Retention and Biotransformation of Arsenic Compounds Administered Intraperitoneally to Carp

The arsenic metabolism in fish was examined using carp Cyprinus carpio and five arsenic compounds (arsenate, dimethylarsinate, arsenobetaine, trimethylarsine oxide, and arsenocholine). In orderto avoid the bacterial action in the gut tract suggested previously, the arsenic compounds were administered to the fish not orally but intraperitoneally. Low retention of arsenicby the fish was observed after administration of arsenate, dimethylarsinate, or trimethylarsine oxide, while the arsenic administered as either arsenobetaine or arsenocholine was highly retained.After extraction and partial purification by Dowex 50 column chromatography, arsenic compounds accumulated inviscera and muscle were analyzed by HPLC-ICP / AES.As a result, arsenate and arsenocholine were found to be converted to arsenite and arsenobetaine, respectively, within the fish. Conversion of trimethylarsine oxide to another compound (probably dimethylarsinate) was also observed. In contrast, no biotransforma-tion of dimethylarsinate and arsenobetaine occurred.