Dames & Moore, 1999 - USDA Forest Service

The food ingestion rate was estimated as:
where
F (kg/d) = 0.0582 x (kg Body
0.65 1 = relationship between body mass and food requirement
Dippers average about 0.055 kg body weight (Dunning, 1993) and when the results of the algorithms are
divided by the body mass the daily ingestion rates for dippers were estimated to be 0.16 kg foodkg
body weighttday and 0.154 Ukg. The total exposure dose (D) From diet, water, and soil (if appropriate) are
summed:
The predicted total daily doses to metals through the worst-case dietary and water sources are shoyn in
Table 7.2.3-7.
Osprey obtain nearly 100 percent of their caloric requirements from the consumption of fish. Ospreys are
migratory and spend the winter months in Latin America and the Caribbean Basin (Poole, 1993). They are
not abundant in the Pacific Northwest, except in the Coeur d'Alene area of Idaho. In the west, they are
largely dependent upon freshwater lakes, large rivers, and reservoirs for their prey. The southerly migration
usually begins in the last two weeks of August in northern latitudes. Winter populations in Oaxaca Mexico
reach a plateau between October and March, so that any ospreys feeding in the Lake Chelan area would
only be present for about 5 months a year, approximately April 15 to August 15 (Poole, 1993). Since the
birds dive into the water to catch the fish, the waters used for fishing must be at least several feet deep.
Furthermore, ospreys do not hunt in turbulent waters. Although it is very unlikely that ospreys would forage
in Railroad Creek, risk was assessed for ospreys foraging in Railroad Creek.
Ospreys average about 1.55 kg body weight (Dunning, 1993) and consume fish in the 100-300 g weight
class and the 10-14 inch length range (Pool, 1993). Using the algorithm for food consumption, this is a
daily wet weight ingestion rate of 255 g fish. This agrees well with the data provided by Poole (1984).
During the breeding season ospreys need to consume 6 to 8 fish or about 1250 @day (Poole. 1984). Of this.
approximately 400 g is eaten by the male, 360 g by the female, and the remaining 490 g by the young. This
is a wet weight food consumption rate of 0.258 kgkglday by the adult male.
Pacific Northwest Laboratories (PNL, 1992) measured copper, iron, selenium and zinc concentrations in
'muscle and liver of cutthroat trout captured at 1) the wilderness area boundary, 2) tailings pile 3) Lucerne.
and 4) 25-Mile Creek. Although additional rainbow and cutthroat trout data were collected by Ecology
(1993, 1994) at these same locations, and analyzed for aluminum, arsenic, copper, iron, lead, nickel, and
zinc, only Cu, Fe, Hg, Se and Zn were measured above detection limits. There are no reliable toxicity
benchmarks for iron, and iron is an important micronutrient. Therefore, only copper, mercury, selenium and
zinc were evaluated.
The liver of rainbow trout constitutes about a maximum of 2 percent of the total body weight. If it is
assumed that muscle constitutes the remaining 98 percent, the whole fish metals concentrations can be
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