Water Quality & Health Council - Drinking Water & Health Newsletter October 1, 1995

Providing Safe Drinking Water: Risk Reduction Through Operational Flexibility

The long-standing public policy debate about government's role in ensuring the availability of safe drinking water is once again in the forefront as Congress considers reauthorization of the Safe Drinking Water Act. A central feature of the present debate is how implementing rules should be structured to meet this clear societal need. Numerous questions remain about maintaining safety standards and reducing risks while at the same time alleviating some of the regulatory burden on water suppliers and local governments. To answer these questions, all elements of society - government, industry, the public - must be involved in establishing water quality goals and deciding how much we are willing to pay to achieve those goals.

Meeting public health needs by providing safe drinking water is a long process from the source to the tap. There are many steps along the way, and there is no single, simple solution for adequate water treatment to remove contaminants and reduce risks to human health. We now understand that the multifaceted demands of water treatment require operational flexibility and a balancing of costs and benefits for the treatment methods chosen. For example, are there reasons not to rely on chlorination? Or do concerns about disinfection by-products (DBPs) make it necessary to install Granular Activated Carbon (GAC) filters to remove them? Are other methods such as membrane technology as effective for control of DBPs? How can we prevent or eliminate microbial contamination that may present greater risks than those perceived from chemicals?

The most important step toward ensuring safe drinking water supplies is to establish watershed quality and pollution prevention strategies that reduce risks in all stages of the water delivery process. Clean source water may reduce the need for sophisticated treatment, and thus, is ultimately a cost-saving factor for utilities and their consumers. Regulatory policies should focus attention on a broad range of risk reduction strategies that are grounded in science and sensitive to economic realities.

With a wide choice of available technologies, both old and new, water utilities truly are on the cutting edge in terms of optimizing the benefits of different treatment methods. However, many systems are strained by increasingly stringent treatment standards contained in rules for DBPs, total coliform limits, enhanced surface water treatment, and lead and copper removal. Drinking water suppliers may find they cannot meet these demands simply with the multiple barriers approach typically used, possibly forcing them to adopt more complicated and costly technologies. In addition, even areas with excellent water quality and the most modem treatment facilities have experienced recent outbreaks of waterborne disease due to the presence of cryptosporidium or giardia. Given these developments, coupled with an aging infrastructure and ever-tightening budgets, water utilities now face even greater challenges in managing the delivery of safe drinking water. Furthermore, undercapitalized small systems find that reducing risks or upgrading their facilities is especially difficult, a situation that may eventually lead to small systems being merged to create regional water suppliers.

In devising safe drinking water policies that achieve the best results, we should take the approach that one size does not fit all. There are too many variables in terms of source water quality and other environmental factors, facility operations and maintenance, and delivery system integrity to assume that what works in one area will work for all. While there are benefits to national consistency in technical requirements, rules for implementing the Safe Drinking Water Act should also allow flexibility - together with accountability - for the treatment monitoring, and standards necessary for reducing risks. Regulatory flexibility would address the issue of performance standards versus prescriptive technologies. While it is not unreasonable to set limits for DBPs or for lower MCLs, it should be acknowledged that there may be different ways to achieve the same risk reduction without mandating the use of specific treatment methods. Utilities experienced in meeting the needs of their communities should be given the freedom to use the combination of old and new technologies that satisfies performance standards. Such operational flexibility can ease the economic burden on water suppliers without compromising their ability to ensure the availability of safe drinking water.

Chris J. Wiant, Ph.D., MPH, is director of Environmental Health Services, Tri-county Health Department, in Englewood, Co. Chris has over 20 years experience in designing and managing programs for control of environmental toxicology and product safety, with particular emphasis on drinking water safety issues. Chris's service on numerous federal, state, and local advisory committees has included membership on the EPA National Drinking Water Advisory Council and participation in the EPA regulatory negotiation on disinfection by-products.

Between the months of January and April 1994, 78 cases of cryptosporidiosis were reported in Clark County in Southern Nevada. However, Lake Mead, which supplies about 85 percent of the drinking water used in Southern Nevada, is tested weekly and has never tested positive for cryptosporidium protozoa. Federal health officials have since concluded that despite Las Vegas' state-of-the-art water treatment methods, an outbreak of a parasitic infection could have been transmitted through the drinking water. Ironically, Lake Mead has a reputation for being a safe water source because of the small amount of heavy industry and agriculture in the area. Meanwhile, in April l 995' the CDC reported that even drinking water many times better than the current national standards may not be free of cryptosporidium.

Of the 78 cases reported in Clark County within those four months, 61 were in HIV infected adults. The CDC conducted an epidemiological investigation to identify the extent and cause of the outbreak. In their comparison of adults with HIV who had been infected with cryptosporidiosis and a control group of adults with HIV who had not been infected, the primary difference between the two groups was that those who had drunk only bottled water were less likely to get sick. The CDC concluded that "waterborne transmission of cryptosporidium in HIV-infected persons may occur in the absence of a recognized outbreak, despite water quality parameters that are better than current national standards, and without finding cryptosporidium in the water." While a healthy person infected with cryptosporidium might only be sick for a few days, a person with a weakened immune system is at greater risk. The National Institute of Allergy and Infectious Diseases reports that cryptosporidium affected 3-15 percent of AIDS patients in 1993. The CDC investigation of the Las Vegas water supply in early 1994 showed that in 1992 three cases of cryptosporidiosis were reported, and 23 were reported in 1993.

In August 1994, Washington State health department officials tested local well water in Walla Walla, responding to a complaint of chronic gastrointestinal illness from a household served by the well. After receiving more complaints and having issued a "boil water order," cryptosporidiosis was identified in several residents in the community By the end of the month, there were 26 confirmed cases of cryptosporidiosis. The households were all being supplied by a rural water system consisting of two artesian wells.

Health department officials conducted an on-site environmental investigation of the well system, the local wastewater treatment plant, and the local water irrigation system. During the winter before the outbreak, a truck had crashed into and damaged part of the irrigation system. Officials noted that treated wastewater was found dripping along the outer casing, within 20 yards of one of the wells. In September, water passing through this well was found to have two cryptosporidium oocysts per 50 gallons and in November, the well had 12 oocysts per 50 gallons. Health officials have concluded that the damaged irrigation system allowed a flow of treated wastewater into the well and down along its outer casing.

Decontamination of the well was not an option. Cryptosporidium has shown to be resistant to chlorine, and ozonation would not be applicable to the well water system. The well near the damaged irrigation pipes was decommissioned, because decontamination of the well water would have been costly and difficult. The cryptosporidiosis outbreak ended when exposure to the contaminated well water was stopped.

A number of bills are being debated in both houses of Congress that will affect drinking water standards and regulations. Among these are the reauthorizations of the Safe Drinking Water Act (SDWA) and the Clean Water Act, and Risk/Regulatory Reform.

Proposals for the reauthorization of the Safe Drinking Water Act are similar in concept to last year's H.R. 3392 and S. 2019, which were approved separately by the House and Senate during the last Congress. This year's efforts are directed at incorporating additional risk and regulatory reform provisions into existing law, such as enhancing the use of risk assessment, cost-benefit analyses, and greater flexibility in the development and implementation of drinking water regulations.

Negotiations are continuing between Senator John Chafee (R-R.I.), chair, Environment & Public Works Committee, and Senator Dirk Kempthorne (R-Idaho), chair, Subcommittee on Drinking Water, Fisheries & Wildlife. While Senator Chafee prefers last year's bill, S. 2019, Senator Kempthorne supports modifications that would make S. 2019 more workable and consistent with other legislative initiatives that address risk and regulatory reform. Key issues in the negotiation involve the extent to which cost-benefit considerations are applied in the standard-setting process; the regulation of future contaminants; what is defined as "feasible" technology for meeting standards; and funding for infrastructure needs.

Progress on drafting a bill has bogged down due to the press of other business before the Commerce Committee. Legislation may be introduced later this fall. Representative Thomas Bliley (R-Va.), chair of the full committee, and Representative Michael Bilirakis (R-Fla.), chair, Subcommittee on Health & Environment, support SDWA reform.

The reauthorization of the Clean Water Act, H.R. 961, passed the House in May with a 240-185 vote. Contained in the existing Clean Water Act are provisions that would allow more flexibility for industries and local governments to meet pollution-abatement requirements. Also included in H.R. 961 are provisions that authorize federal financial assistance for municipal wastewater treatment construction.

The Senate Committee on Environment and Public Works, where hearings began in July on certain provisions (e.g., wetlands), has yet to develop a bill. Committee Chairman Chafee has announced plans to introduce his own version of the bill this fall if agreements can be reached on the scope of the legislation. Senator Chafee favors a limited reauthorization that addresses nonpoint sources, funding, and additional flexibility to meet the Act's objectives.

Originally introduced into the House by Rep. Bud Shuster (R-Pa.), H.R. 961 includes elements of the House Republican "Contract with America." As such, it includes regulatory reform provisions relating to unfunded federal mandates, risk assessment and cost-benefit analysis, and regulatory actions that result in private property takings.

The bill has the general support of the nation's governors, mayors, industry, and several state and municipal water organizations. It is opposed by a number of environmental groups and the Clinton administration. The President has announced that he will veto the legislation unless substantial changes are made.

Negotiations over Senate regulatory reform legislation (S. 343) remain on hold following Senate Majority Leader Robert Dole's (R-Kan.) inability to secure 60 votes to proceed to consideration of the bill. The bill, which is cosponsored by Sen. Bennett Johnston (D-La.), was debated on the Senate floor for more than a week in late July.

The Dole/Johnston bill would require federal agencies to conduct a risk assessment on all environmental health rules and a cost-benefit analysis on all rules with an impact of $100 million or more annually. The cost-benefit requirements of the Dole bill are meant to supplement, not supercede, existing statutes. The bill also contains a regulatory review provision that requires agencies to establish a schedule for reviewing existing regulations to determine whether they pass a cost-benefit test.

Democratic and Republican senators resumed discussions on the bill when they returned from recess on September 5. There is bipartisan support for a regulatory reform bill provided that a few controversial and complex issues can be worked out.

In February, the House passed a regulatory moratorium bill (H.R. 450) by a vote of 276146. Introduced by House Majority Whip Tom Delay (R-Texas) and other House leaders, H.R. 450 calls for a freeze on federal rulemaking until the end of 1995. The Senate version of the bill (S. 219), sponsored by Senator Don Nickles (R-Okla.), calls for a 45-day congressional review of rules. This congressional veto bill allows the House or Senate to veto a rule that is flawed in some way before it becomes final. If the President signs off on the veto, the rule would be sent back to the agency to be redrafted. Currently, the congressional veto bill is in conference with conferees from both houses.

The Job Creation and Wage Enhancement Act (H.R. 9), passed the House in March by a vote of 277-141. Incorporated in H.R. 9 are the Paperwork Reduction Act (H.R. 830), the Private Property Protection Act (H.R. 925), the Regulatory Reform and Relief Act (H.R. 926), and the Risk Assessment and Cost Benefit Act (H.R. 1022), each having been passed separately.

Another approach to limiting regulation by the EPA has been pursued by the House Appropriations Committee. In July, the VA-HUD and Independent Agencies Subcommittee approved a $60 billion appropriations bill for various federal agencies, which includes provisions limiting the EPA's use of funds to: (1) regulate toxic emissions from oil refineries and cement kilns, (2) issue standards for radon and arsenic in drinking water, (3) require the oil and gas industry to draw up plans for responding to accidents, and (4) control sewer overflows into rivers. Also included in the bill are limitations on the EPA's ability to revoke or deny licenses for pesticides solely because pesticide residues are not allowed in processed foods (Delaney Clause).

SAFE WATER TREATMENT AND STORAGE IN THE HOME
A Practical New Strategy to Prevent Waterborne Disease
by Eric D Mintz, MD; Fred M. Reiff Robert V. Tauxe, MD

Excerpts of article appearing the Journal of the American Medical Association, March 22/29, 1995, Vol. 273, No. 12. Reprinted with permission.

Diarrhea diseases remain a leading cause of illness and death in the developing world. Providing potable water for drinking and washing is critical to reducing diarrhea disease transmission in this setting. However, improving source water quality alone does not always decrease diarrhea disease incidence. Providing a safe drinking water source may fail to reduce diarrhea because transmission of diarrhea pathogens continues through foodborne or person-to-person routes of spread or because people are exposed to contaminated water during bathing and other activities. Drinking water also becomes contaminated after collection, either during transport or storage in the home.

Improvements in source water quality generally depend on expensive, long-term, centralized projects, such as construction of wells, water treatment plants, and water distribution systems. Safe drinking water for all remains an elusive and expensive goal.

In 1990, more than 1 billion people depended on rivers, streams, or other unsafe surface sources for drinking water. In many developing countries, even municipal piped well water is unsafe because of inadequately maintained pipes, low pressure, intermittent delivery, lack of chlorination, and clandestine connections.

An inexpensive strategy is available to improve household drinking water until piped potable water is routinely available. The strategy has two components: water disinfection at the time water is collected (point-of-use disinfection) and water storage in vessels specifically designed to prevent recontamination (safe storage). However, successful implementation of this strategy will require focused educational campaigns stressing the role of contaminated water and domestic hygiene in disease transmission.

When centralized water treatment systems are absent or inadequate, the responsibility for making drinking water safe falls to community residents by default. The traditional emergency prevention measure, boiling the water, is economically and environmentally unsustainable. After cooling, boiled water can easily be recontaminated, especially if it is transferred to a storage container.

Chemical disinfectants are a practical alternative to boiling, although only the safest and least expensive disinfectants are suitable for household use in the developing world. Chlorine gas, the most commonly used disinfectant in water treatment plants, is hazardous and impractical in these situations. However, sodium and calcium hypochlorite are relatively safe, easy to distribute and use, inexpensive, and effective against most bacterial and viral pathogens. When added to water in tightly covered containers, volatilization is minimal and hypochlorite disinfectants provide residual protection for many hours to days.

In a recent review of water contamination occurring during home water storage, observational studies showed that mean coliform levels were substantially higher in household water containers than in water sources, four studies showed coliform levels in water storage containers and sources to be comparable, and only one study showed lower coliform levels in storage containers than in water sources. In five other studies in which paired samples from individual water sources and household storage containers were compared, the results were similar: fecal coliform concentrations were generally, and sometimes dramatically, higher in stored water than in source water. During the recent cholera epidemic in Peru, we sampled water from municipal taps and from stored household water from these taps and noted a thousand-fold increase in mean fecal coliform counts.

A variety of different water storage vessel designs may protect water. To guide the design and approval of water storage vessels, the Centers for Disease Control and Prevention (CDC) and the Pan American Health Organization (PAHO) have proposed the following working design criteria. For safe storage, a water storage vessel should have the following qualities:

Be constructed of translucent, high-density polyethylene plastic or similar material that is durable, lightweight, nonoxidizing, easy to clean, inexpensive, and able to be locally produced;

Safe storage is eminently affordable. Water containers that meet the aforementioned criteria have been purchased by the PAHO and the CDC for prices ranging from US $4.60 to $7.25, depending on the place of manufacture and the transportation costs. A container made of high-density polyethylene may last an average of 5 to 10 years and as long as 20 years, depending on wall thickness. This plastic is used to make milk containers in the United States and is recyclable. Safe containers also may be fabricated from other materials, such as earthenware or tin, but these may offer some disadvantages compared with highdensity polyethylene in terms of durability, cost, weight, or other characteristics.

As long as households collect and store water from unsafe sources, practical point-of-use disinfection methods are the best means of enabling access to potable water. When combined with safe storage vessels, this strategy allows individuals, households, and communities to assume responsibility for purifying their own water and engenders a sense of community empowerment and self-determination. Water treated on-site and safely stored before use also can be put to good advantage in food preparation, dish washing, bathing, and other activities, where it may reduce transmission of foodborne or waterwashed diseases.

In Latin America, the cholera epidemic has entered its fourth year, having caused nearly 1 million cases and 10,000 deaths; it is likely to continue for many years to come. Elsewhere in the developing world, epidemic cholera remains unchecked; 78 countries reported cholera to the WHO in 1993, more than ever before. Driven by the impetus of epidemic cholera, sustainable measures to prevent waterbome diseases could become part of everyday life in many homes in the developing world. Further development of this simple household technology can potentially improve health and quality of life while protecting the environment.

Authors Eric Mintz, MD and Robert Tauxe, MD are with the Foodborne and Diarrhea Diseases Branch, Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Atlanta, GA. Fred M. Reiff is with the Pan American Health Organization, Washington, DC.

Editor's note: Fred Reiff retired from PAHO on July 3, 1995, after 14 years of service. He continues to work on international public health issues involving waterborne disease.

Recent headlines about cryptosporidiosis outbreaks in Milwaukee, Las Vegas, and Washington State have raised public awareness and concern about the safety of drinking water supplies. While chemical contamination of drinking water has been highlighted, assessed, and monitored, little has been done to evaluate microbial contamination, despite data suggesting it remains a significant health risk in the U.S. and insidiously adds to the burden of health care costs.

In light of these recent outbreaks, the need to improve methods for identifying and measuring microbial contaminants in drinking water is now even more urgent. Without adequate risk analysis, attempts to develop control and preventive measures will be difficult.

Cryptosporidium is only one of over 100 different types of waterborne microbial contaminants. Perhaps half of these agents have been identified, but there is still a large percentage of unknown pathogens causing outbreaks of acute gastroenteritis in the United States. Although waterborne typhoid and cholera have been controlled in the U.S., outbreaks of acute gastroenteritis associated with drinking contaminated water have remained steady over the past 70 years.

The Centers for Disease Control and Prevention (CDC) estimated there were 940,000 cases of waterborne disease in the U.S. in 1985 and 900 deaths annually from microbial contaminants in water. Annual mortality rates from waterborne disease will increase once cases from the recent cryptosporidium outbreaks have been tallied.

According to a 1991 study, one-third of all cases of diarrhea can be associated with drinking water. A 10-year study of mortality in the U.S. has shown a dramatic increase in deaths from diarrhea in individuals over age 55. Elderly people are not the only ones at risk. An increasing proportion of the U.S. population is having less resistance to waterborne disease, including those on immunosuppressant medication, those with immunodeficiences (including patients with AIDS), newborns, and pregnant women.

While diarrhea is a common and easily recognized health effect associated with waterbome pathogens, some of these pathogens also are being linked with chronic illnesses, including various forms of heart disease, respiratory disease, meningitis, diabetes, and hepatitis. [This subject will be covered in more detail in future issues of Drinking Water & Health.]

Evidence of the impact of microbial contaminants on public health is clear, and priorities based on scientific information must be established to ensure the most significant risks are addressed first.

Risk assessment modeling is a valuable tool that can estimate adverse effects associated with specific hazards. In particular, quantitative risk assessment (QRA) elicits a statistical estimate or probability of harm This type of formal assessment can provide managers with valuable information on the identity and characterization of the risks, which can then be used to develop appropriate control strategies The four fundamental steps used in a formal risk assessment include: 1) hazard identification, 2) dose-response determination, 3) exposure assessment, and 4) risk characterization.

Although monitoring specific microbial contaminants in water is especially critical for exposure assessment, there is minimal experience with the methods, development of monitoring programs, and the interpretation of data among members of the water industry. Nonetheless, a scientific risk-based approach is desirable for developing cost-effective policies that ensure that the most significant public health risks are being addressed.

Dr. Rose, a nationally recognized expert in water microbiology, is with the Department of Marine Science, University of South Florida, in St. Petersburg. She also serves as vice chair of the Public Health Advisory Board to the Chlorine Chemistry Division of the American Chemistry Council.

Drinking Water & Health Newsletter is a Publication of the Public Health Advisory Board to the Chlorine Chemistry Division of the American Chemistry Council

Vice Chair
JOAN B. ROSE, Ph.D.
Department of Marine Science
University of South Florida
St. Petersburg, Florida

SANFORD M. BROWN, JR., Ph.D.
Department of Health Sciences
California) State University,
Fresno, California

JEROD LOEB Ph.D.
Joint Commission on
Accreditation of Health
Care Organizations
Oakbronk Terrace, Illinois