Toxicity and bioaccumulation of selenium to a three‐trophic level food chain

Abstract

AbstractThree species, Chlorella vulgaris, Brachionus calyciflorus, and Pimephales promelas, were exposed to selenate for 25 d in a three‐trophic level test system. The organisms were linked in a continuous flow‐through system in separate vessels, with each organism feeding on the trophic level below it. These organisms were continually exposed for 25 d to 0, 110.3, 207.7, and 396.1 μg/L total recoverable selenium (Se) from selenate in natural creek water supplemented with nutrients to sustain algal growth. In an initial algal screening test, growth rates were reduced at 81.7 and 1,053.7 μg/L, with no effect at 8.5 μg/L. In the trophic test, algal populations showed evidence of reduced growth rates at 207.7 and 386.1 μg/L, but not at 110.3 μg/L. Rotifer population standing crop (measured as dry weight) was significantly reduced at 207.7 and 396.1 μg/L by day 4, and declined to below detection by day 7 at these treatments. Fathead minnow growth was impaired after 7 d at the 207.7 and 396.1 μg/L levels, with 100% mortality by day 16. A reduction in rotifers and fish biomass was also apparent at the 110.3 μg/L level after day 20. The amount of Se in whole organisms was measured throughout the experiment. Bioconcentration factors were found to be dependent on the species, treatment level, and length of exposure period, and they ranged between 100 and 1,000.