Clastogenic effects of inorganic arsenic salts on human chromosomes in vitro.

Arsenic is well documented as a paradoxical human carcinogen. In West Bengal, several million people were found to be arsenic affected who were exposed to this metalloid principally through drinking water. The arsenic-contaminated drinking water contains both trivalent as well as pentavalent arsenic. In this study, the comparative in vitro cytogenetic effects of two inorganic salts of arsenic, trivalent sodium arsenite (NaAsO(2)) and pentavalent sodium arsenate (Na(2)HAsO4) in three different concentrations, were screened for damage to chromosome and cell division following exposure to human lymphocyte culture. The chromosome-breaking activities in cultured lymphocytes were significantly higher for the compounds with trivalent (NaAsO(2)) than with pentavalent arsenic (Na(2)HAsO(4)), as reflected by the higher chromosomal aberration percentage in the similar doses used. It suggests that sodium arsenite was considerably more clastogenic than sodium arsenate. Moreover, increases in chromosomal aberrations were proportional with the increased dose of exposure for both trivalent and pentavalent forms of arsenic.