Effects of endosulfan on survival and development of Bombina orientalis (Boulenger) embryos.

The developmental toxicity of endosulfan was examined in the anuran Bombina orientalis embryos. Survival rates of embryos following 50 microM endosulfan treatment was significantly lower than vehicle control at 96 h onward. When the embryos develop to the tail fin circulation stage, embryonic survival was significantly decreased by 10 microM endosulfan treatment. Surviving embryos showed various developmental abnormalities including tail dysplasia at 50 microM. By hampering the embryonic development endosulfan may cause the decline in the natural populations of this frog species breeding on farmland and in the surrounding aquatic environment.