Water

:This article focuses on water as it is experienced in everyday life. See water (molecule) for information on the chemical and physical properties of pure water (H2O, hydrogen oxide).

Water in everyday life

All known forms of life depend on water. Water is a vital part of many metabolic processes within the body. Significant quantities of water are used during the digestion of food. (Note however that some bacteria and plant seeds can enter a cryptobiotic state for an indefinite period when dehydrated, and come back to life when returned to a wet environment)

Related Topics:
Metabolic - Digestion - Bacteria - Plant - Seed - Cryptobiotic state

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About 72% of the fat free mass of the human body is made of water. To function properly the body requires between one and seven litres of water per day to avoid dehydration, the precise amount depending on the level of activity, temperature, humidity, and other factors. It is not clear how much water intake is needed by healthy people. However, for those who do not have kidney problems, it is rather difficult to drink too much water, but (especially in warm humid weather and while exercising) dangerous to drink too little. People do often drink far more water than necessary while exercising, however, putting them at risk of water intoxication, which is frequently fatal. The "fact" that a person should consume eight glasses of water per day cannot be traced back to a scientific source. However, leading dieticians and nutritionists will tell you that this is the RDI (Recommended Daily Intake) of water. http://ajpregu.physiology.org/cgi/content/full/283/5/R993. The latest dietary reference intake report by the National Research Council recommended 2.7 liters of water total (including food sources) for women and 3.7 liters for menhttp://www.iom.edu/report.asp?id=18495. Water is lost from the body in urine and feces, through sweating, and by exhalation of water vapor in the breath.

Related Topics:
Human - Litre - Day - Dehydration - Water intoxication - National Research Council - Liters - Urine - Feces - Sweat - Vapor

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Humans require water that does not contain too much salt or other impurities. Common impurities include chemicals and/or harmful bacteria, such as crypto sporidium. Some solutes are acceptable and even desirable for perceived taste enhancement and to provide needed electrolytes.

Related Topics:
Bacteria - Electrolytes

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A rare resource

:See water resources for information about fresh water supplies.

Related Topics:
Water resources - Fresh water

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Because of the growth of world population and other factors, the availability of drinking water per person is shrinking. This issue can be solved through more production, better distribution and through less waste. For this reason, water is a strategic resource for many countries. Many battles and wars, such as the Six-Day War in the Middle East, have been fought to gain access to it. Experts predict more trouble ahead because of the world's growing population, increasing contamination through pollution, and global warming.

Related Topics:
World population - Six-Day War - Middle East - Pollution - Global warming

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UNESCO's World Water Development Report (WWDR, 2003) from its World Water Assessment Program indicates that, in the next 20 years, the quantity of water available to everyone is predicted to decrease by 30%. 40% of the world's inhabitants currently have insufficient fresh water for minimal hygiene. More than 2.2 million people died in 2000 from diseases related to the consumption of contaminated water or drought. In 2004, the UK charity WaterAid reported that a child dies every 15 seconds due to easily preventable water-related diseases.

Related Topics:
UNESCO - Hygiene - 2000 - Disease - Drought - UK - Charity - WaterAid

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Some have predicted that clean water will become the "next oil", making Canada, with this resource in abundance, possibly the richest country in the world.

Related Topics:
Oil - Canada

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Water for everyone

Drinking water is often collected at springs or extracted from artificial borings in the ground, or wells. Building more wells in adequate places is thus a possible way to produce more water assuming the aquifers can supply an adequate flow. Other water sources are the rainwater and river or lake water. This surface water, however, must be purified for human consumption. Popular methods for purifying water are filtering, boiling and distillation. More advanced techniques exist, such as reverse osmosis. Desalination of abundant ocean or seawater is a more expensive solution used in coastal arid climates.

Related Topics:
Springs - Boring - Well - Aquifer - Purified - Filtering - Boiling - Distillation - Reverse osmosis - Desalination - Ocean - Seawater - Arid - Climate

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The distribution of drinking water is done through municipal water systems or as bottled water. Governments in many countries have programs to distribute water to the needy at no charge. Others argue that the market mechanism and free enterprise are best to manage this rare resource, and to finance the boring of wells or the construction of dams and reservoirs.

Related Topics:
Municipal water system - Bottled water - Market - Free enterprise - Dam - Reservoir

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Reducing waste, that is using drinking water only for human consumption, is another option. In some cities, such as Hong Kong, sea water is extensively used for flushing toilets citywide in order to conserve fresh water resources. Polluting water may be the biggest single misuse of water; to the extent that a pollutant limits other uses of the water, it becomes a waste of the resource, regardless of benefits to the polluter. Pharmaceuticals consumed by humans often end up in the waterways and can have detrimental effects on aquatic life if they bioaccumulate and if they are not biodegradable.

Related Topics:
Hong Kong - Polluting water - Pharmaceuticals - Aquatic - Bioaccumulate - Biodegradable

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