美国环境保护局（USEPA）第2阶段消毒剂/消毒副产品规则的目标是提供 通过更一致的连续性监管，为公众提供更公平的保护 系统。连续供水系统是一个公共供水系统，它接收部分或全部水资源 来自一个或多个其他水系统的水。这项研究评估了该地区目前的消毒副产品（DPB）水平 宾夕法尼亚州的49个连续系统及其各自的30个批发商。 3号？根据多年的研究数据，批发商的三卤甲烷（THM）水平平均为45微克/升。 连续系统的THM平均值为56微克/升（增加25%）。 对于THM和卤乙酸（HAA）最大污染物水平（MCL）合规性计算，第2阶段规则将取代现行的年度标准 平均值（RAA）法和位置运行年平均值（LRAA）法。九个 49个连续系统（18%）最近的THM LRAA值超过第2阶段 THM MCL（80微克/升）。另外两个连续系统的THM LRAA刚好低于 MCL。因为大多数连续系统都是小型系统（89%），服务不到10000个 人，只有一个位置被监控；因此，RAA和LRAA的计算是相同的。 因此，第2阶段规则从RAA更改为LRAA计算的影响最小 影响整个州的连续系统。这项研究还表明，THMs（与。 HAAs）对宾夕法尼亚州的连续系统造成了更大的问题。包括8个参考文献、图表。

An objective of the U.S. Environmental Protection Agency's (USEPA's) Stage 2 Disinfectants/Disinfection Byproducts Rule is to provide more equitable protection to the public through more consistent regulation of consecutive systems. A consecutive system is a public water system that receives some or all of its finished water from one or more other water systems. This study evaluates current disinfection byproducts (DPB) levels within 49 consecutive systems in Pennsylvania and their 30 respective wholesalers. For the 3? years of study data, Trihalomethane (THM) levels for the wholesalers averaged 45 µg/L. The THM average for the consecutive systems was 56 µg/L (a 25% increase). For THM and haloacetic acids (HAA) maximum contaminant level (MCL) compliance calculations, the Stage 2 Rule replaces the running annual average (RAA) method with a locational running annual average (LRAA) method. Nine of the 49 consecutive systems (18%) had recent THM LRAA values in excess of the Stage 2 THM MCL (80 µg/L). Two other consecutive systems had a THM LRAA just below the MCL. Because most consecutive systems are small systems (89%), serving less than 10,000 people, only single location is monitored; thus, the RAA and LRAA calculations are identical. Accordingly, the Stage 2 Rule change from an RAA to a LRAA calculation will have minimal affect on Pennsylvania consecutive systems state-wide. This study also indicates that THMs (vs. HAAs) pose a more substantial problem for consecutive systems in Pennsylvania. Includes 8 references, figures.