Developmental and acute toxicity of cetylpyridinium chloride in Bombina orientalis (Amphibia: Anura)

In an effort to evaluate the toxicity of cetylpyridinium chloride (CPC), a cationic surfactant in amphibians, we examined the developmental and acute toxicity of CPC in Bombina orientalis embryos and tadpoles. Embryonic exposure to 2.0 μM (0.72 mg/l) CPC for 7 days significantly decreased the survival rates and increased DNA damage in the intestine of developed tadpoles. Exposure to 1.5 μM (0.54 mg/l) CPC significantly decreased the growth of embryos and increased developmental abnormalities. The 168-h LC50 and EC50 values of CPC were 1.95 μM (0.697 mg/l) and 1.48 μM (0.531 mg/l) in embryos, respectively. In an extended acute toxicity test using tadpoles, the 168-h LC50 value of CPC was 5.07 μM (1.82 mg/l). In terms of survival and growth rates, the lowest observed effective concentration of CPC was 1.5 μM. At sub-lethal concentrations (1.0 and 2.0 μM) CPC treatment to embryos increased lipid peroxidation in the intestine and gills of developed tadpoles, indicating that CPC can impose oxidative stress. At 2.0 μM CPC, pro-apoptotic Bax and Bak mRNA levels were significantly increased together with DNA fragmentation, indicative of apoptotic cell death. CPC in freshwater system may threaten the normal development of amphibian embryos.