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1.
In the Pacific Northwest of the United States, it is urgent to assess accurately the various options proposed to restore wild salmon. For the past 150 years, a variety of analytic approaches have been employed to assess the ecological consequences of salmon management options. Each approach provided useful information to decision makers, but each also suffered from limitations, some relatively minor, others sufficient to undermine any potential utility. Risk assessment has become the most widely used analytic approach to evaluate environmental policy options. To date its use in ecological policy has been largely constrained to evaluating relatively simple technical questions (e.g., regulatory actions associated with specific chemicals or hazardous waste sites). Recently, however, there has been interest in applying risk assessment to more complex ecological policy problems (e.g., the decline of wild salmon in the Pacific Northwest). Although its use has become commonplace and widely accepted, especially among regulatory and land management agencies, risk assessment remains contentious. The most heated debates revolve around delineating the specific meaning of risk; that is, framing the risk “question” to be answered.  相似文献   

2.
Wild Pacific salmon populations are in serious decline, and as a result, a number of salmon stocks are listed as threatened or endangered under the Endangered Species Act. Our research identifies and supports the possibility that certain environmental contaminants can alter salmon survival, and as a result may contribute to these species being at risk. We have shown that juvenile chinook salmon (Oncorhynchus tshawytscha) are exposed to polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) as they migrate through a contaminated urban estuary in Puget Sound WA (the Duwamish Waterway estuary). Immune function was analyzed in these fish by examining the ability of their anterior kidney and splenic leukocytes to produce a primary and secondary in vitro plaque-forming cell (PFC) response to the hapten, trinitrophenyl (TNP), and by determining their susceptibility to a marine pathogen, Vibrio anguillarum. We found that fish outmigrating from the urban estuary produced a significantly lower PFC response to TNP and were more susceptible to the pathogen, compared to juvenile salmon collected from a rural estuary during their outmigration. In the laboratory, we exposed juvenile chinook salmon collected from a hatchery to either a PCB technical mixture or a PAH compound to determine if these contaminants have the potential to alter immune function in salmon. Indeed, we found that salmon exposed in the laboratory to either the PCB mixture or the PAH also produced lower PFC responses and were more susceptible to disease compared to animals treated with the solvent vehicle. In summary, contaminants such as PAHs and PCBs are demonstrated to influence salmon health, and thus have the potential to adversely impact salmon populations.  相似文献   

3.
The functional importance of bacteria and fungi in terrestrial systems is recognized widely. However, microbial population, community, and functional measurement endpoints change rapidly and across very short spatial scales. Measurement endpoints of microbes tend to be highly responsive to typical fluxes of temperature, moisture, oxygen, and many other noncontaminant factors. Functional redundancy across broad taxonomic groups enables wild swings in community composition without remarkable change in rates of decomposition or community respiration. Consequently, it is exceedingly difficult to relate specific microbial activities with indications of adverse and unacceptable environmental conditions. Moreover, changes in microbial processes do not necessarily result in consequences to plant and animal populations or communities, which in the end are the resources most commonly identified as those to be protected. Therefore, unless more definitive linkages are made between specific microbial effects and an adverse condition for typical assessment endpoint species, microbial endpoints will continue to have limited use in risk assessments; they will not drive the process as primary assessment endpoints.  相似文献   

4.
In 1999 and 2000, two environmental consulting companies independently prepared risk assessments of the Lower Fox River waste site in Wisconsin. Because the two assessments produced somewhat different risk characterizations, the Association for Environmental Health & Sciences was asked by the site's Potentially Responsible Party to form a peer review panel to critique and compare the two assessments. The panel found interesting differences between the two risk assessments and recommended that their observations, together with the two risk assessments, be made available as a Teaching Tool for persons interested in conducting human and ecological risk assessments. An accompanying CD contains these and other materials useful for teaching purposes.  相似文献   

5.
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.  相似文献   

6.
Ozone is an unusual trace gas in the atmosphere, presenting a challenge for risk assessors and risk managers. The challenge can be traced to the gas’ complex chemistry in the atmosphere (exposure), toxicology in biological systems (response), and the fledgling enterprise of risk assessment for widely distributed, highly reactive pollutants. This paper addresses the (i) co-evolution of the scientific data underlying ozone risk assessment on human health, natural resources (crops and managed forests), and unmanaged ecosystems, (ii) similarities and differences in risk assessment among these receptors, and (iii) utility of indicators in risk assessment. The scientific community has developed a sound database to underpin the ozone risk assessment, although the breadth and depth differ markedly among the three receptors. There are similarities in ozone risk assessment among human health, natural resources, and ecology, including features of exposure (e.g., temporal variation), response of plants and humans (e.g., sensitive cohorts), and integration of exposure and response (e.g., importance of peak and cumulative exposures). Equally important are the notable differences, and the more prominent are scaling of exposure-response relationships, air quality monitoring, economic valuation, and models to complement more traditional experimental approaches. Of the three receptors, the status of indicators for conducting ecological ozone risk assessment is the weakest.  相似文献   

7.
    
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.  相似文献   

8.
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.  相似文献   

9.
Successful ecological risk assessments are all alike; every unsuccessful ecological risk assessment fails in its own way. Tolstoy posited a similar analogy in his novel Anna Karenina: “Happy families are all alike; every unhappy family is unhappy in its own way.” By that, Tolstoy meant that for a marriage to be happy, it had to succeed in several key aspects. Failure on even one of these aspects, and the marriage is doomed. In this paper, I argue that the Anna Karenina principle also applies to ecological risk assessments involving multiple stressors. In particular, I argue that multiple stressors assessments and environmental decision making will not have a happy marriage unless the following can be achieved: (1) there must be societal and political buy-in to the assessment and decision-making process; (2) the assessment must have the latitude to consider a wide range of stressors and potential risk management options; (3) there must be a commitment to following a rigorous focusing of the assessment and to expending resources for model development and data collection; and (4) an adaptive management strategy must be adopted wherein risk management actions are undertaken, system response intensively observed and assessed, and revised management actions taken as appropriate. Failure to meet any of the above criteria for success will doom a multiple stressors assessment and prevent its use in effective decision-making.  相似文献   

10.
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.  相似文献   

11.
Approaches for Integrated Risk Assessment   总被引:1,自引:0,他引:1  
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.  相似文献   

12.
13.
14.
Interstudy variation among bioavailability studies is a primary deterrent to a universal methodology to assess metals bioavailability to soil-dwelling organisms and is largely the result of specific experimental conditions unique to independent studies. Accordingly, two datasets were established from relevant literature; one includes data from studies related to bioaccumulation (total obs = 520), while the other contains data from studies related to toxicity (total obs = 1264). Experimental factors that affected toxicity and bioaccumulation independent of the effect of soil chemical/physical properties were statistically apportioned from the variation attributed to soil chemical/physical properties for both datasets using a linear mixed model. Residual bioaccumulation data were then used to develop a non-parametric regression tree whereby bootstrap and cross-validation techniques were used to internally validate the resulting decision rule. A similar approach was employed with the toxicity dataset as an independent external validation. A validated decision rule is presented as a quantitative assessment tool that characterizes typical aerobic soils in terms of their potential to sequester common divalent cationic metal contaminants and mitigate their bioavailability to soil-dwelling biota.  相似文献   

15.
城镇化过程生态风险评价案例研究   总被引:13,自引:1,他引:13       下载免费PDF全文
周启星  王如松 《生态学报》1998,18(4):337-342
选择我国小城镇发展较为迅速的浙中地区(主要以巍山镇为例)采用变量相关的生态学方法,对其城镇化过程的生态风险评价作了尝试,结果表明,癌症和高血压等“文明病”的发病率随着城镇化水平的提高而逐年上升,具体表现为与城镇居住人口(包括农业人口和非农业人口)密度,居民人口增加,年龄,性别,乡镇工业和交通发展等有关,是城镇生态系统中有害物浓度和输入通量增加对人类生存与发展作用的结果,反映了城镇化过程中所遭受的生  相似文献   

16.
Over the past 30 years, risk assessment has developed into a scientific discipline. It is critical that the next generation of risk assessors understand the history of our field, and recognize the numerous successes and failures that have taken place. This short Perspective identifies and describes specific books, monographs, and reports that are required reading for any nascent risk assessor.  相似文献   

17.
Inorganic chloramines are formed when chlorine and ammonia are combined in water. These substances are frequently used as a secondary disinfectant for drinking water and are by-products of processes involving the disinfection of wastewaters and the control of biological fouling in cooling water systems. For chloraminate drinking water, the total residual chlorine (TRC) concentration may be almost completely due to monochloramine. Based on 1995 and 1996 survey data, the most significant and prevalent TRC loading to the Canadian environment is from municipal wastewater releases. Drinking water releases are the next most important source of chloramine entry into the Canadian environment, while TRC releases from other sources, such as cooling water, zebra mussel control practices and industrial wastewater, are much less important. A probabilistic water quality model was used to model two wastewater discharges and a cooling water discharge to different freshwater systems. The resulting exposure distributions were then compared with three incipient lethality endpoints, i.e., 50% mortality to the invertebrate Ceriodaphnia dubia and 50% and 20% mortality to juvenile chinook salmon (Oncorhynchus tshawytscha). For each discharge scenario studied, there were moderate to high probabilities of significant adverse effects on aquatic life up to 1.9?km from the effluent sources.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
The scientific approach toward ecological risk assessment (ERA) has advanced greatly during the 1990s. This growth has been accompanied by the development of ERA guidance by USEPA Headquarters, individual USEPA Regions, state environmental agencies, as well as international agencies. This compilation of ERA guidance and procedural documents identifies many of the existing ERA reference materials from the regulatory and/or governmental agency arena. In addition, this compilation provides annotations pertaining to the focus of each reviewed document, and compares/contrasts the approaches presented in the documents. As such, the evaluation provides insight into some of the qualities and levels of detail provided by each document. Examples of documents which are highlighted include recently published USEPA's “Guidelines for Ecological Risk Assessment;” USEPA's “Ecological Risk Assessment Guidance for Superfund;” the U.S. Army's “Procedural Guidelines for Ecological Risk Assessments;” and Environment Canada's “Ecological Risk Assessments Under the Canadian Environmental Protection Act.”  相似文献   

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