doi:10.1093/mutage/get070 Impact of long-term exposure to sodium arsenite on cytogenetic radiation damage

The aim of this work was to investigate the impact of long-term exposure to low concentrations of sodium arsenite on the cellular response to ionising radiation. Human lymph-oblastoid GM1899a cells were cultured in the presence of sodium arsenite for up to six months. Following chemical exposure, acute challenge doses of X-rays were given and chromosome damage (dicentrics, acentric fragments, trans-locations, micronuclei) as well as cell growth and changes in cell cycle kinetics were determined. Initial short-term chem-ical exposures determined 8 ng/ml (60 nM) sodium arsenite as a suitable concentration for chronic exposures, which is below the current World Health Organization limit for arsenic in drinking water. At this concentration, cell growth was slightly, but consistently, slower than in untreated cul-tures throughout the six-month exposure period. Long