title: The effect of low-molecular-weight organic acids on copper toxicity in E. fetida in an acute exposure system.
abstract: 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 Cu2+, 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.
authors.affiliation: College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Chuifan
authors.initials: C
authors.lastname: Zhou
authors.affiliation: College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Huang
authors.affiliation: College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Jiaoda
authors.initials: J
authors.lastname: Yu
authors.affiliation: College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Forestry, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. fjlaq@126.com.
authors.forename: Aiqin
authors.initials: A
authors.lastname: Liu
mesh_terms: D000144:Acids, Acyclic / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D001682:Biological Availability; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D008970:Molecular Weight; D009835:Oligochaeta / Q000187:drug effects* / Q000648:ultrastructure; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000378:metabolism / Q000633:toxicity*; D012996:Solutions
chemical_list: D000144:Acids, Acyclic; D012987:Soil; D012989:Soil Pollutants; D012996:Solutions; D003300:Copper
keywords: Cu; Earthworm; Organic acids; Subcellular distribution; Toxicity; Ultrastructure