污水中基于酶活性分析的硫酸雌酮雌激素效应

在污水处理厂尾水中，雌酮（E1）和硫酸雌酮（E1-3-S）分别是赋存浓度最高的自由态雌激素和结合态雌激素.E1-3-S难以被生物降解且雌激素效应有限，但环境条件适宜时可在芳基硫酸酯酶（AryS）作用下通过水解释放出具有雌激素效应的E1.本论文提出了一种利用AryS活性值和E1-3-S酶促水解动力学参数计算E1-3-S半寿期的方法.根据现场取样分析得到了重庆市某污水处理厂生物处理构筑物内混合液，合流制管道溢流口与尾水受纳水体底泥中在冬、春、夏3个季节的AryS活性值，其均值分别为417.41~941.14，91.55~179.42，28.11~59.64μg对硝基酚/（g·h）.在20℃的实验室条件下，E1-3-S的酶促水解遵循一级动力学模式（P<0.01），且水解速率K_d与AryS活性呈线性正相关（R²=0.9774）.根据春季的AryS活性数据和实验室条件下E1-3-S水解速率与酶活性的线性回归方程推算，得到了在污水处理厂生物构筑物内、合流制管网溢流口和污水厂尾水排放点附近水体中E1-3-S在对应环境温度条件下通过酶促水解的半寿期分别为33.5，153.0，410.0h.该方法可用于评估硫酸型结合态雌激素在水环境中的雌激素效应释放风险.

The estrogenic activity release of estrone-3-sulfate in sewage based on enzyme activity analysis

Estrone (E1) and estrone-3-sulfate (E1-3-S) were the most abundant free and conjugated estrogens, respectively, in final effluent of sewage treatment works (STWs). The stable E1-3-S can release active E1via enzymatic hydrolysis given proper environmental conditions although itself exhibits limited estrogenic activity. A novel method was proposed to calculate the half-life of E1-3-S based on its reaction rate of enzymatic hydrolysis and the according arylsulfatase (AryS) activity. A field survey on AryS activity was carried out in winter, spring and summer along the sewage collection, treatment and discharge of a STWs in Chongqing, China. The mean AryS activities of the bioreactor sludge, the outfall sediments of combined system overflow (CSO) and river sediments were 417.41~941.14, 91.55~179.42and 28.11~59.64 μg p-nitro phenol/(g·h), respectively. The hydrolysis kinetics of E1-3-S in the lab at 20℃ followed the first order reaction (P<0.01), and the reaction rate K_d was positively correlated with the AryS activity in a linear model (R²=0.9774, P<0.01). Based on the AryS activities in the spring and the above linear model, the respective half-lives of E1-3-S in STWs bioreactors, CSO and river water were estimated to be 33.5, 153.0and 410h. This method could be used in the risk analysis on the release of estrogenic activity by sulfated estrogens in water environment.