Indirect exposure pathways

b. Characterizing the individual's and population's activities and exposure

route (i.e., consumption of seafood).

c. Identifying the species consumed.

Defining the exposed population. The assumed exposed population should be of

individuals who potentially consume seafood that is exposed to the contaminants at

the dredged material site. This may be a local population consuming seafood from a

fishery which does not export outside a constrained geographic area. Alternatively,

the fishery may be serving a large metropolitan area. When possible, efforts should

be made to identify any sensitive populations, such as pregnant women and young

children, and any groups that may be subject to disproportionately high exposures,

such as subsistence fishermen [e.g., immigrant groups and Native Americans

(Executive Order 12898)].

Characterize receptor activities. Different exposure scenarios used in a human

health risk assessment may result in different risk estimates and different

management responses to those risks. Therefore, it is important to fully and

accurately characterize the types of activities which lead to exposure within each

scenario. The activities and indirect exposure route that are addressed in this

guidance include consumption/ingestion of seafood from:

a. Recreational or subsistence fishing.

b. Commercial fishing.

More than one exposure scenario for the ingestion of seafood may be required

for full characterization of human receptors. There may be several fisheries

potentially influenced by the disposal site, or the site may be used simultaneously by

commercial and recreational fishermen. Sources of site-specific information that can

be used to define the receptor's activities include:

a. Local and state departments of fisheries.

b. National Marine Fisheries Service (NMFS) National Oceanic and

Atmospheric Administration (NOAA).

c. Local university fishery and/or wildlife departments.

d. Surveys of local residents and fishing groups.

e. Local seafood distributors.

Identify the species. The Exposure Assessment should identify the dominant

species of seafood landed locally for recreational, subsistence, and commercially

caught seafood because the concentration of the contaminants in the seafood will

depend upon the foraging habits of the organisms, their ability to bioconcentrate the

chemicals of concern, and their position in the food web.

Chapter 4 Human Health Risk Assessment