Drinking Water & Health Newsletter
Winter 1997

A Global Decline in Microbiological Safety of Water
by Timothy E. Ford, Ph.D.

In April 1995, the American Academy of Microbiology (AAM) convened an international conference on water quality and safety in Guayaquil, Ecuador. Attended by 65 scientists from 12 countries, the participants represented a range of disciplines: public health microbiology, ecology, economics, microbial (including molecular biology) methods, epidemiology and journalism. The goal of the conference was to develop a report on needs, from policy and scientific viewpoints, concerning microbial risks in drinking water. I was privileged to chair the Steering Committee that organized the conference and to join with Dr. Rita Colwell, chair of the AAM Board of Governors, in preparing its final report, "A Global Decline in Microbiological Safety of Water." The report's purpose was to raise awareness about the importance of microbiological quality of water and the impact of waterborne disease on society. This "Call to Action" is summarized below.

The spread of cholera in tropical nations and cryptosporidiosis outbreaks in temperate regions are clear evidence of an increase in waterborne disease worldwide. However, these represent only two of a multitude of waterborne pathogens that are increasingly prevalent in both developing and developed countries. These pathogens not only cause infectious disease, but many have been linked to other health outcomes ranging from impaired development to heart disease and cancer. We predict that the microbiological safety of drinking water will be a major concern in the 21st century as much of the world's population still lacks access to quality water supplies. The severity of the problem is largely underestimated, not only by the public but also by decision makers and the scientific community.

Pathogen Control and Water Treatment

Waterborne transmission of pathogens can be reduced by watershed protection, proper handling of wastewater, and drinking water treatment that removes and/or inactivates pathogens.

Current water treatment methods for both wastewater and drinking water are adequate, but are often not applied, are poorly applied or are not sufficiently monitored and controlled. In developing countries, the use of the simplest types of treatment will result in significant improvements in human health.

In developed countries, the range of treatment options is generally more diverse even though treatment processes must still be properly maintained, monitored and operated. Inadequate, interrupted or intermittent treatment has repeatedly been associated with waterborne disease outbreaks. There is also increasing concern about pathogens that resist water treatment and disinfection. The combined use of disinfectants -- for example, pre-ozonation following by post-treatment chlorination -- may achieve better inactivation of pathogens. The deteriorating conditions of our cities' distribution systems make it critically important to maintain residual disinfection to prevent recontamination. At present, chlorination provides the most effective residual disinfection, although biofilms that sometimes form in distribution pipes can protect pathogens from residual chlorine. There is a clear need for further research on how to prevent pathogen survival and proliferation in drinking water biofilms.

Competing Health Risks

Health risks posed by microbial pathogens should receive the highest priority in water treatment. Pathogens responsible for a large percentage of waterborne disease are often of unknown origin and must be the focus of the search for new knowledge about microbiological safety of water.

Toxicity of disinfection by-products (DBPs) in drinking water has recently received considerable public attention. However, chlorine and other reactive chemicals have been used successfully for more than 80 years to control waterborne infectious diseases before it was recognized that they produce a variety of by-products. Some by-products have been found to be associated with a variety of toxicological effects when administered at high doses to laboratory animals. While the collective epidemiological and toxicological data suggest that there may be some risk to human health associated with DBPs, the magnitude of these risks is very uncertain. It is important to point out that there is no direct or conclusive evidence that DBPs affect human health at concentrations found in drinking water.

Concerns over the toxicology of DBPs should not be allowed to compromise successful disinfection of drinking water, at least without data to support such decisions.

Public Policy and Economics

In a time of increasing demands on public funds and resources, policymakers in developed countries will be challenged to make decisions that ensure safe drinking and source water. This raises the issue of how to quantify the economic importance of good quality water. The recent outbreaks of cryptosporidiosis in the United Kingdom, United States and Canada offer good examples of the potential consequences of providing contaminated water in a developed country.

For developing countries, the massive cholera epidemics in Latin America and Southeast Asia constitute a significant increase in waterborne disease outbreaks and fatalities, with devastating consequences in terms of human suffering and both local and national economies. The growth in urban, underserved and susceptible populations has outstripped sanitation and water supply, resulting in further outbreaks.

Consistent economic underrating of the true value and costs of water has been recognized as one of the root causes of the deplorable state of many water supplies. The economic value of clean water needs to be recognized as an important force to drive local governments and global associations into action. Accurate valuation of clean water is necessary if costs and benefits are to be correctly estimated.

Education

Improving human health requires a massive effort in public education and raising awareness via the media and schools. In both developed and developing countries, educational efforts should target government authorities, legislators, administrators, industrialists, community leaders, teachers, journalists and the general population.

The public must understand that water safety is important to the quality of life. In developing countries, it is critical to educate the population about good hygiene, maintenance of water delivery systems and safe storage of water in the household.

The media are the main avenues for communication with the public, community leaders and politicians. However, the media may be either generally ill-informed or even misinformed. Authorities must be completely open and candid about potential public health hazards and involve the press on a regular basis, rather than occurred.

We are failing to educate individuals at the graduate level in waterrelated disciplines. Research funding is insufficient to address the critical questions of pathogen recognition and control that must be addressed if we are to reduce the global burden of waterborne disease in a timely manner. Research and training programs must be a priority for governmental, non-governmental and international funding agencies, together with water-related industries.

Conclusion

Water is a requirement for life. Access to water must be viewed as a fundamental human right, with important implications for national and international policy. Water resources, distribution, allocation and safety will rise to the top of the agenda of priorities for all nations as we approach the 21st century.

It is a time for action, for response to the warning signals that are occurring throughout the world. Microbiologically safe drinking water can no longer be assumed, even in the United States and other developed countries. Without early action at the national and international levels, global epidemics of waterborne disease will become the rule, rather than the exception.

Timothy E. Ford, Ph.D., is an Associate Professor of Environmental Microbiology, Department of Environmental Health of the Harvard School of Public Health. In addition to other research into microbiological contaminants and waterborne disease, Dr. Ford is developing an international program in water pollution and drinking water quality.

Washington Update

The Clean Water Act and Superfund will be the two major environmental initiatives slated for the 105th Congress's agenda. During the last Congress, reauthorizing the Clean Water Act and reforming the Superfund law were set aside in favor of completing amendments to the Safe Drinking Water Act. With Congress and the White House now focused on budget, tax and welfare matters, action to enact far-reaching environmental legislation remains questionable.

Senator Bob Smith (R-NH) and 21 Republican cosponsors have introduced the Superfund Cleanup Acceleration Act of 1997, which has been referred to the Environment and Public Works Committee. The House Committee on Transportation and Infrastructure, which has jurisdiction over the Clean Water Act, is still being organized and has not begun drafting a bill.

Regulatory Negotiations Continue on Drinking Water Rules

Work continues on several fronts relating to safe drinking water. The Environmental Protection Agency (EPA) is engaged in formal Federal Advisory Committee meetings to negotiate provisions of the rules -- due in November 1998 -- for controlling microbial contaminants and disinfection by-products. The Chlorine Chemistry Council is a member of this advisory committee. Technical working groups, with representatives from the EPA, the water industry and the environmental community, are assessing new technical information in an effort to reach consensus on the Stage I D/DBP and interim enhanced surface water treatment rules. However, a key concern is that delays in implementing the Information Collection Rule (ICR), intended to provide the data on which to base the new DBP and water treatment rules, may lead prematurely to regulatory requirements that cannot be supported by the ICR results.

Driven by the congressional mandate contained in the SDWA amendments, particular attention will be devoted to methods for controlling Cryptosporidium and Giardia in drinking water supplies.

Safe Drinking Water Act Implementation

Under provisions of the new Drinking Water State Revolving Fund (DWSRF), $1.3 billion will be available to states this year for loans to help finance infrastructure improvements in public water systems. In February, the EPA reported to Congress the results of the first quadrennial drinking water needs survey of public water systems (see sidebar). The survey data will be a significant factor in determining how to allocate funds through the DWSRF.

Most other provisions of the new Act, including the consumer awareness and public notification requirements, will be phased in over three years beginning in 1998.

Drinking Water Infrastructure Needs Survey - EPA Report to Congress

• Of the total infrastructure investment need of $138.4 billion, over $76.8 billion is for infrastructure improvements that are needed now to protect public health. The remaining $61.6 billion is for future needs...to provide safe drinking water through the year 2014.

Chloroform: Research Findings Support Risk Reassessment

In 1996, the Environmental Protection Agency (EPA) announced a revised approach to risk assessment for determining potential human health effects from exposure to biological and chemical substances. Taking advantage of new research tools developed for detecting changes in molecular and cell biology, the agency now will rely more on cellular changes that integrate dose-response reactions in human physiology rather than on simple descriptions of toxicity in laboratory animals.

This new approach has proven valuable in the reconsideration of the risks associated with chloroform. Over the past ten years, significant advances in scientific research have shed new light on EPA's 1986 assessment of chloroform as a potential human carcinogen.

This new data includes findings from over 20 epidemiological studies evaluating the possibility of an association between chloroform and cancer. These findings are supplemented by a vast collection of new data generated through thousands of observations in humans and cancer studies in animals, providing scientists with a greater foundation of knowledge about cancer risks in general.

Following careful review of these studies, scientists now believe that typical human exposures to chloroform -- in drinking water or showers -- do not present an increased risk of cancer. Furthermore, EPA has acknowledged that its 1986 assessment may have inadvertently exaggerated chloroform's risk.

Low-Dose Reassessment

There is a growing body of evidence that extrapolations from high-dose animal studies can at times provide a misleading picture of the effects of low-level exposure. In fact, many scientists now question the accuracy of human cancer risk assessments that are based solely on such extrapolations.

A better understanding of how different compounds affect the human body has led to this change in perspective. In particular, scientists now have the research tools to understand how a chemical's structural features might affect its toxicity and how potential poisons are absorbed, metabolized and distributed in the body. Using these tools, researchers have found that for many compounds the toxic effects of high doses often do not occur at low doses.

This is particularly true for chloroform. Significant research has shown that there is a dose range below which chloroform is not likely to be carcinogenic to animals or humans. Typical human exposures are much lower than this threshold dose range. Moreover, as shown in the chart, careful assessment of current data also illustrates that a Virtually Safe Dose (VSD) for chloroform exists at a far higher level than that specified in the 1986 EPA assessment.

Important Implications for Drinking Water Safety

Virtually all drinking water disinfectants produce disinfection by-products (DBPs). Chloroform is a DBP of water chlorination, the primary drinking water treatment in the United States. For nearly 100 years, chlorine disinfection has played an essential role in preventing the waterborne transmission of infectious diseases and achieving safe drinking water around the world.

Public health concerns about chloroform's carcinogenicity at human exposure typically encountered in drinking water led EPA to propose rules to further reduce the acceptable levels of chloroform and other DBPs in drinking water. However, these draft rules have raised concerns that alteration of water treatment may well increase microbially induced illness and death from waterborne pathogens by reducing the efficacy of water disinfection.

Given the abundance of new data suggesting that EPA's current chloroform risk is significantly overestimated, proposed rules to minimize human exposure to chloroform must be revised.

Chloroform as a Candidate for EPA Cancer Risk Reassessment

Formal EPA reassessment of chloroform's cancer potential will further increase confidence in estimating public health impacts from exposure to chloroform in water and air. Using EPA's revised approach to risk assessment will result in a more scientifically rigorous assessment for chloroform. In the end, chloroform risk estimates will be more defensible for decision-making about trade-offs between competing risks such as those due to chlorination DBPs and those due to microbial diseases from waterborne pathogens.

Conclusion

Scientists now have a wealth of information and research methodologies for assessing the complex relationship between cancer and exposure to chemical compounds. Using these tools, researchers now believe that exposure to chloroform at levels typically found in drinking water and showers does not present an increased risk of cancer in humans.

Robert G. Tardiff, Ph.D., A.T.S., a risk analyst and toxicologist, is president of The Sapphire Group, Inc. Dr. Tardiff previously worked for the U.S. Environmental Protection Agency and managed the environmental health program of the National Academy of Sciences. He is also former president of the International Society for Risk Analysis.

State of the States

States Focus on Source Water Protection

A final agreement for watershed protection regulations to protect the quality of New York City's source waters was signed on January 21, 1997, by the New York State Department of Health, Coalition of Watershed Towns, U.S. Environmental Protection Agency and representatives of environmental organizations. Gov. George Pataki has earmarked $2.1 million to implement the watershed agreement, which includes provisions to control pollution from wastewater treatment plants, septic systems, urban and rural stormwater run-off, hazardous waste and petroleum storage facilities.

Other terms of the agreement include enhanced monitoring activities, incentives for local watershed planning efforts and strategies, and a Watershed Protection and Partnership Council to review water quality issues and recommend future actions.

Under the federal Surface Water Treatment Rule (SWTR), all surface water is required to be filtered unless certain criteria are met. New York water meets SWTR conditions for a filtration waiver for the Catskill/ Delaware watershed, the source of 90 percent of New York City's water. The new agreement enables New York to continue providing unfiltered water to nearly 9 million people at least through 2002.

Maryland Adopts Cryptosporidium Action Plan

In June 1996, health and water utility officials in Maryland finalized a Cryptosporidium Action Plan to prevent waterborne cryptosporidiosis and to educate the public. The plan focuses on watershed protection to prevent pollution at the source, as well as proper maintenance of water treatment plants.

The plan requires performance evaluations at each of the state's 52 water treatment plants and monitoring the effectiveness of treatment processes. To educate the public, the Maryland Department of Health and Mental Hygiene (DHMH) and Maryland Department of the Environment (MDE) distributed information about the illness to residents, water utilities, public health officials and immunocompromised individuals. The action plan also includes a pilot surveillance program for cryptosporidiosis cases and outbreaks and monthly sales of anti-diarrheal medications.

Both DHMH and MDE have emergency response plans available to implement when water quality is known or suspected to be below standard. The agencies will hold discussions with water utilities and local health departments when considering boil water advisories.

Water Relief Network Helps Cuban Hurricane Recovery Effort

Intense winds and rains damaged or destroyed 83,700 homes, 32 schools and 15 hospitals, and resulting floods caused contamination of water supplies.

Disinfection of water supplies and hospitals following the hurricane placed a large burden on already limited chlorine supplies. As a result, sanitation and epidemic control have become a major cause for concern. Cuban Red Cross and local public health officials fear contamination of water supplies as the warmer months approach.

A shipment of 12 metric tons of calcium hypochlorite and one metric ton of sodium hypochlorite arrived in Cuba in February 1997. These products are being used to help restore safe drinking water supplies and proper sanitation in hospitals.

Representatives from the American Red Cross and the Water Relief Network, including Chlorine Chemistry Division of the American Chemistry Council Managing Director Kip Howlett, traveled to Cuba to survey damage caused by the hurricane and meet with International and Cuban Red Cross officials. The mission provided an opportunity to view firsthand how the Network's contribution to the American Red Cross will benefit residents of several Cuban provinces and assist with continuing relief efforts.

This is the first major aid mission of the Water Relief Network since its launch in June 1996. The donation is being made to the American Red Cross Office of International Services to assist its cooperative effort with the Cuban Red Cross.

The Water Relief Network is composed of more than 50 member companies of the Chlorine Chemistry Division of the American Chemistry Council, the Chlorine Institute and the Vinyl Institute. The Network provides the American Red Cross with access to chlorine-based products necessary to restore safe drinking water and other essential human needs following a disaster.

JUMP IN...THE WATER'S CLEAN

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

The Public Health Advisory Board

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

Bruce Bernard, Ph.D.
SRA International
Washington, D.C.

Sanford M. Brown, Jr., Ph.D.
Department of Health Sciences California State University
Fresno, California

Linda Golodner
National Consumers League
Washington, D.C.

Jerod Loeb, Ph.D.
Joint Commission on
Accreditation of Health
Care Organizations
Oakbrook Terrace, Illinois

Fred Reiff, P.E.
Pan American Health
Organization (Retired)
Washington, D.C.

Chris J. Wiant, Ph.D.
Tri-County Health Department
Englewood, Colorado