[M-ZZ51] 環境汚染・環境毒性と生物

[MZZ51-08] Accumulation of arsenicals in green and hawksbill turtles

*阿草 哲郎¹、高木 梢²、Miller Todd³、久保田 領志⁴、阿南 弥寿美¹、岩田 久人²、田辺 信介² (1.熊本県立大学、2.愛媛大学、3.NOAA Fisheries Service、4.国立医薬品食品衛生研究所)

キーワード：ヒ素、ウミガメ

Concentrations of total arsenic (As) and its compounds were determined in the organs/tissues, stomach and intestine contents, bile, and urine of green (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) to understand As accumulation. In addition, stable isotopes of δ¹⁵N and δ¹³C were measured for understanding the relationship between feeding behavior and accumulation of As compounds. In both sea turtles, total As concentration was the highest in muscle among the organs/tissues. Arsenobetaine (AB) was the predominant compound in most organs/tissues of both sea turtles. High concentration of trimethylarsine oxide (TMAO) was detected in hawksbill turtles. Major As species in gastrointestinal contents were unknown water-soluble As, followed by unextracted As. Concentrations of AB and dimethylarsinic acid (DMA) in the tissues were higher than those in the stomach contents (prey items). This indicates high bioaccumulation of these arsenicals. In green turtles, AB concentration was high in bile and increased throughout the gastrointestinal tract, suggesting significant biliary excretion of AB. A significant positive relationship between δ¹⁵N and AB concentration was observed in green turtles, whereas δ¹⁵N was negatively correlated with residual As in hawksbill turtles. These results imply trophic level dependent accumulation of As compounds in green and hawksbill turtles, because feeding behavior of both turtles change with growth.