Environmental Protection Agency
Mail Code: 4607M
1200 Pennsylvania Ave., NW
Washington, D.C. 20460
Re: Drinking Water Contaminant Candidate List 3
Docket Number: EPA–HQ–OW–2007–1189
The American Society for Microbiology (ASM) is submitting comments on the proposed microbial contaminants listed in the draft CCL 3 document. The following comments were developed by the ASM Public and Scientific Affairs Board Committee on Environmental Microbiology.
The ASM is the largest single life science society with more than 42,000 members, including scientists in academic, industrial, clinical, and government institutions, working in areas related to basic and applied research, the prevention and treatment of infectious diseases, laboratory and diagnostic medicine, the environment, and water and food safety.
In providing nominations for CCL 3 in 2006, the ASM strongly encouraged the EPA to develop and implement a systematic strategy and set of criteria to identify and review all potential CCL organisms. Further, the ASM recommended that in evaluating CCL organisms, the EPA should use a formal decision-making process that reflects both the objectives of the CCL and the Safe Drinking Water Act.
The ASM noted that a comprehensive strategy and set of evaluation criteria could lead to inclusion of additional organisms of concern, for example, E. coli O157:H7 and various campylobacteria that did not meet CCL criteria. The ASM applauds the EPA for including these organisms as candidate contaminants, and for including its nominated candidate, Naegleria fowleri.
However, the ASM notes a number of concerns about the draft list. In particular, the use of the details regarding waterborne outbreaks and endemic diseases appear minimal and not to have been adequately incorporated or considered. Further, there appears not to have been adequate scrutiny of scientific papers addressing the occurrence of some of the candidate contaminants.
Vibrio cholerae occurs on the list as does Entamoeba histolytica, presumably due to recorded outbreaks. These outbreaks were limited to the Marshall Islands and a prison, respectively, and appear inappropriate for justifying inclusion of either organism on CCL 3. Cholera is not endemic in the mainland U.S., and the reported E. histolytica cases appear related to sexual transmission and not waterborne. The listing of these two organisms, along with Salmonella enterica and Shigella sonnei, raises questions about the extent to which CCL 3 is oriented to future and current needs and serving public health by addressing and placing appropriate weight on disease outbreaks.
The ASM is also concerned that the CCL 3 pathogen list does not have a strong science-based justification. The data on occurrence in water is very poor for all pathogens, and thus surrogates or other published work are needed. The EPA should examine endemic levels of disease for all enteric pathogens reported to HHS and CDC. A high endemic disease rate suggests that pathogens are being excreted in sewage, and thus occurrence is probably higher than for Vibrio cholerae, which when detected is in marine or saline environment and most often lacks virulence factors.
The ASM is pleased to have this opportunity to provide comments on the draft CCL 3 list, and hopes that its comments and recommendations are of assistance.
Ruth L. Berkelman, M.D., Chair, Public and Scientific Affairs Board
Gary M. King, Ph.D., Chair, Committee on Environmental Microbiology