The U.S. Environmental Protection Agency's Generic Ecological Assessment Endpoints

The U.S. Environmental Protection Agency determined that one of the major impediments to the advancement and application of ecological risk assessment is doubt concerning appropriate assessment endpoints. The Agency's Risk Assessment Forum determined that the best solution to this problem was to define a set of generic ecological assessment endpoints (GEAEs). They are assessment endpoints that are applicable to a wide range of ecological risk assessments; because they reflect the programmatic goals of the Agency, they are applicable to a wide array of environmental issues, and they may be estimated using existing assessment tools. They are not specifically defined for individual cases; some ad hoc elaboration by users is expected. The GEAEs are not exhaustive or mandatory. Although most of the Agency's ecological decisions have been based on organism-level effects, GEAEs are also defined for populations, ecosystems, and special places.     

The Ecological Component of Ecological Risk Assessment: Lessons from a Field Experiment

To improve ecological relevance, regulatory agencies are promoting assessments of effects at higher levels of organization, an objective that requires an understanding of current ecological theories. One such theory, hierarchy theory, contends that the effects of a disturbance acting at one level of organization (e.g., population) are not, as a rule, transmitted to higher levels of organization (e.g., community). Conversely, effects at higher levels of organization only occur if lower level variables have been affected. Further, responses to disturbance depend on disturbance history. In this study, I determined the effects of a disturbance treatment at the population, guild, and community levels of organization for vegetation in five wetlands with a disturbance history ranging from highly to rarely disturbed. The 2-year field experiment revealed that the effects of the disturbance treatment were most strongly felt at the population level of organization in wetlands without a history of disturbance. These observed impacts took place against a backdrop of constant change. Thus, the eventual disappearance of treatment effects was not due to a return to the pre-treatment state, but rather a return to a trajectory similar to that exhibited by the control plots. The implications of these results for ecological risk assessment are: (1) the observed effects of a stressor in a system cannot be extrapolated to other systems unless they have similar disturbance histories, (2) detecting effects before they become serious requires monitoring at lower levels of organization, (3) recovery to a naturally innate state is not a viable concept, and (4) the traditional approach of using one post-treatment measurement to determine if reference and impact sites differ is of very questionable value.     

Ecological Indicators in Risk Assessment: Workshop Summary

Ecological indicators can be defined as relatively simple measurements that relay scientific information about complex ecosystems. Such indicators are used to characterize risk in ecological risk assessment (ERA) and to mark progress toward resource management goals. In late 1997, scientists from the U.S. Environmental Protection Agency and from the Chemical Manufacturers Association (CMA) held a workshop to explore opportunities for collaborative research and scientific exchange on the development and application of ecological indicators. Several scientific challenges were identified as they relate to problem formulation, exposure and effects assessment, and risk characterization. Chief among these were a better understanding of multiple stressors (both chemical and non-chemical), characterization of reference sites and natural variability, extrapolation of measures to ecologically relevant scales, development of comprehensive, ecosystem-based models that incorporate multiple stressors and receptors, and a consistent system for evaluating ecological indicators.     

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.     

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.     

Addressing Susceptibility in Microbial Pathogen Risk Assessment

As concern for vulnerable subpopulations has grown, susceptibility has become a more important element in risk assessment and management processes. However, there is little consensus on how to incorporate or model the concept effectively in microbial pathogen risk assessment (MRA). Susceptibility is fundamentally a complex concept. There are many different definitions for it, reflecting the principles and viewpoints of the fields that contribute to risk assessment. Although susceptibility needs to be addressed in every step of the risk management paradigm, it has not yet been fully integrated into risk assessment, one step within the paradigm. Many factors are involved in characterizing and modeling susceptibility, but little is known about the relationships of many of the factors and many cannot be reliably measured. Recent MRA frameworks and case studies were reviewed for their approaches to susceptibility. Themes identified included limited or no explicit conceptualization of susceptibility in the problem formulation, limited data to assess susceptibility, heavy or exclusive emphasis on susceptibility in the health effects portion of the model, primary focus on host characteristics, and little consideration of susceptibility in risk characterization. Recommendations to improve approaches to susceptibility in MRA are presented.     

Developing A Regional Ecological Risk Assessment: A Case Study of a Tasmanian Agricultural Catchment

A regional ecological risk assessment was conducted for the Mountain River catchment in Tasmania, Australia. The Relative Risk Model was used in conjunction with geographic information systems interpretations. Stakeholder values were used to develop assessment endpoints, and regional stressors and habitats were identified. The risk hypotheses expressed in the conceptual model were that agriculture and land clearing for rural residential are producing multiple stressors that have potential for contamination of local waterbodies, eutrophication, changes in hydrology, reduction in the habitat of native flora and fauna, reductions in populations of beneficial insects in agricultural production systems, increased weed competition in pastures, and loss of aesthetic value in residential areas. In the risk analysis the catchment was divided into risk regions based on topography and land use. Stressors were ranked on likelihood of occurrence, while habitats were ranked on percentage land area. Risk characterization showed risks to the maintenance of productive primary industries were highest across all risk regions, followed by maintenance of a good residential environment and maintenance of fish populations. Sensitivity analysis was conducted to show the variability in risk outcomes stemming from uncertainty about stressors and habitats. Outcomes from this assessment provide a basis for planning regional environmental monitoring programs.     

An Ecological Basis for Integrated Environmental Management

Historically, approaches to environmental management activities have been reactive rather than proactive. Environmental laws and regulations have been generated primarily in response to particular issues (e.g., chemical contamination), creating a piecemeal approach for managing the environment. Responsibilities for managing different resources (e.g., water, air, forests, wildlife) have been assigned to different agencies or groups within government, further fragmenting environmental management. Proactive approaches that recognize the interconnectedness of environmental components are necessary to address complex and long-term environmental management issues. This Perspective proposes an environmental management approach that is comprehensive and systematic, while still being comprehensible to decision-makers and other stakeholders. The proposed approach is based on ecology and environmental values related to decision-making. It considers interrelationships among and between living organisms (including humans) and their physical environment. The proposed approach builds on the ecological risk assessment (ERA) paradigm, including goal (or problem) identification, values identification (ecological and human) for the environment being managed, and data collection and analysis focused on management decision-making. Stakeholder involvement and active participation are essential elements. As demonstrated herein, application of the proposed framework has enabled environmental managers to achieve workable solutions and to avoid or resolve environmental conflicts at both local and regional scales. The proposed framework is demonstrably transportable across political boundaries, applicable to all environments involving natural resources, independent of any particular ideology, and applicable to environmental management activities at all scales.     

Recommended Avian Toxicity Reference Value for Cadmium: Justification and Rationale for Use in Ecological Risk Assessments

The understanding of Cd impacts to avian species has been improved by recent studies and the extensive literature review completed as part of the development of the U.S. Environmental Protection Agency's Ecological Soil Screening Levels (Eco-SSLs). Therefore, we sought to update the Cd toxicity reference value (TRV) for birds used by regulatory agencies and resource trustees in California for predictive ecological risk assessments. We surveyed the available literature sources, particularly TRVs between the currently used TRV (0.08 mg/kg/d) and the Eco-SSL TRV (1.47 mg/kg/d) to identify the lowest, ecologically relevant no observed adverse effect levels (NOAELs) for oral exposure of birds to Cd. As a result, we identified an ecologically protective NOAEL TRV of 0.7 mg/kg/d, based primarily on renal effects in wood ducks, but supported by another study with both renal and reproductive endpoints. In addition, a lowest observed adverse effect level (LOAEL) of 1.0 mg/kg/d was selected based on kidney nephrosis in mallards. Overall, these updated TRVs incorporate more recent studies on Cd toxicity in birds while establishing thresholds based on ecologically relevant endpoints.     

The Changing Focus of the Ecological Risk Assessment of Aquaculture Operations: From Local to Cumulative Risk Assessment

Ecological risk assessment (ERA) methodologies must be continually improved so that resource managers, activity proponents, and stakeholders can better manage the environmental impacts of human activities. One of the largest challenges facing ERA methodologies and approaches is to develop the ability to encompass cumulative and far-field effects of human activities. It is argued here that the ERAs of industrial aquaculture activities have been an example of where ERA practitioners and researchers have responded to the challenge of managing the cumulative risks of a new and rapidly growing industry by developing innovative ERA approaches that can be applied elsewhere.     

Framework for the Integration of Health and Ecological Risk Assessment

The World Health Organization's International Programme on Chemical Safety (IPCS), the Organization for Economic Cooperation and Development (OECD), and the U.S. Environmental Protection Agency have developed a collaborative partnership to foster integration of assessment approaches for human health and ecological risks. This paper presents the framework developed by that group. Integration provides coherent expressions of assessment results, incorporates the interdependence of humans and the environment, uses sentinel organisms, and improves the efficiency and quality of assessments relative to independent human health and ecological risk assessments. The paper describes how integration can occur within each component of risk assessment, and communicates the benefits of integration at each point. The goal of this effort is to promote the use of this internationally accepted guidance as a basis for harmonization of risk assessment.     

Salmon and Complexity: Challenges to Assessment

Salmon in the U.S. Pacific Northwest are in widespread decline despite countless environmental assessment studies and billions of dollars spent. Having been involved in environmental assessment for more than three decades, I am forced to conclude that this decline tells us that our established practices of assessment and management are fundamentally deficient. Rather than studying the salmon, we should examine our own practices. These practices presume that, if individual actions are found to be beneficial through analytical assessments, the cumulative outcomes of many actions will also be beneficial. This “linear” presumption is embedded in institutions, analytical methods, and assessment practices. For a whole class of emerging problems, including declining salmon, this presumption is fundamentally wrong. Declining salmon provide a warning that our own analytical habits of thought and notions of progress are leading to outcomes that are both destructive and contrary to our best intentions. This paper is a response to this warning.     

Bioindicators Versus Biomarkers in Ecological Risk Assessment

The biomarker approach, adopted from medical toxicology, is subject to several theoretical and practical difficulties when used to address environmental problems. The problems are related to the definition that emphasizes measurement but does not specify a requirement to establish cause-effect linkages. An improved definition for a bioindicator is reviewed. The sentinel species approach is judged to be a biomarker rather than a bioindicator, and therefore of limited use for environmental risk assessment. An empirical weight of evidence approach to improve the utility of sentinel species is proposed.     

Applications of Background Data in Ecological Risk Assessment: Various Shades of Gray

This paper discusses general approaches for evaluating the utility and manner of conducting background analyses in soil for ecological risk assessments. The types and sources of background data are discussed, and advantages and disadvantages of using literature-based versus site-specific background data are presented. The value of background evaluations is discussed with regard to the goals and objectives for a project. A comparison of literature-based ecological soil screening levels with generic metal background concentrations is presented to illustrate a typical problem in incorporating background data in ecological risk assessments, which is that many generic background concentrations are higher than ecological screening levels. This brings into question both the relevance of ecological screening levels and generic background levels. These issues are discussed along with cost-benefit considerations in an attempt to provide recommendations for determining the most appropriate type of background evaluation to conduct at a given site.     

Special report of the Massachusetts weight‐of‐evidence workgroup A weight‐of‐evidence approach for evaluating ecological risks

Weight‐of‐evidence is the process by which multiple measurement endpoints are related to an assessment endpoint to evaluate whether significant risk of harm is posed to the environment. In this paper, a methodology is offered for reconciling or balancing multiple lines of evidence pertaining to an assessment endpoint. Weight‐of‐evidence is reflected in three characteristics of measurement endpoints: (a) the weight assigned to each measurement endpoint; (b) the magnitude of response observed in the measurement endpoint; and (c) the concurrence among outcomes of multiple measurement endpoints. First, weights are assigned to measurement endpoints based on attributes related to: (a) strength of association between assessment and measurement endpoints; (b) data quality; and (c) study design and execution. Second, the magnitude of response in the measurement endpoint is evaluated with respect to whether the measurement endpoint indicates the presence or absence of harm; as well as the magnitude. Third, concurrence among measurement endpoints is evaluated by plotting the findings of the two preceding steps on a matrix for each measurement endpoint evaluated. The matrix allows easy visual examination of agreements or divergences among measurement endpoints, facilitating interpretation of the collection of measurement endpoints with respect to the assessment endpoint. A qualitative adaptation of the weight‐of‐evidence approach is also presented.     

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.     

生态风险研究述评

生态风险(ＥｃｏｌｏｇｉｃａｌＲｉｓｋ,ＥＲ),指一个种群、生态系统或整个景观的正常功能受外界胁迫,从而在目前和将来减小该系统健康、生产力、遗传结构、经济价值和美学价值的一种状况[20]。生态风险评估(ＥｃｏｌｏｇｉｃａｌＲｉｓｋＡｓｓｅｓｓｍｅｎｔ,ＥＲＡ)指受一个或多个胁迫因素影响后,对不利的生态后果出现的可能性进行的评估。美国环保局(ＥＰＡ)把这种尚不为人们所重视的领域叫做生态风险评估[20,48]。随着新技术和新方法的应用,ＥＲＡ的研究领域迅速扩展。早期的生态风险评估主要是针对人类健康而言的,也就是人类健康风险…