In addition there also a brief review of fluoride in remineralized water and dental The major methods include reverse osmosis, other membrane.
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WHO Library Cataloguing-in-Publication Data Nutrients in drinking water. 1. Water supply. 2. Potable water. 3. Water treat ment. 4. Nutrition. 5. Micronutrients. I. World Health Organization. ISBN 92 4 159398 9 (NLM classification: WA 687) © World Health Organization 2005 All rights reserved. Publications of the World Health Organization can be obtained from WHO Press, World Health Organization, 20 Avenue Appia, 1211 Geneva 27 , Switzerland (tel: +41 22 791 3264; fax: +41 22 791 4857; email: bookorders@who.int ). Requests for permission to reproduce or translate WHO publications Œ whether for sale or for noncommercial distribution Œ should be addressed to WHO Press, at the above address (fax: +41 22 791 4806; email: permissions@who.int ). The designations employed and the pr esentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimit ation of its frontiers or boundaries. Dotted lines on maps represent approximat e border lines for which there may not yet be full agreement. The mention of specific companies or of certain ma nufacturers™ products does not imply that they are endorsed or recommended by the World Health Organizati on in preference to others of a similar nature that are not mentioned. Errors and omissi ons excepted, the names of proprieta ry products are distinguished by initial capital letters. All reasonable precautions have been taken by WHO to ve rify the information contained in this publication. However, the published material is being distributed with out warranty of any kind, either express or implied. The responsibility for the interpretation and use of the ma terial lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use. The named authors alone are responsible for the views expressed in this publication. Printed at the Printing and Binding Service WHO Geneva, Switzerland
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TABLE OF CONTENTS Preface ..i Acknowledg ements iii 1. NUTRIENTS IN DRINKING WA TER – Consensus at Meeting.1 I. Introduction. 1 II. Topics Examined in the Meeting. ..3 III. Drinking Water and Heal th Relationships6 IV. Conclusions and Recommendations..10 2. DESALINATION GUIDELINES DEVELOPMENT FOR DRINKING WATER BACKGROUND (Joseph A. Cotruvo).13 I. Introduction. .13 II. Drinking Water Production .13 III. Desalination Technologies .16 IV. Membranes. ..17 V. Distillation Technologies .17 VI. Other Sy stems 18 VII. Potential Technical Issues Asso ciated With Desalinatio n.19 VIII. Petroleum Contamination.. .20 IX. Conclusion 23 3. WATER REQUIREMENTS, IMPINGING FACTORS AND RECOMMENDED INTAKES (Ann C. Grandjean).25 I. Introduction. .25 II. Adverse Consequences of Inadequate Water Intake, Requirements for Water, and Factors that Affe ct Requirements. .25 4. ESSENTIAL NUTRIENTS IN DRINKING WATER (Manuel Olivares & Ricardo Uauy).41 I. Introduction. .41 II. Definition of Nutritional Requi rements and Recommendations.41 III. What are the Important Dietary Minerals and Electrolytes in the Diet and Potentially in Water that are Essential for Nutrition a nd Wellbeing?43 IV. What are the RDAs for Minerals and Elect rolytes and how are th ey determined?44
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5. MINERALS FROM DRINKING WATER: BIOAVAILABILITY FOR VARIOUS WORLD POPULATIONS AND HEALTH IMPLICATIONS (C hoon Nam Ong)..61 I. Introduction. .61 II. Studies in Asia. ..61 III. Studies in Pan-America 63 IV. Studies in Africa.. .64 V. Studies in North Amer ica. 64 VI. Studies in Europe.. ..65 VII. Studies in the Western Pacific Region68 VIII. Conclusion 68 6. THE CONTRIBUTION OF DRINKING WATER TO TOTAL DAILY DIETARY INTAKES OF SELECTED TRACE MINERAL NUTRIENTS IN THE UNITED STATES (Joyce Morrissey Donohue, Charles O. Abernathy , Peter Lassovszky, George Hallberg).75 I. Introduction. .75 II. Sources of In formation .76 III. Data and Analysis.. ..77 IV. Results .80 V. Conclusions.. ..88 7. MINERAL ELEMENTS TO CARDIOVASCULAR HE ALTH (Leslie M. Klevay & Gerald F. Combs )..92 I. Introduction. .92 II. Nutritional Determinants of Heart Di sease Risk92 III. Water and H eart Disease.. ..93 IV. Other Illnesses Related to Water Mineral Conten t..93 V. Hardness Good or Softness Bad?.93 VI. Trace Elements in Water Supplies.9 4 VII. Conclusion 95 8. STUDIES OF MINERAL AND CARDIAC HEALTH IN SELECTED POPULATIONS (Floyd J. Frost).101 I. Introduction. ..101 II. Magnesium Deficiency.. .101
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III. Calcium, Copper, and Zinc Defici encies.103 IV. Magnesium, Strenuous Exercise, and Sudden Card iac Death.103 V. Conclusions.. 103 9. HOW TO INTERPRET EPIDEMIOLOGICAL ASSOCIATIONS (Gunther F. Craun & Rebecca L. Calderon)..108 I. Introduction. ..108 II. Types of Epidemio logical Studies..109 III. The Exposure-Disease Association..111 IV. Causality of an Association. 113 V. Web of Causation ..114 VI. Conclusions.. 114 10. WATER HARDNESS AND CARDIOVASCULAR DISEASE: A REVIEW OF THE EPIDEMIOLOGICAL STUDIES, 1957-78 (Rebecca L. Calderon & Gunther F. Craun))..116 I. Introduction. ..116 II. Scientific Reviews by Expert Groups116 III. Summary of the Epidem iological Studies..118 IV. Strength of Association.. ..121 V. Exposure-Response Relations hip..122 VI. Specificity of th e Association. ..122 VII. Reversibility ..122 VIII. Biological Plausibility.. ..123 IX. Conclusions.. 123 11. DRINKING WATER HARDNESS AND CARDIOVASCULAR DISEASES: A REVIEW OF THE EPIDEMIOLOGICAL STUDIES, 1979-2004 (Silvano Monarca, Francesco Donato, Maria Zerbini) .127 I. Introduction. ..127 II. Methods 128 III. Results ..128 IV. Discussion..130 V. Conclusions.. 133
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12. HEALTH RISKS FROM DRINKING DEMINERALISED WATER (Frantisek Kozisek)148 I. Introduction. ..148 II. Health Risks from Consumption of Demineralised or Low- mineral Water.150 III. Desirable Mineral Content of Demineralised Drinking Wate r155 IV. Guidelines and directives for calcium, magnesium, and hardness levels in drinking water. .157 V. Conclusions.. 158 13. NUTRIENT MINERALS IN DRINKING WATER : IMPLICATIONS FOR THE NUTRITION OF INFANTS AND YOUNG CHILDREN (Erika Sievers) 164 I. Introduction. ..164 II. Assessment of Mineral Intake in infant Nutritio n..164 III. The Quantitative Intake of Drinking Wa ter in Infancy a nd early Ch ildhood165 IV. The Contribution of Drinking Water to Nutrient Mineral Intake in Infancy and Early Childhood 169 V. Conclusions.. 175 14. FLUORIDE (Michael Lennon, Helen Whelton, Dennis O’Mulla ne, Jan Ekstrand) .180 I. Introduction. ..180 II. Fluoride Intake in Humans 180 III. Dental Effects of Ingested Fluoride18 1 IV. Ingested Fluoride and Health .182 V. Implications of Desalination 182 VI. Conclusion .183
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ii remineralization of processed wate r is desirable for health reas ons, another logical question is whether some natural waters would also be more healthful if they also contained appropriate amounts of beneficial minerals. The meeting concluded that only a few mine rals in natural waters had sufficient concentrations and distribution to expect that their consum ption in drinking water might sometimes be a significant supplement to diet ary intake in some popul ations. Magnesium and possibly calcium were the two most likely significan t contributors to dietary intake in populations that consumed ‚hard™ water. Information was provided on about 80 of many epidemiology studies of varying quality over the last 50 years that had addressed the issue of hard water consumption and possibly reduced incidence of ischemic car diovascular disease in populations. Although the studies were mostly ecological and of varied qua lity, the meeting concluded that on balance they indicated that the hard water /CVD beneficial hypothesis was pr obably valid, and that magnesium was the more likely positive contributor to the benefits. This conclusion was supported by several case control studies as well as clinical studies. Th ere were other possible health benefits that had been reported, but there was not sufficient data in hand to address those matters. The meeting also concluded that before making a Guidance determination, WHO should undertake a more detailed assessment of that hypothesis to include an examin ation of its biological plausibility. A follow-up symposium and meeting is being planned in 2006 to address that recommendation. In respect to fluoride, the meeting concluded that optimal levels of fluoride intake from water are known to contribute beneficially to dental health. It also noted that higher intake levels can contribute to dental fluorosis, and much highe r levels cause skeletal fluorosis. It concluded that a decision to remineralize demineralized water with fluoride would depend upon: the concentration of fluoride in the existing water supply, the volume of water consumed, the prevalence of risk factors for dental caries, oral hygiene practices and the level of public dental health awareness in the community, and the presen ce of alternative vehicles for dental care and fluoride available to the population.
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iii ACKNOWLEDGEMENTS WHO wishes to express its appreciation to Houssain Abouzaid, Coordinator, Healthy Environments, in the WHO Eastern Mediterranean Regional Office, for initiating the desalination guidance development process, and to Roger Ae rtgeerts, WHO European Regional Advisor for Water and Sanitation, and Helena Shkarubo of the WHO Rome office for hosting the meeting. Joseph Cotruvo, USA, and John Fawell, UK, organized the meeting. Professor Choon Nam Ong, Singapore, chaired the meeting. Gunther Craun, USA, contributed to the document editing and reviews of comments. Specific thanks are due to the experts that participated in the WHO Workshop on ‘Nutrient Minerals in Drinking Water’, whose work was crucial to the development of this document: Rebecca Calderon, Gerald Combs, Gunther Crau n, Jan Ekstrand, Floyd Frost, Ann Grandjean, Suzanne Harris, Frantisek Kozisek, Michael Le nnon, Silvano Monarca, Manuel Olivares, Denis O’Mullane, Souleh Semalulu, Ion Shalaru and Erika Sievers. WHO especially wishes to acknowledge the or ganizations that generously sponsored the meeting. These included: the International Life Sc iences Institute (ILSI), the U.S. Environmental Protection Agency™s Office of Science and Techno logy (Washington), and Office of Research and Development (Research Triangle Park, North Carolina), the American Water Works Association Research Foundation, the Center for Human Nutriti on at the University of Nebraska Medical Center (Omaha), and Health Canada™s Water Quality and Health Bureau (Ottawa, Ontario).
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1 1. NUTRIENTS IN DRINKING WATER Potential Health Consequences Of Long-Term Consumption Of Demineralized, Remineralized And Altered Mineral Content Drinking Water Expert Consensus Meeting Group Report _________________________________________________________________________ I. INTRODUCTION Desalination of sea water and brackish water is widely practiced and it is rapidly growing as the principal source of new fresh water in the world. Water treatment processes including desalination followed by remineralization alte r the mineral compositi on of drinking water compared to water derived from many fresh water sources. The WHO Guidelines for Drinking-water Qual ity (GDWQ) provide a point of reference for drinking water quality regulations and standards setting world-wide. The Guidelines are kept up-to-date through a process of ‚rolling revision™ that includes the development of accompanying documents substantiating the content of th e guidelines and providing guidance on experience with good practice in achieving safe drinking-water. This plan of work includes the development of guidance on good practices of desalination as a source of safe drinking water. In 1999, WHO™s Eastern Mediterranean Regional Office initiated a proposal to develop WHO “Guidance for Safe Water: Health and En vironmental Aspects of Desalination”, because numerous existing facilities had developed on a case-by-case basis with potentially inconsistent consideration of important prin ciples of siting, coastal zone protection, chemicals and contact surfaces used in plant operation, water treatment and plant construction , contaminants, water distribution, microbial control and final product water quality. International guidance would reduce ad hoc decision making and facilitate informed decision making, assist the provision of higher quality water, assure consideration of environmental protection factors, reduce costs and allow more rapid project completion. Such guidance would be timely given the rapidly increasing application of desalination world-wi de. In 2000, the proposal to proceed was endorsed at a WHO Guidelines for Drinking-water Qua lity Committee meeting in Berlin, Germany. In May 2001, the proposal was examined at a dedica ted expert consultation in Manama, Bahrain and an operating plan and program were proposed. This report and its supporting papers were the product of an meeting conducted in the WHO offi ce for the European Region in Rome, Italy in 2003. That meeting was part of the development plan for the Desalination Guidance describe above. Health considerations addressed in this report are those potentially arising from long-term consumption of water that has unde rgone major alteration in its mine ral content, such that it must be remineralized to be compatible with piped di stribution systems. The report also considers the relationships between calcium and magnesium in drinking water on certain cardiovascular disease risks. In addition there also a brief revi ew of fluoride in remine ralized water and dental effects in relation to associated water consumption. 1. Background Drinking water, regardless of its source, may be subjected to one or more of a variety of treatment processes aimed at improving its safety and/or aesthetic quality. These processes are selected in each case according to the source wa ter and the constituents and contaminants that require removal. Surface fresh waters will of ten undergo coagulation, sedimentation, rapid sand
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2 filtration and disinfection. Ground waters, which are often naturally filtered, usually undergo less treatment that could be limited to disinfection alone. Other treatment processes may include pH adjustment, softening, corrosion control chemi cals addition, alkalinity adjustment, carbon filtration/adsorption, membrane filtration, slow sand filtration and supplemental fluoridation. The disinfectants applied could include chlorine, chlorine dioxide, ozone, or chloramines. Some substances will be added by the chemicals used for treatment, i.e. direct and indirect additives. For waters with high salinity (e.g. from perh aps 1000 ppm up to about 40,000 ppm) such as brackish waters or sea water, treatment processe s must remove most of the dissolved salts in order to make the water potable. The major met hods include reverse osmosis, other membrane treatments or several distillation/vapor conde nsation processes. These processes require extensive pretreatment and water conditioning a nd subsequent remineralization, so that the finished water that is now significantly different from the source water will not be overly aggressive to the piped distribution systems that it will pass th rough on the way to consumers. In the course of treatment of fresh water, contaminants and some potentially beneficial nutrients will be removed and some might be added. Other waters, such as those treated by softening or membrane filtration may also underg o significant changes in their mineral content due to the treatment processes. Remineralization and increasing alkalinity for the purpose of stabilizing and reducing corrosivity of water from which dissolved solids have been substantially reduced are often accomplished by use of lime or limestone. Sodium hydroxide, sodium bicarbonate, sodium carbonate, phosphates, and silicates are also sometimes used alone or in combination. The mineral composition of limestone is highly vari able depending upon the quarry location and it is usually predominantly calcium car bonate, but it sometimes also c ontains significant amounts of magnesium carbonate along with numerous other mine rals. Quality specifications exist in many countries for chemicals and materi als including lime used in the treatment of drinking water. These specifications are intended to assure that drinking water treatment grade chemicals will be used and that their addition will not concurrently contribute significant levels of potentially harmful contaminants to the finished dr inking water under foreseeable use conditions. 2. Scope of the Review Several issues were examined relating to the composition of drinking water that has undergone significant treatment relevant to drin king water guidelines aimed at protecting and enhancing public health: What is the potential contribution of drinking water to total nutrition? What is the typical daily consumption of drinking water for individuals, considering climate, exercise, age etc.? Which substances are often found in drinking water that can contribute significantly to health and well-being? Under what conditions can drinking water be a significant contribution to the total dietary intake of certain beneficial substances? What conclusions can be drawn on the relationship between calcium, magnesium, and other trace elements in water and mortality fr om certain types of car diovascular disease? For which substances, if any, can a case be ma de for supplementation of mineral content in treated reduced mineral content drinking wate r from the public health perspective? What is the role of fluoride in remineralized drinking water with respec t to dental benefits and dental fluorosis, and skeletal fluorosis?
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