US EPA, Office of Research and Development, Research Triangle Park, NC 27709, United States.
US EPA, Office of Research and Development, Research Triangle Park, NC 27709, United States.
Sci Total Environ. 2016 Jan 15;542(Pt A):505-20. doi: 10.1016/j.scitotenv.2015.10.074. Epub 2015 Nov 3.
In 2010, a dramatic increase in the levels of total trihalomethane (THM) and the relative proportion of brominated species was observed in finished water at several Pennsylvania water utilities (PDW) using the Allegheny River as their raw water supply. An increase in bromide (Br(-)) concentrations in the Allegheny River was implicated to be the cause of the elevated water disinfection byproducts. This study focused on quantifying the contribution of Br(-) from a commercial wastewater treatment facility (CWTF) that solely treats wastes from oil and gas producers and discharges into the upper reaches of the Allegheny River, and impacts on two downstream PDWs. In 2012, automated daily integrated samples were collected on the Allegheny River at six sites during three seasonal two-week sampling campaigns to characterize Br(-) concentrations and river dispersion characteristics during periods of high and low river discharges. The CWTF discharges resulted in significant increases in Br(-) compared to upstream baseline values in PDW raw drinking water intakes during periods of low river discharge. During high river discharge, the assimilative dilution capacity of the river resulted in lower absolute halide concentrations, but significant elevations Br(-) concentrations were still observed at the nearest downstream PDW intake over baseline river levels. On days with active CWTF effluent discharge the magnitude of bromide impact increased by 39 ppb (53%) and 7 ppb (22%) for low and high river discharge campaigns, respectively. Despite a declining trend in Allegheny River Br(-) (2009-2014), significant impacts from CWTF and coal-fired power plant discharges to Br(-) concentrations during the low river discharge regime at downstream PDW intakes was observed, resulting in small modeled increases in total THM (3%), and estimated positive shifts (41-47%) to more toxic brominated THM analogs. The lack of available coincident measurements of THM, precursors, and physical parameters limited the interpretation of historical trends.
2010 年，宾夕法尼亚州的几个供水公司（PDW）发现，使用阿勒格尼河作为原水供应的饮用水中总三卤甲烷（THM）水平和溴代物种的相对比例显著增加。阿勒格尼河溴化物（Br(-)）浓度的增加被认为是导致水中消毒副产物升高的原因。本研究重点定量分析了一家专门处理石油和天然气生产商废物并排放到阿勒格尼河上游的商业污水处理厂（CWTF）对 Br(-)的贡献，以及对两个下游 PDW 的影响。2012 年，在三个季节性两周的采样活动中，在阿勒格尼河的六个地点进行了自动化每日综合采样，以在高、低河流量期间对 Br(-)浓度和河流扩散特性进行特征描述。在河流量低的时期，CWTF 的排放导致 PDW 原水饮用水进水处的 Br(-)浓度相对于上游基线值显著增加。在河流量高的时期，河流的同化稀释能力导致卤化物浓度绝对值较低，但在最近的下游 PDW 进水处仍观察到显著高于基线水平的 Br(-)浓度。在 CWTF 废水排放活跃的日子里，低河流量和高河流量采样活动中溴化物的影响分别增加了 39 ppb（53%）和 7 ppb（22%）。尽管阿勒格尼河 Br(-)呈下降趋势（2009-2014 年），但在下游 PDW 进水处低河流量期间，仍观察到 CWTF 和燃煤电厂排放对 Br(-)浓度的显著影响，导致总三卤甲烷（THM）略有增加（3%），估计溴代 THM 类似物的毒性也略有增加（41-47%）。缺乏 THM、前体和物理参数的可用同期测量结果限制了对历史趋势的解释。
