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An objective of the U.S. Environmental Protection Agency's (USEPA's) Stage 2 Disinfectants/Disinfection Byproducts Rule is to providemore equitable protection to the public through more consistent regulation of consecutivesystems. A consecutive system is a public water system that receives some or all of its finishedwater from one or more other water systems. This study evaluates current disinfection byproducts (DPB) levels within49 consecutive systems in Pennsylvania and their 30 respective wholesalers.For the 3? years of study data, Trihalomethane (THM) levels for the wholesalers averaged 45 g/L.The THM average for the consecutive systems was 56 g/L (a 25% increase).For THM and haloacetic acids (HAA) maximum contaminant level (MCL) compliance calculations, the Stage 2 Rule replaces the running annualaverage (RAA) method with a locational running annual average (LRAA) method. Nine ofthe 49 consecutive systems (18%) had recent THM LRAA values in excess of the Stage 2THM MCL (80 g/L). Two other consecutive systems had a THM LRAA just below theMCL. Because most consecutive systems are small systems (89%), serving less than 10,000people, 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 minimalaffect 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.

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Edition: Vol. - No. Published: 06/01/2007 Number of Pages: 34File Size: 1 file , 450 KB