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<br />, <br /> <br />The mean concentration is close to The Colorado Department of Public Health and <br /> <br /> <br />_"O()2''Z&vironment standard and the US Environmental Protection Agency maximum <br /> <br /> <br />contaminant level for the dissolved selenium in the water suooll( for agriculture "fetor <br /> <br />supply -'irrigation and livestock, 20 micro grams/liter). Numerous samples exceeded <br /> <br />the standards. Selenium is an element which is subject to bioaccumlation in the food <br /> <br />chain ll[ll;lwf::llGR is concentrated in green plants as mit takes up water. As drains <br /> <br />within the irrigation system pick up water, selenium concentrations become very high. <br /> <br />The water from these drains is reused for irrigation throughout the watershed and <br /> <br />downstream. <br /> <br />Five species of fish in the Arkansas River and the John Martin Reservoir had <br /> <br />selenium concentrations ranging from 2.1 to 18.5 micro grams/gram with samples of <br /> <br />20 micro grams/gram. All but 3 of the 59 total fish samples exceeded the 85th- <br /> <br />percentile national baseline for selenium in fish (2.45 micro grams/gram dry weight), <br /> <br />and 21 of the samples had concentrations exceeding the range associated with <br /> <br />reproductive failure in blue gil1.2 About one-haif of the samples had selenium <br /> <br />concentrations that exceeded the dietary concentration known to increase the rate of <br />mortalities and deformities in mallard embryos,4 <br /> <br />Investigations found that selenium levels in aquatic plants exceeded acceptable <br /> <br />dietary limits of avion species. No evidence of deformity or reproductive failure was <br /> <br />observed for any bird or fish species, The study was not designed to assess <br /> <br />reproduction or to determine the extent of embryonic deformities.. <br /> <br />, . <br />~lt> <br />. Aquatic cycling of Selenium:, United States Department of the Interior, USFWS Leaflet 12, 1987 <br />, 't <br />~I& <br /> <br />llt=5 <br />