几种典型土壤中铜对赤子爱胜蚓的毒性差异比较研究

土壤污染物基础生态毒理数据是开展污染土壤生态风险评价和构建土壤生态筛选基准的重要依据.以湖南红壤、北京潮土、吉林黑土和经济合作与发展组织(OECD)推荐的人工土壤为测试介质,按照国际标准化组织(ISO)颁布的测试方法,研究了铜在4种不同土壤中对赤子爱胜蚓(Eisenia fetida)的急性和慢性毒性.结果表明,铜在4种不同类型土壤中对赤子爱胜蚓的毒性效应差异较大,在湖南红壤、北京潮土、吉林黑土和人工土壤中的半致死浓度(14d LC50)分别为134.4、557.7、715.2和867.0mg·kg-1;赤子爱胜蚓体重对较低浓度铜污染响应相对不敏感,而较高浓度铜污染(接近引起蚯蚓死亡的高浓度)则可导致蚯蚓体重显著降低;铜对赤子爱胜蚓生殖(产茧量)的影响较为明显,其在湖南红壤、北京潮土、吉林黑土和人工土壤中对蚯蚓产茧量产生50%抑制作用的有效中浓度(28d EC50)分别为58.2、140.1、258.9和150.4mg·kg-1,无可见效应浓度(NOECs)分别为50、50、200和100mg·kg-1.鉴于我国土壤类型的多样性十分丰富,不同地区土壤性质差异较大等特点,在制定土壤筛选基准时需考虑污染物在不同土壤中生物有效性与毒性的差异。

Comparative Study on Toxicity Differences of Copper to Earthworm Eisenia fetida in Four Typical Soils

Terrestrial ecotoxicity data are very necessary for environmental risk assessment of contaminated soils and the development of effects-based soil screening values. In this study, copper toxicity to earthworm Eisenia fetida was investigated in four soils, red earth from Hunan, fluvo-aquic soil from Beijing, black soil from Jilin and OECD artificial soil, using standardized methods in ISO guidelines. Results showed that copper toxicity to E. fetida differed in different soils, and 50% lethal concentrations(14d LC50)of 134.4, 557.7, 715.2 and 867.0mg·kg-1 were determined in red earth, fluvo-aquic soil, black soil and OECD soil, respectively. Body weight of E. fetida was insensitive to low concentrations of Cu, while high concentrations of Cu could induce reduction of body weight of E. fetida significantly. Cocoon production of E. fetida was the most sensitive test-endpoint responding to copper in the present study. The 28d EC50 values for cocoon production were 58.2, 140.1, 258.9 and 150.4mg·kg-1 in red earth, fluvo-aquic soil, black soil and OECD soil, and the no-observed-effect concentrations(NOECs)were 50, 50, 200 and 100mg·kg-1, respectively. Considering the fact that China is one of the countries that share the richest soil diversity in the world, influence of soil properties on bioavailability and toxicity of contaminants should be taken into account in developing soil screening values.