Integrated Risk Assessment — Results from an International Workshop

The World Health Organization's International Programme on Chemical Safety and international partners have developed a framework for integrated assessment of human health and ecological risks and four case studies. An international workshop was convened to consider how ecological and health risk assessments might be integrated, the benefits of and obstacles to integration, and the research and mechanisms needed to facilitate implementation of integrated risk assessment. Using the case studies, workshop participants identified a number of opportunities to integrate the assessment process. Improved assessment quality, efficiency, and predictive capability were considered to be principal benefits of integration. Obstacles to acceptance and implementation of integrated risk assessment included the disciplinary and organizational barriers between ecological and health disciplines. A variety of mechanisms were offered to overcome these obstacles. Research recommendations included harmonization of exposure characterization and surveillance methods and models, development of common risk endpoints across taxa, improved understanding of mechanisms of effect at multiple scales of biological organization, and development of methods to facilitate comparison of risks among endpoints.     

Integrated Human and Ecological Risk Assessment: A Case Study of Tributyltin and Triphenyltin Compounds

Tributyltin and triphenyltin (TBT and TPT) are biocides that have been used to prevent fouling of boats, preserve wood, kill molluscs, and other uses. Due to observed effects on oysters and snails, their use in boat paints has been banned in many nations. However, use on ships and some uses other than as antifouling paints continue. These uses, the relative persistence of these compounds, their tendency to bioaccumulate, and their toxicity cause lingering concerns about risks to humans and non-human organisms. This paper outlines an integrated assessment of TBT and TPT. Based on prior human health and ecological assessments, it suggests that an integrated assessment that recognized common pathways of transport, fate and exposure, and common modes of action would be more efficient and complete than additional independent assessments. The presentation of risks in an integrated manner could also lead to better decisions by defining the various benefits of any management action.     

The Contribution of Systematic Review and Meta-Analysis Methods to Human Health Risk Assessment: Neurobehavioral Effects of Manganese

Current methods of human health risk assessment may lack transparency in respect of identification, review, and synthesis of potentially relevant human and animal evidence. The nature, degree, and source of uncertainties are often unclear. This article aims to demonstrate the contribution that systematic review and meta-analysis methods can make to providing more structured, transparent, and systematic risk assessments. We focus on disparities between five risk assessments for neurobehavioral effects of manganese, and then illustrate advantages of a systematic approach. Fifty-five human epidemiological studies and 37 animal experiments were identified. Where appropriate, meta-analysis methods demonstrated consistent adverse effects associated with manganese exposure across species. In particular, there was reduced activity in subjects exposed to manganese, although exposed rats tended to be more active than controls. Limitations of exposure measurement and reporting restricted use of more quantitative methods of evidence synthesis. From a methodological viewpoint, we conclude that systematic review and meta-analysis methods can contribute to a more systematic and transparent human health risk assessment making more efficient use of available evidence, compared to current methods of risk assessment. More complex methods could encompass further differences between relevant studies and so further improve the risk assessment process.     

Using Ecological Risk Assessment Principles in a Source Water Protection Assessment

It has become increasingly common to apply ecological risk assessment (ERA) principles to watershed and regional scale environmental management. This article describes the application of watershed ERA principles to the development of a source water protection assessment and a strategic watershed management plan. The primary focus was on the protection of drinking water quality, a concern typically addressed by human health risk assessors. The approach emphasizes adaptations to the problem formulation phase of ERA (defining assessment endpoints, developing conceptual models and an analysis plan) suitable for watershed management planning in a multi-objective, multi-stressor context. Physical, chemical, and biological attributes were selected for primary drinking water quality assessment endpoints, and coupled with additional assessment endpoints relevant to other environmental and social management objectives. Conceptual models helped the planning team to better understand and communicate the multiple natural and human stressors in the watershed and the causal pathways by which they affected drinking water. The article provides an example of the types of adaptations that can make ERA principles suitable for watershed management related to human health goals, and illustrates the efficiency of integrating health and ecological assessments.     

Ecological Risk Assessment and Ecological Epidemiology for Contaminated Sites

After 20 years of development, ecological risk assessment is widely accepted. However, it is evolving in response to a variety of technical and societal pressures. First, pressure for greater simplicity and standardization arise from the expectation that risk assessments should require little time and resources but be defensible. Second, the advance of the environmental sciences and increasing awareness of the complexity of ecological responses generate pressure for greater realism. Third, the dominance of human health risk assessment generates a pressure to integrate ecological risk assessment with that dominant field. Fourth, the demand for cost-benefit analysis creates pressure for integration with environmental economics. Finally, the need to connect the practice of ecological epidemiology with risk-based decision-making creates a pressure of the formation of a single integrated ecological assessment practice.     

Approaches for Integrated Risk Assessment

Recognizing the need to enhance the effectiveness and efficiency of risk assessments globally, the World Health Organization's International Programme on Chemical Safety, the U.S. Environmental Protection Agency, the European Commission, and the Organization for Economic Cooperation and Development developed a collaborative partnership to foster integration of assessment approaches used to evaluate human health and ecological risks. The objectives of this effort included: improving understanding of the benefits of integration, identifying obstacles to the integration process, and engaging key agencies, organizations, and scientific societies to promote integration. A framework with supporting documentation was developed to describe an approach for integration. Four case studies were constructed to illustrate how integrated risk assessments might be conducted for chemical and nonchemical stressors. The concepts and approaches developed in the project were evaluated in an international workshop. The goal of this effort was international acceptance of guidance for integrated risk assessment.     

The Concept of Data Utility in Health Risk Assessment: A Multi-Disciplinary Perspective

Human and ecological health risk assessments and the decisions that stem from them require the acquisition and analysis of data. In agencies that are responsible for health risk decision-making, data (and/or opinions/judgments) are obtained from sources such as scientific literature, analytical and process measurements, expert elicitation, inspection findings, and public and private research institutions. Although the particulars of conducting health risk assessments of given disciplines may be dramatically different, a common concern is the subjective nature of judging data utility. Often risk assessors are limited to available data that may not be completely appropriate to address the question being asked. Data utility refers to the ability of available data to support a risk-based decision for a particular risk assessment. This article familiarizes the audience with the concept of data utility and is intended to raise the awareness of data collectors (e.g., researchers), risk assessors, and risk managers to data utility issues in health risk assessments so data collection and use will be improved. In order to emphasize the cross-cutting nature of data utility, the discussion has not been organized into a classical partitioning of risk assessment concerns as being either human health- or ecological health-oriented, as per the U.S. Environmental Protection Agency's Superfund Program.     

Issues in Exposure and Dose Assessment for Epidemiology and Risk Assessment

Epidemiologic studies have been effective in identifying human environmental and occupational hazards. However, most epidemiologic data has been difficult to use in quantitative risk assessments because of the vague specification of exposure and dose. Toxicologic animal studies have used applied doses (quantities administered, or exposures with fixed duration) and well characterized end points to determine effects. However, direct use of animal data in human risk assessment has been limited by uncertainties in the extrapolation. The applied dose paradigm of toxicology is not suited for cross species extrapolation, nor for use in epidemiology as a dose metric because of the complexity of human exposures. Physiologically based pharmacokinetic (PBPK) modeling can estimate the time course of tissue concentrations in humans, given an exposure-time profile, and it has been used for extrapolating findings from animals to humans. It is proposed that human PBPK modeling can be used in appropriately designed epidemiologic studies to estimate tissue concentrations. Secondly, tissue time courses can be used to form dose metrics based on the type and time course of adverse effects. These dose metrics will strengthen the determination of epidemiologic dose-response relationships by reducing misclassification. Findings from this approach can be readily integrated into quantitative risk assessment.     

生态安全评价研究中的若干问题

生态安全评价是对生态系统完整性以及对各种风险下维持其健康的可持续能力的识别与研判,以生态风险和生态健康评价为核心内容,并体现人类安全的主导性．生态风险识别和生态脆弱性是生态风险评价的构成要素,生态健康则表现在生态完整性、生态系统活力与恢复力三方面．生态安全评价的准则与指标体系应将生态风险与生态健康有机结合。同时兼容不同空间尺度并能体现动态变化,其中在EDI、REI和IRI分类基础上叠加暴露分析指标是较大空间尺度生态安全指标体系建立的发展方向．文中综述了现阶段主要的生态安全评价方法,表明暴露-响应综合评价模式在现阶段应用最为广泛,生态模型法评价不同尺度的生态安全则是未来主要发展领域,并注重生态过程安全评价．生态安全评价研究需要与生态安全预测及预警研究相结合,并将生态安全的保障、维护与管理研究纳入其范畴．     

Species Risk Assessment of Microscopic Exotic Organisms Associated with Forest-Related Commodities and Goods

Recent increases in international trade have increased the cost to control and eradicate exotic species. Although many species are under quarantine control for agriculture, forestry, and public health, most species invisible to the naked eye are ignored because of the lack of both specialized assessors and risk assessments. We developed a species risk assessment particularly adapted to fungi, nematodes, and mites, that might be unintentionally introduced with exotic forest products and become threats to terrestrial ecosystems. We developed our assessment with reference to existing risk assessments for exotic organisms, including their ecological features such as phoresy and parasitism. We then tested our assessment with well-known organisms and assessed the risks of organisms unintentionally introduced into Japan. The assessment demonstrated scientifically acceptable scores for each organism. We suggest quarantine control of risk pathways as a practical approach for controlling unintentionally introduced organisms that are invisible to the naked eye.     

Safety and risk assessment for the human superorganism

This editorial on safety evaluation and risk assessment for the human superorganism introduces a series of papers arguing for a fundamental shift in how we approach human health risk assessment. In this series emphasis is placed on the risk of infectious disease. Our 21^stst century understanding of human biology is that, as holobionts, we possess a majority of microbial cells and genes. In fact, our microbes fundamentally affect our interactions with the external environment, metabolism, physiology, and risk of both pathology and disease. As holobionts, we require our microbial partners for us to be both complete and healthy. Using the 20^th century understanding of human biology, we failed to capture the effects of the microbiome in evaluating health risks. But 21^st century risk assessments such as those associated with exposure to specific microbial pathogens need to include the human microbiome. Microbiome status will be central in determining the health risks for both individuals and populations.     

Current Perspectives on Issues in Risk Assessment Methods

The Office of Research and Development (ORD) of the U.S. Environmental Protection Agency was reorganized in 1995 to follow the risk assessment paradigm developed by the National Research Council. With the reorganization, a number of different research strategies and plans were developed on problem-driven topics (e.g., arsenic, particulate matter, and microbial pathogens/disinfectant byproducts) as well as on core research (e.g., ecological research, human health risk assessment research, and pollution prevention research). The human health risk assessments research strategy, which is currently under development, addresses a variety of issues which affect all human health risk assessments. These include mechanism of action, variation in response, aggregate risk, and effect on public health. While all of the issues that have been identified are important, the challenge to ORD is to identify which will have the greatest impact on improving risk assessment so that resources can be most strategically applied.     

城市综合生态风险评价——以淮北市城区为例

城市面临复杂的生态风险,为了保障城市安全,需要对单一灾害或污染源的生态风险评估结果进行整合。基于城市复合生态系统特性,将当前城市地域常见的生态风险区分为自然灾害、环境污染及生态退化等3种主要类型,以土地利用单元作为风险受体,整合自然、人文、景观及环境因子,在现有生态风险评价研究方法基础上,构建了城市综合生态风险评价的空间分析框架。研究中选择淮北市城区作为研究区,针对研究区内存在的洪涝、干旱、水污染、大气污染、采煤塌陷及生态服务降低等生态风险类型,定量评价其空间差异,并提出相应的风险防范措施。案例分析结果表明,研究区综合生态风险较高的区域包括龙河、岱河、龙岱河与闸河等过境河流流经塌陷密集带的河段,北湖、东湖、中湖及南湖等人工湖泊沿岸,化家湖湖岸,及土型、新蔡、北杨新杨煤矿及其外围地区。由降低生态风险保障城市生态安全角度,在未来城市的整体规划中,建议结合城市外围绿地与城市内部的高风险区域,划设禁建或限建区域,共同构建淮北城市生态风险防范的空间结构。     

A Probabilistic Human Health Risk Assessment for Environmental Exposure to Dibutylphthalate

In the European Union, Directive 92/32/EC and EC Council Regulation (EC) 793/93 require the risk assessment of industrial chemicals. In this framework, it is agreed to characterise the level of “risk” by means of the deterministic quotient of exposure and effects parameters. Decision makers require that the uncertainty in the risk assessment be accounted for as explicitly as possible. Therefore, this paper intends to show the advantages and possibilities of a probabilistic human health risk assessment of an industrial chemical, dibutylphthalate (DBP). The risk assessment is based on non-cancer endpoints assumed to have a threshold for toxicity. This example risk assessment shows that a probabilistic risk assessment in the EU framework covering both the exposure and the effects assessment is feasible with currently available techniques. It shows the possibility of comparing the various uncertainties involved in a typical risk assessment, including the uncertainty in the exposure estimate, the uncertainty in the effect parameter, and the uncertainty in assessment factors used in the extrapolation from experimental animals to sensitive human beings. The analysis done did not confirm the reasonable worst-case character of the deterministic EU-assessment of DBP. Sensitivity analysis revealed the extrapolation procedure in the human effects assessment to be the main source of uncertainty. Since the probabilistic approach allows determination of the range of possible outcomes and their likelihood, it better informs both risk assessors and risk managers.     

Ecology,Environmental Impact Statements,and Ecological Risk Assessment: A Brief Historical Perspective

Ecological risk assessment will continue to increase in importance as a conceptual and methodological basis for evaluating environmental impacts as required by the National Environmental Policy Act. Understanding the historical strengths and limitations of more traditional environmental assessments performed in support of the NEPA can facilitate the effective incorporation of ecological risk assessment into the NEPA process. Such integration will also benefit from a knowledge of the historical and continuing development of the ecological risk assessment process, as well as from a recognition of the contri butions from modern quantitative ecology and ecosystem science. Adopting a risk-based approach can improve the NEPA process by providing a framework for consistent and comprehensive ecological assessment and by providing a conceptual and methodological basis for addressing the varied uncertainties attendant to environmental assessments. The primary concern in integrating ecological risk assessment into the NEPA process is that ecological risk assessment not merely become a new name for traditional environmental impact assessments. While the integration of ecological risk assessment into the NEPA process occurs, it is important to begin to outline the next transition in environmental assessment capabilities. Operationally linking ecological risk assessment methods with formal decision models appears as a worthwhile objective in beginning this transition.     

Hormesis and ecological risk assessment: Fact or fantasy?

Hormesis is a widespread phenomenon across occurring many taxa and chemicals, and, at the single species level, issues regarding the application of hormesis to human health and ecological risk assessment are similar. However, interpreting the significance of hormesis for even a single species in an ecological risk assessment can be complicated by competition with other species, predation effects, etc. In addition, ecological risk assessments may involve communities of hundreds or thousands of species as well as a range of ecological processes. Applying hormetic adjustments to threshold effect levels for chemicals derived from sensitivity distributions for a large number of species is impractical. For ecological risks, chemical stressors are frequently of lessor concern than physical stressors (e.g., habitat alteration) or biological stressors (e.g., introduced species), but the relevance of hormesis to non‐chemical stressors is unclear. Although ecological theories such as the intermediate disturbance hypothesis offer some intriguing similarities between chemical hormesis and hormetic‐like responses resulting from physical disturbances, mechanistic explanations are lacking. While further exploration of the relevance of hormesis to ecological risk assessment is desirable, it is unlikely that hormesis is a critical factor in most ecological risk assessments, given the magnitude of other uncertainties inherent in the process.     

The Use of Epidemiology in Risk Assessment: Challenges and Opportunities

The assessment of risk from environmental and occupational exposures incorporates and synthesizes data from a variety of scientific disciplines including toxicology and epidemiology. Epidemiological data have offered valuable contributions to the identification of human health hazards, estimation of human exposures, quantification of the exposure–response relation, and characterization of risks to specific target populations including sensitive populations. As with any scientific discipline, there are some uncertainties inherent in these data; however, the best human health risk assessments utilize all available information, characterizing strengths and limitations as appropriate. Human health risk assessors evaluating environmental and occupational exposures have raised concerns about the validity of using epidemiological data for risk assessment due to actual or perceived study limitations. This article highlights three concerns commonly raised during the development of human health risk assessments of environmental and occupational exposures: (a) error in the measurement of exposure, (b) potential confounding, and (c) the interpretation of non-linear or non-monotonic exposure–response data. These issues are often the content of scientific disagreement and debate among the human health risk assessment community, and we explore how these concerns may be contextualized, addressed, and often ameliorated.     

Wildlife strike risk assessment in several Italian airports: lessons from BRI and a new methodology implementation

The presence of wildlife in airport areas poses substantial hazards to aviation. Wildlife aircraft collisions (hereafter wildlife strikes) cause losses in terms of human lives and direct monetary losses for the aviation industry. In recent years, wildlife strikes have increased in parallel with air traffic increase and species habituation to anthropic areas. In this paper, we used an ecological approach to wildlife strike risk assessment to eight Italian international airports. The main achievement is a site-specific analysis that avoids flattening wildlife strike events on a large scale while maintaining comparable airport risk assessments. This second version of the Birdstrike Risk Index (BRI2) is a sensitive tool that provides different time scale results allowing appropriate management planning. The methodology applied has been developed in accordance with the Italian Civil Aviation Authority, which recognizes it as a national standard implemented in the advisory circular ENAC APT-01B.     

Determination of Field Effects of Contaminants—Significance of Pollution-Induced Community Tolerance

The concept of pollution-induced community tolerance (PICT) consists of the phenomenon that communities in an ecosystem exhibit increased tolerance as a result of exposure to contaminants. Although a range of ‘classic’ ecological principles explains the processes that increase tolerance of a community, the value of PICT for ecological risk assessment was recognized only recently (Blanck et al. 1988). The following issues are recognized: First, regarding the question on the role of suspect compounds causing ecological effects, the PICT approach covers the issue of causality better than ‘classical’ ecological community response parameters like species densities or species diversity indices. This relates to the fact that the level of PICT is assumed to be relatively constant (compared to density and diversity), whereas the suspect compound causing the observed effect can be deduced with relative clear inference from artificial exposure experiments. Second, PICT directly addresses a level of biological organization (the community), the level of concern for many ecological risk assessment methods. Other methods for risk assessment, like toxicity testing or bioassays, focus on individual or population-level effects, and need extrapolation of the results to the field. Such extrapolation step may pose problems regarding validity of the outcome of risk assessment. The occurrence of PICT is, however, not (yet) a community endpoint that is sufficiently underpinned to trigger risk mitigation activities. This paper especially focuses on the possibility to improve risk assessment approaches by incorporation of PICT assessments, especially focusing on the issue of causality and on the ecological meaning of PICT. Despite the advantages over ‘classical’ parameters, literature analysis suggests that the PICT approach may be strengthened by determining to which degree the PICT approach relates to ecological changes, like shifts in community structure, functioning, and stability. The aim of this paper is to summarize some literature, putting the emphasis on terrestrial studies, to get insights whether PICT is a sensitive and powerful tool to quantify ecological effects in field conditions, to link them to toxicant stress, and thus to determine whether PICT may be taken into consideration in risk assessment.