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<br />~n2356 <br /> <br />the NCBP concentrations converted to dry-weight concentrations using <br />75-percent moisture should be considered estimates. For example, the 85th <br />percentile for selenium of 0.71 ~g/g wet weight (Lowe and others, 1985) was <br />converted to about 2.8 ~g/g dry weight using 75-percent moisture [0.71 divided <br />by (1-0.75)]. <br /> <br />Interpretation of some trace-element data for biota samples collected <br />for the reconnaissance investigation was not possible. Biota samples were <br />analyzed at two laboratories, and some trace-element data from one of the <br />laboratories had reporting limits that exceeded background concentrations. <br />For example, the reporting limits for cadmium, copper, and lead for many of <br />the whole-body fish samples were several times greater than the NCBP 85th <br />percentile; therefore, interpretation of the sample concentrations was not <br />possible. <br /> <br />Inorganic Trace Elements <br /> <br />Generally, concentrations of chromium, nickel, strontium, tin, and <br />vanadium were less than analytical reporting limits; however, a few concen- <br />trations exceeded reporting limits. Background information on those trace <br />elements is very limited, but some concentrations exceeded concentrations <br />reported in the literature. For example, tin was detected in some of the bird <br />samples collected at the Escalante State Wildlife Area (site 10 in table 20). <br />Several tin concentrations in fish from various sites were much greater than <br />background concentrations of 2.0 to 21.6 ~g/g dry weight reported by Jenkins <br />(1980). The significance of the tin is not known. Nickel was detected in a <br />few biota samples; for example, an immature, pre-fledgling Canada goose sample <br />collected at site 10 had a nickel concentration of 106 ~g/g dry weight. That <br />concentration was much larger than the nickel concentrations (3.3 to 75.7 ~g/g <br />dry weight) reported by Cain and Pafford (1981) in livers of mallard ducklings <br />that died of nickel toxicity within 60 days of birth. <br /> <br />Except for selenium, cadmium, copper, mercury, and zinc, other trace- <br />element concentrations either were all less than reporting limits or were <br />determined to be representative of background concentrations listed in the <br />literature. There were many concentrations of selenium and a sufficient <br />number of concentrations of cadmium, copper, mercury, and zinc in biota <br />samples that exceeded various guidelines to warrant further discussion of <br />those trace elements. <br /> <br />Selenium in biota, Sweitzer Lake <br /> <br />Selenium concentrations in fish, invertebrate, and aquatic plant samples <br />were greater in samples collected from Sweitzer Lake (table 23) than in <br />samples collected from the streams (tables 20-22). The much larger selenium <br />concentrations in fish from Sweitzer Lake are readily apparent in figure 16 <br />and table 13. All the selenium concentrations in fish collected from the lake <br />exceeded the NCBP 85th-percentile concentration of 2.8 ~g/g dry weight at <br />75-percent moisture (0.71 ~g/g wet weight). Selenium concentrations were <br />large in all fish species regardless of trophic level (table 13). For example, <br />selenium concentrations (dry weight) in whole-body fish samples (table 23) <br />were 32.4 ~g/g in a channel catfish, 39.0 ~g/g in a black bullhead, 22.0 and <br /> <br />51 <br />