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Filters: partyWithName: Canton, Steven P (X) > Types: Journal Citation (X) > Extensions: Citation (X)

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Waterborne and sediment selenium (Se) data, in conjunction with selected physicochemical parameters, were collected from streams of the middle Arkansas River basin, Colorado, USA, to examine the factors affecting sediment Se accumulation in a lotic environment. An empirical model of dissolved-to-sediment Se transfer in western streams, as an interactive function of sediment organic carbon content (R2 = 0.78, p < 0.001, n = 34), was developed and validated. Sediment Se and associated biological effects data were compiled from the literature, to provide an estimate of sediment Se concentration thresholds that have biological effects. Based on this preliminary analysis, sediment Se concentrations of 2.5 ?g/g would...
The benthic invertebrates of the Dolores River in southwest Colorado were sampled during three seasons in an area of historic mine drainage. Benthic density exhibited significantly lower values below the mine drainage. However, the number of species did not decrease significantly, indicating that the effect of the mine drainage was primarily non-selective (i.e. favoring no one taxon). This pattern was seasonal with the least effects evident in summer and the greatest effects found in spring. Diversity indices used to assess the effects of this stress on the invertebrate community were MargalePs, Simpson's, Shannon-Weaver's, Brillouin's, and the Biotic Condition Index. None of the indices tested adequately responded...
The U.S. Environmental Protection Agency's (U.S. EPA's) current acute aquatic life criterion for selenium (Se), 20 ?g/L, was based on a back-calculation from the chronic criterion of 5 ?g/L, using the acute-to-chronic ratio in reverse. While bioaccumulation and subsequent toxicity through dietary uptake are important factors in chronic toxicity, acute toxicity is a shortterm phenomenon, which should be promulgated with an acute value derived from direct toxicity studies, similar to other metals and metalloids. Acute toxicity values from the U.S. EPA Se criteria document were updated with more recent toxicity data for the two primary forms of Se, selenite (Se IV) and selenate (Se VI). Using this updated toxicity...