Risk-Based Management of Site Soils Contaminated with a Mixture of Hazardous Substances: Methodological Approach and Case Study

A novel approach to improve the accuracy and to reduce the uncertainty associated with the assessment of ecotoxicological risks and the determination of remedial objectives was developed herein for a scenario involving multiple contaminants in soil. This approach used laboratory-derived site-specific toxicological data (i.e., obtained from toxicity testing using species in direct contact with soil such as plants and invertebrates) instead of the more traditional approach using generic toxicological benchmarks for corresponding groups of organisms. Inherent to this approach were the data exploration and reduction; the use of generalized linear models to integrate the data for stressors (site-specific chemical and edaphic characteristics with the potential for influencing toxicity) and effects (biological responses for multiple species and multiple endpoints); and the derivation of tools that could predict the level of impairment associated with any combination of metals’ concentrations measured on site and compare it to a pre-specified acceptable threshold. A case study is presented whereby this method was applied to a large site contaminated with a mixture of metals. Ultimately, the distributions of predicted levels of risk for both soil invertebrates and plants were determined for the entire site and compared to those obtained using the traditional approach using benchmarks.     

污染场地土壤生态风险评估研究进展

随着我国快速城市化以及产业结构的调整,遗留下了大量的污染场地,发展和实施污染场地土壤生态风险评估是进行大规模污染场地修复行动的必要条件。本文围绕污染场地土壤生态风险评估的科学原理、框架构建及技术方法等方面的关键问题: 1)评估框架的场地实际针对性;2)概念模型的不确定性;3)土壤复合污染毒性机制;4)评估终点筛选;5)评估方法和框架构建等展开讨论,指出土壤复合污染的制毒机制,即污染物生物有效性和联合效应是污染场地土壤生态风险评估的关键科学问题。耦合美国环保局四步法和欧盟层级法的“证据-权重法”评估框架适用于野外复杂环境条件下的土壤污染生态风险评估。建议今后重点开展以下5个方面的工作: 1)污染场地土壤生态风险评估技术框架与风险管控技术框架之间的联合;2)概念模型研究;3)基于过程的场地土壤污染物反应运移模型研究;4)场地土壤复合污染生态毒理学机制研究;5)生态系统高水平生态风险评估终点研究。旨在为形成我国本土污染场地土壤生态风险评估技术指南提供理论基础和构架。     

土壤污染生态毒性效应评价研究进展

随着社会经济的高度发展,人类活动加剧,我国土壤污染问题突出,不仅威胁人体健康,同时也严重威胁动植物及微生物的安全,生态安全问题不容忽视。但是我国土壤污染风险管控目前主要关注人体健康,对生态系统的关注较少,缺乏土壤污染生态风险评估技术指南及基于生态风险的土壤环境质量基准及标准。准确评价土壤污染生态毒性效应,是制定土壤环境质量标准、实现生态风险评估及预警与管控的重要基础。针对土壤污染生态毒性效应评价问题,分别对土壤污染生态毒性效应特征、评价方法、评价终点、暴露-效应关系构建、生态毒性效应外推,以及群落水平与复合污染生态毒性效应评价等方面的关键问题展开了讨论,指出目前土壤污染生态毒性效应评价主要是基于单物种的急性毒性测试,利用个体和亚个体水平的指示物作为评价终点,缺乏针对群落及生态系统高水平评价终点的生态毒性效应评价方法,定量评价污染物尤其是复合污染物对土壤生物群落及生态系统的影响,是土壤污染生态毒性效应评价的关键问题和难点问题。建议今后重点开展以下3方面的工作1)群落及生态系统水平评价终点的筛选;2)土壤污染生态毒性效应环境影响因子识别及影响机制研究;3)土壤复合污染联合毒性效应定量评价及...     

Plan for an Integrated Human and Environmental Risk Assessment in the S. Domingos Mine Area (Portugal)

The need for the integration of the assessment of human and ecological risks in contaminated areas, such as derelict mines, widely increases. The risk assessment process is becoming a powerful tool to provide sound scientific bases for decision-making processes. In Portugal, the risk assessment process is in its early years and the lack of multidisciplinary teams of experts is frequently mentioned as the main obstacle to its implementation. Therefore, the majority of the reclamation actions are based on impact assessment studies that usually are characterized by few biological and toxicological considerations. In order to account for some of these constraints, the ecological risk assessment framework proposed by the U.S. Environmental Protection Agency was used to plan the assessment of human and ecological risks posed by the high concentrations of metals scattered in the vicinity of S. Domingos mine, a cuprous pyrite mine located in the Southeast Alentejo (Portugal). This study presents the problem formulation phase of the assessment. It includes all the scientific information available for the area, a conceptual model, and an analysis plan for the risk assessment process. Following a tiered approach, several tasks were planned in order to acquire chemical, toxicological, and ecological information, in order to compensate for the lack of toxicity data for site-specific species.     

Ecotoxicity Test Data for Total Petroleum Hydrocarbons in Soil: Plants and Soil-Dwelling Invertebrates

Ecotoxicity benchmarks for petroleum mixtures can be used in a screening-level ecological risk assessment. Data from studies evaluating the toxicity of total petroleum hydrocarbons (TPH) to plants and soil invertebrates were reviewed for possible application to soil benchmark development. Toxicity data included LOAECs; estimated EC25s, EC20s, and LC50s; effective concentrations that caused greater than a 20% level of effect; and NOAECs. The variabilities in petroleum material, chemical analytical methodology, age of hydrocarbon-soil contact, nutrient amendment, and measured effects levels did not permit much meaningful aggregation of the data. Tenth, twenty-fifth, and fiftieth percentiles of toxicity and no-effects data are presented for unaggregated results within studies. Effects on invertebrates often occurred at concentrations of TPH lower than those associated with effects on plants. Lighter mixtures generally were associated with lower ranges of effects concentrations than heavier crude oil. Few aged and non-aged samples were available from the same study, and these did not show obvious trends regarding toxicity. Similarly, the addition of nutrients to promote bioremediation was not observed across studies to alter effective or nontoxic concentrations in a systematic way. Existing toxicity data are not sufficient to establish broadly applicable TPH ecotoxicity screening benchmarks with much confidence, even for specific mixtures.     

低剂量混合污染生态毒理与风险评价研究进展

环境中的化学品往往以低剂量混合形式存在.对单一化学品高剂量暴露下的生态毒性研究成果,难以适用于环境中低剂量混合物的生态毒理效应诊断及风险评价.文中概述了低剂量化学品混合污染生态毒理及风险评价方面的研究进展,主要包括低剂量化学品混合污染诊断的分子毒理研究方法、风险评价方法,并介绍了简单和复杂混合物的风险评价方案.对低剂量混合污染生态毒理与风险评价研究的发展动向提出了见解,指出低剂量化学混合物的研究需要寻找敏感终点,引入多学科手段,积累更多的数据,建立完善、统一的评价体系.     

A Regional Multiple-Stressor Rank-Based Ecological Risk Assessment for the Fjord of Port Valdez,Alaska

We conducted an ecological risk assessment of the marine environment of Port Valdez, a fjord in south-central Alaska. Because the assessment was regional rather than site-specific and contained a large number of different stressors in a variety of environments, we required a nontraditional method to estimate risks. We created a Relative Risk Model to rank and sum individual risks numerically within each subarea, from each source, and to each habitat. Application of this model involved division of Port Valdez into 11 subareas containing specific ecological and anthropogenic structures and activities. Within each subarea, the stressor sources were analyzed to estimate exposure of receptors within habitats leading to effects relevant to the chosen assessment endpoints. The subareas were analyzed and compared to form a Port-wide perspective of ecological risk. Available chemical concentrations from sediment and mussels collected from the Port were compared to various toxicological benchmarks as a partial confirmation of the risk analysis. An estimation of the risk of polycyclic aromatic hydrocarbons (PAHs) to marine invertebrates indicated low risk. The municipal boat harbor had the highest estimate, which reflected our relative risk rankings. The Relative Risk Model approach appears robust and has potential for use in situations where multiple stressors are of concern and for assessments covering broad geographic areas. In the Port Valdez assessment the approach provided relative risk rankings for chemical and physical stressors from various sources. But data were available for confirmation of risk estimates only for the chemical stressors. The rankings are relative, and extrapolation beyond the scenario in which they were developed is not warranted. Uncertainty is large, and the numerical scores collapse a multidimensional space into a single value. Use of just the numerical score out of context is more valid than with other indexes. The value of the approach lies in the relative rankings and the accounting of the components of the relative risk score.     

Quantitative Exposure-Response Assessment Approaches to Evaluate Acute Inhalation Toxicity of Phosgene

Phosgene has been a long-term subject of toxicological research due to its widespread use, high toxicity, and status as a model of chemically induced lung injury. To take advantage of the abundant data set for the acute inhalation toxicity of phosgene, methods for exposure-response analysis that use more data than the traditional no-observed-adverse-effect level approach were used to perform an exposure-response assessment for phosgene. Categorical regression is particularly useful for acute exposures due to the ability to combine studies of various exposure durations, and thus provide estimates of effect severity for a range of both exposure concentrations and durations. Results from the categorical regression approach were compared to those from parametric curve fitting models (i.e., benchmark concentration models) that make use of information from an entire dose-response, but only for one exposure duration. While categorical regression analysis provided results that were comparable to benchmark concentration results, categorical regression provides an improvement over that technique by accounting for the effects of both exposure concentration and duration on response. The other major advantage afforded by categorical regression is the ability to combine studies, allowing the quantitative use of a larger data set, which increases confidence in the final result.     

Extending life cycle assessment normalization factors and use of machine learning – A Slovenian case study

Within a life cycle assessment (LCA), normalization is an essential part for interpretation. In Europe, only the European Union normalization factors (EU NFs), with 2000 as the reference year, are available for LCA practitioners, although they work on a regional level. The hypothesis of this research was based on the assumption that some regional NFs deviate from the EU NFs due to unique regional profiles, or because of previously omitted or generalized human impact. In this particular case study set in Slovenia has been tested. By working on the ReCiPe 1.08 life cycle impact assessment methodology, 18 impact categories were investigated, and an additional 3 were added: electromagnetic radiation, light pollution and electric use. To meet practitioners’ needs, the most up-to-date inventory data was used with the reference years of 2007–2012. Out of 440 environmental interventions that were investigated, 139 had no characterization factors (CFs), 97 were estimated using machine learning and 42 had to be omitted. The final result confirmed our hypothesis. Twenty NFs were compared with the EU NFs, and the results have shown that on average, the NFs differ by a factor of 9.76 (median = 1.65). The reasons for the high deviation are due to natural land transformation, and ionising radiation, toxicological and ecotoxicological impact categories; where there are major data gaps in the CFs. The primary concern of the research was data availability for toxicological and ecotoxicological parameters for toxicity-related emissions, and the fact that original CFs covered only 50.25% of plant protection products used in Slovenia. Toxicological and ecotoxicological uncertainties were illustrated by comparing four different results. Future studies should be focused on the use of machine learning to provide the next generation of CFs and to go beyond the CFs’ damage-oriented assessment. Remediation should be the new endpoint category and its units should be Joules.     

The Food Web Approach in Ecotoxicological Risk Assessment

The Standing Committee on Ecotoxicology of the Health Council of the Netherlands (see note at the end of this article) has reported on the potential and limitations associated with the use of food web models in ecotoxicological risk assessment. This paper closely follows the executive summary of that report. The current appoach in ecotoxicological risk assessment is based on single species toxicity tests. It is felt that the food web approach, which takes feeding relationships between species in ecosystems into account, provides an opportunity to address effects of toxic substances on the ecosystem level. It is considered to be particularly useful in site-specific risk assessment concerning specific (types of) ecosystems. However, supplementary research must be carried out before food web models can be used in ecotoxicological risk assessment.     

Harmonization: Developing Consistent Guidelines for Applying Mode of Action and Dosimetry Information to Cancer and Noncancer Risk Assessment

The 1983 book, Risk Assessment in the Federal Government: Managing the Process, recommended developing consistent inference guidelines for cancer risk assessment. Over the last 15 years, extensive guidance have been provided for hazard assessment for cancer and other endpoints. However, as noted in several recent reports, much less progress has occurred in developing consistent guidelines for quantitative dose response assessment methodologies. This paper proposes an approach for dose response assessment guided by consideration of mode of action (pharmacodynamics) and tissue dosimetry (pharmacokinetics). As articulated here, this systematic process involves eight steps in which available information is integrated, leading first to quantitative analyses of dose response behaviors in the test species followed by quantitative analyses of relevant human exposures. The process should be equally appropriate for both cancer and noncancer endpoints. The eight steps describe the necessary procedures for incorporating mechanistic data and provide multiple options based upon the mode of action by which the chemical causes the toxicity. Given the range of issues involved in developing such a procedure, we have simply sketched the process, focusing on major approaches for using toxicological data and on major options; many details remain to be filled in. However, consistent with the revised carcinogen risk assessment guidance (USEPA, 1996c), we propose a process that would ultimately utilize biologically based or chemical specific pharmacokinetic and pharmacodynamic models as the backbone of these analyses. In the nearer term, these approaches will be combined with analysis of data using more empirical models including options intended for use in the absence of detailed information. A major emphasis in developing any harmonized process is distinguishing policy decisions from those decisions that are affected by the quality and quantity of toxicological data. Identification of data limitations also identifies areas where further study should reduce uncertainty in the final risk evaluations. A flexible dose response assessment procedure is needed to insure that sound toxicological study results are appropriately used to influence risk management decision-making and to encourage the conduct of toxicological studies oriented toward application for dose response assessments.     

A review on the ecological quality status assessment in aquatic systems using community based indicators and ecotoxicological tools: what might be the added value of their combination?

The European Water Framework Directive (WFD) represents a transformation of the guidelines for water quality assessment and monitoring across all EU Member States. At present, it is widely accepted that the WFD requires holistic and multidisciplinary ecological approaches by integrating multiple lines of evidence. Within the scope of the WFD, the scientific community identified clear opportunities to take advantage of an ecotoxicological line of evidence. In this context, ecotoxicological tools, namely biomarkers and bioassays, were proposed to contribute to the integration of the chemical and biological indicators, and thus to provide an overall insight into the quality of a water body. More than one decade after the publication of the WFD, we reviewed the studies that have attempted to integrate ecotoxicological tools in the assessment of surface water bodies. For this purpose, we reviewed studies providing an ecological water status assessment through more conventional community based approaches, in which biomarkers and/or bioassays were also applied to complement the evaluation. Overall, from our review emerges that studies at community level appear suitable for assessing the ecological quality of water bodies, whereas the bioassays/biomarkers are especially useful as early warning systems and to investigate the causes of ecological impairment, allowing a better understanding of the cause–effect-relationships. In this sense, community level responses and biomarkers/bioassays seem to be clearly complementary, reinforcing the need of combining the approaches of different disciplines to achieve the best evaluation of ecosystem communities’ health.     

Environmental Risks Caused by Pesticides at Forest Nurseries in Finland

Previously, various persistent pesticides were used extensively in the production of seedlings at Finnish forest nurseries. The extent and magnitude of the risks arising from the consequent environmental contamination are largely unknown. Therefore, we selected two representative nurseries for which we conducted tiered health risk assessments (HRA) using risk-based benchmarks and two calculation tools (SSL and Risc-Human software). Ecological risk assessments (ERA) involved comparisons of environmental concentrations with ecotoxicological benchmarks. Site investigations revealed that the concentration of several pesticides exceeded the Finnish soil quality guidelines in some places. The compost pile for organic residues and the pond receiving runoffs contained traces of pesticides and the maximum concentration of atrazine and terbuthylazine in groundwater exceeded the corresponding guideline for household water. Hexachlorobenzene proved to pose the highest health risks, the maximum hazard quotient being around 10 (carcinogenity-based) in the residential land use scenario. Owing to the conservative assumptions, health risks are expected to remain insignificant, however. Risks to the local terrestrial ecosystem would also remain low, while only further studies will reveal the actual risks to the adjoining aquatic ecosystem. Both calculation tools showed shortcomings that generate uncertainty in the HRA, whereas the ERA was hampered particularly by the lack of benchmarks.     

Evaluation of Ecotoxicological Field Studies for Authorization of Plant Protection Products in Europe

An increasing number of ecotoxicological field studies are being submitted in the European Union procedure for authorization of pesticides. Although there is some guidance on how these studies can be used for risk assessment, not all aspects of field tests are covered and the guidance differs per type of test and per non-target group. To facilitate a more uniform approach by the regulatory authorities in the EU, a basic scheme is proposed with qualitative tools to: (i) assess the scientific reliability of individual field tests, and (ii) to assess the usefulness of field tests for regulatory risk assessment of the pesticide under registration. In this way, the treatment, evaluation, and the mutual comparability of field data for regulatory purposes is harmonized. It thereby provides a more consistent foundation for further risk assessment.     

Environmental benchmarks for buildings: a critical literature review

Purpose

To reduce the environmental impact of the building sector, environmental targets considering the full life cycle of buildings can be supportive. In recent years, various benchmarks based on Life Cycle Assessment (LCA) have been developed as part of regulations, labelling systems, sustainability rating tools and research studies. The objective of this paper is to critically analyse 23 existing benchmarking systems focusing on the benchmark methodology but also on the benchmark applications and communication.

Methods

The critical literature review consists of two parts. In a first part, the choices related to the assessment method, functional equivalent, definition of benchmark values, benchmark scope, benchmark applications and benchmark communication are compared. In the second part, benchmark values are compiled from literature and statistically analysed.

Results and discussion

The comparative analysis allows to identify the main approaches and methods used in benchmarking systems. For each evaluation aspect, the strengths and weaknesses of the various approaches are highlighted. The statistical analysis provides insight in the spread of benchmark values. Important variations are found between the literature sources which can be explained by differences in benchmark approach, scope, system boundaries and applications.

Conclusions

Based on the comparative analysis, recommendations are formulated for the development of LCA benchmarks for the building sector. The results of the statistical analysis furthermore provide reference values which can be used for the validation of future benchmarks. For global warming, the statistical values for the full life cycle impacts (i.e. embodied and operational impacts) range from about 15 up to 35 kg CO₂ eq/m².a.

     

Benchmark dose profiles for joint‐action continuous data in quantitative risk assessment

Benchmark analysis is a widely used tool in biomedical and environmental risk assessment. Therein, estimation of minimum exposure levels, called benchmark doses (BMDs), that induce a prespecified benchmark response (BMR) is well understood for the case of an adverse response to a single stimulus. For cases where two agents are studied in tandem, however, the benchmark approach is far less developed. This paper demonstrates how the benchmark modeling paradigm can be expanded from the single‐agent setting to joint‐action, two‐agent studies. Focus is on continuous response outcomes. Extending the single‐exposure setting, representations of risk are based on a joint‐action dose–response model involving both agents. Based on such a model, the concept of a benchmark profile—a two‐dimensional analog of the single‐dose BMD at which both agents achieve the specified BMR—is defined for use in quantitative risk characterization and assessment.     

A benchmarking and assessment framework to operationalise ecological indicators based on time series analysis

The call for ecosystem considerations in marine management has instigated the use of ecosystem indicators. Many ecosystem indicators have been suggested under new policy frameworks such as the EU Marine Strategy Framework Directive or the Common Fisheries Policy. But many of these indicators are still under development and cannot be considered as yet operational for environmental assessments. A common reason for this lack of operationability is the absence of valid assessment benchmarks. This study introduces a two-stage approach for the benchmarking and assessment of time series (TSBA) against a priori chosen rationale of improvement or maintenance of current conditions. TSBA uses breakpoint- and trend-analysis to obtain long-term benchmarks and assess short term progress. Depending on the outcome of both analyses the action requirements for management can be determined. The method is exemplified on a case study on the size-structure of large North Sea gadoid stocks, which are considered as being sensitive to the impacts of fishing. Three out of six stocks reached their assessment benchmarks, while the three other stocks failed. TSBA is generic and can be applied to any indicator used within any marine policy assessment framework. A strength–weaknesses–opportunity–threat analysis (SWOT) investigated the advantages and disadvantages of TSBA in the context of the currently high political demand of operational ecosystem indicators. Contrary to benchmarks derived from ecological concepts or pressure-state relationship TSBA benchmarks are not specifically linked to limits of resilience or sustainability. However, TSBA may be especially useful in situations where assessment benchmarks from other sources will not be readily available or are associated with high uncertainty.     

蚯蚓在环境安全研究中的应用

蚯蚓在环境污染的生态毒理学诊断方面具有重要生态学意义,这是蚯蚓在环境安全研究中应用的基础。本文概述了蚯蚓生态毒理诊断的一些试验方法,包括急性毒性试验法、田间生态毒性试验法、污染环境的生物检测法和微观生物指标检测法。在这基础上,就蚯蚓的环境安全生态指示研究进展进行了剖析与展望。还从蚯蚓处理生活垃圾与农业有机废弃物以及污水的蚯蚓过滤处理等应用方面,论述了蚯蚓在污染环境解毒过程中的重要生态作用及今后的发展方向。