Morphological and histological effects of copper sulfate on the larval development of green toad, Bufo viridis

Authors: MERT GÜRKAN, SİBEL HAYRETDAĞ

Abstract: Declines in populations of amphibians have been occurring more dramatically over the past 25 years. The declines have various causes. One of the possible causes of amphibian declines is pesticides. Copper sulfate is commonly used as a fungicide in vineyards and gardens in Turkey. In this study, our purpose was to explain the morphologically and histologically acute toxic effects of copper sulfate on Bufo viridis tadpoles. B. viridis tadpoles at Gosner stage 21 were exposed to different concentrations (0.01, 0.05, and 0.1 mg/L) of copper sulfate for 120 h. The LC_5_0 value of copper sulfate was calculated as 0.058 mg/L. Morphological measurements indicated that copper sulfate concentrations of 0.05 and 0.1 mg/L caused poor larval development and growth. Edema was observed in the histological sections, especially on the cross-sections passing from the head (>=0.01 mg/L CuSO_4). Furthermore, hepatocellular degeneration in the liver, deformation of gastrointestinal epithelial cells, and deformation and anomalies in somite formations were all observed (>=0.01 mg/L CuSO_4). Reduced reaction to stimuli, loss of equilibrium, and shortening of swimming distance were observed in the tadpoles of the 0.05 and 0.1 mg/L CuSO4 treatment groups.

Keywords: Amphibian, Bufo viridis, copper sulfate, tadpole, development

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