| Abstract: | Accumulation, biomethylation and excretion of arsenic by an autotrophic freshwater alga, and the transport and transformation of the arsenic in the freshwater food chain alga (autotroph)-moina (planktonic grazer) or shrimp (herbivore)-guppy (carnivore)] were investigated. These experimental results lead to the conclusion that total arsenic concentrations in organisms after accumulation from foods decreased one order of magnitude per elevation of the trophic level and biomethylation of the arsenic increased successively with an elevation in the trophic level. Predominant methylated arsenic species in moina and guppy were dimethyl- and trimethyl-arsenic compounds, respectively. Shrimp accumulated dimethyl- and trimethyl-arsenic compounds in nearly equivalent quantities. No or little monomethylarsenic compound was detected either in herbivores or carnivores. |
