Tissue retention of arsenic in rats fed witch founder or cacodylic acid.

Weanling rats were fed one of five diets for 42 days either ad libitum or on a restricted-equalized feeding regimen. The five diets included a low arsenic control and a medium or high level of arsenic from either witch flounder (Glyptocephalus cynoglossus) tissue or cacodylic acid. Dietary arsenic in either form did not influence any of the biological indices of exposure examined except tissue arsenic levels. Retentions of arsenic in the livers and spleens of rats fed the highest level of fish arsenic (28.8 ppm) were about 7 and 2 times higher, respectively, than controls. Retentions of arsenic in the livers and spleens of rats fed the highest level of arsenic from cacodylic acid (22.1 ppm) were about 30 and 110 times higher, respectively, than controls. Retention of arsenic within the erythrocytes of rats fed the highest level of fish arsenic were equal to controls whereas it was about 130 times higher than controls among rats fed the highest level of arsenic as cacodylic acid. Apparently the chemical form of the arsenic in the edible tissue of witch flounder is uniquely metabolized by the rat compared to other arsenic forms.