Some Drinking Water Disinfectants And Contaminants Including Arsenic

A working group of 23 experts from 13 countries met in Lyon to evaluate the evidence for carcinogenicity of arsenic (mostly naturally occurring) as a contaminant of drinking-water, and of the water-disinfectant chloramine. The working group also evaluated or re-evaluated four chlorination by-products found in drinking-water, namely chloral hydrate, di- and trichloroacetic acids, and 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (also known as MX). High-level exposure to arsenic in drinking-water occurs in some regions such as China, Latin America, Bangladesh and West Bengal. The Working Group reviewed epidemiological studies of human cancer (mainly ecological studies in Taiwan and Chile, and several case-control and cohort studies) in relation to arsenic in drinking-water. Arsenic in drinking-water (primarily inorganic, as arsenate and to a lesser extent arsenite) was evaluated as carcinogenic to humans (Group 1) on the basis of sufficient evidence for an increased risk for cancer of the urinary bladder, lung and skin. Studies on inorganic arsenic in experimental animals provided limited evidence for its carcinogenicity, but sufficient evidence was found in experimental animals for the carcinogenicity of dimethylarsinic acid (an organic form of arsenic), which produced urinary bladder tumours in rats and lung tumours in mice after oral administration.

This work provides those involved in water purification research and administration with a comprehensive resource of methods for analyzing water to assure its safety from contaminants, both natural and human caused. The book first provides an overview of major water-related issues in developing and developed countries, followed by a review of issues of sampling for water analysis, regulatory considerations and forensics in water quality and purity investigations. The subsequent chapters cover microbial as well chemical contaminations from inorganic compounds, radionuclides, volatile and semi-volatile compounds, disinfectants, herbicides, and pharmaceuticals, including endocrine disruptors, as well as potential terrorist-related contamination. The last chapter describes the Grainger prize-winning filter that can remove arsenic from water sources and sufficiently protect the health of a large number of people. - Covers the scope of water contamination problems on a worldwide scale - Provides a rich source of methods for analyzing water to assure its safety from natural and deliberate contaminants - Describes the filter that won the $1 million Grainger prize and thereby highlighting an important approach to remediation

This Scientific Publication reviews the information on cancer sites and mechanistic events for the more than 100 agents classified in Group 1 (carcinogenic to humans) by the IARC Monographs Program. This category of agents is diverse and includes chemicals and chemical mixtures; occupations; metals, dusts, and fibres; radiation; viruses and other biological agents; personal habits; and pharmaceuticals. For the Group 1 agents, there were cross-cutting questions about the relevance to humans of certain cancer sites or mechanistic pathways in animals. This publication is based on a systematic identification and comparison of the cancer sites observed in humans and those observed in experimental animals, and a compilation of mechanistic events for agents known to cause cancer in humans. Relevant information was analyzed on all the agents classified in Group 1 in Monographs up to and including Volume 109, most of which are reviewed in Volume 100A-F. A database of tumor sites seen in humans and animals was used to examine the degree of concordance by use of an anatomically based tumor classification scheme. The analysis of mechanistic aspects of the IARC Group 1 agents focused on 10 key characteristics of human carcinogens developed during the course of this work. Genotoxicity was the most prevalent mechanistic characteristic, consistent with the process of carcinogenesis necessarily involving genomic changes. The IARC concordance database represents a useful source of information for comparing animal and human data with respect to the tumors caused in different species. The results of the mechanistic analysis can provide a basis for future efforts to categorize mechanistic data for carcinogens through a systematic review process. These reviews and analyses were discussed during a two-part Workshop on Tumour Site Concordance and Mechanisms of Carcinogenesis convened by IARC. This Scientific Publication is the report of that Workshop and of subsequent work by the participants, both individually and collectively. This publication also presents a statement of consensus among the Workshop participants, which summarizes the main findings and their implications for human cancer risk assessment.

"This volume of the IARC Monographs provides evaluations of the carcinogenicity of shiftwork, painting and firefighting. Shiftwork is estimated to involve about 15-20% of the total working population. It is most prevalent among workers in the health care, transportation, communication, leisure and hospitality sectors. Shiftwork involving work at night is the most disruptive for the circadian clock. Painters are potentially exposed to the chemicals found in paint products during their application and removal, and may also be exposed to other workplace hazards, such as asbestos or crystalline silica dust. Firefighters may be exposed at different intensity levels depending on crew assignment, tasks, and/or the time spent at fires. All fires generate a very large number of toxic combustion products, including known, probable or possible carcinogens. An IARC Monographs Working Group reviewed epidemiological evidence, animal bioassays where appropriate, and mechanistic and other relevant data to reach conclusions as to the carcinogenic hazard of these three exposure circumstances to humans."--Books.google.

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.

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).

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.

A range of natural earth materials, like arsenic or fluoride, have long been linked to significant human health effects. Improved understanding of the pervasive and complex interactions between earth materials and human health will require creative collaborations between earth scientists and public health professionals. At the request of the National Science Foundation, U.S. Geological Survey, and National Aeronautics and Space Administration, this National Research Council book assesses the current state of knowledge at the interface between the earth sciences and public health disciplines. The book identifies high-priority areas for collaborative research, including understanding the transport and bioavailability of potentially hazardous earth materials, using risk-based scenarios to mitigate the public health effects of natural hazards under current and future climate regimes, and understanding the health risks that result from disturbance of earth systems. Geospatial information - geological maps for earth scientists and epidemiological data for public health professionals - is identified as one of the essential integrative tools that is fundamental to the activities of both communities. The book also calls for increased data sharing between agencies to promote interdisciplinary research without compromising privacy.