U.S. Geological Survey Leetown Science Center Aquatic Ecology Laboratory, Kearneysville, WV, USA.
U.S. Geological Survey Utah Water Science Center, West Valley City, UT, USA.
Environ Monit Assess. 2021 Feb 1;193(2):105. doi: 10.1007/s10661-021-08899-1.
Endocrine-disrupting compounds (EDCs), specifically estrogenic endocrine-disrupting compounds, vary in concentration and composition in surface waters under the influence of different landscape sources and landcover gradients. Estrogenic activity in surface waters may lead to adverse effects in aquatic species at both individual and population levels, often observed through the presence of intersex and vitellogenin induction in male fish. In the Chesapeake Bay Watershed, located on the mid-Atlantic coast of the USA, intersex has been observed in several sub-watersheds where previous studies have identified specific landscape sources of EDCs in tandem with observed fish health effects. Previous work in the Potomac River Watershed (PRW), the largest basin within the Chesapeake Bay Watershed, was leveraged to build random forest regression models to predict estrogenic activity at unsampled reaches in both the Potomac River and larger Chesapeake Bay Watersheds (CBW). Model outputs including important variables, partial dependence plots, and predicted values of estrogenic activity at unsampled reaches provide insight into drivers of estrogenic activity at different seasons and scales. Using the US Environmental Protection Agency effects-based threshold of 1.0 ng/L 17 β-estradiol equivalents, catchments predicted to exceed this value were categorized as at risk for adverse effects from exposure to estrogenic compounds and evaluated relative to healthy watersheds and recreation access locations throughout the PRW. Results show immediate catchment scale models are more reliable than upstream models, and the best predictive variables differ by season and scale. A small percentage of healthy watersheds (< 13%) and public access sites were classified as at risk using the "Total" (annual) model in the CBW. This study is the first Potomac River Watershed assessment of estrogenic activity, providing a new foundation for future risk assessment and management design efforts, with additional context provided for the entire Chesapeake Bay Watershed.
内分泌干扰化合物（EDCs），特别是雌激素类内分泌干扰化合物，在不同景观源和土地覆盖梯度的影响下，在地表水中的浓度和组成上有所不同。地表水中的雌激素活性可能导致水生物种在个体和种群水平上产生不利影响，通常表现为雄性鱼类的雌雄间性和卵黄蛋白原诱导。在美国中大西洋海岸的切萨皮克湾流域，已经在几个次流域观察到雌雄间性，此前的研究已经确定了这些次流域特定的 EDC 景观源，并观察到与鱼类健康影响相关的情况。此前在波托马克河流域（PRW）的工作（切萨皮克湾流域中最大的流域）被利用来构建随机森林回归模型，以预测波托马克河和更大的切萨皮克湾流域（CBW）中未采样河段的雌激素活性。模型输出包括重要变量、偏依赖图以及未采样河段雌激素活性的预测值，这些都为不同季节和尺度下雌激素活性的驱动因素提供了深入的了解。使用美国环境保护署基于效应的 1.0ng/L 17β-雌二醇当量的阈值，预测超过该值的集水区被归类为有暴露于雌激素化合物产生不利影响的风险，并与整个 PRW 的健康流域和娱乐访问地点进行了比较。结果表明，直接集水区尺度模型比上游模型更可靠，并且最佳预测变量因季节和尺度而异。在 CBW 中，使用“总”（年度）模型，只有不到 13%的健康流域和公共接入点被归类为有风险。本研究是对波托马克河流域雌激素活性的首次评估，为未来的风险评估和管理设计工作提供了新的基础，并为整个切萨皮克湾流域提供了额外的背景信息。
