Cell Biology Division CSIR-Indian Institute of Toxicology Research, Lucknow 226001, India.
Cell Biology Division CSIR-Indian Institute of Toxicology Research, Lucknow 226001, India.
Ecotoxicol Environ Saf. 2014 Feb;100:218-25. doi: 10.1016/j.ecoenv.2013.11.006. Epub 2013 Dec 7.
To establish the use of Metaphire posthuma as a sensitive test model for ecotoxicological studies, acute toxicity testing of carbaryl, carbofuran, cypermethrin and fenvalerate on Eisenia fetida and Metaphire posthuma were carried out. Two different types of bioassays, contact filter paper toxicity and soil toxicity bioassays were used to determine LC50 values for these insecticides. Among the tested chemicals, carbofuran was the most toxic to both the earthworm species. In paper contact method, 72 h-LC50 values of carbofuran in M. posthuma and E. fetida were found to be 0.08 μg/cm(2) and 1.55 μg/cm(2) respectively while in soil test, 14-d LC50 values were 0.49 mg/kg and 21.15 mg/kg respectively. On comparing the toxicity data of these chemicals for both the earthworm species, M. posthuma was found to be more sensitive than E. fetida. Based on the acute toxicity data, the order of toxicity of insecticides in both the test procedures was carbofuran>cypermethrin>carbaryl>fenvalerate for M. posthuma whereas for E. fetida it was carbofuran>carbaryl>fenvalerate>cypermethrin. Morphological changes also appeared in the organisms exposed to these chemicals which were more pronounced in M. posthuma at lower concentrations than E. fetida in both the test procedures. The results of the present study advocates the use of M. posthuma for ecotoxicity studies, being a more sensitive and reliable model than E. fetida. Based on the data on partial atomic charges, structural features and spectroscopic studies on carbaryl and carbofuran, a possible mechanism of toxicity of carbamate insecticides in earthworm was proposed.
为了将 Metaphire posthuma 确立为生态毒理学研究的敏感测试模型，我们对 E. fetida 和 M. posthuma 进行了甲萘威、克百威、氯菊酯和氰戊菊酯的急性毒性测试。我们使用了两种不同类型的生物测定方法，即接触滤纸毒性测定法和土壤毒性生物测定法，以确定这些杀虫剂的 LC50 值。在所测试的化学物质中，克百威对这两种蚯蚓物种的毒性最大。在接触滤纸法中，M. posthuma 和 E. fetida 中克百威的 72 h-LC50 值分别为 0.08 μg/cm(2)和 1.55 μg/cm(2)，而在土壤测试中，14 天 LC50 值分别为 0.49 mg/kg 和 21.15 mg/kg。比较这两种蚯蚓物种对这些化学物质毒性的数据，发现 M. posthuma 比 E. fetida 更敏感。根据急性毒性数据，在两种测试程序中，这些杀虫剂的毒性顺序均为克百威>氯菊酯>甲萘威>氰戊菊酯，而对于 E. fetida，其毒性顺序为克百威>甲萘威>氰戊菊酯>氯菊酯。在接触这些化学物质的生物体中也出现了形态变化，在两种测试程序中，这些变化在 M. posthuma 中比 E. fetida 更为明显，且浓度较低时更明显。本研究的结果支持将 M. posthuma 用于生态毒性研究，因为它是一种比 E. fetida 更敏感和可靠的模型。基于甲萘威和克百威的部分原子电荷、结构特征和光谱研究数据，提出了氨基甲酸酯类杀虫剂对蚯蚓毒性的可能机制。
