Abstract

More than 500 million people live in communities with artificially or naturally fluoridated drinking water that has been treated with 1 ppm or more of fluoride. Workers in aluminum plants, phosphate fertilizer plants and other fluoride-related factories are also exposed to high concentrations of fluoride. It is reported that workers in aluminum plants suffer from an increased risk of leukemia. To date, information concerning the topic remains controversial. It is important to evaluate the genotoxic effects of fluoride by in vivo test systems because of its increasing usage. We tested the induction of mutagenic effects by in vivo and in vitro bone marrow micronucleus tests. A significant increase in micronucleated polychromatic erythrocytes was observed 24 h after intraperitoneal injection of sodium fluoride at a dose of 30 mg/kg body weight. In the in vitro micronucleus test, the frequency of micronucleated polychromatic erythrocytes was increased significantly at concentrations of 2 and 4 mM. These results indicate that the micronucleus test may be useful in evaluating the cancer risk of sodium fluoride.