Oxidation Stress Response And Ecological Risk Assessment For Zebra Fish Induced By Streptomycin Wastewater

In this study, we choose the secondary clarifier influent and effluent in a representativestreptomycin production plant in the North China as the research object. The InternationalStandardization Organization recommed species Zebra fish was selected for experiments.The toxicity of the wastewaters is assessed preliminary by the acute toxicity test onzebrafish. On the basis of acute toxicity experiments, the subacute toxicity tests wereconducted, measuring the activity of antioxidant enzymes (SOD, POD, GSH, GSH-PX) andMDA content in the muscle tissue of Zebra fish and screening the sensitive biomarkers. Inaddition, the toxicity mechanism of wastewater was explored tentatively. Finally, ecologicalrisks of the two kinds of wastewater were calculated by using IBR.Acute toxicity experiments indicated that streptomycin wastewater influent and effluentat the maximum concentration did not cause the all death of Zebra fish within96h. Thus,acute toxic effects of streptomycin wastewater influent and effluent on Zebra fish did notexist.Subacute toxicity experiments indicated that SOD activity was induced then suppressedwhen Zebra fish were exposed to different concentrations of streptomycin wastewaterinfluent, POD activity did not show a significant relationship with dose and dose-time.During exposure time, GSH activity changed significantly. GSH-PX activity in exposedgroups was higher than control groups except70%concentration group. MDA content wasinduced. Overall, Zebra fish exposed in various concentrations all subjected to oxidativedamage. When Zebra fish were exposed to streptomycin wastewater effluent, SOD activitywas increased firstly and finally returned to the control group level. POD activity did notchange significantly, and POD activity returned to the level of the control group in the laterperiod of exposure. GSH activity was inhibited when exposed3d, and each concentrationgroup presented a change trend of incerase-suppression-increase during exposure time.GSH-PX activity was only induced in individual concentration. MDA activity changed littleduring the entire exposure. Zebra fish did not cause irreversible oxidative damage.The IBR value of streptomycin influent wastewater to Zebra fish was between0.6079~6.5485. Streptomycin wastewater influent has produced a big ecological risk. TheIBR value of streptomycin effluent wastewater to Zebra fish was between0.5589~4.3898,The IBR values of Streptomycin wastewater effluent were constantly changing and there is a downward trend with small risk.During exposure to streptomycin influent and effluent, SOD, GSH, GSH-PX, MDAactivity in the muscle tissue of Zebra fish changed significantly. The results are consistentwith the radar map. So these antioxidant enzymes can be applied as potential biomarkers forevaluating toxicological effect of streptomycin wastewater on Zebra fish. The ecotoxicologyindicators of antibiotic wastewater should be monitored after treatment to make sure thewastewater discharge reaches the emission standards and does not cause toxicologicalinfluence on aquatic organisms.