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Research Contributions
EPA's Drinking Water Research Program in EPA's Office of Research and Development is providing the science needed to support regulatory decision making to protect water quality and ensure safe drinking water for Americans.
Research contributions include:
Assessment Tools: Methods Developed to Gather Contaminant Data
Analytical methods developed by researchers and grantees enable EPA, states, and local agencies to evaluate the prevalence of waterborne contaminants in drinking water sources and assess the impacts of treatment and distribution systems on water quality. The use of consistent, validated methods to monitor water quality allows for results from different drinking water systems to be compared. Researchers have developed several important analytical methods that have improved our capabilities for measuring explosives (Method 529), nitrosamines (Method 521), acetanilide degradation products (Method 535) and perchlorate (Method 332.0), and other contaminants in drinking water systems. Over 4,700 drinking water utilities will be required to develop monitoring programs under the Unregulated Contaminant Monitoring Rule UCMR. Methods developed by researchers will be used to support over 60 percent of the approximately 600,000 measurements that will be needed under the UCMR.
Source Water: Health Effects Findings Support Rule Making
Research targeted at controlling waterborne pathogens in drinking water systems can have direct public health benefits. Regulatory approaches to control exposure to waterborne pathogens rely on a sound scientific basis for linking knowledge about the prevalence of waterborne pathogens in drinking water sources (surface water and ground water) with strategies to control microbial proliferation through drinking water systems.
The availability of reliable methods to evaluate protozoan pathogens in drinking water is an on-going research emphasis. Research grants supported through the STAR (Science to Achieve Results) program under the Drinking Water Research Program led to the development and application of a serological method to detect exposure to infectious Cryptosporidium.
This method was applied to assess how low-levels of Cryptosporidium in drinking water systems derived from surface water sources may pose health risks. Evaluation of potential infections, coupled with waterborne disease outbreak information, permitted the calculation of health risk reduction benefits and assisted the EPA in promulgating its surface water and ground water treatment rules. These rules strengthen public health protection through reducing exposure to microbial contaminants, especially Cryptosporidium.
More information on Long Term 2 Enhanced Surface Water Treatment Rule
Treatment: Research Assists Small Communities
Research has assisted small communities by developing and testing treatment technologies for control of arsenic, a waterborne contaminant that is regulated through the Safe Drinking Water Act (SDWA). In 2006, the MCL (Maximum Contaminant Limit) for arsenic was decreased to 10 parts per billion (ppb) to reduce exposure to arsenic through public water systems. Compliance with this more stringent standard is challenging for small utilities due to the need for cost-effective and reliable treatment technologies. EPA's arsenic field-demonstrations, supported by the Drinking Water Research Program, provide full-scale treatment systems to small public water systems across the United States for intensive testing and evaluation of arsenic. To date, over 40 demonstration projects have been initiated. The valuable field data generated through this project is designed to help small utilities develop and implement cost-effective approaches for removing arsenic from drinking water sources.
More information at arsenic research at EPA
Distribution Systems: Discoveries Help Protect Water Systems
All public water systems are required to disinfect water to inactivate potential pathogens and prevent regrowth in water distribution systems. While disinfection is critical for protection of public health and control of waterborne disease, the chemicals that are used for disinfection also react with other constituents in water such as organics, bromide, nitrogen-based compounds, and trace contaminants. Disinfection byproducts (DBPs) are the products of reactions between disinfectant chemicals (chlorine, chloramines, ozone, chlorine dioxide) and other constituents. Research has provided new knowledge on the formation of DBPs in water distribution systems and potential health risks. Research has:
- Identified formation mechanisms for DBPs from alternative disinfection approaches (including ozonation and chloramination)
- Identified bromonitromethanes and other DBPs in water disinfected by chloramination
- Identified a new generation of DBPs in water disinfected by pre-ozonation followed by post-chlorination including iodinated phenols, and bromodichloropropenoic acids.
A major nationwide occurrence study was completed that quantified DBPs in drinking water across the U.S. In addition, important new discoveries have been made regarding the use of alternative disinfectants other than chlorination.
More information on identification of new chemical disinfection by-products
Science Supports Development of Water Regulations
Research has been instrumental in helping to quantify exposure to disinfection byproducts (DBPs) through drinking water systems and the potential for related health risks such as cancer or reproductive and developmental health effects. The Drinking Water Research Program provides scientific support for development, review, revision, and implementation of regulations under the Safe Drinking Water Act. For example, research has broadened understanding of dietary exposure of DBPs for use in health risk assessments. Researchers also provided important scientific calculations for several DBPs, including monochloroacetic acid (MCA), dichloroacetic acid (DCA), and trichloroacetic acid (TCA) that provided input for regulatory decisions.
Exposure/Health Effects/Health Outcomes: Arsenic Research
Arsenic research has led to a better understanding of the links between contaminant concentrations in water and health effects. The research has been used to understand concentrations of arsenic in drinking water, the extent to which U.S. populations are exposed to arsenic and how exposure can impact health. The results of this research contributed to the development of the revised maximum contaminant limits (MCLs) for arsenic in drinking water that were implemented in 2006 and will be used in future review of EPA's arsenic rule.