Dames & Moore, 1999 - USDA Forest Service

,
Hazard quotients for osprey consuming copper-contaminated trout (Table 7.2.4-6) were calculated by
dividing the doses estimated in Table 7.2.3-8 by the TRVs in Table 7.2.3-4A. The default assumptions
were:
osprey fed only on trout from Railroad Creek and its tributaries
ospreys drink only the UCL concentrations from Railroad Creek
the modeled whole body trout concentrations are accurate
From Table 7.2.4-6, it is apparent that there is no risk to osprey under worst case exposure conditions to
copper, mercury or zinc. Therefore, there is no need to conduct further analyses of risk to this ROC.
- Mink
Hazard quotients for mink feeding on trout (Table 7.2.4-7) were calculated by dividing the doses estimated
in Table 7.2.3-9 by the TRVs in Table 7.2.3-4B. T'le default assumptions were:
mink fed only on trout from Railroad Creek and its tributaries
mink drink only the UCL concentrations from Railroad Creek
the modeled whole body trout concentrations are accurate
From Table 7.2.4-7 it is apparent that there is no risk to mink under worst case exposure conditions to
copper, mercury or zinc. Therefore, there is no need to conduct further analyses of risk to this ROC in the
aquatic habitat.
Terrestrial Exposure Pathways
Bioavailabilitv of Metals
Although there are many studies that show low food to tissue relationships for metals (Pascoe et al., 1994;
Stevens, 1992; Connor et al., 1994; Beyer et al., 1985) there are few studies that analyzed the bioavailable
dose from food. Custer et al., 1984 showed that kestrels fed biologically-incorporated lead were able to
withstand 10 times the dose that caused adverse effects when dosed as lead acetate. Similarly, NAS (1989)
reported that the bioavailability of zinc from meat is about 20 percent. Therefore, the dietary doses of lead
and zinc were so adjusted. However, for the remaining metals, no such data was found. Therefore, it was
assumed that the bioavailability of cadmium and copper from the diet was 100 percent.
There are however, several studies that show that the bioavailability of metals from soils ingestion is far
lower than 100 percent (Owens, 1964; Dodds-Smith et al., 1992; Talmadge and Walton, 1993; Davis et al.,
1992; Hamel et al., 1998). At least some of this results from the presence of insoluble metals salts in the soil
matrix. Ore bodies, such as that at Holden Mine, were deposited on the sea floor as sulfide salts. The
sulfide salts are particularly insoluble and probably form the bulk of the metal salts still found at the site.
Therefore, the bioavailability of the soils that may be ingested incidentally by wildlife, was adjusted as
shown in Table 7.2.3- 1 1.
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17693.00S-Ol9Uuly 27.1999;5:16 Phl;DRAFT FINAL RI REPORT