Ecological Risk Assessment of China's Freshwater Ecosystems Applying the Relative Risk Model: Toward an Ecosystem-Based Water Management in China

The relative risk model (RRM) was applied to evaluate the ecological risk characterization of the freshwater ecosystems in China, from both overall and region-specific levels. Ten large-scale river basins (further broken into 15 risk regions) in China were chosen as the study objects; 10 sources, two habitats, and seven endpoints were identified as risk components. The results reveal the status of ecosystem conditions, key ecological risk issues, and the spatial heterogeneity of the freshwater ecosystems in China. The policy implications for the ecosystem-based water management contained in the results are discussed. The results obtained in this article provide a deeper understanding of the ecological risk characterization of the freshwater ecosystems in China, and aid in promoting the applications of the RRM as the tool for ecosystem-based water management.     

Quantitative Consideration of Ecosystem Characteristics in an Ecological Risk Assessment: A Case Study

Development of assessment endpoints and conceptual models aids ecological risk assessors in identifying measurable attributes that will allow quantification and prediction of risk. Measures of exposure and effect are explicitly considered, usually quantitatively, in nearly every ecological risk assessment, while measures of ecosystem characteristics are generally addressed only implicitly, if at all. Yet these characteristics influence both the behavior and location of assessment endpoint entities and the spatial and temporal distribution of stressors. This case study illustrates use of a regression partitioning model to quantify the influence of ecosystem characteristics (e.g., land use patterns, nutrient concentrations) on the concentration of a chemical stressor (atrazine) in surface waters of a large river basin. The model partitioned the basin into five land use groups ranging from High Forested to Very High Agriculture. Literature-derived chronic effects data were used with a joint-probability model to characterize atrazine risk to an aquatic assessment entity in each of these land use subgroups. Atrazine concentrations and risk directly correlated with the intensity of agricultural land use. This permits risk management to focus on agricultural areas within the basin; a focus that would not have been possible without explicitly considering ecosystem characteristics.     

Trends in the Development of Ecological Risk Assessment and Management Frameworks

Ecological risk assessment and management have grown from a long history of assessment and management activities aimed at improving the everyday lives of humans. The background against which ecological risk assessment and management has developed is discussed and recent trends in the development of risk assessment and management frameworks documented. Seven frameworks from five different countries are examined. All maintain an important role for science, suggest adaptive approaches to decision-making and have well-defined analytical steps. Differences in approaches toward the separation of policy and science, the preference for management over assessment, the inclusion of stakeholders, the iterative nature of the analytical cycle, the use of decision criteria and economic information suggest considerable evolution in framework design over time. Despite the changes, no consensus on the design of a framework is apparent and work remains to be done on refining an integrative framework that effectively incorporates both policy and science considerations for environmental management purposes.     

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.     

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.     

太子河流域河流生态功能评价及其管理策略

在河段尺度下,采用指标评价法对太子河流域的水生生物多样性维持、生境维持、水环境支持和水文支持4项生态功能进行评价,排序求和得到河流的主导功能和综合功能评分. 结果表明：全部河段可评定为4个综合生态功能等级,整体上呈现由山区向平原区递减的趋势. 结合综合生态功能和主导生态功能评价结果,提出了6项河流生态管理策略.其中,对于水生生物多样性维持功能和生境维持功能的河段,管理策略以生态管理为主,即“生态保护”、“生态维持”和“生态修复”;对于水环境支持功能和水文支持功能的河段,管理策略则以开发管理为主,即“限制开发”、“优化开发”和“开发利用”.     

Role of Ecological Modeling in Risk Assessment

Ecological models are useful tools for evaluating the ecological significance of observed or predicted effects of toxic chemicals on individual organisms. Current risk estimation approaches using hazard quotients for individual-level endpoints have limited utility for assessing risks at the population, ecosystem, and landscape levels, which are the most relevant indicators for environmental management. In this paper, we define different types of ecological models, summarize their input and output variables, and present examples of the role of some recommended models in chemical risk assessments. A variety of population and ecosystem models have been applied successfully to evaluate ecological risks, including population viability of endangered species, habitat fragmentation, and toxic chemical issues. In particular, population models are widely available, and their value in predicting dynamics of natural populations has been demonstrated. Although data are often limited on vital rates and doseresponse functions needed for ecological modeling, accurate prediction of ecological effects may not be needed for all assessments. Often, a comparative assessment of risk (e.g., relative to baseline or reference) is of primary interest. Ecological modeling is currently a valuable approach for addressing many chemical risk assessment issues, including screening-level evaluations.     

Ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments from the middle and lower reaches of the Yellow River,China

In this research, ecological risks for eight individual polycyclic aromatic hydrocarbons (PAHs) and ∑PAH₈ in surface sediments from middle and lower reaches of Yellow River are evaluated using overlapping areas of probability density curves and margin of safety (MOS), based on the toxicity data and the exposure concentrations of PAHs in sediments collected from 23 sites. In the overlapping areas of probability density curves, the risk of Ant and Pyr are the highest, then the risk level is in the order of Flua > Nap > Phe > BaP > Flu > Ace. The values of MOS₁₀ present that Pyr (4.62 × 10^?4), Ant (5.60 × 10^?3), and Flua (6.4 × 10^?3) have a significantly high ecological risk level, while Nap and Phe have middle-level ecological risk. As for Ace, BaP, and Flu, they pose limited risk to the ecological system with MOS₁₀ greater than 1.0. The ∑PAH₈ (2.66 × 10^?5) is a higher risk level than that of any individual PAHs, where the probabilities of ∑PAH₈ in excess of the 10th percentile of the toxicity data were 86%.     

Indicators for Human and Ecological Risk Assessment: A U.S. Environmental Protection Agency Perspective

Assessment of risk to public health or environmental resources requires competent characterization of stressors and corresponding effects. Because of the complexity of most stressor-response relationships, it is impossible to completely characterize all the variables, so a select set of measurements is made to reflect the most critical components. Such measurements, or indicators, are included in monitoring programs to estimate trend, stressor source, or magnitude of effects and lead to thresholds for management action or restoration. Although a wide variety of programs and program objectives exists, there are some common challenges for indicator development, including a strong link to management actions. Indicator measurements used in U.S. Environmental Protection Agency (USEPA) risk assessment activities must stem from collaboration among managers, risk assessors, scientists and stakeholders. The primary objective of the USEPA's Fifth Symposium of the National Health and Ecological Effects Research Laboratory was to improve health and ecological risk assessment through dedicated sessions that maximized interaction and discussion among these groups. Existing measurements were challenged for appropriateness, efficiency and scientific validity. Emerging science was explored for greater understanding, better interpretation, and improved methodology. A secondary objective was to uncover and exploit common indicators and supporting data for human health and ecological models.     

A Regional Ecological Risk Assessment of the Kaipara Harbour,New Zealand,Using a Relative Risk Model

A regional ecological risk assessment was conducted for the Kaipara Harbour catchment in New Zealand. The Relative Risk Model was used to prioritize management of the sources of stress and habitats of concern in the basin. Semi-structured interviews with 25 representative stakeholders were conducted to obtain the resource-users’ perspectives and to identify the regional stressor sources and receptor habitat data for the model. For this risk analysis we divided the catchment into nine ecological districts. Mixed-methodological approaches including content analysis, geospatial analysis, and source documentation were used to categorize source and habitat rankings, based on the relative abundance of each in the nine ecological districts. Risk characterization revealed that fishing pressure and tidal energy pose the largest sources of perceived risk to the catchment; shellfish and Maui dolphin habitats are the receptors estimated to be at greatest risk; and the Kaipara and Rodney ecological districts are the sub-regions estimated with the greatest combined risk. A Monte Carlo analysis confirmed the source inputs and revealed greater uncertainty than the estimated habitat input results. The results of this assessment can be used by policy-makers, conservation groups, and municipalities to inform the future management efforts in the harbor and catchment.     

黄河口湿地生态需水量估算

黄河口拥有中国暖温带面积最广阔、自然属性最显著、结构最完整的滨海湿地生态系统,因处在河-海-陆交汇的复杂界面,湿地生态系统十分脆弱。满足生态需水是维持湿地生态系统健康的基础和关键,但以往估算缺乏系统综合性视角且存在时间尺度较粗的问题。从维持湿地面积、保护生物多样性及稳定生态系统功能和过程3个目标出发,构建了包含5项指标的湿地生态需水指标体系,对湿地3个等级、3个时段生态需水进行了估算,并据此判断了2000年至2019年黄河口湿地在极端丰水年及枯水年生态需水的满足状况,结果表明：黄河口湿地全年的最小、适宜、最大生态需水量分别为13.33×10⁸ m³、22.33×10⁸ m³、35.31×10⁸ m³;4—6月、7—10月、11—3月的适宜生态需水量分别为6.76×10⁸ m³、10.10×10⁸ m³、5.47×10⁸ m³;...     

黄河上游流域生态系统服务变化及其权衡协同关系

黄河上游是我国重要的生态屏障和生态功能区,研究其生态系统服务的时空演化及其权衡协同关系对实现黄河流域生态保护和高质量发展具有重要意义。基于土地利用、土壤、气象等数据,借助InVEST模型、相关性分析以及空间自相关分析等方法,定量分析了2000-2020年黄河上游生态系统服务的时空演化特征及其权衡与协同关系。结果表明:(1)黄河上游各项生态系统服务整体表现为"西南高,东北低"的分布格局,高值区主要分布于流域西南部,低值区主要分布于流域东北部;(2)研究期内,黄河上游各项生态系统服务均呈现波动变化的趋势,产水量和土壤保持呈现整体减少趋势,生境质量与碳储量呈现增加的趋势;(3)各项生态系统服务两两之间均存在不同程度的相关关系,产水量与生境质量、碳储量呈现此消彼长的权衡关系,产水量-土壤保持、生境质量-碳储量与土壤保持-碳储量之间呈现协同关系;(4)在空间分布格局上,各项生态系统服务间的权衡与协同关系表现出显著的空间异质性与尺度效应,不同分区之间差异较大。本文可为科学管理区域生态系统,促进流域可持续发展提供参考。     

Types of Integration in Risk Assessment and Management,And Why They Are Needed

Risk-based decision making requires that the decision makers and stakeholders are informed of all risks that are potentially significant and relevant to the decision. The International Programme on Chemical Safety of the World Health Organization has developed a framework for integrating the assessment of human health and ecological risks. However, other types of integration are needed to support particular environmental decisions. They are integration of exposure and effects, of multiple chemicals and other hazardous agents, of multiple routes of exposure, of multiple endpoints, multiple receptors, multiple spatial and temporal scales, a product's life cycle, management alternatives, and socioeconomics with risk assessment. Inclusion of all these factors in an integrated assessment could lead to paralysis by analysis. Therefore, it is important that assessors be cognizant of the decision process and that decision makers and those who will influence the decision (stakeholders) be involved in planning the assessment to ensure that the degree of integration is necessary and sufficient.     

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.     

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.     

A Human Health Risk Assessment Software for Facilitating Management of Urban Contaminated Sites: A Case Study: The Massa Site,Tuscany, Italy

The goal of this article is to present the Human Health Risk Assessment (HRA) software developed as one of the NORISC ^{1 1}NORISC is the acronym of the project “Network Oriented Risk assessment by In-situ Screening of Contaminated sites” realized under under the 5th European Union Community Framework Programme for Research, Technological Development and Demonstration Activities. View all notes decision support software system components that could be used as a tool for facilitating management of urban contaminated sites. The NORISC-HRA software provides sufficient technical and procedural support to conduct a simple site-specific risk assessment. The employed HRA methodology is generally based on U.S. Environmental Protection Agency (USEPA) procedures. The software determines the level and spatial distribution of human health risks at a given site and sets up site-specific preliminary Health-Based Remedial Goals (HBRGs)/Risk-Based Concentrations (RBCs) for soil and groundwater. The NORISC-HRA software is recommended for use when national soil and groundwater limit values are exceeded. Exposure pathways considered in this software are associated with three land use patterns—residential, industrial/commercial, and recreational. The aricle also presents the software testing results obtained at one of the NORISC test sites—the Massa site (Avenza-Carrara, Tuscany, Italy). Findings of the HRA indicated that the contaminated soil at the Massa test site might pose potential cancer and non-cancer risks to industrial workers in its present condition. Arsenic was the dominant substance responsible for most of the baseline risk and at the RBC of 1.77 mg/kg it was the primary driver of remedial decisions at the Massa site.     

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.     

Approaches to Ecological Risk Characterization and Management: Selecting the Right Tools for the Job

Chemical-specific hazard quotient (HQ) risk characterization in ecological risk assessment (ERA) can be a value-added tool for risk management decision-making at chemical release sites, when applied appropriately. However, there is little consensus regarding how HQ results can be used for risk management decision-making at the population, community, and ecosystem levels. Furthermore, stakeholders are reluctant to consider alternatives to HQ results for risk management decisions. Chemical-specific HQs risk characterization should be viewed as only one of several approaches (i.e., tools) for addressing ecological issues; and in many situations, other quantitative and qualitative approaches will likely result in superior risk management decisions. The purpose of this paper is to address fundamental issues and limitations associated with chemical-specific HQ risk characterization in ERA, to identify when it may be appropriate, to explore alternatives that are currently available, and to identify areas that could be developed for the future. Several alternatives (i.e., compensatory restoration, performance-based ecological monitoring, ecological significance criteria, net environmental benefit analysis), including their limitations, that can supplement, augment, or substitute for HQs in ERA are presented. In addition, areas of research (i.e., wildlife habitat assessment/landscape ecology/population biology, and field validated risk-based screening levels) that could yield new tools are discussed.     

Distribution and Contamination Risk Assessment of Dissolved Trace Metals in Surface Waters in the Yellow River Delta

This study investigated the dissolved trace metal contamination levels of Zn, Sr, B, Al, Ba, Fe, Mn, Li, V, Be, Cd, Cr, Cu, Mo, Ni, Se, and Pb in 23 surface waters of the Yellow River Delta (YRD) in China. Coefficients of variation with 66–260% reflected large spatial variations of concentrations of metals. Compared to drinking water guidelines established by the World Health Organization and the U.S. Environmental Protection Agency, the primary trace metal pollution components (Al, B, V, and Zn) were above drinking water standard levels by 82.6%, 47.8%, 52.2%, and 52.2%, respectively. Preliminary risk assessments were determined via the Hazard Quotient (HQ) to evaluate the human health risk of these metals. HQ_ingestion of V indicated potential deleterious health effects for residents. Hierarchical cluster results revealed that clusters 1, 2, and 3 were primarily affected by pollution from industrial and domestic activities, natural and agriculture activities, and oil fields, respectively. Principal component analysis results indicated Fe, Mn, Al, and Ba were controlled by natural sources, whereas anthropogenic activities led to high pollution levels of Al, B, V, Zn, and Sr.