的土壤迁移风险。冗余分析结果显示,空间异质性是影响土壤重金属弱酸可溶态含量变异的主要因素。土壤pH和重金属弱酸可溶态是影响潜在生态风险指数(RI)的2个重要因素。综合风险评价手段与多尺度分析方法的联合应用有助于提高区域风险评价的准确性。     

Ecological risk assessment for aquatic species exposed to contaminants in Keelung River, Taiwan

An ecological risk assessment was conducted for Keelung River in northern Taiwan. The objective of this study was to assess the risk to fish, aquatic insects, and benthic macroinvertebrates associated with chemical-of-potential-concern (COPC) in the river and to rank ecological risk for these chemicals. The protection of at least 95% of the species 90% of the time from acute and chronic COPC exposures was the defined assessment endpoint. Nine inorganic and organic contaminants were selected to evaluate the impact to aquatic community in the Keelung River. The quotient method served as screen level estimation of risk. The Aquatic Ecological Risk Assessment model was used to analyze exposure and ecological effects and to estimate community level risk. The logarithmic regression model between probability and lethal concentration was established. The combined risks of multiple chemicals were evaluated under assumption of additive risk. The results indicated that zinc and copper pose higher risk among metals. Ammonia, copper, and zinc posed virtually all of the risk, while organic COPCs posed a negligible risk. Potential ecological risk from ammonia exposure was greatest. The probability of more than 5% of the species being affected by acute or chronic toxicity of COPCs is about 100%. In average (50% of the time), 99% of the species would be affected by acute toxicity of COPCs, and about all the species would be affected by chronic toxicity of COPCs. Uncertainties in this assessment were associated with variability in ecosystem stressors, exposure data, ecological effect data, and risk characterization.     

区域农田镉含量空间变异与综合风险的不确定性评估

我国小麦镉 (Cd) 污染格局多样,从不确定性角度评估区域小麦田Cd累积风险有助于提升污染防治决策的准确性。本研究基于不确定性理论,将蒙特卡洛 (Monte-Carlo) 随机模拟方法引入到区域土壤-小麦系统Cd污染综合风险评估中,结合多元统计和空间分析开展实例研究。结果表明河南省某小麦主产区92.8%的土壤样品Cd含量超过农田土壤风险筛选值 (0.6 mg·kg⁻¹) ,84.0%的小麦籽粒样品Cd含量超过国家食品安全限量标准 (0.1 mg·kg⁻¹) 。区域土壤-小麦系统Cd累积水平整体上呈现西北高东南低的空间分布格局。区域Cd生态风险以中度污染为主。区域人群Cd摄入量超过WHO推荐安全值的风险概率为31.6%,控制土壤Cd累积趋势可将该超标风险下降至7.3%。不确定性模拟、空间分析和场景分析的综合应用可准确识别农田Cd污染风险等级和相应概率,为区域Cd污染防治提供决策建议。     

Assessing potential risks to wildlife and sportsmen from exposure to dioxin in pulp and paper mill sludge spread on managed woodlands

Potential human and wildlife exposures to TCDD in landspread pulp and paper mill sludge in the State of Maine were evaluated by means of a human health and an ecological risk assessment methodology. The highest historical concentrations of TCDD reported for these sludges do not present a risk to American woodcock, selected as an indicator species for this analysis. Concentrations of TCDD as high as 50 ppt in soil are not likely to produce adverse effects in the embryonic/hatchling stage of the woodcock. This soil concentration of TCDD does not present a significant risk to sportsmen and their families that may consume birds which inhabit these sites.     

Quantifying risks of toxic chemicals to aquatic populations and ecosystems

The objectives of regulatory practice have evolved from eliminating all risks of pesticides and toxic chemicals to the environment to reducing risks to acceptable levels. This change in philosophy requires the development of methods for quantifying the risks of toxicant exposure to the exposed biota. Ecological risk assessment models that are comparable those used in human health risk assessment have been developed using methods drawn from ecotoxicology, ecology, statistics, and mathematical modeling. Initial applications have shown that the regulation of pesticides and toxic chemicals can be substantially improved through the use of ecological risk assessment.     

A review of models for estimating terrestrial ecological receptor exposure to chemical contaminants

In instances where empirical measurements are not practicable, ecological risk assessments may rely on site-specific exposure models for estimating uptake of chemical contaminants. This paper presents, based on a review of the literature, a compilation of relatively simple quantitative models that can be combined to produce site- and species-specific first-order estimates of uptake of chemicals from abiotic media. These models have proved useful in providing order-of-magnitude estimates for screening and sample program design purposes. This paper intended as both a practical guide for choosing models to estimate terrestrial wildlife exposures and as a step toward development of a more comprehensive and standard approach to exposure assessment in terrestrial ecological receptors.     

Risk assessment and interpretation of heavy metal contaminated soils on an urban brownfield site in New York metropolitan area

In this study, soil samples were collected at 22 sites in Liberty State Park, New Jersey, in 2005, for metal enrichment and potential ecological risk assessment. The geoaccumulation index (I _geo) showed that enrichment levels of trace metals followed an order of Cu > Pb > Zn > As > Cr > Hg while the potential ecological risk factor (\( {E}_r^i \)) indicated that the potential ecological risk of the metals was in the order of Cu > Pb > As > Hg > Zn > Cr. Among these 22 sites, this investigation identified 9 sites at moderate ecological risk, 3 sites at considerable ecological risk, and 4 sites at high ecological risk according to the potential ecological risk index (RI). Hierarchical cluster analysis (CA) of soil metal concentrations separated the study sites into four groups, which are supported by the significant difference in RI values. Geographically, three regions in the Liberty State Park brownfield site were determined based on the CA results and RI values. Subarea 1 had low ecological risk while subareas 2 and 3 had a greater potential for ecological risk. Significant correlations of Pb with Cr and Zn were observed in subareas 2 and 3, respectively. This study shows that statistical approaches coupled with a risk assessment index provide a more comprehensive interpretation of land contamination than a single approach in support of planning land redevelopment.     

The application of predictive models in the environmental risk assessment of ECONOR

Environmental risk assessment of products requires information on the physico-chemical properties, persistence and ecotoxicity of the product, its constituents and possible metabolic and degradation products. Experimental investigations are usually required to generate this information and consequently risk assessment can be costly and time consuming. One possible approach to minimising the amount of experimental testing is to supplement experimental data with data predicted using models such as quantitative structure-activity relationships (QSARs). Using these models, information can be generated based primarily on the knowledge of the chemical structure of the substance(s) under investigation. In this study predictive models were used to assess the environmental risk of the veterinary medicine, ECONOR which contains the active ingredient valnemulin. Available experimental data on the properties, degradability and ecotoxicity of valnemulin was supplemented with predicted data. Where possible, experimental data was used to validate the predicted approaches and this indicated that the predictions were accurate. Information on usage, properties and degradability was input to fate models to predict environmental concentrations (PECs) of valnemulin in soil, pore water and groundwater. Comparison of PECs with experimental and predicted ecotoxicity data for valnemulin indicated that that even under 'worst case' scenarios the environmental risk posed by valnemulin was low.     

Vulnerability of Canadian aquatic ecosystems to nuclear accidents

Several cesium and strontium bioaccumulation models are used widely in national and international guidance for ecological and human health risk assessments for radiocesium (¹³⁴Cs and ¹³⁷Cs) and radiostrontium (⁹⁰Sr), but have not been used to make predictions of radiological risk from nuclear accidents under variable environmental conditions on broad geographical scales. In this paper, we first present models for predicting the bioaccumulation of cesium and strontium by aquatic biota based on ambient concentrations of dissolved potassium and calcium, respectively, and then test these models using independent data from aquatic ecosystems at Canadian nuclear sites. Secondly, models yielding the best predictions across a wide range of input parameters were selected to estimate bioaccumulation factors (BAFs) for cesium and strontium in aquatic ecosystems across Canada, using trophic level of organisms and dissolved potassium for cesium and calcium concentrations for strontium as predictor variables, and presented as contour maps of radiological risk. The models show that risk from bioaccumulation of cesium and strontium can vary by several orders of magnitude depending on site-specific environmental conditions and trophic ecology. Overall, our results suggest that single-parameter approaches taken by regulatory standards may either over- or under-predict radiological risk at many locations, and are thus not readily suitable to inform siting decisions for new nuclear developments.     

Environmental risk assessment of phosphonates,used in domestic laundry and cleaning agents in The Netherlands

In the long-term cooperative project Voluntary Plan of Action (1990) between the Dutch Soap and Detergent Association (NVZ) and the Dutch Ministry of Housing, Spatial Planning and the Environment (VROM) environmental risk assessments of several main components of laundry cleaning formulations were completed. As a part of that project the environmental risk assessment of HEDP, ATMP, EDTMP and DTPMP phosphonates used in detergent applications has been carried out according to the EU Technical Guidance Document for Environmental Risk Assessment for New and Existing Chemicals. All PEC/PNEC ratios were well below 1. Results of this assessment based on the total industry volumes from 1995 and 1998 indicate that the environmental risk of these phosphonates is low in The Netherlands with properly functioning sewage treatment plants.     

Ecological risk of pesticide residues in the British Columbia environment: 1973–2012

An updated ecological risk assessment was conducted to re-evaluate and review the overall risk of pesticide residues to certain aquatic life. The focus was the impact on offsite non-target, freshwater organisms of pesticide operational sprays in British Columbia from 1973 until 2012. The values of risk quotients for pesticides of selected indicator organisms were determined to measure the effect. When compared with organophosphorus, carbamate, and other miscellaneous pesticides, this risk assessment analysis suggests that the historical use of persistent and highly toxic organochlorine pesticides posed, and continue to pose, a deleterious ecological risk. The risk is both short-term acute and long-term sub-acute, chronic toxicity to offsite, non-target aquatic invertebrates and juvenile salmonid fish. Data indicated that these organisms were, and remain, subjected to harmful effects of pesticide residues to varying degrees. Most vulnerable were, and also are, benthic organisms inhabiting bottom sediments. This substrate is the natural sink for persistent pesticide residues, predominantly organochlorine pesticides from historical use, as well as dioxins, furans, and polycyclic aromatic hydrocarbons from wood preservatives, and other sources. Environment Canada's main aquatic protection strategy was a 10 metre no-treatment buffer zone, augmented with an additional appropriate setback along shorelines of fishery and wildlife resource-sensitive water bodies. This study discusses why this guideline was necessary, useful and effective, but was only partially successful. The physical-chemical properties of pesticide residues, from either an individual compound or different compounds in combination, also influence the nature of biological impacts on non-target, aquatic organisms. Few studies have been conducted in British Columbia aquatic environments to investigate the significance of this aspect.     

Marine ecosystem modeling beyond the box: using GIS to study carbon fluxes in a coastal ecosystem

Studies of carbon fluxes in marine ecosystems are often done by using box model approaches with basin size boxes, or highly resolved 3D models, and an emphasis on the pelagic component of the ecosystem. Those approaches work well in the ocean proper, but can give rise to considerable problems when applied to coastal systems, because of the scale of certain ecological niches and the fact that benthic organisms are the dominant functional group of the ecosystem. In addition, 3D models require an extensive modeling effort. In this project, an intermediate approach based on a high resolution (20x20 m) GIS data-grid has been developed for the coastal ecosystem in the Laxemar area (Baltic Sea, Sweden) based on a number of different site investigations. The model has been developed in the context of a safety assessment project for a proposed nuclear waste repository, in which the fate of hypothetically released radionuclides from the planned repository is estimated. The assessment project requires not only a good understanding of the ecosystem dynamics at the site, but also quantification of stocks and flows of matter in the system. The data-grid was then used to set up a carbon budget describing the spatial distribution of biomass, primary production, net ecosystem production and thus where carbon sinks and sources are located in the area. From these results, it was clear that there was a large variation in ecosystem characteristics within the basins and, on a larger scale, that the inner areas are net producing and the outer areas net respiring, even in shallow phytobenthic communities. Benthic processes had a similar or larger influence on carbon fluxes as advective processes in inner areas, whereas the opposite appears to be true in the outer basins. As many radionuclides are expected to follow the pathways of organic matter in the environment, these findings enhance our abilities to realistically describe and predict their fate in the ecosystem.     

利用AQUATOX模型评价淀山湖二氯甲烷生态风险

淀山湖地处上海的饮用水源地,水体中有机污染物的生态风险逐渐引起人们的重视。淀山湖水质监测结果显示,淀山湖中的挥发性有机物以二氯甲烷为主。应用美国环境保护署的AQUATOX模型对淀山湖水体中二氯甲烷进行模拟,并进行生态风险评价,旨在构建基于AQUATOX模型的水环境中有机物浓度模拟方法及风险评价的研究体系。结果显示,淀山湖中的二氯甲烷尚处于安全范围,但是需要加强观测,避免高风险的发生。     

Potential Impact on Standards for Toxic Air Contaminants

Since the Bhopal incident, the public has placed pressure on regulatory agencies to set community exposure limits for the dozens of chemicals that may be released by manufacturing facilities. More or less objective limits can be established for the vast majority of these chemicals through the use of risk assessment. However, each step of the risk assessment process (i.e., hazard identification, dose-response assessment, exposure assessment, and risk characterization) contains a number of pitfalls that scientists need to avoid to ensure that valid limits are established. For example, in the hazard identification step there has been little discrimination among animal carcinogens with respect to mechanism of action or the epidemiology experience. In the dose-response portion, rarely is the range of “plausible” estimated risks presented. Physiologically based pharmacokinetic (PB-PK) models should be used to understand the difference between the tissue doses and the administered dose, as well as the difference in target tissue concentrations of the toxicant between rodents and humans. Biologically-based models like the Moolgavkar-Knudson-Venzon (MKV) should be developed and used, when appropriate. The exposure assessment step can be significantly improved by using more sensitive and specific sampling and analytical methods, more accurate exposure parameters, and computer models that can account for complex environmental factors. Whenever possible, model predictions of exposure and uptake should be validated by biological monitoring of exposed persons (urine, blood, adipose) or by field measurements of plants, soil, fish, air, or water. In each portion of an assessment, the weight of evidence approach should be used to identify the most defensible value. In the risk characterization, the best estimate of the potential risk as well as the highest plausible risk should be presented. Future assessments would be much improved if quantitative uncertainty analyses were conducted. Procedures are currently available for making future assessments. By correcting some of these shortcomings in how health risk assessments have been conducted, scientists and risk managers should be better able to identify scientifically appropriate ambient air standards and emission limits.     

The current practice of health risk assessment: potential impact on standards for toxic air contaminants

Since the Bhopal incident, the public has placed pressure on regulatory agencies to set community exposure limits for the dozens of chemicals that may be released by manufacturing facilities. More or less objective limits can be established for the vast majority of these chemicals through the use of risk assessment. However, each step of the risk assessment process (i.e., hazard identification, dose-response assessment, exposure assessment, and risk characterization) contains a number of pitfalls that scientists need to avoid to ensure that valid limits are established. For example, in the hazard identification step there has been little discrimination among animal carcinogens with respect to mechanism of action or the epidemiology experience. In the dose-response portion, rarely is the range of "plausible" estimated risks presented. Physiologically based pharmacokinetic (PB-PK) models should be used to understand the difference between the tissue doses and the administered dose, as well as the difference in target tissue concentrations of the toxicant between rodents and humans. Biologically-based models like the Moolgavkar-Knudson-Venzon (MKV) should be developed and used, when appropriate. The exposure assessment step can be significantly improved by using more sensitive and specific sampling and analytical methods, more accurate exposure parameters, and computer models that can account for complex environmental factors. Whenever possible, model predictions of exposure and uptake should be validated by biological monitoring of exposed persons (urine, blood, adipose) or by field measurements of plants, soil, fish, air, or water. In each portion of an assessment, the weight of evidence approach should be used to identify the most defensible value. In the risk characterization, the best estimate of the potential risk as well as the highest plausible risk should be presented. Future assessments would be much improved if quantitative uncertainty analyses were conducted. Procedures are currently available for making future assessments. By correcting some of these shortcomings in how health risk assessments have been conducted, scientists and risk managers should be better able to identify scientifically appropriate ambient air standards and emission limits.     

胶州湾表层沉积物重金属污染分布特征及其生态风险评价

根据2009年对胶州湾东岸表层沉积物中重金属调查结果,对重金属含量分布及富集特征进行分析,并采用潜在生态危害指数(RI)法对其生态危害程度进行评价。结果表明,胶州湾东岸表层沉积物中的重金属含量,除7月的Cu、Cr平均含量略低于12月外,其他重金属(Cd、Zn、Pb、As)平均含量7月均高于12月。在表层沉积物中Cd的污染程度最高,7月平均污染指数达1.68。单个重金属潜在生态危害系数(Eir)表明,Cd的Eir大于其他重金属的Eir,其他重金属的Eir均小于轻微危害程度的划分标准,表明对胶州湾东岸生态环境具有潜在影响的重金属主要是Cd,从多个重金属的RI均值看,均小于150,属于轻微生态危害。