February 29, 1996 - Reauthorization of the Safe Drinking Water Act: The Need for Appropriate Inclusion of Microbial Contaminants
The American Society for Microbiology (ASM), the single largest life science society in the world with over 40,000 members, welcomes the opportunity to provide comments concerning the reauthorization of the Safe Drinking Water Act (SDWA). Members of the ASM have broad expertise in microbiology including with disease causing microorganisms that may be distributed through potable water supplies. ASM members, like all citizens, are concerned with the safety of the drinking water supply. ASM is especially concerned that any regulatory policy as a result of the SDWA reauthorization be scientifically based. The following comments have been developed by the Subcommittee on Drinking Water of the ASM's Public and Scientific Affairs Board Committee on Environmental Microbiology.
Waterborne pathogenic microorganisms are a major source of disease worldwide. In spite of measures that have been instituted to ensure the microbiological safety of drinking water, disease causing microorganisms are regularly transmitted via potable water supplies. Only in the cases of major disease outbreaks have we traced the source of infection back to potable water supplies. Generally, in the absence of waterborne outbreaks, the sources of sporadic cases of enteric waterborne disease caused by these pathogenic microorganisms are not identified.
Ensuring the safety of potable water requires that the levels of disease causing microorganisms be reduced below levels that cause human infections, and that test procedures be carried out to ensure drinking water does not serve as a conduit of disease transmission. Regulations aimed at reducing the risk of waterborne disease transmission, however, are still employing tests that were developed a century ago. These tests detect levels of indicator microorganisms, specifically coliform bacteria that live in the human intestines, rather than specific disease causing microorganisms. This is a very different approach than used to ensure that the water is "free" of toxic and cancer-causing chemicals. In the case of chemicals, there are specific maximum contaminant levels (MCL) which are established based upon the risk of exposure to chemicals in terms of human health. Comparable MCLs for microorganisms are lacking even though specific pathogens present acute public health risks.
The historical use of the coliform test is based upon the philosophy that if coliform bacteria are present, then there is evidence of recent contamination with human fecal matter that may be carrying enteric pathogens. The corollary to this premise is that water which is free of coliform bacteria will also be free of any pathogens, and is therefore safe to drink. This latter premise is clearly false. While it is true that there is a relatively good correlation between the presence of coliform bacteria and certain enteric pathogens - such as the Salmonella species that cause typhoid fever, the Vibrio species that causes cholera, and the Shigella species that cause bacterial dysentery - it is also true that various enteric viruses - such as hepatitis A virus, and several pathogenic protozoa - such as Giardia and Cryptosporidium, do not always correlate well the presence or absence of coliform bacteria. Hence, there remains the risk of large outbreaks occurring such as the 400,000 people infected with Cryptosporidium from Milwaukee's water supply. Knowing that coliforms are not adequate indicators of all waterborne microbial pathogens and given the availability of detection methods, we should be moving toward assessing whether setting MCLs for specific pathogens are needed.
For many microorganisms, further research will be necessary before it can be determined if a separate MCL is needed and before a reasonable MCL could be established. For example, although there have been a few outbreaks of viral illness associated with coliform-free water, the magnitude of the public health problem associated with viruses and other fastidious microorganisms in finished water, which does not exceed the MCL for coliforms, is not known. Before asking for utilities to routinely test their water for specific viruses, it will be important to show that the public health consequences of such viruses and other fastidious microorganisms justify routine testing.
Furthermore, current tools used to detect viruses are not well-adapted for routine monitoring and further technology development is needed. We would recommend that emphasis be placed on further research on public health consequences of viruses in treated water and further development of monitoring tools so that they are inexpensive, easy-to-use, and timely (i.e. provide results in hours rather than days or weeks, so public health actions can been taken while the suspect water is still in the system.)
On the other hand, Cryptosporidium has been shown to be inadequately addressed by existing water treatment monitoring and practices. A concerted effort to develop data and tools necessary to set an MCL for Cryptosporidium may be reasonable, but even for this organism, further research regarding the viability of the organism in finished water, better dose-response data, and improvements in technology for measuring Cryptosporidium in drinking water are all essential before an MCL can be developed.
The ASM strongly feels that Cryptosporidium and other microorganisms of public health concern be included in an occurrence data base.
At present there are insufficient data on pathogens to conduct risk assessments needed to set MCLs. Thus, development of better data bases describing human health effects, pathogens, and occurrence in water are urgently needed. The development of these data bases and any ensuing regulations that may set MCLs or treatment techniques for specific microbial pathogens should be the result of cooperative efforts within the government and between the scientific community, the water industry, and public.
Within the government, there is great expertise in microbiology and epidemiology within the Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA). These agencies should be mandated to and given resources to cooperatively assess the risks of specific waterborne pathogens using risk assessment methods. In addition, they should work jointly to assess detection and treatment methods for ensuring that the water supplies used for drinking water are free of dangerous levels of pathogenic microorganisms. We believe that public health, biomedical, and other research should be conducted by those agencies with experience and capacity in these areas. Additionally, the National Institute of Environmental Health and Safety should begin to assist in the assessment of public health risks from microorganisms in drinking water. The use of an external advisory panel composed of members of professional scientific societies with expertise in public health and microbiology should be involved in development of appropriate programs aimed at developing the necessary data for ensuring the safety of the drinking water supply.
Congress should mandate cooperation between those agencies responsible for protecting public health and drinking water and provide the resources necessary. We also urge consultation with scientific experts to ensure gathering of necessary data so that risk based assessments form a scientific basis for regulation.
Adequate attention should be given to distribution systems. Typically, the safety of source water is addressed. However, we often fail to give adequate attention to the importance of monitoring distribution systems for microbial contaminants such as Legionella and Mycobacterium. Although source water may be relatively free of pathogens prior to entering a distribution system, it still has the potential to pose a serious health risk to the end users due to microorganisms in the distribution system. These systems, if not properly monitored and tested, can provide environments where microorganisms may flourish. We support regulating and monitoring distribution systems to avoid dangerous levels of microorganisms in the water supply for the end user.
Reauthorization of the SDWA gives the public and Congress the opportunity to be assured that microbial contaminants are put in proper perspective for the future development of safe drinking water. The SDWA must recognize the dangers of microbial contaminants that cause waterborne infectious disease. There have been considerable research monies already invested in determining the long term health effects of chemicals. It is essential that in this reauthorization of the SDWA, greater attention is focused on the immediate acute health effects of microbial contaminants. At present the focus on the health effects of chemicals, which tend to be longer term, are emphasized, and while this focus is important it should not be at the expense of the equally important area of microbial contaminants.
The SDWA, which was designed to provide safe drinking water and protect public health, has historically treated microbial and chemical contaminants differently. Under the Act, the EPA was required to develop maximum contaminant levels, occurrence data bases, monitoring programs, analytical methods and risk assessment for specific chemical contaminants. Microbial contamination was treated simplistically. The EPA developed broad treatment techniques to control microorganisms and two bacteriological indicators. Microorganisms were treated as a broad category of contaminant regardless of the actual differences in health risks, occurrence in water, and resistance to treatment of each individual microorganism. Legislation is needed to require the EPA to monitor for both regulated and unregulated microbial contaminants, develop an occurrence data base for microorganisms, and conduct risk assessment and standard setting for microorganisms.
With reauthorization of the SDWA, lies the opportunity to address the important microbial contaminants found in water. It is essential at this time that microorganisms are specifically incorporated into the SDWA for development of safe drinking water in the future. Outlined below is an analysis of S. 1316 and H.R. 3392 as requested by Congressman Michael Bilirakis.
H.R. 3392 (103rd Congress): Requires EPA to establish MCLs, treatment techniques and monitoring programs for contaminants in bottled water as appropriate. S. 1316: Requires EPA to develop a regulation for contaminants which is appropriate for bottled water including establishing MCLs and monitoring.
Comments: With respect to microorganisms, S. 1316 will address only coliforms unless specified otherwise. H.R. 3392 would address those contaminants regulated by treatment techniques, which is the current approach used by EPA for setting microbial standards, and require the Food and Drug Administration (FDA) to develop rules addressing microbial contaminants which may be found in bottled water.
Recommendation: Support the legislative language contained in H.R. 3392 which would include demonstrating that microbial contaminants have been addressed by EPA and FDA.
H.R. 3392 (103rd Congress): Requires EPA to establish an Maximum Contaminant Level Goal (MCLG) and a MCL for Cryptosporidium to take effect in 2 years. Potential delay due to the difficulties EPA has encountered with the ICR.
S. 1316: Cryptosporidium is addressed under ICR section with possible extension of the development of an MCL or treatment technique. Research on the health effects of Cryptosporidium has been provided for in the bill.
Comments: MCLGs currently for viruses and Giardia under the Surface Water Treatment Rule (SWTR) are zero, no MCLs have been set for any microorganism other than coliforms. Developing scientific sound MCLs for any microorganism, including Cryptosporidium, is dependent on the ICR which needs to be done well. It should be noted that the provisions in the Senate bill is an example of an area where CDC is already conducting extensive research, but the authorization language relates to EPA.
Recommendation: The feasibility of developing MCLs should be reassessed as appropriate for microbial contaminants with improvements in the detection methods and as better data on the relationship between water levels of microbial contaminants and human health effects are available. This would provide greater assurance of the safety of the water and treatment reliability. In addition, the need for further research prior to setting an MCL should also be considered. The cooperation between CDC and EPA should be required in this activity.
Cost-Benefit H.R. 3392 (103rd Congress): Legislative language provides for marginal costs and benefits to be considered in setting MCLs with the exclusion of the D-DBP reg-neg agreement (including Cryptosporidium) and radionuclides.
S. 1316: Under this bill, non-quantifiable costs and benefits are to be excluded in deciding justification of an MCL. Language supports cost-benefit analysis for setting MCLs.
Comments: There are significant benefits to reduction of potentially pathogenic microbes that are difficult to quantify, yet no less real. For example, the costs associated with reactive arthritides or other chronic conditions which could be associated with microorganisms in water are currently unquantified.
Recommendation: A best effort should be made to include all the costs and benefits, both quantifiable and non-quantifiable with applicable uncertainties.
Distribution Systems H.R. 3392 (103rd Congress): Language states measures to protect distribution systems from leaking sewer lines.
S. 1316: Language requires monitoring of contaminants formed in distribution systems, most likely referring only to disinfection byproducts.
Comments: Many waterborne outbreaks are associated with distribution systems. Both bills fail to address microorganisms, such as Legionella, Mycobacterium, or other heterotrophic bacteria that grow in distribution systems. In addition, EPA has no occurrence data base available for microbial contaminants in distribution systems.
Recommendation: Legislation reauthorizing the SDWA should require the monitoring of microbial contaminants likely to be found in distribution systems.
H.R. 3329 (103rd Congress): Requires EPA to develop a regulation governing the recycling of filter backwash. S. 1316: Legislative language provide no specifics.
Comments: Filter backwash is likely to be an issue for Cryptosporidium or other chlorine-resistant microorganisms which may be identified.
Recommendation: Support the language contained in H.R. 3392 which requires EPA to develop a regulation on filter backwash.
Ground Water Issues
H.R. 3392 (103rd Congress): Not specifically addressed other than in source water protection.
S. 1316: Requires EPA to promulgate criteria regarding the appropriateness of the disinfection of ground water, establishes a research plan for supporting the ground water disinfection rule, authorizes $20 million for grants to States for comprehensive groundwater protection programs and the reestablishment of a partnership between Kerr Environmental Research Laboratory and National Center for Ground Water Research to conduct research, training and technology transfer for ground water quality protection and restoration.
Comments: Currently there is no pathogen-related drinking water research being conducted through the Kerr Environmental Research Laboratory or the National Center for Ground Water Research. In addition, for most waterborne outbreaks that occur in ground water, viruses are suspected as the causative agents.
Recommendation: Legislation should strongly support the need for data to support the ground water disinfection rule. In addition, some portion of research, training and technology transfer should be directed towards microbial contaminants.
H.R. 339 (103rd Congress): Language calls for revising the list for monitoring new contaminants (unregulated). Then, within 1 year address 15 contaminants, and revise every 4 years. The new list of contaminants will come from the occurrence data base. Relief for monitoring will not be given for microorganisms.
S. 1316: Requires EPA to select new contaminants with initial review within 2 years, and develop a list of 12 contaminants (use public health experts and general public) every 5 years. Selection will be based on data from the occurrence data base and nature of health effects. From this list, priorities in research on health effects, occurrence data needs and treatment techniques will be addressed.
Comments: Only coliforms are routinely monitored for. There is no occurrence data base for other microbial contaminants, therefore, it is likely that microorganisms will be left out unless legislation specifies that a portion of the new contaminants be microbial, and specialized monitoring is undertaken, such as what will occur under the ICR.
Recommendation: If legislation is going to require EPA to select new contaminants for monitoring, then some portion of new contaminants chosen for monitoring should be microbial contaminants.
Occurrence Data Base
H.R. 3392 (103rd Congress): Requires EPA to assemble and maintain an occurrence data base on regulated and unregulated contaminants in no later than 2 years.
S. 1316: Requires EPA in no later than 3 years to assemble and maintain a national drinking water occurrence data base for both regulated and unregulated contaminants. EPA shall solicit recommendations from National Academy of Sciences, and any person may submit recommendations as to what contaminants should be included on the basis of whether the contaminant occurs or is likely to occur, and the risk to public health it poses.
Comments: Microbial contaminants have been left completely out of the National Occurrence Data Base. There is no data base for currently regulated microbial contaminants (i.e. coliforms). Only contaminants with MCLs (i.e. chemical contaminants) are monitored for under regulated contaminants. New contaminants are chosen from Chemical Release records and other discharge permitting programs which focus on chemicals. There is no provision for including new microbial contaminants despite the evidence that microbial contaminants are found in drinking water, that do pose a public health risk (like Legionella) and continue to cause waterborne outbreaks.
Recommendation: Legislative language should instruct EPA to develop a Microbial National Occurrence Data Base with appropriate development of methods, and solicit recommendations from the National Academy of Sciences and scientific societies.
Private Drinking Water
H.R. 3392 (103rd Congress): Legislative language provides no specifics.
S. 1316: Legislation requires that EPA conduct a study, and report to Congress the extent and seriousness of contamination of private sources of drinking water within 3 years.
Comments: A study of private drinking water more than likely will not include any data for microbial contaminants other than indicator criteria (i.e. coliforms).
Recommendation: Support Senate language. The study should include viruses as well as virus surrogates (e.g. coliphage), since viruses are a major cause of ground water related disease. Federal agencies, like the Centers for Disease Control and Prevention and the National Institute for Environmental Health and Safety, should be brought into assist with the study.
H.R. 3392 (103rd Congress): Legislative language provides no detailed information.
S. 1316: Requires EPA to develop analytical methods for microbial contaminants, develop means to determine viability of oocysts of Cryptosporidium, develop dose-response curves for Cryptosporidium and Norwalk virus, develop indicators of treatment effectiveness, bench pilot and full-scale studies; determine strategy for determining risks including subpopulations at risk.
Comments: Both bills fail to mention how to include newly recognized microorganisms, water quality in the distribution system, or develop an occurrence data base. In addition, a dose-response curve has already been developed for Cryptosporidium.
Recommendation: EPA should be required to develop criteria documents for all microbial contaminants currently regulated and emerging using scientific risk assessment approaches, and identifying data gaps and research needs.
Residential Treatment Units
H.R. 3392 (103rd Congress): Legislation requires for Point-of-Use (POU) units, EPA work with the Federal Trade Commission (FTC) to evaluate false claims, and report in 3 years recommendations for legislation.
S. 1316 : Legislation provides no specific details.
Comments: Currently POU units are registered with EPA through Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). POU units have to be tested for microorganisms only if they are labeled as a microbial purifier. There are many false claims suggested, especially during crisis situations. For example, during the Milwaukee outbreak only a few POU units had actually been tested against Cryptosporidium.
Recommendation: Support the House language.
Source Water Protection
H.R. 3392 (103rd Congress): Legislation calls for EPA to delineate boundaries of assessment areas, identify regulated contaminants' origins, and determine susceptibility of public water systems.
S. 1316: EPA required to delineate source protection areas, conduct vulnerability assessments, and identify risks. Recommendation: Legislation should include assessment of animal and human waste inputs which are sources of microorganisms, and assess microbial loading, survival and transport.
H.R. 3392 (103rd Congress): Legislation states "sound, unbiased and objective" science required; expected risk and reasonable range or equivalent description of uncertainty"; subpopulations at greater risk should be identified.
S. 1316: Legislation states "best-available peer reviewed science and supporting studies", "data collected by accepted methods or best available methods"; subpopulations should be identified.
Comments: Risk assessment methods have been established for chemicals with development of MCLs and criteria documents. There has been no formal risk assessment published by EPA for any microbial contaminant.
Recommendation: Within a designated time period, EPA should reassess regulated microbial contaminants using risk assessment methods. In addition, a list of unregulated microbial contaminants for potential regulation in the future should also be assessed.
H.R. 3392 (103rd Congress): Legislation calls for treatment techniques as well as performance criteria to be established for Point-of-Entry treatment units. There is no variance for best available affordable technology (BAAT) for microorganisms.
S. 1316: Legislation proposes EPA develop a regulation containing a list of techniques which can be used as treatment technology. Requires proper operation and maintenance required, compliance with MCLs. Modification for monitoring requirements for any contaminant other than microbial or indicators.
Comments: MCLs only address chemicals or coliforms. Evaluating treatment performance is needed for microorganisms using trial seeded tests or defined indicators. Currently small systems left out of all monitoring for microbial contaminants other than coliforms.
Recommendation: Support the House bill with language specifying that performance criteria for microbial contaminants be included.
H.R. 3392 (103rd Congress): Legislation language does not address.
S. 1316: Legislation states, "Administrator is authorized to make grants to institutions of higher learning to establish and operate not fewer than five small public water system technology assistance centers in the United States."
Recommendation: Support Senate language and require that at least one of the five centers should be directed specifically towards the control of microorganisms.