Overview of the Ecological Risk Assessment Process

Once these steps have been completed, the final step of problem formulation is to develop an analysis plan, which defines how the gocds, endpoints, and measures of effect will be evaluated at the site. 

To illustrate these steps, let s compare two sites with identical contamination in surface water and sediment. At one site, the surface water and sediment is part of a recreational fishing area (e.g., a lake stocked with trout). At the other site, the surface 

For the second example, the goal would be to protect individual ospreys from eating fish contaminated by chemiccds in the surface water and sediments. Because the osprey is a protected species, we need to manage effects at the level of the individual in a risk assessment. Because the management goals and our endpoint species differ between the two sites, our assessment endpoints and measures of effect will also differ. Based on our perceived relative value of the two habitats, we can tolerate more effects on individual trout at the first site than we can to individual ospreys at the second site. 

There are two components to the analysis phase characterization of exposure and characterization of effects. Overall, this phase is similar to the exposure and toxicity assessment components of a human health risk assessment. The primary differences relate to the variety of ways in which exposure and toxicity can be measured in an ecological risk assessment. 

Characterization of exposure includes identifying measures of exposure and conducting an exposure analysis, and culminates in development of an exposure profile. Exposure can be based on assumed intake assumptions, as is done for human health risk assessments, or can be based on direct measurements from animals or plants collected at the site. 

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Figure 8.4. Overview of the Ecological Risk Assessment Process [Adapted from U.S. ERA, 1998]...

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