Ecosystem ecological risk

In broad terms risk assessments are carried out to examine the effects of an agent on humans (Health Risk Assessment) and ecosystems (Ecological Risk Assessment). Environmental Risk Assessment (ERA) is the examination of risks resulting from technology that threaten ecosystems, animals and people. It includes human health risk assessments, ecological or ecotoxicological risk assessments, and specific industrial applications of risk assessment that examine end-points in people, biota or ecosystems. 

A risk estimate indicates Uie likelihood of occurrence of the different types of health or enviroinnental effects in exposed populations. Risk assessment should include both liuimn health and environmental evaluations (i.c., impacts on ecosystems). Ecological impacts include actual or potential effects on plants and animals (other than domesticated species). The number produced from the risk characleriznlion, representing the probability of adi crse... 

EcoFate EcoFate is a software package for conducting ecosystem based environmental and ecological risk assessments of chemical emissions by point and non-point sources in freshwater and marine aquatic ecosystems, including lakes, rivers and marine inlets... 

Brock TCM, Lahr J, Van den Brink PJ (2000) Ecological risks of pesticides in freshwater ecosystems, Part 1 Herbicides. Alterra-Rapport 088, Alterra, Wageningen... 

Critical load exceedances may serve as the basis for interpreting ecological impacts as ecological risks (or rather changes in the level of current risk to ecosystem health ). This would refer to the process of ecological risk characterization. 

These peculiarities of urban area development led to the technogenic biogeochemical provinces, i.e., the areas with local increase of pollutants in different components of urban ecosystems such as soils, grounds, surface and ground waters, plants, atmosphere. These pollutants create ecological risk to human and ecosystem health by their accumulation in the biogeochemical food webs (food stuffs and water). 

Thus the application of the conceptual model to monitoring data shows an existence of the ecological risk of river waters entering in the Caspian Sea. This is connected with (a) loss or leaching of DDT and HCH residues with relatively low transformation from LPA, (b) possible secondary risk of water contamination by POCs desorbed from bottom sediments, and (c) POCs content in aquatic ecosystems at toxic concentrations for the most sensitive organisms. 

Risk assessment Some participants suggested that further development and validation of appropriate methods to assess the ecological risks of chemical agents are required. Dose-response curves should be established at the community and ecosystem levels. Several participants suggested that when applying for an exemption of chemicals according to the Stockholm Convention, China might need to support its application with risk-based analysis. 

Markwiese, J.T. Ryti, R.T. Hooten, M.M. Michael, D.I. Hlohowskyj, I. Toxicity bioassays for ecological risk assessment in arid and semiarid ecosystems. Rev. Environ. Contam. Toxicol. 2001, 168, 43-98. 

It is essential to define the assessment scenario within which the assessment endpoint will be assessed. The assessment scenario should specify the spatial, temporal, and ecological boundaries within which the endpoint is assessed, since these have substantial implications for the structure of the assessment model and the scope of the input data. The assessment scenario should also describe those aspects of the ecosystem that are relevant to the assessment, that is, those aspects that have an influence on the mechanisms of exposure and effects that will be assessed. This step is important in all ecological risk assessments it places the assessment activity into the real context of an ecosystem, helps to prevent construction of inappropriate models, and helps with interpretation and communication of results. 

Calow P (1998) Ecological risk assessment risk for what How do we decide Ecotoxicol Environ Saf, 40, 15-18. Giesy, J.P. (2001) Hormesis - does it have relevance at the population-, community-or ecosystem-levels of organization Belle, 10, 14-17. 

Figure 28.3 The response time and sensitivity of an ecological receptor is a function of the level of biological organization. Higher levels of organization have greater ecosystem relevance. However, as the level of biological organization increases, response time increases, sensitivity decreases, and causal relationships become more uncertain. Ecological risk assessments must balance the need for sensitive, timely, and well-established responses with ecological relevance.

Burton, G.A. Jr., Chapman, P.M. and Smith, E.P. (2002a) Weight-of-evidence approaches for assessing ecosystem impairment, Human and Ecological Risk Assessment 8, 1657-1673. 

---