Overview of thematic articles

World Water Day 2001: Water for Positive Health

Summary - Links - Introduction - Swimming - Springs & spas - Further information:

Summary

• Water as a source of positive health: hygiene, cleanliness, relaxation
• Swimming and water sports
• The tradition of water spas and mineral waters
• Water and tourism

Links

Theme articles on:

• water and natural hazards
• floods and droughts
• water scarcity
• water and food
• water challenges
• water and oral health

Disease fact files:

Amoebic meningitis Cholera Cryptosporidium Cyanobacteria Dengue Diarrhoeal diseases Drowning Giardiasis Guinea worm disease

Hepatitis A Legionnaires' disease Leptospirosis Malaria Norwalk-like virus Plague Schistosomiasis Spinal injury

Introduction

Water is essential for health, which means not just absence from disease but the maintenance of well being Box 1). The health aspects of hygiene, prevention of infection and nutrition all depend to some extent on access to water and to water quality. This theme article focuses on the meaning of water health for individuals and for communal use of water in our environment. Water plays an important part in rest and relaxation, as well as in cleanliness and the supply of basic needs. These positive aspects are taken for granted in many water rich countries, such as in the use of water spas, swimming and recreational use of water resources. The desperate need to address water scarcity and water related poverty inevitably means that the recreational role of water is not seen as a health priority. Nevertheless, access to safe water is an important part of general health, whether it is used for bathing or for play: children will play in water, whether it is safe or not. Research into handwashing has also demonstrated that the motivation for keeping hands clean is often based more on aesthetic reasons than a concern for health (Curtis 2002): so programmes designed to reduce diarrhoea by handwashing need to take account of human behaviour and motivation, which includes understanding the human desire to use water for pleasure and to look and smell clean. Some water activities are intended to maintain and improve health: for example, the postulated healing effects of spas, physical benefits of swimming and the health benefits claimed for consumption of some spring and mineral waters. Long established traditions also demonstrate the symbolic importance of water for health and cleanliness in all societies and religions.

Box 1: The WHO definition of health Health is a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.

SWIMMING and other recreational contact with water

Recreational contact with water includes use of surface waters (rivers, lakes, oceans) and artificial waters (swimming pools, spa-pools). Recreational use by large numbers of people is a relatively recent development, particularly in developed and industrialised countries (Box 2).

Box 2 Bathing as a ‘healthful practice’ in 1850 “All are agreed that bathing is a healthful practice, first because it is cleanly, and second because it is a precautionary measure against the risk [to] life by drowning. ‘We are fully prepared’, says the Lancet, “to endorse the proposition that boys be allowed to bathe as often and as freely as may be practicable.” from an English medical pamphlet of 1850 (Hartley 1978)

Natural water resources have been used for health and recreation throughout human history, although swimming on a wide scale is a recent development. A hundred and fifty years ago, very few people could swim. Bathing was undertaken more for health than for pleasure: for example, wetting the head was thought to prevent apoplexy (stroke) in Europe. Apart from spas and other health related resorts, swimming pools were a late development. Swimming as a sport and means of recreation was only widely established during the 20th century. Swimming is now recognised as one of the most beneficial forms of exercise and learning to swim an essential skill for both boys and girls.

Over the last century the size of urban populations has increased dramatically across the planet. About 33% of the population in Asia and Africa live in urban settlements, while urban dwellers account for 76% of the population in Latin America (UN, 2000). Where there is no access to safe swimming facilities, young boys in particular may risk bathing, playing and swimming in polluted urban rivers or beaches. Providing well-maintained pools is important for urban dwellers, but also for tourists. Tourism is the world's third largest industry and tourism receipts increased by about 11% a year during the last decade (WHO, 1998). While the millions of tourists seeking sun, sand and water sports bring much needed income to developing countries, such as the resorts in the Caribbean, they expect and demand high standards of water safety. Improvement of the recreational facilities for local residents may depend on the complex relationship between risk assessment, cost-benefit and maintenance of an attractive image for tourists.

The hazards of recreational water use.

There are hazards in the recreational use of water even in well-designed pools or designated bathing areas in natural waters (Table 1). These can be grouped into four types:

1. physical hazards, causing drowning or accidents such as spinal injury.
2. microbial hazards
3. exposure to chemicals
4. excessive exposure to the sun (leading to sunburn and sun stroke) and to ultraviolet radiation (leading to skin cancers) in outdoor facilities or natural sources.

Hazards vary according to the type of water and the geographical location. Swimming pools may be private (domestic), semi-public (in clubs and hotels and schools) or public (municipal or governmental). The risks also differ between outdoor and indoor pools, for example in the greater possibility of accidents around open pool areas, due to factors such as slippery surfaces around the pool,fewer structures designed to prevent injury or access; and greater access to unsupervised children. There is also a larger potential health risk of chemical exposure in indoor pools. Similarly, recreational use of natural waters includes supervised designated beaches, as well as rural or undeveloped water areas, with a corresponding range of risk. Water sports with particular risks include white-water rafting and canoeing, slalom, water ski-ing and windsurfing. In terms of mortality the most important risks are of drowning or spinal injury, but some of the microbiological hazards are associated with serious illness, such as legionnaires’ disease and some may occur frequently such as diarrhoeal disease caused by Giardia lamblia and Cryptosporidium parvum.

Table 1: Types of hazard associated with recreational waters
(from WHO, 1998; WHO 2000(a))

Hazard	Example
Drowning and near-drowning	For all waters, risk is increased for swimmers under the influence of alcohol or with poor swimming ability; absence of supervision; diving accidents and entrapment. Sea water: caught in tidal and rip currents; cut off by rising tides, caught by submerged obstacles, drifting away from the shore Swimming pools: insufficient supervision of young children or poor swimmers; hair or body parts caught in inlets and outlets, particularly where there is high suction
Injury	Impact against hard surfaces/ sharp objects, e.g. spinal injury after diving accidents or accidents involving broken glass or jagged metal; attack by aquatic animals
Physiological	Chilling, leading to exhaustion, reduced inability to swim or coma in some circumstances; thermal shock; acute exposure to heat or ultra violet radiation; cumulative exposure to sun (skin cancers such as squamous cell carcinoma and melanoma)
Infection	Ingestion, inhalation or contact with pathogenic bacteria, viruses, fungi, protozoa and other parasites, including worms - naturally occurring or the result of faecal contamination by humans or animals; also insect bites and ingestion or exposure to the toxins produced by some species of cyanobacteria (blue green algae)
Poisoning and toxicoses	Ingestion or inhalation of chemical contaminants, including oil slicks; stings by venomous animals e.g. jelly fish and stingrays in seawater; inhalation of chemically contaminated water.
Aesthetic	Revulsion from visible pollution, turbidity, scums or odour

Physical hazards: Drowning, injuries and safety in swimming pools or bathing in natural water bodies

Drowning statistics are not kept consistently in many countries, but studies suggest that the overall annual rate of drowning worldwide is around 6 per 100,000 population (WHO, 2000 (a)) and a major global cause of DALYS (disability adjusted life years) (Table 2). It is one of the leading causes of death in children aged 5-14 (Krug 1999; World Congress on Drowning, 2002) although the death rate is highest in children aged under five years. A child can drown in as little as 5-8 centimetres of water after brief immersion - as little as 30 seconds (WHO, 2000 (a)) and a recent study in the UK reported an increase in drowning incidents in garden ponds (Sibert et al 2002). Infants are more likely to drown in the home, usually in a bathtub; and toddlers more likely to drown in bodies of water close to the home (Brenner 2002). Although there is less information on drowning in data from developing countries, WHO data (Table 3) and available studies suggest that comparable patterns exist in poor nations: for example, 60% of drowning incidents among children aged 1-4 years in a region of Mexico were in underground cisterns close to the home (Celis 1997).

Table 2. Global burden of disease from injuries in disability-adjusted life years (DALYS) for 1999 (WHO, 1999 (a))

Injuries	Both sexes		Males		Females
Population	5 961 628		3 002 288		2 959 340
	No.	% of total	No.	% of total	No.	% of total
Total due to injuries*	201 307	14	132 343	17.6	68 965	10
All unintentional injuries	152 464	10.6	101 190	13.5	51 275	7.5
Drowning only	12 987	0.9	8 583	1.1	4 404	0.6

* Includes intentional (violence, war, suicide) and unintentional injuries (road traffic injuries, poisonings, falls, fires, drowning)

Table 3. Estimated global burden of disease in DALYS for all injuries and for drowning in WHO Regions in 1999 (WHO 1999 (a))

Type of injury†	Africa††	The Americas	Eastern Mediterranean	Europe	South East Asia	Western Pacific
Total injuries	36 103	17 738	13 214	19 323	65 289	49 641
Unintentional injuries	24 526	10 746	10 459	12 894	56 176	37 663
Largest cause of DALYS from unintentional injury	Road traffic accidents	Road traffic accidents	Road traffic accidents	Road traffic accidents	Falls	Road traffic accidents
2nd largest cause of DALYS associated with unintentional injury	Drowning	Falls	Falls	Falls	Road traffic accidents	Falls
3rd largest cause of DALYS associated with unintentional injury	Falls	Drowning	Drowning	Poisoning	Drowning	Drowning
Drowning, DALYS	2 512	735	781	962	3 140	4857
Drowning, % of total injuries	7.0	4.1	5.9	5.0	4.8	10.0

† Data for causes other than drowning omitted from this table
†† Cause of injury ranked in order of number of DALYS: Road traffic injuries, drowning, falls, fires and poisoning. Other unintentional injuries not classified in these groups account for between 1280 DALYS (Eastern Mediterranean) and 6 143 DALYS (SE Asia).

In terms of global burden of disease from injuries, drowning forms only 0.9% of the total (WHO 1999(a)), Table 2) but with a disproportionate worldwide importance to public health, since many of these deaths and injuries are preventable. Injuries are now the leading cause of death of children in the richest nations and the drowning is the second leading cause of injury related death, exceeded only by deaths due to road traffic accidents (UNICEF 2001).

Injury data is more comprehensive for swimming pool use than for bathing in natural water bodies. For example, there are nearly 1000 swimming pool injuries recorded each year in the UK, mostly through falling or bumping into something (WHO, 1996). While most injuries are minor (cuts and bruises; minor head injuries), spinal injury is a recognised risk from swimming and inevitably leads to drowning in some cases. Drowning associated with spinal injury is more common in men and boys, probably related to both greater exposure and higher risk taking. It is not known how many incidents are directly related to inability to swim. In the European region, the estimate of deaths related to drowning is about 28,000 a year, less than 10% of overall accidental deaths (WHO, 1996). Alcohol consumption is an important contributory factor to drowning and other swimming accidents. The wet surfaces around swimming pools can cause injuries, many of which go unreported. The preventive value of interventions is difficult to quantify because of the lack of research or detailed accident data, but measures that have been identified as likely to reduce the physical injuries associated with swimming include:

• Teaching children aged over 5 to swim
• Education - both for children and for adults e.g. in basic life saving techniques;
• Supervision, particularly of infants using bathtubs or external bodies of water;
• Isolation fencing surrounding the pool;
• Warning signs;
• Recommending or supervising time limits for exposure in water, particularly in swimming pools and outdoor bathing areas, to reduce exposure to hazards and to reduce risk of accidents through exhaustion.

Education and supervision appear to be the most important factors but a combination of preventive interventions is needed to reduce the risk of drowning. Teaching more children and adults to swim could increase drowning due to more people swimming and greater risks taken by experienced swimmers; also, legislation and regulations are probably required to ensure appropriate isolation fencing of bathing areas and safe design of paddling pools.

Microbial hazards

The type of infection hazard varies with different water sources and recreational uses. Those associated with freshwater and sea bathing include:

• naturally occurring bacteria or parasites, such Cryptosporidium parvum, Campylobacter pylori, Mycobacterium marinum or Pseudomonas aeroginosa, causing gastrointestinal infection (Campylobacter and Cryptosporidium) or skin infections (Mycobacteria and Pseudomonas). Vibrio cholerae, the cause of cholera, has occasionally been reported after exposure in warm estuarine waters or pools in endemic areas using partially or untreated water. Cyanobacteria in freshwater or seawater can cause skin irritations, and severe health effects if the toxins are ingested.
• microorganisms surviving in human and animal sewage, causing diarrhoeal disease, ear, nose, and throat infections. Shigella sonnei (causing dysentery) and Escherichia coli O157 are examples of bacterial diarrhoeal infections associated with swimming in sewage polluted waters. Viruses linked to swimming pool outbreaks include adenoviruses, Hepatitis A, Norwalk-like virus and echovirus and are also likely to be important in coastal and freshwater.

While ear, nose and throat infections are generally viral in origin, skin infections include bacterial infection with Pseudomonas aeroginosa and Mycobacterium marinum. Skin irritation may also result from chemical irritation such as from agents used to disinfect water in pools (e.g. bromine) or from industrial pollution, although there is no convincing research evidence as yet to indicate that the latter is a significant hazard. Studies of seawater bathing suggest that the risk of major infection is very uncommon, but that the risk of minor infection is related to the degree of microbial contamination. Unusual risks include poisoning from the venom of jellyfish, eels and some fish species. Freshwater sources such as lakes and rivers carry a higher risk of infection, including leptospirosis, schistosomiasis and micro-organisms from human or animal waste. A mild form of schistosomiasis is one of the causes of ‘swimmers’ itch’ in areas where snails are vectors for this infection.

In swimming pools, the infection risk is related to several factors:

• the quality of the water source
• pool design, including drainage and filters;
• operation and maintenance;
• the type of water treatment or disinfection
• the age, health and hygiene behaviour of people using the pool;
• the duration of use each day and number of bathers. .

In any pool with concentrated bather loads, pollution is likely to be high and the operation and maintenance should allow for this. The load is greater in the shallow part of pools with variable depths, and this is also likely to be the part most used by very young children. Contamination of the water by urine or faeces may occur in these areas or in toddler pools. Gross faecal contamination of a pool cannot be controlled by disinfection and outbreaks of cryptosporidiosis and other diarrhoeal infections have been attributed to such faecal accidents. Control of hazards requires a risk-benefit approach taking account of all the factors and balancing the benefits of swimming against the operation and maintenance costs. The risk benefit varies according to the local and national economic development. Poor pool maintenance in tourist areas may have a serious economic impact if tourists become ill with infections such as Cryptosporidium, or Vibrio cholerae in pools using estuarine water (Stanwell-Smith & O'Brien, 1998).

Chemical hazards

Chemicals found in swimming pool water include disinfectants used in water treatment and their by-products produced by reaction with organic and inorganic material in the water. Swimmers may also introduce chemicals, such as soap residues, cosmetics, suntan oil, sweat and urine. Chemical disinfectants used in swimming pools include chlorine, ozone, bromine, iodine and various combinations or other products, of which the commonest is chlorine. Chlorine and bromine form trihalomethanes (THMs) and other by-products. THMs, such as chloroform cause concern because they are volatile and may vaporise above the water, where swimmers may inhale the vapour. There is concern about the possible long-term toxicological effects of these compounds. While the adverse effects of ingesting disinfectants in drinking water are well documented (WHO, 2000b), much less is known about the effects of inhalation or skin contact. Chloramines in pool water may irritate the conjunctiva of the eye and the mucous membranes of the nose and throat. Incidents due to fumes from excess chlorine disinfection are rare: for example less than 15 people are affected annually in the UK, including staff as well as users (Pool Water Treatment Advisory Group 1999). ‘Swimmers' itch’ may be infectious or chemical in origin. The risk of skin irritation is much higher in bromine pools than in those disinfected with chlorine. Spas and hot tubs are associated with particular risks, covered in the next section.

SPRINGS & SPAS: the long tradition of using water for pleasure and health

Waters with a reputation for health giving properties are found all over the world. The word ‘spa’, meaning mineral water, comes from Belgian resort of Spa. The term now includes hot tubs, whirlpools and mineral baths drawn from natural springs. Hydrotherapy pools, and other warm pools used primarily for medical purposes, draw on long established experience of the beneficial effects of water treatment. Since ancient times, drinking or bathing in mineral waters has been reputed to cure a variety of illnesses, including heart diseases, joint disorders, respiratory inflammation and kidney stones. While there have been few scientific studies of these postulated effects, there is no doubt of the benefits of warm water therapy in pain relief, joint mobility and relaxation. Naturally occurring hot springs were particularly valued in colder climates, for example the springs developed by the ancient Romans in Europe. The Baden-Baden springs in Germany, developed by the Romans as Aquae Aureliae, are the hottest in Europe and like most other thermal springs, are slightly radioactive. In many of the springs in Central and Eastern Europe, the ritual of combining cold, warm and hot baths for health has survived almost unchanged. In North America, native Americans believed in the curative effects of hot springs: one spring that became a famous spa, Saratoga, derives from the Mohawk word meaning “the place of the medicine waters of the great spirit.” Religion played a part in establishing the use of spas. The thermal baths in Budapest were developed during the Ottaman rule of Hungary: the inspiration was the Islamic tradition of cleanliness.

The health hazards of spas

Spas, hot tubs and whirlpools may not be drained, cleaned or refilled after each use. The health hazards associated with their use include those associated with swimming pools, although the high temperatures in some types of spas exacerbate the effects of alcohol or drugs and the risk of drowning may be enhanced by the lack of transparency in coloured or turbid spa waters. While deaths are rare, most have been associated with the combination of high water temperature and use of alcohol or drugs. The resulting drowsiness increases the risk of drowning. In the USA, 67% of all drownings occur in spas, hot tubs and back yard pools (WHO, 2000 (a)). Of 700 deaths in spas and hot tubs recorded in the USA since 1980, a third were children under five years of age, emphasising the importance of supervision of children playing with water. The high bather load and high turnover rate of users in many spas and whirlpools pose an infection risk, including microorganisms from the bathers and those present in the water. The warm, nutrient containing, aerobic water provides an ideal environment for many organisms, such as Legionella pneumophila, the cause of legionellosis (legionnaires’ disease) and Pseudomonas aerugionosa, which causes folliculitis, an infection of the hair follicles associated with an itchy rash. Natural hot spas may contain a species of amoeba that can cause meningitis (Acanthamoeba): cases have been reported after swimming in natural spas or exposure to fountains in warm climates. Infections of the ear (otitis externa), urinary tract, respiratory tract, eye and wounds have also been linked to spas. These infections are difficult to control and require frequent monitoring of the pH (degree of acidity/ alkalinity) of the water, disinfection and filtration. Water treatment may present chemical hazards unless the chemical disinfection is well managed. There is also a risk of accidents around spas due to slips, trips and falls: bathers may also pick up fungal and other infections from the wet surfaces.

WHO activities and safe recreational environments

Water has been used for positive health for millennia, and recreational use is not just a luxury. It provides opportunities for physical exercise, rest and pleasure, all fundamental components of the well being essential to health. Health aspects of the recreational use of the water environment have attracted increasing attention by members of the public, concerned professionals and regulatory agencies. The WHO programme on water, sanitation and health includes development of guidelines for safe recreational water environments for coastal, freshwaters, swimming pools and spas (WHO 1998, 2000 (a)); and a manual on the monitoring and assessment of bathing waters, including a code of good practice agreed with the European Commission (Bartram and Rees 1999). In 1998, a meeting between the WHO and USEPA (United States Environmental Protection Agency) produced the Annapolis Protocol (WHO 1999 (b)). This acknowledged the limitations in establishing ways of monitoring recreational water quality and the need to agree possible alternative approaches, with particular emphasis on the control of microbiological hazards.

The mineral content of ‘spa’ water and its effects

Natural mineral and spa waters collect their constituents as they filter through rock strata, such as calcium from limestone strata or magnesium from dolomites. Iron may be present in suspension. Minor elements include fluoride and several other trace elements. The mineral content is usually higher in warmer waters. Waters from volcanic sources may contain high concentrations of sodium and bicarbonates, giving them a natural effervescence.

The main difference between ‘mineral’ and ‘spring’ water is that no therapeutic claims are made for the latter, although a water does not have to have a therapeutic claim to be described as ‘mineral’. Microbiological quality control is required for both. The standards for microbiological purity and frequency of testing are usually less strict than for mains supplied water. The waters may be alkaline (pH above 7) or acid. Mineral waters are, by definition, bottled at source without treatment, except filtration, but their production is strictly regulated. Some mineral waters have marked effects on the gastrointestinal tract, often acting like a laxative. Bottled mineral water may be preferred for taste and supposed health benefits. This links back to the spa/mineral-water tradition, but is also determined by fashion. Bottled water consumption is rapidly increasing in many countries, for example reported as up by 35% in Thailand in 2001 (Watertech Online 2001). This has raised concerns, not least for the environment and cost: tap water is often as good as bottled water and costs up to 1,000 times less (Ferrier, 2001): domestic treatment of water (for example by chlorinating, boiling or Sodis) is the recommended option where supplies are unreliable and for people on low incomes.

Further information:

Bartram J, Rees G (eds). Monitoring Bathing Waters: a practical guide to the design and implementation of assessments and monitoring programmes. Published on behalf of the WHO. E& FN Spon, UK: 1999

Brenner RA. Childhood drowning is a global concern. Editorial. British Medical Journal 2002; 324: 1049-50

Celis A. Home drowning among preschool age Mexican children. Inj Prev 1997;3:252-6

Curtis V. Talking Dirty: How to Save a million lives without mentioning health. Abstract from presentation at IFH conference Home Hygiene and the prevention of disease in developing countries April 2002 (www.ifh-homehygiene.org )

Ecologically Sustainable Development (ESD) Working Group on Tourism. Ecologically Sustainable Development Working Groups: Final Report -Tourism. Canberra, Australia: AGPS, 1991

Ferrier C. Bottled water: understanding a social phenomenon. World Wide Fund for Nature (WWF) Discussion paper 26, p24 (http://www.panda.org/livingwaters/pubs/bottled_water.pdf)

Hartley D. Water in England. London: Macdonald and James, 1978

Krug E. ed. Injury: a leading cause of the global burden of disease. Geneva: WHO, 1999, www.who.int/violence_injury_prevention/pdf/injuryburden.pdf

Mineral/ spa waters:
WHO Fact Sheet No. 256. Bottled Drinking Water. Geneva: WHO, October 2000. http://www.who.int/inf -fs/en/fact256.html
Codex Standard for Natural Mineral Waters and Code of Practice: http:/www.fao.org/WAICENT/FAOINO/ECONOMIC/ESN/codex
Green T, Green M. The Good Water Guide. Rosendale Press: London, 1985
Public Health Laboratory Service. Hygiene for spa pools. London, UK: PHLS, 1994
Source Weekly special features edition covering bottled water: ‘Battle boils up over boom in bottled water’. 18 October 2001, http://www.irc.nl/source/bulletin/sb19.html#battlebo;

Pool water treatment advisory group. Swimming pool water treatment and quality standards. LREO Books Ltd, Holly Lodge, Botesdale, Diss, Norfolk IP22, UK, 1999

Public Health Laboratory Service. Hygiene for hydrotherapy pools. London, UK: PHLS, 1999

Read, Sturgess and Associates. Evaluation of economic values of water for the Thomson catchment. Report prepared for Melbourne Water, cited in http://www.erin.gov.au/life/general_info/op1.html

Sibert JR, Lyons RA, Smith BA, Cornall P, Summer B, Craven MA et al. Preventing deaths by drowning in the United Kingdom: have we made progress in 10 years? British Medical Journal 2002; 324: 1070-1

Stanwell-Smith R, O'Brien S. Cholera in tourists returning from Kenya. Eurobulletin 1998;2:0416 (eurowkly@eurosurv.org or http://www.eurosurv.org)

Unicef. A league table of child deaths by injury in rich nations. Florence, Unicef Innocenti Research Centre, 2001.

United Nations Population Division, 2000. World Population Nearing 6 Billion Projected Close to 9 Billion by 2050. New York, United Nations Population Division, Department of Economic and Social Affairs (Internet communication of 21 September 2000 at web site http://www.popin.org/pop1998/1.htm).

Wechsberg J. The lost world of the great spas. New York: Harper & Row, 1979

World Congress on Drowning http://www.drowning.nl/csi/drowning.nsf/index/home. (June 2002)

WHO 1996. World Health Statistics 1995. WHO: Geneva, 1996

WHO 1998. Guidelines for safe recreational water environments. Coastal and fresh-waters (Draft for consultation). WHO: Geneva, 1998

WHO 1999(a). Statistics on International Injury by cause and sex, 1999; International Injury in WHO Region, 1999. Geneva: WHO, 1999

WHO 1999(b). (Annapolis Protocol). Health based monitoring of recreational waters: the feasibility of a new approach. Geneva: WHO/SDE/WSH99.1, 1999

WHO 2000 (a). Guidelines for safe recreational water environments. Swimming pools, spas and similar recreational-water environments (Draft for consultation) WHO: Geneva, November 2000

WHO 2000 (b). Disinfectants and disinfectant by-products. Environmental Health Criteria 216, WHO: Geneva, 2000

WHO, 2000 (c). The world health report 2000 - Health systems: Improving performance. Geneva, World Health Organization, 2000.

The views expressed in documents by named authors are solely the responsibility of those authors.

Prepared for World Water Day. Written by Dr. Rosalind Stanwell Smith, and reviewed by the Injuries and Violence Programme (VIP) and the Water, Sanitation and Health Programme (WSH), World Health Organization (WHO), Geneva

WHO/WSH/WWD/TA.5
June 2002