TY - JOUR T1 - Acute toxicity of rice paddy herbicides simetryn, mefenacet, and thiobencarb to Silurana tropicalis tadpoles. A1 - Saka,Masahiro, PY - 2010/03/04/received PY - 2010/04/19/revised PY - 2010/05/02/accepted PY - 2010/6/12/entrez PY - 2010/6/12/pubmed PY - 2010/12/29/medline SP - 1165 EP - 9 JF - Ecotoxicology and environmental safety JO - Ecotoxicol Environ Saf VL - 73 IS - 6 N2 - I examined the toxicity of rice paddy herbicides simetryn, mefenacet, and thiobencarb to amphibians by conducting acute toxicity tests with tadpoles of Silurana tropicalis, which has attracted as a new model species instead of Xenopus laevis. The tadpoles at stages 49 and 50 were exposed to the herbicides at several concentrations during 96 h, and median lethal concentration (LC50) values were calculated at 24-h intervals. The LC50 values of simetryn, mefenacet, and thiobencarb were 16.9-3.70 mg/L (79.3-17.4 microM), 3.06-2.70 mg/L (10.3-9.04 microM), and 1.77-0.752 mg/L (6.85-2.92 microM), respectively. The most toxic herbicide was thiobencarb followed by mefenacet and simetryn. As for thiobencarb, the sensitivity of S. tropicalis was similar to that of X. laevis reported previously. This suggests that S. tropicalis as well as X. laevis can act as a model species in acute toxicity tests. The LC50 values of the three herbicides were very close to or at most two orders of magnitude higher than the maximum concentrations likely to occur in paddy water. Therefore, the three herbicides can be harmful to amphibian larvae living in paddy water. SN - 1090-2414 UR - https://www.unboundmedicine.com/medline/citation/20537391/Acute_toxicity_of_rice_paddy_herbicides_simetryn_mefenacet_and_thiobencarb_to_Silurana_tropicalis_tadpoles_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0147-6513(10)00095-3 DB - PRIME DP - Unbound Medicine ER -