Use of Higher-Level Food Chain Models

Use of Higher-Level Food Chain Models

In some cases, the risk assessment may require a more sophisticated food chain

model which addresses exposure through food, water, and sediments. These models

(summarized in Appendix B) often address a group of species and allow calculation

of exposure concentrations through more complicated food chains. It is difficult to

provide simple guidance regarding when the risk assessor should consult such a

model. However, the complexity of the food chain models used in risk assessment

will generally increase as:

a. The number of contaminants of concern increases.

b. The number of receptor species increases.

c. Higher trophic levels are a focus of concern.

d. The potential area affected by the dredged material management site

increases.

e. The number of potential dredged material management options increase.

f. The number of exposure pathways increases.

The product of this step is an exposure dose, a dietary concentration, or a body

burden calculated under the assumptions of a site-specific scenario. Subsequent

sections will compare these to doses, dietary concentrations, or body burdens which

are associated with a potential ecological or biological effect.

Chapter 3 Ecological Exposure Assessment