Sodium Arsenite Impacts the Development of the Toad Bufotes viridis

Sodium arsenite (NaAsO₂ = NA) is mainly released into the environment from anthropogenic sources such as mining and pesticides. This study examined the effects of NA on the development of Bufotes viridis by exposing eggs and larvae to NA at 11 different concentrations including absence of NA (control) and comparing their developmental patterns. the seven lowest concentrations are often found in the environment (500, 1000, 1500, 2000, 6000, 12,000, 24,000, 25,000, 32,000, 36,000 µg/l). Our results suggest that low concentrations of NA positively affect growing larvae of B. viridis by increasing their length and maximum swimming speed compared to the control group. However, high concentrations of NA significantly reduced the larval growth and swimming speed compared to the control group. LC50 values were found for B. viridis eggs at NA concentration of 260,000 µg/l after nine days of exposure. A high mortality rate and both internal and external abnormalities (e.g. hepatocytes and intestinal epithelium reduction, abdominal oedema and tail flexures) were observed at high concentrations, suggesting that NA can have important effects to those environmentally relevant NA levels.