Water Quality & Health Council - Drinking Water & Health Newsletter July 1, 1996

Microbial contamination remains a significant cause of waterborne disease in the United States today. Information on the effects of exposure to high levels of contamination can be obtained from epidemiological studies of waterborne outbreaks. This information, however, does not provide a clear understanding of the impacts on individuals or a community of exposure to low-level contamination of a water supply.

Instead, risk assessment can better evaluate the public health significance of exposure to low levels of microorganisms in treated drinking water. Risk assessment methodology commonly has been used to assess and monitor the risks associated with chemical contamination in the environment. Only recently, however, has a formal risk assessment approach been employed to determine the risks involved with exposure to pathogenic microorganisms (e.g., viruses, bacteria and protozoa) in treated drinking water.

The risk assessment methodology involves four basic steps: 1) hazard identification; 2) dose-response assessment; 3) exposure assessment; and 4) risk characterization. These steps were used to assess the risk of obtaining a rotavirus or coxsackievirus infection from exposure to contaminated drinking water. Risk of infection from different levels of exposure can be determined from dose- response information obtained from human feeding studies. Appropriate mathematical models are then selected for the risk characterization.

**Percentages of Case-Fatality and Hospitalization for Rotovirus Infections**
Case-Fatality
Overall	0.01
Hospitalized	0.12
Elderly	1
Transplant patients	50
Hospitalization
Chlidren
of those clinically ill	3.6
of all admissions for gastroenteritis	30-60
Adults:
of all admissions for gastroenteritis	5-10

Rotavirus is a common cause of gastroenteritis in humans and is believed to be responsible for the deaths of 4 to 5 million persons annually worldwide. Although rotavirus is usually associated with childhood illnesses, it can also produce serious illness in adults. The following table shows the case-fatality and hospitalization rates for rotavirus

There have been several waterborne outbreaks of rotavirus In 1981, a waterborne outbreak of rotavirus in Colorado yielded an overall attack rate (exposed people who become ill) of 32% and an attack rate of nearly 44% for the exposed adult population. All of the outbreaks of rotavirus have been associated with a direct fecal contamination of the water supply or improper treatment.

Rotavirus has been detected in treated drinking water supplies in developing countries where surface water was the source. In one situation, the water supply was receiving complete conventional treatment, including disinfection. Although laboratories capable of detecting these viruses are not often found in developing countries, occurrence data of rotavirus were obtained from surveys conducted by scientists from South America and the United States. Levels of rotavirus have been reported to range from less than 1 to 100 viral units per liter of drinking water. There are no data on the concentration levels of rotavirus in treated drinking water supplies in developed countries; however, average concentrations from untreated surface waters in North America have been reported to range from 0.24 to 29 viral units per liter.

Rotavirus has been reported to be more resistant to chloramines and ultraviolet light disinfection than enteroviruses and is more resistant to inactivation by preformed chloramines and ozone than poliovirus type 1. However, inactivation can be achieved by removal with conventional flocculation, sedimentation and filtration, followed by disinfection that has sufficient contact time and includes free chlorine residuals.

Coxsackievirus is the most common non-polio enterovirus in terms of frequency of infection. It is associated with a variety of serious illnesses including heart disease, respiratory illness, aseptic meningitis and insulin-dependent diabetes mellitus. Coxsackievirus has been associated with numerous common source outbreaks, including at least two documented waterborne outbreaks. An attack rate as high as 64% has been documented from a waterborne outbreak of coxsackievirus

Coxsackievirus type B has been detected in treated drinking water supplies at levels ranging from 0.00005 to 0.31 viral units per liter.

Disinfection studies have shown coxsackievirus (types AS and B5) to be the most resistant virus to chlorine treatment except for poliovirus type 2. Nevertheless, it was noted that concentrations of residual chlorine of 0.1-0.4 mg/L with a contact time of 30 minutes or more achieves a destruction rate over 99.99%.

Certain contact times and concentrations of a disinfectant, preceded by filtration, are necessary for adequate disinfection of both rotavirus and coxsackievirus For example, depending on water temperature and pH values, virus destruction can be achieved with free chlorine residuals of 0.5 mg/L, with a minimum 30 minute contact time, or with an ozone residual of 0.2-0.4 mg/L for four minutes. Ozone is considered an effective treatment, but only if combined with a chlorine compound for residual disinfection.

Risks of infection, illness and mortality were assessed for rotavirus and coxsackievirus type B. Coxsackievirus type B was chosen because it is associated with a greater number of serious illnesses than type A and is frequently isolated from water.

Risk of rotavirus and coxsackievirus type B infections were calculated for 2 liters (for the general population) and 4 liters (for the elderly) of daily exposure of drinking water. The U.S. Environmental Protection Agency (EPA) recommends that risks of infection from pathogenic microorganisms in potable waters should not exceed one infection per 10,000 people per year.

Based on average concentrations of 0.24-29 viral units per liter found in untreated surface water in the United States, risks of infection for rotavirus have been calculated to be greater than one in 1,000 per year, assuming a 99.99% inactivation of enteric viruses in the surface water. In order to meet the EPA recommendation of one in 10,000 annual risk of infection, 5 to 6 logs of virus removal would have to be achieved.

Concentrations of 0.00005 to 0.31 viral units per liter of coxsackievirus yield yearly risks of infection of one in 10,000 to one in 10, respectively, for the general population.

Special populations (e.g., the elderly, the very young and the immunocompromised) are at an even greater risk of becoming seriously ill and dying. Risk of mortality from a rotavirus infection is 100 times greater for the elderly than for the general population. Coxsackievirus infections in these individuals can lead to severe or even fatal illnesses.

The major limitation in completing a risk assessment of waterborne rotavirus and coxsackievirus is the lack of quantitative data on their occurrence in water, especially in developed countries.

Coxsackievirus represents the virus associated with a greater number of serious illnesses. Although it does not cause the greatest number of documented outbreaks in the United States, rotavirus is the most infectious waterborne agent known, with a greater severity of outcomes in certain populations. Unfortunately, rotavirus is particularly difficult to detect in water by the laboratory methods currently used.

More studies analyzing water supplies for rotavirus and coxsackievirus (as well as other microbial pathogens) need to be conducted in order to perform a more complete risk analysis. Because of their resistance to inactivation by water disinfection, these viruses also should receive further study to determine the public health significance of their occurrence in water.

Kristina D. Crabtree is currently pursuing a doctorate at the University of Arizona Department of Soil, Water and Environmental Science. Her dissertation work consists of risk assessments of microbial pathogens in water. In 1991, Kristina received a BA in biology from Franklin College of Indiana and an MPH from the University of South Florida in 1993.

Natural Disasters - Scenarios For Protecting Public Health

Hurricanes, earthquakes, floods and blizzards all of these natural disasters have struck somewhere in America during the last few years, destroying lives and property. Disasters that cause massive disruptions to entire communities and states strain our ability to meet basic needs, especially for drinking water, food and shelter.

Although the impact of disasters may be unpredictable, those in charge of response and recovery operations have learned a valuable lesson - drastic situations often require innovative solutions to resolve the crisis and protect public health.

In Des Moines, Iowa, the water utility was flooded and more than 250,000 residents in the area were without drinking water. The Army Corps of Engineers, assisted by the Iowa National Guard, provided tanker trucks to deliver 2.5 million gallons per day of drinking water to the city and surrounding communities. The chlorine industry supplied water treatment chemicals, which water facilities used for "superchlorination" to disinfect their equipment as well as the hundreds of miles of pipe that delivered tap water to residents.

The California earthquake in January was a major catastrophe in the Los Angeles area, but new approaches adopted by federal and state response agencies permitted substantial recovery in far less time than in the past. The American Red Cross and Salvation Army, along with a number of federal agencies, provided immediate relief with emergency shelters and supplies of food, water and clothing. The Army Corps of Engineers filled a critical need for drinking water by distributing over one million gallons per day to more than 100,000 earthquake victims. This distribution continued for two weeks until the City of Los Angeles was able to complete restoration of potable water service to homes in the area. Additional water distribution units were deployed to ten sites from the Camp Pendleton Marine Corps base.

As flooding followed heavy snows in early 1996, the Federal Emergency Management Agency (FEMA) oversaw disaster relief efforts in nine states that had experienced severe flooding. Millions of dollars were allocated for the repair of public infrastructure, including public utilities that supply electrical power, water and sewage treatment.

Some states experienced special dangers to public health. Sewage treatment facilities were not operational in parts of Oregon. In Idaho, the National Guard deployed two water purification systems. Washington State's Division of Emergency Management received reports that many towns had possible contamination of drinking water supplies. The water treatment plant for Hagerstown, Maryland, experienced a broken valve that led to activation of a back-up water supply. Since that supply was unfiltered, a boil-water advisory was put into effect for a week while the entire system was tested, treated and repaired.

The Chlorine Chemistry Division of the American Chemistry Council Water Relief Network (described in the winter issue of Drinking Water & Health) has already assisted the Red Cross with overseas disaster relief by facilitating the donation of water purification chemicals for use in the Caribbean (Antigua) following Hurricane Luis.

Prior to the Network's creation, individual Chlorine Chemistry Division of the American Chemistry Council member companies also participated in international relief efforts. Olin and PPG provided nearly 50,000 pounds of water treatment chemicals to Chechenya. In Rwanda, water disinfectants, medical supplies and technical expertise were donated by Chlorine Chemistry Division of the American Chemistry Council member companies and partners to improve health conditions for refugees.

The U.S. is fortunate to have a disaster response infrastructure that is primed to react promptly when needed. Following a disaster, local government officials and volunteer agencies conduct needs assessments that may cause FEMA to recommend that the President declare a major disaster or emergency. This disaster declaration activates the federal response plan, making available the resources of the federal government.

Twenty-seven agencies, plus the American Red Cross, participate in the federal response plan, each assigned different functions. The Army Corps of Engineers is responsible for drinking water; the Department of Transportation rebuilds highways and clears debris off roadways; the Department of Housing and Urban Development and Small Business Administration assist with housing and business repair and rebuilding.

Individual. Immediate needs of food, water, shelter and clothing. Much of this is handled through the American Red Cross, the Salvation Army and other volunteer agencies.

Public. Longer-term recovery for rebuilding the infrastructure and restoring essential services such as electrical power, water supplies and sewage disposal. All government agencies - local, state and federal - have responsibility for these functions.

Mitigation. Planning and making funds available to help prevent damage from future disasters.

During the chaotic period immediately following a disaster, response and recovery operations must have access to and be able to mobilize many resources. In addition to the coordinated response of government and volunteer agencies, the private business sector can offer support through public-private partnerships. Examples of contributions by public and private organizations include:

The key to appropriate disaster response is getting the right product to the right place at the right time. It is important for corporate America to work with the government and volunteer agencies that conduct disaster assessments to find out what is needed, where it is needed and how to ensure proper delivery.

Washington Update

A bill to reauthorize the Safe Drinking Water Act, which passed the Senate last fall, was approved by the House in late June. A House-Senate Conference Committee will work out differences between the two bills, and Members are optimistic that they can enact this major piece of environmental legislation during this session.

The House bill, H.R. 3604, retains the Senate provision exempting the proposed disinfection by-products rule from cost-benefit analysis. There was an unsuccessful effort in the health and environment subcommittee to amend this provision, based on concerns about potential public health risks from microbial contaminants in drinking water that might be exacerbated by reducing water disinfection.

Several environmental and regulatory reform bills on which action was expected during this Congress have been delayed due to substantive disagreements between the House and Senate. With little time left on the legislative calendar, chances of passing most of these bills this year are slim.

A Senate hearing was held last December to review the Clean Water Act, but House legislation passed one year ago to amend the Act has not progressed any further.

It is possible that the Senate will take up legislation that would require the government to compensate property owners whose holdings lost value when they were forced to comply with environmental laws. This bill was proposed to offset some of the costs to private property owners associated with wetlands protection and hazardous waste cleanup requirements.

Regulatory reform has stalled in the Senate since the Risk Assessment and Cost-Benefit Act, sponsored by former Senate Majority Leader Robert Dole (R-Kansas), was defeated.

State Of The States

Editor's Note: We begin a new feature that spotlights interesting and worthwhile activities initiated in the states to address drinking water and health issues. Please feel free to let us know about other projects that you would like to see reported for our readers.

Allegheny County, Pennsylvania, (Pittsburgh area) adopted a unique cooperative action plan between the Health Department and Surface Water Treatment Facilities to safeguard consumers against waterborne disease caused by cryptosporidium and giardia. The eight-point plan, based on guidelines suggested by the American Water Works Association and the Centers for Disease Control and Prevention, helps local authorities protect drinking water supplies from microbial contaminants and educate the public about potential health risks.

In November 1993, Allegheny County began an annual Filter Plant Performance Evaluation program. Cryptosporidiosis outbreaks in Milwaukee, Nevada and Georgia prompted the county to make it a reportable disease in September 1994.

Optimize water treatment processes to remove particulate matter;
Establish communications guidelines to notify the county health department about treatment problems;
Increase testing for cryptosporidium and giardia in both source and finished water;
Form a "Public Health Alliance Early Warning System" to track cases of waterborne illness;
Evaluate all available pertinent information about water quality, plant conditions and disease outbreaks before issuing boil-water advisories;
Provide current information regarding water quality and public health risks to customers, public health officials, vulnerable populations, the public and the media;
Use the established Allegheny County Health Department Public Drinking Water Advisory Committee to continually evaluate cryptosporidium and giardia issues;
Emphasize source protection to reduce treatment plant burdens and prevent recreational exposure.

The Pennsylvania Department of Environmental Protection and Department of Health also have launched a statewide cryptosporidium action plan.

For more information, contact:
John Schomburt or Sean
Conley, Division of Public
Drinking Water and Waste
Management, Allegheny
County Health Department,
(412) 578-8047.

ARKANSAS: Cryptosporidium information for water utilities and their customers

In 1994, the Arkansas Department of Health (ADH) responded to the Milwaukee crisis by developing a cryptosporidium education program primarily geared to water utilities. ADH created an information kit containing materials that, in lay language, describe the public health risks associated with cryptosporidium along with its origins, detection and treatment. A brochure entitled "Cryptosporidium and Drinking Water: What You Should Know" was prepared for water utilities to reproduce and distribute to customers. The program also provides water suppliers with communication tools, such as sample press releases, to help them inform the media in the event of a cryptosporidium outbreak.

Another brochure specifically directed to the AIDS community, "Cryptosporidium and HIV/AIDS: What You Should Know," is complemented by the department's public education effort among at-risk populations.

In addition to alerting utilities through its early warning system, ADH has been working with the Epidemiology Department to classify cryptosporidiosis as a reportable disease.

For more information, contact:
Sue Casteel, Division of Engineering, Arkansas Department of Health, (501) 661-2623.

Chlorine Chemistry Division of the American Chemistry Council Launches Internet Web Site

Chlorine has kept our drinking water safe for almost a century. Yet growing concerns about water quality mean that public health departments and water utilities are continually faced with questions from members of their communities. To equip health officials and water supply administrators with current information about chlorine's role in disinfection processes and other public health issues, the Chlorine Chemistry Division of the American Chemistry Council has developed an on-line resource that brings a wide range of information together in an easy-to-use home page on the World Wide Web.

Information available on the Chlorine Chemistry Division of the American Chemistry Council Web site includes updates on current issues, uses of chlorine in society, and answers to questions regarding the role of chlorine in public health and water disinfection. The site also provides public health and water industry professionals with summaries of the most recent research being conducted on chlorine and related topics.

The Chlorine Chemistry Division of the American Chemistry Council will update and expand the site regularly to continue to provide its users with the latest information on chlorine chemistry. Users can send an e-mail message to the Chlorine Chemistry Division of the American Chemistry Council with questions and requests for information not yet found on the site.

The address is http://c3.org for the Chlorine Chemistry Division of the American Chemistry Council Web site.

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
Oakbrook Terrace, Illinois

Waterborne Rotavirus And Coxsackievirus: A Risk Assessment Approach by Kristina D. Crabtree, MPH

Natural Disasters - Scenarios For Protecting Public Health

Washington Update

State Of The States

Chlorine Chemistry Division of the American Chemistry Council Launches Internet Web Site

Waterborne Rotavirus And Coxsackievirus: A Risk Assessment Approach
by Kristina D. Crabtree, MPH