Arsenic elevates the sister chromatid exchange (SCE) rate in human lymphocytes in vitro

The number of sister chromatid exchanges (SCE) per metaphase was determined in normal human lymphocytes by the Hoechst-Giesmsa procedure. The addition of inorganic trivalent arsenic (Na2HAsO4) 10(-6) M and 2 x 10(-6) M induces a significant and dose-dependent increase of SCE. This phenomenon is as sensitive as the evidence of arsenic-induced chromosomal aberrations in vitro.