Zhou Chuifan, Huang Meiying, Yu Jiaoda, Li Ying, Liu Aiqin
College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
Environ Sci Pollut Res Int. 2017 Mar;24(9):8805-8813. doi: 10.1007/s11356-017-8594-4. Epub 2017 Feb 18.
In the present study, the effects of low-molecular-weight organic acids (OAs) on the toxicity of copper (Cu) to the earthworm Eisenia fetida (E. fetida) were investigated in a simulated soil solution. We exposed E. fetida to soil solution containing Cu and a variety of OAs (acetic acid, oxalic acid, citric acid, and EDTA). We found that the addition of OAs reduced the toxicity of Cu to E. fetida, where the reduction was strongest in EDTA and weakest in acetic acid. These compounds decreased the mortality rate of E. fetida that were exposed to Cu and reduced levels of antioxidant enzymes and malondialdehyde to unexposed control levels. E. fetida were exposed to Cu with OAs had reduced Cu, which were likely caused by Cu forming complexes with the OAs, reducing the availability of Cu. The presence of OAs also reduced Cu-induced damage on earthworm cellular ultrastructures and changed the subcellular distribution of Cu. These results demonstrated that OAs could reduce the toxicity, as well as the bioavailability, of heavy metals in soil solutions where both OAs and heavy metals often coexist.
在本研究中，在模拟土壤溶液中研究了低分子量有机酸（OAs）对铜（Cu）对蚯蚓赤子爱胜蚓（E. fetida）毒性的影响。我们将赤子爱胜蚓暴露于含有铜和多种有机酸（乙酸、草酸、柠檬酸和乙二胺四乙酸）的土壤溶液中。我们发现，添加有机酸降低了铜对赤子爱胜蚓的毒性，其中乙二胺四乙酸的降低作用最强，乙酸的最弱。这些化合物降低了暴露于铜的赤子爱胜蚓的死亡率，并将抗氧化酶和丙二醛水平降低到未暴露对照组的水平。暴露于含有有机酸的铜中的赤子爱胜蚓体内铜含量降低，这可能是由于铜与有机酸形成络合物，降低了铜的有效性。有机酸的存在还减少了铜对蚯蚓细胞超微结构的损伤，并改变了铜的亚细胞分布。这些结果表明，在有机酸和重金属经常共存的土壤溶液中，有机酸可以降低重金属的毒性及其生物有效性。
