Atkinson S F, Johnson D R, Venables B J, Slye J L, Kennedy J R, Dyer S D, Price B B, Ciarlo M, Stanton K, Sanderson H, Nielsen A
Institute of Applied Science, Department of Biological Sciences, University of North Texas, Denton, TX 76203-0559, USA.
Sci Total Environ. 2009 Jun 15;407(13):4028-37. doi: 10.1016/j.scitotenv.2009.02.029. Epub 2009 Mar 31.
Surfactants are high production volume chemicals that are used in a wide assortment of "down-the-drain" consumer products. Wastewater treatment plants (WWTPs) generally remove 85 to more than 99% of all surfactants from influents, but residual concentrations are discharged into receiving waters via wastewater treatment plant effluents. The Trinity River that flows through the Dallas-Fort Worth metropolitan area, Texas, is an ideal study site for surfactants due to the high ratio of wastewater treatment plant effluent to river flow (>95%) during late summer months, providing an interesting scenario for surfactant loading into the environment. The objective of this project was to determine whether surfactant concentrations, expressed as toxic units, in-stream water quality, and aquatic habitat in the upper Trinity River could be predicted based on easily accessible watershed characteristics. Surface water and pore water samples were collected in late summer 2005 at 11 sites on the Trinity River in and around the Dallas-Fort Worth metropolitan area. Effluents of 4 major waste water treatment plants that discharge effluents into the Trinity River were also sampled. General chemistries and individual surfactant concentrations were determined, and total surfactant toxic units were calculated. GIS models of geospatial, anthropogenic factors (e.g., population density) and natural factors (e.g., soil organic matter) were collected and analyzed according to subwatersheds. Multiple regression analyses using the stepwise maximum R(2) improvement method were performed to develop prediction models of surfactant risk, water quality, and aquatic habitat (dependent variables) using the geospatial parameters (independent variables) that characterized the upper Trinity River watershed. We show that GIS modeling has the potential to be a reliable and inexpensive method of predicting water and habitat quality in the upper Trinity River watershed and perhaps other highly urbanized watersheds in semi-arid regions.
表面活性剂是大量生产的化学品，用于各种各样的“排入下水道”的消费品中。污水处理厂（WWTPs）通常能从进水去除85%至超过99%的所有表面活性剂，但残留浓度会通过污水处理厂的废水排放到受纳水体中。流经得克萨斯州达拉斯 - 沃思堡大都市区的三一河，由于夏末几个月污水处理厂废水与河流流量的比例很高（>95%），是研究表面活性剂的理想场所，为表面活性剂进入环境提供了一个有趣的场景。该项目的目的是确定能否根据易于获取的流域特征来预测三一河上游的表面活性剂浓度（以毒性单位表示）、河流水质和水生栖息地。2005年夏末，在达拉斯 - 沃思堡大都市区及其周边的三一河上的11个地点采集了地表水和孔隙水样本。还对排入三一河的4家主要污水处理厂的废水进行了采样。测定了常规化学指标和单个表面活性剂浓度，并计算了总表面活性剂毒性单位。根据子流域收集并分析了地理空间、人为因素（如人口密度）和自然因素（如土壤有机质）的GIS模型。使用逐步最大R(2)改进方法进行多元回归分析，以开发使用表征三一河上游流域的地理空间参数（自变量）来预测表面活性剂风险、水质和水生栖息地（因变量）的模型。我们表明，GIS建模有潜力成为一种可靠且廉价的方法，用于预测三一河上游流域以及半干旱地区其他高度城市化流域的水和栖息地质量。
