长江中下游环境激素效应的污染特征及生态风险

摘要

生活污水和养殖废水排放导致受纳水环境中激素类物质的污染,对水生生物产生不利影响。分别利用嵌入雌激素受体和雄激素受体的基因重组酵母菌测定了长江中下游流域不同时期水体和沉积物中4种环境激素效应,即雌激素效应、抗雌激素效应、雄激素效应和抗雄激素效应。结果表明,雌激素效应污染最为普遍,在地表水和沉积物中检出率均超过50%,水体和沉积物的最高浓度分别为2.05 ng•L￣1雌二醇当量(EEQ)和0.43 ng EEQ•g￣1。其他3种激素效应在水体和沉积物介质中的检出率均低于雌激素效应,按总体检出率来看：抗雄激素效应>雄激素效应>抗雌激素效应,3种激素效应在水体中最大检出浓度分别为144μg•L￣1氟他胺当量(FEQ)、37.9 ng•L￣1二氢睾酮当量(DEQ)和103μg•L￣1他莫西芬当量(TEQ),在沉积物中分别为53.6μg FEQ•g￣1、12.0 ng DEQ•g￣1和51.5μg TEQ•g￣1。环境激素效应的浓度分布在水体中均呈现季节性的差异,雌激素效应的区域性高值位于武汉段、鄱阳湖口和芜湖￣南京段,其他3种激素效应没有明显的高污染区域。环境激素效应与当地人口数量、有机质、氨氮等呈现一定相关性,表明环境激素效应与人类活动排放密切相关。雌激素效应仅在鄱阳湖口点位具有高风险,其他区域为中等风险,雄激素效应无高风险区域。研究结果有助于认识长江中下游区域的环境激素效应污染态势,为相关污染控制提供基础数据。%Discharge of domestic sewage and livestock wastewater results in the pollution of endocrine disrupting chemicals in the aquatic environment, which may cause adverse effects on aquatic organisms. This study aimed to evaluate four kinds of environmental hormone effects including estrogenic activity, anti￣estrogenic activity, andro￣genic activity and anti￣androgenic activity in surface water and sediment of the middle and lower reaches of the Yangtze River during different seasons by using recombinant yeast screening assays. The results showed wide￣spread detection of estrogenic activity in the river, with the detection frequencies higher than 50% in both surface water and sediment. The highest estrogenic activity was up to 2.05 ng•L￣1 estradiol equivalents (EEQ) in surface water and 0.43 ng EEQ•g￣1 in sediment. In contrast, the detection frequencies of the other three hormonal activities were generally lower than that of estrogen activity in the river. The overall detection frequencies of those three hor￣monal activities ranked as follows:anti￣androgenic activity>androgenic activity>anti￣estrogenic activity, with the maximum detected concentrations of 144 μg•L￣1 flutamide equivalents (FEQ), 37.9 ng•L￣1 dihydrotestosterone e￣quivalents (DEQ) and 103 μg•L￣1 tamoxifen equivalents (TEQ) in surface water, and 53.6 μg FEQ•g￣1, 12.0 ng DEQ•g￣1 and 51.5 μg TEQ•g￣1 in sediments. Seasonal variations were observed for the four hormonal activities in surface water. Sites with relatively higher estrogenic activity were located at Wuhan, Nanjing￣Wuhu sections and the outlet of Poyang Lake. However no obvious regional differences were observed for the other three hormonal activities. The hormonal activities in the river were positively correlated to the general environmental parameters such as local population, organic matter, and ammonia nitrogen, suggesting that environmental hormones are mainly originated from the wastewater discharge due to human activities. A preliminary risk assessment showed a high es￣trogenic risk level at the site of Poyang Lake, with medium risk levels in the rest sites. For the all study sites, no high androgenic risks were found in surface water. The results of this study provide better understanding of the pol￣lution characteristics of those chemicals with hormonal activities in the middle and lower reaches of Yangtze River, which can help take proper control measures.