Centre for Ecology and Hydrology, Wallingford, OX10 8BB.
Environ Sci Technol. 2010 Oct 15;44(20):7865-70. doi: 10.1021/es101799j.
Daily steroid estrogen concentrations as 17β-estradiol equivalents (E2 equiv.) were modeled from 1992 to 2008 for single locations on the well populated Thames and Soar rivers in England. The historic daily mean flow values which were the basis of this exercise came from a selected gauging site on each river. The natural variation in flow from winter to summer typically produced a 20- to 30-fold difference in predicted estrogen concentration over the course of a year. Based on all the predicted values from minimum to maximum over the 1992 to 2008 period there was a 98-fold difference in estrogen concentrations on the basis of flow alone for the Thames (0.1-12.7 ng/L E2 equiv.) and 67-fold for the Soar (0.2-13.3 ng/L E2 equiv.). This compares to a predicted 0.5-fold difference that could arise from differences in sewage treatment and 0.1-fold difference due to differences in in-stream biodegradation. The seasonal variation in flow generated a repeating "roller coaster" in predicted estrogen concentrations. Regularly measured phosphate data for the river Avon over the period 1993 to 1996, where point sources also dominate, was compared against flow and predicted estrogen concentrations. The pattern of predicted estrogen and measured total phosphate concentration were very closely related. This dramatic variation in contaminant concentration over the year due to flow poses questions over what we mean by environmental relevance and the representation of the real environment in aquatic ecotoxicity tests.
1992 年至 2008 年，对英格兰人口稠密的泰晤士河和索亚尔河的单一地点进行了类固醇雌激素浓度（以 17β-雌二醇当量（E2 equiv.）表示）建模。这项研究的基础是从每条河流的一个选定的测量点获得的历史日平均流量值。从冬季到夏季，流量的自然变化通常会导致一年中预测的雌激素浓度产生 20 至 30 倍的差异。根据 1992 年至 2008 年期间所有预测值的最小值到最大值，仅基于流量，泰晤士河（0.1-12.7ng/L E2 equiv.）的雌激素浓度差异高达 98 倍，索亚尔河（0.2-13.3ng/L E2 equiv.）的雌激素浓度差异高达 67 倍。相比之下，由于污水处理的差异，预测的雌激素浓度可能会出现 0.5 倍的差异，由于在流中生物降解的差异，预测的雌激素浓度可能会出现 0.1 倍的差异。流量的季节性变化产生了预测雌激素浓度的重复“过山车”。对 1993 年至 1996 年期间阿冯河的定期测量磷酸盐数据进行了比较，该河也以点源为主，与流量和预测的雌激素浓度进行了比较。预测的雌激素和实测总磷酸盐浓度的模式非常密切相关。由于流量，污染物浓度在一年内的这种急剧变化引发了对环境相关性以及水生生态毒性测试中真实环境代表性的质疑。
