基于体内生物测试方法的污水处理过程中环境雌激素去除评价

Evaluation of the environmental estrogens removal from the sewage treatment via an in vivo bioassay

污水处理过程对环境雌激素的不完全去除是水环境中雌激素污染物浓度升高的一个重要原因。采集焦作市污水处理厂主要处理工艺的出水,以雄性金鱼(Carassius auratus)为受试生物,采用体内生物测试方法研究各处理工艺对环境雌激素的去除效果。结果表明,相比于对照组,所有主要处理工艺的出水(稀释体积分数为5%和10%)均显著诱导了雄性金鱼体内VTG(卵黄蛋白原)的表达并显著抑制了雄鱼性腺的发育。对于5%污水暴露组,雄鱼体内VTG诱导水平随污水处理进程的深入而降低,且氧化沟为环境雌激素的主要去除工艺。10%曝气沉砂池出水和10%生物选择池出水由于毒性作用,限制了雄鱼体内VTG的诱导。5%二沉池出水暴露组鱼的GSI(性腺成熟系数)最高(0.57%),暴露于10%曝气沉砂池出水的鱼GSI最低(0.36%)。污水处理工艺并不能完全去除雌激素污染物,尾水中的环境雌激素能够对雄性金鱼产生雌性化效应,暴露于受纳水体的鱼类存在雌性化风险。

The present paper is aimed at our evaluation of removing environmental estrogens from the sewage treatment via an in-vivo bioassay. For our research purpose, we have collected sewage sam- pies of different major sewage treatment processes from Jiaozuo munic- ipal sewage-treating plant. In our investigation, we have chosen adult male goldfish （ Carassius auratus ） as subjects. In order to investigate responses of the male goldfish to various concentrations of estrogens in the sewage, we have prepared the testing solutions by a serial dilutionof the sewage （5% and 10%, volume fraction） in the dechlorinated municipal water. The male goldfish were exposed to the various dilu- tions of the sewage. When the blood samples were taken after 7 days＇ exposure, the fish were killed by cervical transaction. At this, we have done assessement over the effects of biomarkers, such as serum vitellogenin （VTG） and gonadosomatic index （ GSI ）. The bioassay indicates significant serum VTG induction and gonad atrophy in all the sewage-treated fish. Of all the 5% sewage treatment groups, serum VTG levels in the fish were found reduced with the exposure solutions treated throughout the process in the plant. In addition, the oxidation ditch proves to be the main process for removing the envi- ronmental estrogens. The 10% of the sewage collected from aerated grit chamber and the other 10% collected from the bio-seleeting tank both inhibited the VTG induction to the male goldfish for their toxici- ty. The highest GSI was observed in the response to the treatment of the 5 % sewage from the secondary sedimentation tank （0.57 % ） and the lowest GSI （0.36%） was observed in the fish exposed to the 10% sewage from the aerated grit chamber. And, finally, it was found that it was impossible for the environment estrogens to be re- moved totally from the sewage treatment process, and with a feminiza- tion effect left over in the male goldfish due to the effluent, which means that the receiving water of the effluent of the Jiaozuo municipal sewage treatment plant can be contaminated by the environmental es- trogens and fish in them can be exposed to risk of being femininized.