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The effects of selenium on streamecosystems were studied in outdoor,experimental stream mesocosms during a dosingperiod in which sodium selenite was added atnominal concentrations of 30 µg/L,10 µg/L, and 2.5 µg/L. The durationof the high, medium, and low treatments were573 d, 972 d, and 311 d, respectively. Apost-dosing period of three years (hightreatment) and two years (medium, lowtreatments) also was studied. Seleniumconcentrations in water, sediment, plants, andmacroinvertebrates were measured throughoutthe dosing and recovery periods. Fatheadminnows and bluegill sunfish were periodicallyheld in the streams to measure seleniumaccumulation and its effects on fish survivaland reproduction. Quantitative samples ofmacroinvertebrates were collected to assessselenium effects on macroinvertebratecommunities. |
