Grantee Research Project Results
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7. Drinking Water
The Safe Drinking Water Act requires that public water supplies be disinfected and that the EPA set standards and establish processes for treatment and distribution of disinfected water to ensure that no significant risks to human health occur. Scientific evidence suggests that exposure to chemical byproducts formed during the disinfection process may be associated with adverse health effects. Reducing the amount of disinfectant or altering the disinfection process may decrease byproduct formation; however,these practices may increase the potential for microbial contamination. EPAs current challenge is to balance the health risks caused by exposure to microbial pathogens with the health risks caused by exposure to disinfection byproducts.
This section of the solicitation invites research grant applications in two areas of special interest to its mission: Microbial Pathogens in Drinking Water Systems and Drinking Water Disinfection Byproducts (DBPs).
7A. Microbial Pathogens in Drinking Water Systems
The incidence of waterborne disease in the U.S. is highly uncertain. While the health effects caused by drinking water pathogens are generally known, limited information is available on the doses and conditions that produce effects. Limited information is also available on alternative disinfection methods for pathogens resistant to the conventional chlorine-based disinfection methods. Research is needed in the following areas:
- In many cases, the causative agents for waterborne disease outbreaks have not been identified. Emerging pathogens, such as Cyclospora and Helicobacter pylori, could play a role in many of these outbreaks. Efficient methods for measuring the incidence and viability of pathogens in water are needed to assist in identifying the causative agents in future outbreaks. For example, research is needed to develop and field test a practical method for determining the viability and occurrence of Cyclospora in drinking water. Research is needed to determine Helicobacter occurrence patterns in raw water via the development and field testing of a suitable recovery and culture assay method. Innovative proposals for methods development for other emerging pathogens are also encouraged. These methods should be useful for dose-response and exposure estimates for risk assessment.
- Research is needed to develop an understanding of the risks associated with exposure to primary waterborne pathogens (e.g., Giardia, Cryptosporidium, and enteric viruses) andto emerging pathogens (e.g., Cyclospora, Mycobacteria, Helicobacter pylori, microsporidia, caliciviruses, adenovirus 40/41, and coxsackievirus B) as a function of such susceptibility factors as age (e.g., children), nutrition, protective immunity, and behavioral patterns.
- The safety of drinking water is compromised by pathogenic microorganisms resistant to standard disinfection methods. Research is required on the efficacy of ultraviolet radiation (pulsed and continuous) as a disinfectant in drinking water from various groundwater and surface water sources, including those that may pose limitations. In addition, research is needed on the optimal ultraviolet light wavelengths for inactivating specific species. Also needed is a better understanding of why pulsed UV light has a more destructive impact on cyst viability than continuous UV light.
7B. Drinking Water Disinfection Byproducts
Public water systems disinfect drinking water with chlorine or alternate disinfectants. While chlorine reduces microbial risk, the use of chlorine creates new potential risks from disinfection byproducts formed during the water treatment process. Research is needed to improve methods for estimating human exposures (via the oral, inhalation, and dermal routes) to the byproducts of different disinfection treatments. For the inhalation and dermal routes, research is especially needed on haloacetic acids, haloacetonitriles, haloketones, and aldehydes. Proposals should address research on biochemical markers of human exposure and/or the development and validation of models of human exposure to DBPs.
It is recognized that there are many other problems in assuring a safe drinking water supply to the public which this solicitation cannot address. EPA anticipates additional solicitations in the future which will focus on some of these.
Approximately $3 million is expected to be available in fiscal year 1997 for awards in this program area. The projected award range is $75,000 to $200,000/year with a duration of 2 or 3 years.