Oxidative Toxicity And Genotoxicity Of Phenanthrene To Loach Larvae

Polycyclic aromatic hydrocarbons(pahs)are persistent and highly toxic carcinogens.Their wide environmental distribution makes them a considerable threat to the ecological environment and human health.As one of the representatives of polycyclic aromatic hydrocarbons,phenanthrene can be detected in large quantities in the environment.According to existing experiments and observations,phenanthrene is found to be potentially toxic to fish,shellfish and other aquatic animals,requiring priority control.In this study,the activity of Superoxidedismutase(SOD),Catalase(CAT),Glutamic-pyruvic transaminase(GPT)and Glutamic-oxaloacetic transaminase(GOP)in liver were determined by pyrogallol autoxidation,ammonium molybdate colorimetry and spectrophotometry,respectively.The purpose of this study is to accumulate scientific data for the toxicological research of phenanthrene and provide the basis for the environmental safety evaluation of phenanthrene.The research results are as follows:1.Effect of phenanthrene on antioxidant enzyme activity in liver of loach larvaeFour concentration groups were set according to the semi-lethal concentration and safe concentration determined by the 96-h hydrostatic experiment: 1.26 mg/L,1.58 mg/L,2.00 mg/L,and 2.51 mg/L.According to the analysis of the experimental data,the liver superoxide dismutase(SOD)and catalase(CAT)activities of loach larvae showed a trend of increasing first and then decreasing.In the low concentration group(1.26 mg/L),the SOD and CAT activities were not significantly changed,while in the high concentration group(2.00,2.51 mg/L),the SOD and CAT activities were significantly changed.The activity of SOD and CAT in each concentration group reached the maximum value at 7d or 14 d,and the activity decreased and reached the minimum value at 28 d,indicating that phenyl had significant time-dose effect on SOD and CAT.2.Effect of phenanthrene on liver transaminase activity of loach larvaeThe activity of GPT and GOP in the four concentration groups of 1.26 mg/L,1.58 mg/L,2 mg/L and 2.51 mg/L increased and then decreased at 7-28 days,and the activity reached the maximum at 7 or 14 days.The phenanthrene showed a trend of inducing and then inhibiting the activity of hepatic transaminase in lotifish larvae.With the increase of phenanthrene concentration,the activity of GPT and GOP increased significantly in the same period.At 28 d,the maximum and minimum values of both GPT and GOP in the high concentration group(2.51 mg/L)were significantly different from those in other groups,that is,the higher the concentration of phenanthrene,the more significant the change of liver transaminase activity in loach larvae was.3.Mutagenesis effect of phenanthrene on erythrocyte micronucleus of loach larvaeCompared with the control group,the micronucleus rate of loach larvae significantly increased when they were exposed to low concentration of phenol(1.26 mg/L)for 7 days,and showed a significant increase trend with the increase of exposure concentration.In all the phenanthrene concentration treatment groups,the micronucleus rate of loach larvae showed a gradually increasing trend with the extension of exposure time,but the micronucleus rate of loach larvae decreased when exposed at high concentration for 28 days.This indicated that there was a significant time-dose effect of phenanthrene on the genetic toxicity of loach larvae,and the toxicity increased with the increase of phenanthrene concentration or the extension of treatment time,which may inhibit the normal cell division and cause damage to the body after reaching the peak.