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In the early 1980's, waterfowl at the Kesterson National Wildlife Refuge (KNWR) in the San Joaquin Valley of California indicated that something had gone terribly awry in the environment. In the photo at right, S-313 is a normal embryo, but others are grotesquely deformed, lacking eyes (S-302) or feet (S-35) or other deformities (S-9). Testing of source waters showed that selenium was present in extremely high concentrations such that the wastewater at KNWR was classified as toxic waste. Underground drainage from agricultural irrigation systems promoted the excessive concentration of this hazardous trace element (from Presser and Ohlendorf, 1987).
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http://geology.wr.usgs.gov/wreg/env/birds.html
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