Ecotoxicological Effects of NDMA on Crucian carp Seedlings in Fresh Water
N-nitrosodimethylamine(NDMA)is a strong carcinogen with high toxicity and environmental persistence.It exists widely in human living environment and has attracted great attention.The toxic effect of NDMA on juvenile Crucian carp was studied by semi-static acute toxicity test and determination of protein content,superoxide dismutase(SOD)and catalase(CAT)activities.The results showed that high concentration of NDMA was significantly toxic to juvenile Crucian carp,and the 50%lethal concentration(LC50)at 24 h,48 h,72 h and 96 h were 9.83 mg/L,9.14 mg/L,8.11 mg/L and 7.05 mg/L,respectively.The safe concentration(SC)was 0.71 mg/L.NDMA had different effects on protein content and SOD and CAT activities of juvenile Crucian carp.With the increase of NDMA concentration,protein content showed inducible effect.SOD activity was induced in low concentration group(1.18 mg/L and 1.76 mg/L),but significantly inhib-ited in high concentration group(3.68 mg/L).CAT activity was mainly induced,but inhibited in 3.68 mg/L concentration group.With the extension of exposure time,the inhibition rate of each index was as SOD enzyme activity>CAT enzyme activity>protein content.In this study,the acute toxicity and oxidative stress toxicity of NDMA on juvenile Crucian carp were discussed,which provided a scientific basis for preventing and reducing the toxicity of disinfection by-products to aquatic organisms.