Accumulation Features of Arsenic in Hawksbill Turtles and Green Turtles

In the marine ecosystem, arsenic exists as various species through biogeochemical cycling involving accumulation, transformation, and decomposition. Inorganic arsenic, which is predominant in sea water, is biotransformed to organic arsenicals by marine biota [1,2]. Among arsenic compounds, arsenobetaine (AB) is the major species in lower-order marine animals such as fishes, crustaceans and echinoderms, while arsenosugars are detected in marine algae at high concentrations [1,2]. On the contrary, studies on arsenic accumulation and speciation are very less in higher-order marine animals. So far, we have investigated arsenic speciation in higherorder marine animals such as marine mammals [3-9], sea birds [6,7,9-11], and sea turtles [5-7,9,12]. Among these animals, hepatic concentrations of arsenic in sea turtles were higher than those in marine mammals and comparable to levels in lower-order animals, suggesting specific metabolism and accumulation mechanisms of arsenic in sea turtles. To characterize specifically the arsenic accumulation features in sea turtles, concentrations of total arsenic and individual arsenic compounds were determined in various tissues and stomach contents of hawksbill turtles (Eretmochelys imbricata) and green turtles (Chelonia mydas) in this study.