Induction by mercury ions (II) of micronuclei in erythrocytes of green toad larvae

The frequencies of micronuclei and nuclear anomalies in erythrocytes of larvae of the toad Bufo viridis were studied after 6-, 12-, 18-, and 24-hour exposure to water containing mercury (II) ions at concentrations of 5, 10, 20, 50, 100, and 150 µg/l. At mercury concentrations of 5-50 μg/l, a 6-hour exposure led to a statistically insignificant increase in the frequencies of micronuclei and nuclear anomalies. Increasing the concentration to 100 and 150 µg/l caused a statistically significant increase in the frequency of micronuclei and nuclear anomalies. Exposure to mercury ions for 12, 18 and 24 hours caused a statistically significant increase in the frequencies of micronuclei and nuclear anomalies at all concentrations studied. Possible causes of the anomalies are considered and a brief review of mercury mutagenicity studies is given.