Toxicological Effect Of Perfluorooctanoic Acid Exposure On Eisenia Foetida

Perfluorooctanoic acid ?PFOA? is a kind of synthetic chemicals and widely exists in the environment. It can be accumulated in higher animals because of its good chemical stability and thermal stability, which makes it become a persistent organic matter of concern. Toxicity studies of PFOA in Eisenia foetida have a small amount of research about lethal effect and acute toxicity effect, which is also lack of a more comprehensive study. Due to the interaction between drugs and biology is start from molecular level. It is necessary to carry out the protein gene expression research from molecular level about PFOA exposure on earthworm,which cause Specific protein gene response with expression.This experiment reference OECD207 method, Eisenia foetida is used as Model organisms,on the basis of preliminary experiment preliminary results, by studying the change of the indicators, such as the level of gene expression,LC50,coelomocyte DNA damage and the growth inhibition rate,which due with the acute and subacute of PFOA exposure on earthworms to reveal ecological and biological toxicity of PFOA. The main results:1.The acute toxicological effect of different exposure concentration of PFOA to Eisenia foetida was studied by using filter paper method and the artificial soil contact method with a cycle of 48 h and 14 d. The results of filter paper method of contact shows that the LC50 ?24 h,48 h? values of PFOA in acute toxicity test were 0.235 mg.cm^-2 and 0.144 mg.cm^-2 respectively. Based on the results of artificial soil method of contact, the LC50?7 d,14 d? value of PFOA in acute toxicity test were 710.691 mg.kg^-1 and 544.404 mg.kg^-1 respectively. The results indicated that the mortality of Eisenia foetida increased following exposure to PFOA with a dose-dependent manner.2.The effect of PFOA on Survival, growth and reproduction of Eisenia foetida was studied by using natural soil contact method with a cycle of 28 d.Results show that cocoon number and hatching rate of earthworm have a significant dose-effect relationship between drug concentration, which decreased with the increase of the concentration, Shows that with the increase of drug concentration, leading to the non-essential functions such as growth and reproduction of survival of earthworm is restrained.3.The effect of PFOA on 3 kinds of antioxidant enzymes SOD, CAT, GST gene expression levels of Eisenia foetida was studied by using natural soil contact method with a cycle of 28 d. The results show that gene transcription expression level of SOD, CAT, GST under long-term exposure of to low doses of PFOA are inducted and inhibited by varying degrees. The changes of SOD and CAT gene expression and PFOA concentrations appear good dose-effect relationship.4.The effect of PFOA on DNA damage of Eisenia foetida coelomocyte was studied by using natural soil contact method with a cycle of 28 d.The results show that PFOA can cause the earthworm coelomocyte DNA damage, and damage degree is closely relative to the concentration, the values of Tail length?TL?, tail moment?TM?,tail DNA content?TD? are in good consistency.The results showed that DNA damage and the changing of gene express of antioxidant enzymes of earthworm could be as a biomarker to indicate the effect of PFOA on soil organisms. To monitor soil biological toxicity of PFOA effect on earthworms, provide important basis for the early molecular diagnosis of subacute toxicity effect and ecological risk assessment of PFOA exposure on earthworm.