In 2004, the Disinfection Byproducts Rule will require small water systems in the United States to comply with the regulated levels of 0.080 mg/L Trihalomethanes (TTHM) and 0.060 mg/L Haloacetic Acids (HAA5). Under this regulation, surface water systems that serve 500 to 10,000 people will be obligated to take samples quarterly and surface systems serving less than 500 people will need to take one sample set per year. The Pennsylvania Department of Environmental Protection (DEP) needed to determine the full impact of the DBP Rule on Pennsylvania's small surface water systems serving populations of less than 3,300. DEP collected samples at 97 small water systems across the state for TTHM and HAA5 analysis during the summer of 2000. This preliminary information was used to determine current levels of DBPs in small water systems in order to aid those systems that would violate the future regulations. The results identify TTHM as the main contaminant of concern. Approximately 20 percent of Pennsylvania's small surface water systems will need assistance complying with the future MCL (Maximum Contaminant Level) for TTHM before 2004. The levels of TTHM in small surface water systems are similar to those in medium and large systems when comparing data collected under the Interim Enhanced Surface Water Treatment Rule and the Information Collection Rule. The levels of HAA5 in small surface water systems are less than those of the medium and large systems. No small surface water systems in this study should have trouble complying with the future MCL for HAA5. Furthermore, over half of the systems will be eligible for reduced TTHM and HAA5 monitoring. The results of this sampling program will provide DEP staff with water quality information before the regulation becomes effective. This will give them the opportunity to identify systems that could have trouble complying with the Rule and allow sufficient time to work with water system staff in resolving problems through operational and/or infrastructure improvements. Without TTHM and HAA5 data beforehand, systems may be confronted with a potential violation of the Rule in 2004 and respond with inappropriate adjustments to treatment. Even worse, operators could reduce disinfectant levels and compromise inactivation of Giardia, viruses and bacteria. In essence, the results of this analysis were used for a screening survey in preparation for the Rule. Furthermore, this is currently the only statewide study on the levels of HAA5 and TTHM in small water systems in Pennsylvania and may set the stage on what other states can expect in terms of disinfection byproducts. Includes 2 references, figures.
