Toxicity of selenomethionine- and seleno-contaminated sediment to the amphipod Corophium sp.

The acute toxicity of four chemical species of selenium to juvenile amphipods (Corophium sp.) was assessed in water-only tests. The seleno-amino acid compounds seleno-L-methionine and seleno-DL-cystine were found to be more toxic (96-h LC(50) values of 1.5 and 12.7 microg Se/L) than the inorganic selenite and selenate (96-h NOEC values of 58 and 116 microg Se/L). New marine sediment testing procedures were developed using juvenile and adult Corophium sp. Both life stages were highly sensitive to seleno-L-methionine-spiked sediment. The juveniles were approximately five times more sensitive, with a 10-day LC(50) of 1.6 microg Se/g (dry weight) compared to 7.6 microg Se/g (dry weight) for the adults. Sediment collected from three sites in Lake Macquarie, a marine barrier lagoon with elevated concentrations of total selenium, had no effect on the survival of adult Corophium over 10 days. The toxicity of seleno-L-methionine to other amphipod species occurring in Lake Macquarie was assessed in water-only tests, with Paracalliope australis being highly sensitive (96-h LC(50) 2.58 microg Se/L).