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<br />002344 <br /> <br />Table 5.--Geochemical data for selected trace elements in soils in <br />irrigated areas near Delta and in the Grand valley <br /> <br />[Data from T.F. Harms, U.S. Geological Survey, Branch of Exploration <br />Geochemistry, written commun., 1988; concentrations are in micrograms <br />per gram; <, less than] <br /> <br />Trace element <br /> <br />Median <br /> <br />Range <br /> <br />Arsenic <br />Cadmium <br />Copper <br />Mercury <br /> <br />SOILS NEAR DELTA, 16 SAMPLES <br />9 <br /><1 <br />13 <br />.04 <br />SOILS IN THE GRAND VALLEY, 28 SAMPLES <br />14 <br />.04 <br />.15 <br />3.73 <br />122 <br /> <br />8-60 <br /><1-2 <br />8-18 <br />.03-.09 <br /> <br />Arsenic <br />Mercury <br />Selenium <br />Uranium <br />Zinc <br /> <br />0.26-91 <br />.02-.20 <br /><.1-.692 <br />3.06-4.48 <br />71-141 <br /> <br />and fish and because of concerns for human consumption of fish from the lake. <br />The Colorado Division of Wildlife reported large selenium concentrations in <br />fish samples. A summary of mean selenium concentrations is listed in table 6. <br />Maximum concentrations (dry weight) of selenium in individual samples were <br />243 ~g/g in flesh samples and 255 ~g/g in liver samples; both concentrations <br />were in samples from flannelmouth suckers collected in 1974. The mean <br />selenium concentration in three crayfish was 122 ~g/g dry weight and in five <br />aquatic plant samples was 200 ~g/g dry weight. <br /> <br />Table 6.--Mean selenium concentrations in flesh and liver samples in fish <br />from Sweitzer Lake, 1974 and 1977 <br /> <br />[Data from the Colorado Division of Wildlife, written commun., 1987; <br />concentrations are in micrograms per gram dry weight; -- indicates <br />no data] <br /> <br />Species <br /> <br /> Mean selenium concentration <br /> Flesh Liver <br />1974 1977 1974 1977 <br />96 64 75 74 <br />129 100 154 103 <br /> 79 <br />109 48 87 81 <br />141 185 <br />128 95 147 <br /> 99 <br /> 84 <br /> <br />Channel catfish <br />Green sunfish <br />Carp <br />Bullhead <br /> <br />Flannelmouth sucker <br />White sucker <br />Langnase sucker <br />Chub <br /> <br />27 <br />