污水厂尾水中消毒副产物对小球藻的生长生理影响

Effects of disinfection by-products in sewage treatment plant effluent on the growth and physiology of Chlorella vulgaris

通过检测无锡某污水厂疫情期间排放尾水中消毒副产物的种类和浓度,发现一氯乙酸(CAA)占全年总检出量的30.22%.采用毒性标准实验方法研究CAA对小球藻生长和抗氧化系统的影响.结果表明在CAA胁迫下,小球藻生长速率减慢,最大光化学量子产量(Fv/Fm)较空白组出现明显下降,96 h叶绿素a浓度明显降低.CAA对小球藻的96 h半数效应浓度(EC_(50))为14.734 mg·L^(-1).中、低浓度CAA胁迫会诱导超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和还原型谷胱甘肽(GSH)含量的上升,减少丙二醛(MDA)含量的积累;而高浓度胁迫下,SOD、CAT活性和GSH含量持续下降,MDA含量先升高再下降.

This study investigated the species and concentration of disinfection by-products in a sewage treatment plant effluent in Wuxi during the COVID-19 pandemic.It was found that chloroacetic acid(CAA)accounted for 30.22%of the total amount of disinfection by-products detected in the whole year.The effects of CAA on the growth and antioxidant system of Chlorella vulgaris were studied via standard toxicity tests.The results showed that upon the exposure of CAA,the growth rate of Chlorella vulgaris was slowed down,the maximum photochemical quantum yield(Fv/Fm)decreased significantly compared to the control group,and the concentration of chlorophylla was significantly decreased at 96 h.The EC_(50)for 96 h-exposure of CAA was found to be 14.734 mg·L^(-1).The activities of superoxide dismutase(SOD)and catalase(CAT)and the content of reduced glutathione(GSH)were increased while the accumulation of MDA was reduced upon the exposure of medium and low concentrations of CAA.However,high concentration exposure could lead to a decreasing trend in SOD and CAT activities as well as GSH content,while the content of MDA was first increased and then decreased.