Public Health Assessment Public Comment Release
(2 [mg/kg/day]-1) to be used for such exposures as food chain exposure, sediment or soil
ingestion, presence of dioxin-like congeners, and early-life exposures. EPA also calculated less
conservative oral slope factors for use in other situations (for example, when toxic PCB
congeners make up less than % of the mixture or for more water-soluble congeners) [8].
Complete Exposure Pathways and Contaminants of Concern
Fish Pathway
(particularly PCBs) build up over time in fish tissue, people who eat the fish might be exposed to
contaminants by eating the fish.
Composite samples of fish were collected in May 2003 during the remedial investigation. Fish
were sampled from the unnamed tributary to Little Brier Creek and the Brier Creek Reservoir.
Whole body samples of fish from the unnamed tributary were collected, and both whole body
and filet (with skin) samples were collected from the Brier Creek Reservoir. ATSDR used all the
May 2003 data to screen for contaminants of concern, and further evaluation was performed
using only the fish filet data, since it is assumed recreational fishers in the area do not eat the
whole fish.
To evaluate the potential for health effects from eating the fish, ATSDR assumed the 95th
percentile fish ingestion rate for freshwater recreational anglers of 25 grams per day for adults
[17]. Small children weighing 22 pounds were estimated to consume 12.5 grams of fish per day,
on average. These consumption rates correspond to about one fish meal per week, where adults
eat 6 ounces of fish per meal and small children eat 3 ounces of fish. These assumptions are
considered conservative for recreational consumption of fish from Brier Creek Reservoir. The
reservoir is posted with "Do Not Eat Fish" signs, but ATSDR received anecdotal reports of
people fishing there in the past. Also, fishers are unlikely to fish exclusively on the Brier Creek
Reservoir, as assumed in this evaluation.
Table 2. Contaminants of Potential Concern in Composite Fish Filet Samples
Maximum
Excess Cancer
Estimated
Health
Health Guideline
Composite Filet
Risk, if
Contaminant
Dose for Child,
Guideline,
Source (defined
Concentration,
applicable∗
mg/kg/day
mg/kg/day
in Appendix A)
mg/kg
Chronic MRL for
Total mercury
1.1
0.001
0.0003
Not Applicable
organic mercury
Chronic MRL for
Aroclor 1260
2.6
0.003
0.00002
7 in 10,000
PCBs
∗
Based on 25-year exposure duration at adult dose of 0.00093 mg/kg/day.
Source: [4]
guidelines. These contaminants will be evaluated in the following paragraphs.
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