The Water Science and Technology Board has released the first report of the Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks, which is studying water quality issues associated with public water supply distribution systems and their potential risks to consumers. The distribution system, which is a critical component of every drinking water utility, constitutes a significant management challenge from both an operational and public health standpoint. This first report was requested by the EPA, as the agency considers revisions to the Total Coliform Rule with potential new requirements for ensuring the integrity of the distribution system. This first report identifies trends relevant to the deterioration of drinking water quality in distribution systems and prioritizes issues of greatest concern according to high, medium, and low priority categories. Of the issues presented in nine EPA white papers that were reviewed by the committee, cross connections and backflow, new or repaired water mains, and finished water storage facilities were judged by the committee to be of the highest importance based on their associated potential health risks. In addition, the report noted that two other issues should also be accorded high priority: premise plumbing and distribution system operator training. This first report will be followed in about 18 months by a more comprehensive final report that evaluates approaches for risk characterization and identifies strategies that could be considered to reduce the risks posed by water-quality deteriorating events.
Protecting and maintaining water distributions systems is crucial to ensuring high quality drinking water. Distribution systems-consisting of pipes, pumps, valves, storage tanks, reservoirs, meters, fittings, and other hydraulic appurtenances-carry drinking water from a centralized treatment plant or well supplies to consumers' taps. Spanning almost 1 million miles in the United States, distribution systems represent the vast majority of physical infrastructure for water supplies, and thus constitute the primary management challenge from both an operational and public health standpoint. Recent data on waterborne disease outbreaks suggest that distribution systems remain a source of contamination that has yet to be fully addressed. This report evaluates approaches for risk characterization and recent data, and it identifies a variety of strategies that could be considered to reduce the risks posed by water-quality deteriorating events in distribution systems. Particular attention is given to backflow events via cross connections, the potential for contamination of the distribution system during construction and repair activities, maintenance of storage facilities, and the role of premise plumbing in public health risk. The report also identifies advances in detection, monitoring and modeling, analytical methods, and research and development opportunities that will enable the water supply industry to further reduce risks associated with drinking water distribution systems.
Protecting and maintaining water distributions systems is crucial to ensuring high quality drinking water. Distribution systems-consisting of pipes, pumps, valves, storage tanks, reservoirs, meters, fittings, and other hydraulic appurtenances-carry drinking water from a centralized treatment plant or well supplies to consumers' taps. Spanning almost 1 million miles in the United States, distribution systems represent the vast majority of physical infrastructure for water supplies, and thus constitute the primary management challenge from both an operational and public health standpoint. Recent data on waterborne disease outbreaks suggest that distribution systems remain a source of contamination that has yet to be fully addressed. This report evaluates approaches for risk characterization and recent data, and it identifies a variety of strategies that could be considered to reduce the risks posed by water-quality deteriorating events in distribution systems. Particular attention is given to backflow events via cross connections, the potential for contamination of the distribution system during construction and repair activities, maintenance of storage facilities, and the role of premise plumbing in public health risk. The report also identifies advances in detection, monitoring and modeling, analytical methods, and research and development opportunities that will enable the water supply industry to further reduce risks associated with drinking water distribution systems.
The Water Science and Technology Board has released the first report of the Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks, which is studying water quality issues associated with public water supply distribution systems and their potential risks to consumers. The distribution system, which is a critical component of every drinking water utility, constitutes a significant management challenge from both an operational and public health standpoint. This first report was requested by the EPA, as the agency considers revisions to the Total Coliform Rule with potential new requirements for ensuring the integrity of the distribution system. This first report identifies trends relevant to the deterioration of drinking water quality in distribution systems and prioritizes issues of greatest concern according to high, medium, and low priority categories. Of the issues presented in nine EPA white papers that were reviewed by the committee, cross connections and backflow, new or repaired water mains, and finished water storage facilities were judged by the committee to be of the highest importance based on their associated potential health risks. In addition, the report noted that two other issues should also be accorded high priority: premise plumbing and distribution system operator training. This first report will be followed in about 18 months by a more comprehensive final report that evaluates approaches for risk characterization and identifies strategies that could be considered to reduce the risks posed by water-quality deteriorating events.
Chronic and episodic water shortages are becoming common in many regions of the United States, and population growth in water-scarce regions further compounds the challenges. Increasingly, alternative water sources such as graywater-untreated wastewater that does not include water from the toilet but generally includes water from bathroom sinks, showers, bathtubs, clothes washers, and laundry sinks- and stormwater-water from rainfall or snow that can be measured downstream in a pipe, culvert, or stream shortly after the precipitation event-are being viewed as resources to supplement scarce water supplies rather than as waste to be discharged as rapidly as possible. Graywater and stormwater can serve a range of non-potable uses, including irrigation, toilet flushing, washing, and cooling, although treatment may be needed. Stormwater may also be used to recharge groundwater, which may ultimately be tapped for potable use. In addition to providing additional sources of local water supply, harvesting stormwater has many potential benefits, including energy savings, pollution prevention, and reducing the impacts of urban development on urban streams. Similarly, the reuse of graywater can enhance water supply reliability and extend the capacity of existing wastewater systems in growing cities. Despite the benefits of using local alternative water sources to address water demands, many questions remain that have limited the broader application of graywater and stormwater capture and use. In particular, limited information is available on the costs, benefits, and risks of these projects, and beyond the simplest applications many state and local public health agencies have not developed regulatory frameworks for full use of these local water resources. To address these issues, Using Graywater and Stormwater to Enhance Local Water Supplies analyzes the risks, costs, and benefits on various uses of graywater and stormwater. This report examines technical, economic, regulatory, and social issues associated with graywater and stormwater capture for a range of uses, including non-potable urban uses, irrigation, and groundwater recharge. Using Graywater and Stormwater to Enhance Local Water Supplies considers the quality and suitability of water for reuse, treatment and storage technologies, and human health and environmental risks of water reuse. The findings and recommendations of this report will be valuable for water managers, citizens of states under a current drought, and local and state health and environmental agencies.
In the quest to reduce costs and improve the efficiency of water and wastewater services, many communities in the United States are exploring the potential advantages of privatization of those services. Unlike other utility services, local governments have generally assumed responsibility for providing water services. Privatization of such services can include the outright sale of system assets, or various forms of public-private partnershipsâ€"from the simple provision of supplies and services, to private design construction and operation of treatment plants and distribution systems. Many factors are contributing to the growing interest in the privatization of water services. Higher operating costs, more stringent federal water quality and waste effluent standards, greater customer demands for quality and reliability, and an aging water delivery and wastewater collection and treatment infrastructure are all challenging municipalities that may be short of funds or technical capabilities. For municipalities with limited capacities to meet these challenges, privatization can be a viable alternative. Privatization of Water Services evaluates the fiscal and policy implications of privatization, scenarios in which privatization works best, and the efficiencies that may be gained by contracting with private water utilities.
The most recent volume in the Drinking Water and Health series contains the results of a two-part study on the toxicity of drinking water contaminants. The first part examines current practices in risk assessment, identifies new noncancerous toxic responses to chemicals found in drinking water, and discusses the use of pharmacokinetic data to estimate the delivered dose and response. The second part of the book provides risk assessments for 14 specific compounds, 9 presented here for the first time.
Pharmacokinetics, the study of the movement of chemicals within the body, is a vital tool in assessing the risk of exposure to environmental chemicals. This bookâ€"a collection of papers authored by experts in academia, industry, and governmentâ€"reviews the progress of the risk-assessment process and discusses the role of pharmacokinetic principles in evaluating risk. In addition, the authors discuss software packages used to analyze data and to build models simulating biological phenomena. A summary chapter provides a view of trends in pharmacokinetic modeling and notes some prospective fields of study.
New York City's water supply system is one of the oldest, largest, and most complex in the nation. It delivers more than 1.1 billion gallons of water each day from three upstate watersheds (Croton, Catskill, and Delaware) to meet the needs of more than eight million people in the City, one million people in Westchester, Putnam, Orange, and Ulster counties, and millions of commuters and tourists who visit the City throughout the year. The Catskill and Delaware portions, which make up about 90 percent of the supply, receive no filtration or treatment other than disinfection, except for rare instances of high turbidity when a coagulant is added to increase deposition of suspended solids. The remaining 10 percent of the supply comes from the Croton watershed and receives treatment via filtration. The drinking water supply is managed by the Bureau of Water Supply within the New York City Department of Environmental Protection (NYC DEP). To continue to avoid filtration of the Catskill/Delaware portion of the water supply, in 2007, NYC DEP reexamined its control of turbidity in the Catskill portion of the water supply, including both structural improvements to the system and operational changes. The Operations Support Tool (OST) was developed as part of these efforts. OST couples models of reservoir operations and water quality; it uses real-time data on streamflow, snow pack, water quality, reservoir levels, diversions, and releases; and it incorporates streamflow forecastsâ€"all in order to predict future reservoir levels, water delivery to customers, and water quality within the system. These predictions inform the system operators, who then make decisions based on the most current data and forecasts. This report reviews the use of OST in current and future reservoir operations. It considers potential ways in which the City can more effectively use OST, makes recommendations for additional performance measures, and reviews the potential effects of climate change on the City's water supply to help identify and enhance understanding of areas of potential future concern with regard to the use of OST.
Concern over terrorist attacks since 2001 has directed attention to potential vulnerabilities of the nation's water and wastewater systems. The Environmental Protection Agency (EPA), which leads federal efforts to protect the water sector, initiated a research program in 2002 to address immediate research and technical support needs. This report, conducted at EPA's request, evaluates research progress and provides a long-term vision for EPA's research program. The report recommends that EPA develop a strategic research plan, address gaps in expertise among EPA program managers and researchers, and improve its approaches to information dissemination. The report recommends several high-priority research topics for EPA, including conducting empirical research in behavioral science to better understand how to prepare people for water security incidents.
The regulation of potentially hazardous substances has become a controversial issue. This volume evaluates past efforts to develop and use risk assessment guidelines, reviews the experience of regulatory agencies with different administrative arrangements for risk assessment, and evaluates various proposals to modify procedures. The book's conclusions and recommendations can be applied across the entire field of environmental health.
In the early 1980s, two water-supply systems on the Marine Corps Base Camp Lejeune in North Carolina were found to be contaminated with the industrial solvents trichloroethylene (TCE) and perchloroethylene (PCE). The water systems were supplied by the Tarawa Terrace and Hadnot Point watertreatment plants, which served enlisted-family housing, barracks for unmarried service personnel, base administrative offices, schools, and recreational areas. The Hadnot Point water system also served the base hospital and an industrial area and supplied water to housing on the Holcomb Boulevard water system (full-time until 1972 and periodically thereafter). This book examines what is known about the contamination of the water supplies at Camp Lejeune and whether the contamination can be linked to any adverse health outcomes in former residents and workers at the base.
The National Research Council closes the landmark series Drinking Water and Health with Volume 9, published in two parts: Part I: DNA Adducts provides an overview of DNA adducts and their effects on human health, explores the techniques currently in use for detecting them, offers an outlook on future toxicity testing, and lists specific recommendations for action. Part II: Mixtures explores the issues surrounding multiple-chemical exposure from drinking water and reviews options for grouping compounds so their toxicity in mixtures can be reliably assessed. The book describes alternative approaches and considers the option of developing a modified "hazard index" for chemical compounds.
Risk assessments are often used by the federal government to estimate the risk the public may face from such things as exposure to a chemical or the potential failure of an engineered structure, and they underlie many regulatory decisions. Last January, the White House Office of Management and Budget (OMB) issued a draft bulletin for all federal agencies, which included a new definition of risk assessment and proposed standards aimed at improving federal risk assessments. This National Research Council report, written at the request of OMB, evaluates the draft bulletin and supports its overall goals of improving the quality of risk assessments. However, the report concludes that the draft bulletin is "fundamentally flawed" from a scientific and technical standpoint and should be withdrawn. Problems include an overly broad definition of risk assessment in conflict with long-established concepts and practices, and an overly narrow definition of adverse health effects-one that considers only clinically apparent effects to be adverse, ignoring other biological changes that could lead to health effects. The report also criticizes the draft bulletin for focusing mainly on human health risk assessments while neglecting assessments of technology and engineered structures.
Pharmacokinetics, the study of the movement of chemicals within the body, is a vital tool in assessing the risk of exposure to environmental chemicals. This book--a collection of papers authored by experts in academia, industry, and government--reviews the progress of the risk-assessment process and discusses the role of pharmacokinetic principles in evaluating risk. In addition, the authors discuss software packages used to analyze data and to build models simulating biological phenomena. A summary chapter provides a view of trends in pharmacokinetic modeling and notes some prospective fields of study.
The most recent volume in the Drinking Water and Health series contains the results of a two-part study on the toxicity of drinking water contaminants. The first part examines current practices in risk assessment, identifies new noncancerous toxic responses to chemicals found in drinking water, and discusses the use of pharmacokinetic data to estimate the delivered dose and response. The second part of the book provides risk assessments for 14 specific compounds, 9 presented here for the first time.
The most recent volume in the Drinking Water and Health series contains the results of a two-part study on the toxicity of drinking water contaminants. The first part examines current practices in risk assessment, identifies new noncancerous toxic responses to chemicals found in drinking water, and discusses the use of pharmacokinetic data to estimate the delivered dose and response. The second part of the book provides risk assessments for 14 specific compounds, 9 presented here for the first time.
The most recent volume in the Drinking Water and Health series contains the results of a two-part study on the toxicity of drinking water contaminants. The first part examines current practices in risk assessment, identifies new noncancerous toxic responses to chemicals found in drinking water, and discusses the use of pharmacokinetic data to estimate the delivered dose and response. The second part of the book provides risk assessments for 14 specific compounds, 9 presented here for the first time.
Risk assessment has become a dominant public policy tool for making choices, based on limited resources, to protect public health and the environment. It has been instrumental to the mission of the U.S. Environmental Protection Agency (EPA) as well as other federal agencies in evaluating public health concerns, informing regulatory and technological decisions, prioritizing research needs and funding, and in developing approaches for cost-benefit analysis. However, risk assessment is at a crossroads. Despite advances in the field, risk assessment faces a number of significant challenges including lengthy delays in making complex decisions; lack of data leading to significant uncertainty in risk assessments; and many chemicals in the marketplace that have not been evaluated and emerging agents requiring assessment. Science and Decisions makes practical scientific and technical recommendations to address these challenges. This book is a complement to the widely used 1983 National Academies book, Risk Assessment in the Federal Government (also known as the Red Book). The earlier book established a framework for the concepts and conduct of risk assessment that has been adopted by numerous expert committees, regulatory agencies, and public health institutions. The new book embeds these concepts within a broader framework for risk-based decision-making. Together, these are essential references for those working in the regulatory and public health fields.
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