Chemical Safety Of Drinking Water

Contamination of drinking-water is a significant concern for public health throughout the world. Microbial hazards make the largest contribution to waterborne disease in developed and developing countries. Nevertheless, chemicals in water supplies can cause serious health problems--whether the chemicals are naturally occurring or derive from sources of pollution. At a global scale, fluoride and arsenic are the most significant chemicals, each affecting perhaps millions of people. However, many other chemicals can be important contaminants of drinking-water under specific local conditions. Often, identification and assessment of risks to health from drinking-water relies excessively on analysis of water samples. The limitations of this approach are well recognized, and contributed to the delay in recognizing arsenic in drinking-water as a significant health concern in Bangladesh and elsewhere. To overcome such limitations, the latest edition of the World Health Organization (WHO) Guidelines for Drinking-water Quality (WHO, 2004; WHO,2006) emphasizes effective preventive management through a 'framework for drinking-water safety' that incorporates 'water safety plans.' Effective preventive management of chemicals in drinking-water requires simple tools for distinguishing the few chemicals of potential local or national concern from the unmanageably long list of chemicals of possible significance. The aim is to identify and prioritize the chemicals of concern, to overcome the limitations of direct analysis of water quality, and ensure that limited resources are allocated towards the monitoring, assessment and control of the chemicals that pose the greatest health risks. Identifying and prioritizing chemical risks presents a challenge, especially in developing countries, because information on the presence of chemicals in water supplies is often lacking. This document provides guidance to help readers to meet that challenge. It shows how information on aspects such as geology and industrial and agricultural development, which is often readily available, can be used to identify potential chemical contaminants (and potential sources of chemicals), from catchment to consumer, and thus prioritize risks. As a supporting document to the Guidelines for Drinking-water Quality (WHO, 2004; WHO, 2006), this publication is aimed at policy-makers, regulators, managers and public health practitioners at national and local level. It is divided into three parts: Part A provides general guidance on using limited information in prioritizing chemicals in drinking-water for risk management. The need for such guidance is outlined in Chapter 1,which also describes the administrative and policy context. Chapter 2 describes the principles applied in prioritizing chemicals, provides information on some factors that affect chemical concentrations along pathways, and highlights several specific chemicals that are frequently considered priorities because of their widespread occurrence or significant health effects. Chapter 3 discusses the role of drinking-water standards and guidelines, and provides an overview of contemporary water quality management procedures. Part B provides practical guidance on identifying specific chemicals that are likely to be of concern in individual water supply systems. It groups chemical contaminants into five categories on the basis of their potential sources: naturally occurring, from agriculture activities, from human settlements, from industrial activities, and from water treatment and distribution processes themselves. Part C comprises the appendices. It includes guidance on the most likely sources of potential contaminants and on identifying chemicals that could be of concern in particular circumstances. The appendices address potential sources of chemicals considered in the WHO drinking-water guidelines (WHO, 2004; WHO, 2006), chemicals potentially discharged in effluents from industrial sources, and the association of pesticides with crops and crop types. This information is presented in an accessible format that will help users to determine the chemical hazards that can arise in the catchment, in treatment and in distribution, in large, medium and small water supplies. Many experts worldwide contributed to this work over a period of several years, beginning with the 1st Meeting of Experts on Monitoring Chemicals in Drinking Water, held in Bangkok, Thailand, in January 2001. This was followed by the 2nd Meeting of Experts on Monitoring Chemicals in Drinking Water, also held in Bangkok, in December 2001. Both meetings were sponsored by WHO and hosted by the Department of Health, Ministry of Public Health, Thailand. The draft guidance document was subsequently tested in a series of field trials in 2002-2003 in Indonesia, Fiji, Nepal, Mongolia, the Philippines and Thailand. Lessons learnt through the field trials provided feedback that was valuable in revising and finalizing the document. Readers should note that while this publication has been developed as a supporting document for, and with reference to, the Guidelines for Drinking-water Quality, the guidelines themselves are frequently updated and the latest information should always be sought by reference to relevant World Health Organization publications and web site. (http://www.who.int/water_sanitation_health/dwq/guidelines/en/index.html).

This is the third edition of the WHO's guidelines which are used by countries worldwide to set standards for the regulation of drinking water quality and effective approaches to water safety management. This revised edition has been updated to take account of recent developments in risk assessment and management. Topics discussed include: a framework for drinking water safety and discussion of the roles and responsibilities of different stakeholders, such as national regulators, water suppliers and independent surveillance agencies; guidance on microbial safety of drinking water through safety plans; new scientific information on chemicals, waterborne pathogens and individual chemical hazards of actual or potential concern. It also considers the application of the guidelines in specific circumstances, such as in emergencies and disasters, and to specific applications, such as bottled water. It also contains information on over 130 documents which substantiate or explain the content of the Guidelines, and on good practice guidance in achieving drinking-water safety.

A comprehensive reference on state-of-the-art risk assessment methodologies for drinking water Risk Assessment for Chemicals in Drinking Water discusses the major steps and goals in risk assessments and suggests ways to improve the methodologies and accuracy, while consolidating up-to-date information on the current principles and practices in one authoritative reference. After an enlightening overview of risk assessment practices and regulatory guidelines, it: Includes descriptions of the use of variability analysis, exposure analysis, physiologically based pharmacokinetics, and modeling for both cancer and non-cancer endpoints Describes the practices of major organizations, including the U.S. EPA, Health Canada, World Health Organization, and California Office of Environmental Health Hazard Assessment Includes complete chapters on risk assessment for essential nutrients, arsenic, chloroform, and perchlorate Explains how to address susceptible sub-populations, including the elderly and infants and children, in risk assessments Covers the potential of using genomic and proteomic screens Addresses recent advances, emerging issues, and future challenges With contributions and perspectives from leading scientists, this is the definitive resource for health and environmental scientists, toxicologists, risk assessors and managers, regulators, consultants, and other professionals responsible for the safety of drinking water.

The safety of the nation's drinking water must be maintained to ensure the health of the public. The U.S. Environmental Protection Agency (EPA) is responsible for regulating the levels of substances in the drinking water supply. Copper can leach into drinking water from the pipes in the distribution system, and the allowable levels are regulated by the EPA. The regulation of copper, however, is complicated by the fact that it is both necessary to the normal functioning of the body and toxic to the body at too high a level. The National Research Council was requested to form a committee to review the scientific validity of the EPA's maximum contaminant level goal for copper in drinking water. Copper in Drinking Water outlines the findings of the committee's review. The book provides a review of the toxicity of copper as well as a discussion of the essential nature of this metal. The risks posed by both short-term and long-term exposure to copper are characterized, and the implications for public health are discussed. This book is a valuable reference for individuals involved in the regulation of water supplies and individuals interested in issues surrounding this metal.

Originally published in 1978, this volume addresses the scientific, economic, and administrative aspects of the public policy problem raised by the United States’ Safe Drinking Water Act of 1974. In this collection of papers, the authors examine the various problems presented by drinking public water in the United States, the United Kingdom, and throughout Europe. This is an ideal title for students interested in environmental studies and public policy reform.

This volume describes the methods used in the surveillance of drinking water quality in the light of the special problems of small-community supplies, particularly in developing countries, and outlines the strategies necessary to ensure that surveillance is effective.

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.

This new book covers drinking water regulations such as disinfectant by-products, synthetic organics, inorganic chemicals, microbiological contaminants, volatile organic chemicals, radionuclides, fluoride, toxicological approaches to setting new national drinking water regulations, and trihalomethanes. In addition, organic and inorganic compounds scheduled to be regulated in 1989 and new candidates for the 1990s regulations are detailed.