Arsenic in induced hair of the rat and its relation to the content in various organs during chronic exposure.

The behaviour of the rate of transfer of arsenic to hair induced at various times during a long-term exposure experiment was examined in rats supplied with 3 mg arsenic per litre of drinking water in the form of chloride. The arsenic was supplied during a period of 560 days. At the beginning a sharp increase was seen in the rate of transfer of arsenic to induced hair, as well as in the content of arsenic in the various organs. Subsequently, the rate of transfer to hair increased slowly but steadily up to the end of the experiment. During that time the level of arsenic in the liver and in the kidneys remained constant, whereas that in the brain and in some other organs increased slowly and irregularly. The correlation between the arsenic in the induced hair and that in the organs was statistically significant in all comparisons. Correlation coefficients greater than 0.7 were found in the comparisons of the content in the induced hair with those in the heart, the pancreas and the forebrain. The findings suggest that the rate of transfer of endogenous arsenic depends on two factors, one being the level of body intake of arsenic during the period of hair growth, the other the degree to which the element had accumulated in the body during the time which elapsed between the onset of arsenic supply and the start of hair growth.