Description of Indirect Pathway - Consuming Winter Flounder

d. All the models used in the assessment are linear. Therefore, a simple

sensitivity analysis can be performed using the ranges of various

parameters.

Note that this estimate of potential risk applies to PCB exposures. The risk

from the other COCs at this hypothetical site (PAHs and mercury) should be

estimated as well. Also the risk characterization is iterative. At this point, the risk

assessor may want to implement more sophisticated estimates of sediment

concentrations using data intensive modeling. The assessor may also use a more

sophisticated food chain model (e.g., Appendix C).

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.

Body Burdens in Winter Flounder

As indicated earlier, the risk assessor has identified a population in the area

potentially exposed to PCBs from flounders in a commercial catch. The proposed

disposal site will influence a fraction of this flounder catch. As described earlier,

a tissue concentration of total PCBs can be calculated for flounder, based on

measured sediment concentrations and observed biota-to-sediment concentration

factors. These calculations resulted in a wet weight tissue concentration of 3.3 ug

total PCB/g flounder tissue for flounders foraging over the disposal site. This is

the EPC for total PCBs in the human health risk assessment.

Calculation of Fraction Ingested (FI) by Humans

Based on Fishery Statistics for Consumption of

Commercially Caught Flounder

The State Division of Marine Fisheries' winter flounder catch statistics

indicate that 30 percent of all of the flounder landed in the State come from

Statistical Area 4. For this example, Area 4 contains the hypothetical dredged

material disposal site and its area of influence. It is known that the foraging area

of a flounder is approximately 2 percent of Area 4.

F12

Appendix F Hypothetical Example