Microbial risk in drinking water. (Fellowships, Grants, & Awards).

One of the high-priority research areas identified by the U.S. Environmental Protection Agency (EPA) Office of Research and Development is drinking water. Threats to drinking water safety come from the occurrence of chemical contaminants or pathogens in drinking water, and research is needed in a variety of areas to improve the ability to assess and thereby reduce the public health risks from America's public water systems.

Estimates from the Centers for Disease Control and Prevention indicate there are over 200 million cases of acute gastrointestinal illnesses per year in the United States. Household intervention epidemiologic studies have suggested that 10-40% of these illnesses may be associated with drinking water, a rate that is substantially greater than the EPA's current estimates of illness caused by individual pathogens. Many waterborne illnesses will be reduced substantially by the EPA's recent regulatory efforts to treat for pathogens originating in the source water. But uncertainty remains regarding the extent to which waterborne disease incidence may still exist resulting from both problems with distribution systems (e.g., intrusion of pathogens during periods of negative water pressure or growth and release of pathogens from biofilm) and the variability among pathogens in their infectivity, virulence, and response to treatment approaches (e.g., when one pathogen, such as Cryptosporidium, is targeted in treatment and other pathogens respond differently to the treatment).

Methodologies, analytical tools, and data are needed to help estimate the extent of gastrointestinal illness attributable to drinking water in populations served by community water and to determine its chief causes. Current approaches for estimating risk include using epidemiologic studies for estimating attributable risk of gastrointestinal illness from drinking water and application of the dose--response relationship for specific pathogens to their occurrence in finished waters to derive pathogen-specific risks. Limitations of the first approach are that epidemiologic studies tend to be very costly and that the data for a particular system may not be relevant to other systems. Limitations of the second approach include the lack of pathogen-specific information to conduct the analyses and the fact that many pathogens behave differently than the target pathogen for which the risk assessment is made.

To address this situation, the EPA is soliciting research proposing innovative approaches for estimating microbial risk. Proposed approaches, tools, and data should contribute to providing a better understanding of the magnitude of microbial risk in drinking water or the relative significance of risks from distribution systems versus treatment deficiencies.

There are two distinct areas of research covered by this solicitation: 1) development of indices or classification schemes or actual risk characterizations based on data collection and analysis that indicate relative degrees of potential risk from pathogens in source water, pathogen passage through treatment barriers, or vulnerability of a distribution system to pathogen intrusion or growth; and 2) epidemiologic studies of groundwater- or surface water--based systems that generate data to indicate attributable risk from drinking water and/or the relative contributions of risk from distribution systems versus treatment deficiencies.

Examples of research in either of the above two areas may involve characterizations of relative risk from different causes (e.g., source water pathogen loadings versus vulnerabilities within the distribution system) or characterization of risk associated with one cause such as vulnerability in distribution systems (e.g., risks from chronic or periodic exposure to pathogens released from biofilm or intrusion events). The use of innovative research approaches is encouraged.

Approximately $3 million is expected to be available for awards in response to this request. The projected award amounts for this RFA are as follows: total costs of up to $175,000 per year with a duration of two or three years for proposals responsive to the first research area (development of indices or classification schemes to characterize microbial risk), and total costs of up to $400,000 per year with a duration of up to three years for proposals responsive to the second research area (epidemiologic investigations). Instructions for applying for a Science to Achieve Results grant are available online at http://es.epa.gov/ncer/rfa/ forms/downlf.html. The deadline for receipt of applications is 17 September 2001.

Contact: Maggie Breville, 202-564-6893, fax: [phone], e-mail: [e-mail] (email inquiries are preferred). Reference: 2001-STAR-V1