Quantify exposure

Example 15: Description of Indirect Pathway - Consuming Winter Flounder

The management site is within a larger area representing a winter flounder commercial fishery. The site is

close enough to shore to be a recreational fishery as well (although this example carries through only the

commercial fishing scenario).

The flounder are landed at a medium-sized city on the local bay, and the consumers are the people in the

local metropolitan area. The State Department of Marine Fisheries indicates that little, if any, of the

flounder are exported to a larger area.

Step 3: Quantify exposure

The quantification of indirect exposure proceeds by:

a. Specifying the equation to calculate a dose.

b. Estimating the exposure point concentration.

c. Reviewing site specific information for exposure factors.

d. Reviewing EPA default assumptions.

e. Running the calculation.

The exposure assessment quantifies exposure to human populations using a set

of fairly standard equations the choice of which depends upon the receptor,

exposure pathway, exposure route, and receptor activities. The equations calculate a

dose based on:

a. Exposure point concentrations.

b. Ability of the receptor to absorb the contaminant.

c. Ingestion rate.

d. Amount of seafood ingested from the area under the influence the

management area.

e. Frequency of seafood meals.

f. Body weight of the receptor.

g. Time over which the receptor consumes seafood.

This section describes those equations and their use for the indirect pathway.

Appendix E provides a set of equations to use for the less likely direct pathway.

Chapter 4 Human Health Risk Assessment