The combined toxic effects of arsenic and perfluorooctanoic acid on the earthworm Eisenia fetida
Earthworms(Eisenia fetida)were exposed to sub-lethal doses of arsenate(As(Ⅴ)),perfluorooctanoic acid(PFOA),and their mixture for 28 days to analyze the bioaccumulation of two toxins and to characterize the response of multiple biomarkers,thereby assessing the combined toxic effects of As(Ⅴ)and PFOA.The results of bioaccumulation analyses showed that the coexistence of As(Ⅴ)and PFOA in soil increased arsenic bioaccumulation while decreasing PFOA's bioaccumulation.As exposure levels increased,the majority of the biomarkers demonstrated significant alterations,indicating inhibition of earthworm growth and oxidative damage.The Integrated Biomarker Response Index(IBR)was utilized to summarize multiple biomarker responses,revealing significant dose-effect relationships in both the single and combined contamination groups of As(Ⅴ)and PFOA.Subsequently,IBR was combined with two mixture toxicity indices,the Effect Addition Index(EAI)and the Concentration Addition Index(CAI),to assess the toxic interaction between As(Ⅴ)and PFOA.The results indicated that the joint toxicity of As(Ⅴ)and PFOA was dependent on the concentration of As(Ⅴ).At higher concentrations of As(Ⅴ),a synergistic interaction was observed across all effect levels.Conversely,at lower concentrations of As(Ⅴ),the interaction shifted from antagonism to synergism as the exposure level increased.As(Ⅴ)emerged as the primary toxicant,significantly impacting earthworm biomarkers and influencing the overall toxicity of the As(Ⅴ)/PFOA mixture.These findings provide valuable insights for the risk assessment of the combined toxicity of As(Ⅴ)and PFOA.
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维普
