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- -methionine and seleno- -cystine were found to be more toxic (96-h LC50 values of 1.5 and 12.7 μg Se/L) than the inorganic selenite and selenate (96-h NOEC values of 58 and 116 μg Se/L). New marine sediment testing procedures were developed using juvenile and adult Corophium sp. Both life stages were highly sensitive to seleno- -methionine-spiked sediment. The juveniles were approximately five times more sensitive, with a 10-day LC50 of 1.6 μg Se/g (dry weight) compared to 7.6 μg 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- -methionine to other amphipod species occurring in Lake Macquarie was assessed in water-only tests, with Paracalliope australis being highly sensitive (96-h LC50 2.58 μg Se/L).