Biotransformation of arsenite in freshwater food-chain models

Bioaccumulation and biotransformation of arsenite by freshwater organisms consisting Daphnia magna, Neocaridina denticulata and Tilapia mossambica has been studied. When organisms were exposed to a medium containing arsenite, the total arsenic concentration accumulated by the organisms increased with an increase in the arsenic concentration in the medium, The order of total arsenic accumulation by freshwater organisms was D. magna > N. denticulata > T. mossambica, Bioaccumulation and biotransformation of arsenite in three-step laboratory food-chain models was investigated by feeding a diet of arsenite-dosed alga (Chlorella vulgaris) to herbivorous grazers (D. magna and N. denticulata) and then the herbivores were fed to carnivorous fish (T. mossambica and Zacco platypus), Total arsenic concentrations in the organisms decreased by an order of magnitude for each step in the food chain. Arsenite and arsenate were accumulated as the predominant arsenic species in organisms. Little methylation of arsenic in organisms occurred at each step in the food chain. Copyright (C) 2001 John Wiley & Sons, Ltd.