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, and Water (disambiguation) for other meanings. |
Impact of a drop of water. |
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Water in Lake Huron, a freshwater lake between the United States and Canada. |
Water (in its pure form) is a
tasteless,
odorless substance that is essential to all known forms of
life, is known as the
universal solvent, and is the main
natural resource said to be affected by
Global Warming. It appears
colorless to the naked eye in small quantities, though it can be seen to be
blue in large quantities or with scientific instruments.
[The Color of Water: Visibility Under Water] An abundant substance on
Earth (the
UN Environment Program estimates there are 1400 million cubic kilometers
[http://www.unep.org/vitalwater/01.htm of it]), water exists in many forms. It appears mostly in the
oceans, (saltwater) and polar
ice caps, but also as
clouds,
rain water,
rivers, freshwater
aquifers, and
sea ice. Water in these bodies continuously moves through a
cycle of
evaporation,
precipitation, and
runoff to the
sea. Clean water is
essential to human health and in many parts of the world it is in short supply. Although mostly found on Earth, it can also be found on the moons
Europa and
Enceladus.
Thales of Miletus, an early Greek philosopher, known for his analysis of the scope and nature of the term "
landscaping," believed that "all is water."
The word "water" comes from the
Old English wæter. The word is derived from the
Proto-Indo-European language root *wod-or with other forms including
*ud- and
*wed-; the source of the word
wet. This root is the source for words about water in many
European language c.f
German "Wasser",
Latvian "Å«dens" or
Russian "вода" (
voda).
[The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.]Water has the
chemical formula H2O meaning that one
molecule of water is composed of two
hydrogen atoms and one
oxygen atom. It can also be described ionically as HOH, with a hydrogen
ion (H
+) that is bonded to a
hydroxide ion (OH
-). It is in
dynamic equilibrium between the
liquid and
vapor states at
standard temperature and pressure. At
room temperature, it is a nearly
colorless,
tasteless, and
odorless liquid. It is often referred to in the sciences as
the universal solvent and the only pure substance found naturally in all three
states of matter.
Color
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Iron-rich rocks have turned this river red. |
Water strongly absorbs
infrared radiation. As infrared radiation is next to red-colored light on the
EM spectrum, a small amount of visible red light is absorbed as well. This results in
pure water appearing slightly blue, when seen in mass quantities such as a lake or ocean. The blue color can easily be seen as one sees the blue color of the sea or a clear lake under an overcast sky, which means that it is not a reflection of the blue sky.
In
practice, the color of water can vary strongly, depending on impurities.
Limestone turns bodies of water turquoise, while
iron compounds turn it red/brown and
copper compounds create an intense blue.
Algae commonly colors water green.
Solvation
Water is a very good
solvent, dissolving many types of substances. The substances that will mix well and dissolve in water (e.g.
salts) are known as "
hydrophilic" (water-loving) substances, and those that do not mix well with water (e.g.
fats and oils), are known as "
hydrophobic" (water-fearing) substances. Whether or not a substance dissolves or not is decided by whether or not the substance can match or better the strong
attractive forces that water molecules generate between themselves. If they cannot, the molecules are "
pushed out" from amongst the water, and do not dissolve. Substances dissolved in water are referred to as "aqueous".
Cohesion and adhesion
Water sticks to itself (
cohesion) because it is
polar, meaning one end of the molecule has slightly more negative charge than another (and vice-versa). In water, this happens because the oxygen atom is more
electronegative - that is, it has a stronger "
pulling power" on the molecule's
electrons, drawing them closer (along with their negative charge), and making the area around the oxygen atom more negative than the area around both the hydrogen atoms.
Due to the polar nature of water, it is also very good at sticking to other things (
adhesion).
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This daisy is under the water level, which has risen gently and smoothly. Surface tension prevents the water from submerging the flower. |
Surface tension
Water has a high
surface tension caused by the strong cohesion between water molecules. This can be seen when small quantities of water are put onto a nonsoluble surface such as
polythene: the water stays together as drops. On extremely clean
glass the water may form a thin film because the molecular forces between glass and water molecules (adhesive forces) are stronger than the cohesive forces.
In biological cells and
organelles, water is in contact with membrane and protein surfaces that are
hydrophilic, that is, surfaces that have a strong attraction to water.
Irving Langmuir observed a strong repulsive force between hydrophilic surfaces. To dehydrate hydrophilic surfacesâ€"to remove the strongly held layers of water of hydrationâ€"requires doing substantial work against these forces, called hydration forces. These forces are very large, but decrease rapidly over a nanometer or less. Their importance in biology has been extensively studied by
V. Adrian Parsegian of the
NIH.
[ Physical Forces Organizing Biomolecules (PDF)] They are particularly important when cells are dehydrated by exposure to dry atmospheres or to extracellular freezing.
Capillary action
Capillary action refers to the process of water moving up a narrow tube against the force of
gravity. It occurs because water adheres to the sides of the tube, and then more water is pulled on top of that water due to cohesion, which sticks to the sides of the tube. The process is repeated as the water flows up the tube until there is enough water that gravity can counteract the adhesive force.
Heat capacity and heat of vaporization
Water also has the second highest
specific heat capacity of any known chemical compound, as well as a high
heat of vaporization (40.65 kJ/mol), both due to the extensive
hydrogen bonding between its molecules. These two unusual properties allows water to moderate Earth's
climate by buffering large swings in temperature.
Water's freezing point anomaly
A simple but environmentally important and unique property of water is that its common solid form,
ice, floats on its liquid form. This solid phase is not as dense as liquid water, due to the geometry of the strong hydrogen bonds which are formed only at lower temperatures. For almost all other substances and for all other 11 uncommon phases of water ice except ice-XI, the solid form is denser than the liquid form. Fresh water at standard atmospheric pressure is most dense at 3.98 °C, and will sink by
convection as it cools to that temperature, and if it becomes colder it will rise instead. This reversal will cause deep water to remain warmer than shallower freezing water, so that ice in a body of water will form first at the surface and progress downward, while the majority of the water underneath will hold a constant 4 °C. This effectively insulates a lake floor from the cold. While this behavior may seem obvious, even intuitive, it should be noted that almost all other chemicals are denser as solids than they are as liquids, and freeze from the bottom up.
Electrical conductivity
A common misconception about water is that it is a powerful conductor of
electricity, with risks of
electrocution explaining this popular belief. Any electrical properties observable in water are due to the
ions of mineral salts and
carbon dioxide dissolved in it.
Water does self-ionize where two water molecules become one
hydroxide anion and one
hydronium cation, but not enough to carry enough
electric current to do any work or harm for most operations. Pure water can also be
electrolyzed into oxygen and hydrogen gases but without any dissolved ions, this is a very slow process and thus very little current is conducted. The taste advertised in
spring water or
mineral water derives from the minerals present, while pure H
2O is tasteless. As such,
purity in spring and mineral water refers to purity from
toxins,
pollutants, and
microbes.
Forms of water
Water takes many different forms on Earth:
water vapor and
clouds in the sky,
waves and
icebergs in the
sea,
glaciers and
rivers in the
mountains,
aquifers in the ground, to name but a few. Through
evaporation,
precipitation, and
runoff, water is continuously flowing from one form to another, in what is called the
water cycle.
Because of the importance of precipitation to
agriculture, and to
mankind in general, different names are given to its various forms: while
rain is common in most countries, other phenomena are quite surprising when seen for the first time.
Hail,
snow,
fog or
dew are examples. When appropriately lit, water drops in the air can
refract sunlight to produce
rainbows.
Similarly, water runoffs have played major roles in human history as
rivers and
irrigation brought the water needed for agriculture. Rivers and
seas offered opportunity for
travel and
commerce. Through
erosion, runoffs played a major part in shaping the environment providing river
valleys and
deltas which provide rich soil and level ground for the establishment of population centers.
Water also infiltrates the ground and goes into
aquifers. This
groundwater later flows back to the surface in
springs, or more spectacularly in
hot springs and
geysers. Groundwater is also extracted artificially in
wells.
Because water can contain many different substances, it can taste or smell very differently. In fact, humans and other animals have developed their senses to be able to evaluate the drinkability of water: animals generally dislike the taste of
salty
sea water and the putrid
swamps and favor the purer water of a mountain spring or aquifer.
 |
Over two thirds of the earth's surface is covered with water, 97.2% of which is contained in the five oceans. The Antarctic ice sheet, containing 90% of all fresh water on the planet, is visible at the bottom. Atmospheric water vapor can be seen as clouds, contributing to the earth's albedo. |
Scientists theorize that most of the universe's water is produced as a byproduct of star formation. Gary Melnick, a scientist at the
Harvard-Smithsonian Center for Astrophysics, explains: "For reasons that aren't entirely understood, when stars are born, their birth is accompanied by a strong outward wind of gas and dust. When this outflowing material eventually impacts the surrounding gas, the shock waves that are created compress and heat the gas. The water we observe is rapidly produced in this warm dense gas."
[ ]The coexistence of the solid, liquid, and gaseous phases of water on Earth is vital to existence of life on Earth. However, if the Earth's location in the
solar system were even marginally closer to or further from the
Sun (ie, a million miles or so), the conditions which allow the three forms to be present simultaneously would be far less likely to exist.
Earth's mass allows
gravity to hold an
atmosphere.
Water vapor and
carbon dioxide in the atmosphere provide a
greenhouse effect which helps maintain a relatively steady surface temperature. If Earth were less massive, a thinner atmosphere would cause temperature extremes preventing the accumulation of water except in
polar ice caps (as on
Mars).
The distance between Earth and the Sun, the combination of solar radiation received and the greenhouse effect of the atmosphere ensure that Earth's surface is neither too cold nor too hot for liquid water. If Earth were more distant from the Sun, most water would be frozen. If Earth were nearer to the Sun, its higher surface temperature would limit the formation of ice caps, or cause water to exist only as vapor.
It has been proposed that life itself may maintain the conditions that have allowed its continued existence. The surface temperature of Earth has been relatively constant through
geologic time despite varying levels of incoming solar radiation (
insolation), indicating that a dynamic process governs Earth's temperature via a combination of greenhouse gases and surface or atmospheric
albedo. This proposal is known as the
Gaia hypothesis.
 |
A lion drinking water. |
From a
biological standpoint, water has many distinct properties that are critical for the proliferation of
life that set it apart from other substances. It carries out this role by allowing
organic compounds to react in ways that ultimately allows
replication. All known forms of life depend on water. Water is both vital as a
solvent in which many of the bodies solutes dissolve, and an essential part of many
metabolic processes within the body (e.g. significant quantities of water are used during the
digestion of food).
Fresh water has its greatest
density under normal atmospheric pressure at 4 °
C, then becoming less dense as it
freezes or
heats up from this point - the only reason bodies of water do not freeze all the way through (which would kill all the organisms within it). As a stable,
polar molecule prevalent in the atmosphere, it plays an important role as a
greenhouse gas absorbing
infrared radiation, without which, Earth's average surface temperature would be -18 °C.
Life forms that live in water
Earth's waters are filled with life.
Fish live exclusively in water, and there are many types of marine mammals, such as
dolphins and
whales that also live in the water. Some types of animal, such as
amphibians spend portions of their lives in water, and portions on land. Plants such as
kelp and
algae grow in the water, and are the basis for some underwater ecosystems.
Plankton, however, is generally the foundation of the ocean food chain.
Different water creatures have found different solutions to obtaining oxygen in the water. Fish have
gills instead of
lungs, though some species of fish, such as the
lungfish have both.
Marine mammals, such as dolphins, whales,
otters, and
seals need to surface periodically to breath from the air.
Civilization has historically flourished around rivers and major waterways;
Mesopotamia, the so-called cradle of civilization, was situated between the major rivers
Tigris and
Euphrates. Large
metropolises like
London,
Montreal,
Paris,
New York, and
Tokyo owe their success in part to their easy accessibility via water and the resultant expansion of trade. Islands with safe water ports, like
Singapore and
Hong Kong, have flourished for precisely this reason. In places such as
North Africa and the
Middle East, where water is scarcer, access to clean drinking water was and is a major factor in human development.
Human uses of water
 |
Water pressure in a sprinkler. |
Humans use water in typically three variety of ways.
For drinking - 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 depends on the level of activity, temperature, humidity, and other factors. Most of this is ingested through foods or beverages other than drinking straight water (hot tea being often used in deserts to avoid dehydration, etc.) 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 can drink far more water than necessary while exercising, however, putting them at risk of
water intoxication, which can be fatal. The "fact" that a person should consume eight glasses of water per day cannot be traced back to a scientific source.
[ "Drink at least eight glasses of water a day." Really? Is there scientific evidence for "8 × 8"? by Heinz Valdin, Department of Physiology, Dartmouth Medical School, Lebanon, New Hampshire ] There are other myths such as the effect of water on weight loss and constipation that have been dispelled.
[ Drinking Water - How Much?, Factsmart.org web site and references within ] |
A shower, used to wash the human body. |
The latest dietary reference intake report by the US
National Research Council recommended (including food sources): 2.7 liters of water total for women and 3.7 liters for men.
[ Dietary Reference Intakes: Water, Potassium, Sodium, Chloride, and Sulfate, Food and Nutrition Board] Water is lost from the body in
urine and
feces, through
sweating, and by exhalation of
water vapor in the breath.
Humans require water that does not contain too many impurities. Common impurities include metal salts and/or harmful
bacteria, such as
vibrio. Some solutes are acceptable and even desirable for perceived taste enhancement and to provide needed
electrolytes.
As a solvent - Water is a good solvent,
dissolving (or
suspending) is used to wash everything from the human body, clothes, floors, cars, food, pets, and just about anything and everything in between. Sometimes water is not enough, and many chemicals can be added in order to improve the solvating power of water. These chemicals include soap, shampoo, alcohol, vinegar and various surfectants; these are all examples of
emulsifying agents. When water will not do (eg removing a none water-soluble substance such as paint), other solvents are used, such as
ethanol (in meths) or
acetone (in nailvarnish remover).
As a thermal transferrer - Boiling, steaming, and simmering are popular cooking methods that often require immersing food in water or its gaseous state, steam. Water is also used in industrial contexts, as a coolant during
metallurgy, and in almost all powerstations as a coolant and to drive steam turbines to generate electricty. In the nuclear industry, water can also be used as a
neutron moderator.
Recreational use of water
Humans use water for many recreational purposes, and for exercise, and in many sports. Some of these include
swimming,
waterskiing,
boating,
ice skating,
skiing,
fishing, and
diving. In addition, some sports, like
hockey, are played on ice.
Lakesides and beaches are popular places for people to go to relax and enjoy recreation.
Health and pollution
Water fit for
human consumption is called
drinking water or "potable water". Water that is not specifically made for drinking, but is not harmful for humans when used for food preparation is called
safe water.
This natural resource is becoming scarcer in certain places, and its availability is a major social and economic concern.
Currently, about 1 billion people around the world routinely drink unhealthy water. Most countries have accepted the goal of halving by 2015 the number of people worldwide who do not have access to
safe water and
sanitation during the
2003 G8 Evian summit.
[ G8 "Action plan" decided upon at the 2003 Evian summit ] Even if this difficult goal is met, it will still leave more than an estimated half a billion people without access to safe drinking water supplies and over 1 billion without access to adequate sanitation facilities. Poor water quality and bad sanitation are killers; some 5 million deaths a year are caused by polluted drinking water.
That is hardly surprising, since in the developing world, 90% of all wastewater still goes untreated into local rivers and streams. Some 50 countries, with roughly a third of the world's population, also suffer from medium or high water stress, and 17 of these extract more water annually than is recharged through their natural water cycles . The strain affects surface freshwater bodies like rivers and lakes, but it also degrades groundwater resources.
See water resources for information about fresh water supplies; see also Category:Water and politics for articles treating about water politicsBecause of
overpopulation in many regions of the world,
mass consumption and
water pollution, the availability of
drinking water per capita is inadequate and shrinking as of the year 2006. For this reason, water is a strategic resource in the globe, and an important element in many political conflicts. 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. There is a long history of conflict over water, including efforts to gain access to water, the use of water in wars started for other reasons, and tensions over shortages and control.
[ A Chronology of Water-Related Conflicts ] 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. Fresh water, now more precious than ever in our history for its extensive use in agriculture, high-tech manufacturing, and energy production, is increasingly receiving attention as a resource requiring better management and sustainable use.
Water in the OECD countries
With nearly 2,000
cubic metres of water per person and per year, the
United States leads the world in water consumption per capita (a large quantity of
golf fields and
car washing partly explain this massive consumption). In the Organization for Economic Co-operation and Development (
OECD) countries, the U.S. comes first for water consumption, then Canada with 1,600 cubic metres of water per person per year, which is about twice the amount of water used by the average person from
France, three times as much as the average
German, and almost eight times as much as the average
Dane. Since 1980, overall water use in Canada has increased by 25.7%. This is five times higher than the overall OECD increase of 4.5%. In contrast, nine OECD nations were able to decrease their overall water use since 1980 (
Sweden, the
Netherlands, the United States, the
United Kingdom, the
Czech Republic,
Luxembourg,
Poland,
Finland and Denmark).
[ Water consumption indicator in the OECD countries ] [ ]Ninety-five percent of the United States' fresh water is underground. One crucial source is a huge underground reservoir, the 800-mile (1,300 km)
Ogallala aquifer which stretches from
Texas to
South Dakota and waters one fifth of U.S. irrigated land. Formed over millions of years, the Ogallala aquifer has since been cut off from its original natural sources. It is being depleted at a rate of 12 billion cubic metres a year, amounting to a total depletion to date of a volume equal to the annual flow of 18
Colorado Rivers. Some estimates say it will dry up in as little as 25 years. Many farmers in the
Texas High Plains, which rely particularly on the underground source, are now turning away from
irrigated agriculture as they become aware of the hazards of overpumping.
[ ]Water in Mexico
In
Mexico City, an estimated 40% of the city's water is lost through leaky pipes built at the turn of the 20th century. Many people advise that it is not safe to drink.
[ ]Water in the Middle East
The
Middle East region has only 1% of the world's available fresh water, which is shared between 5% of the world's population. Thus, in this region, water is an important strategic resource. By 2025, it is predicted that the countries of the Arabian peninsula will be using more than double the amount of water naturally available to them.
[ ] According to a report by the
Arab League, two-thirds of Arab countries have less than 1,000 cubic meters water per person per year, which is considered the limit.
[ "Major aspects of scarce water resources management with reference to the Arab countries", Arab League report published for the International Conference on water gestion and water politics in arid zones, in Amman, Jordan, December 1-3, 1999. Quoted by French journalist Christian Chesnot in - French original version freely available here. Compare with the 1,600 cubic meters of water used per person and per year in Canada, for example ]Jordan, for example, has little water and
dams in other countries have reduced its available water over the years. The
1994 Israel-Jordan Treaty of Peace stated that Israel would give 50 million cubic meters of water per year to Jordan, which it refused to do in 1999 before backtracking. The 1994 treaty stated that the two countries would cooperate in order to allow Jordan better access to water resources, notably through dams on the
Yarmouk River.
[ See 1994 Israel-Jordan Treaty of Peace, annex II, article II, first paragraph ] Confronted by this lack of water, Jordan is preparing new techniques to use non-conventional water resources, such as second-hand use of irrigation water and desalinization techniques, which are very costly and are not yet used. A desalinization project will soon be started in
Hisban, south of
Amman. The
Disi groundwater project, in the south of Jordan, will cost at least $250 million to bring out water. Along with the
Unity Dam on the Yarmouk River, it is one of Jordan's largest strategic projects. Born in 1987, the "Unity Dam" would involve both Jordan and
Syria. This "Unity Dam" still has not been implemented because of
Israel's opposition, Jordan and Syrian conflictual relations and refusal of world investors. However, Jordan's reconciliation with Syria following the death of
King Hussein represents the removal of one of the project's greatest obstacles.
[ See Christian Chesnot in - French original version freely available here. ]Both
Israel and Jordan rely on the
Jordan River, but Israel controls it, as well as 9/10 of the water resources in the region. Water is also an important issue in the
conflict with the Palestinians - indeed, according to former Israeli prime minister
Ariel Sharon quoted by Abel Darwish in the BBC, it was one of the causes of the
1967 Six-Day War. In practise the access to water has been a
casus belli for Israel. The
Israeli army prohibits
Palestinians from pumping water, and
settlers use much more advanced pumping equipment. Palestinians complain of a lack of access to water in the region.
[ ] Israelis in the
West Bank use four times as much water as their Palestinian neighbours.
[ ] According to the
World Bank, 90% of the West Bank's water is used by Israelis
. Article 40 of the appendix B of the
September 28,
1995 Oslo accords stated that "Israel recognizes Palestinians' rights on water in the West Bank".
The
Golan Heights provide 770 million cubic meters of water per year to Israel, which represents a third of its annual consumption. The Golan's table water goes to the
Sea of Galilee, which is Israel's largest reserve, which is afterward redistributed throughout the country by the
National Water Carrier. The Golan, which Israel annexed, represents, for Israel, a strategic territory because of its water resources.
. However, the level on the Sea of Galilee has dropped over the years, sparking fears that Israel's main water reservoir will become salinated. On its northern border, Israel threatened military action in
2002 when
Lebanon opened a new pumping station taking water from a river feeding the Jordan. To help ease the crisis, Israel has agreed to buy water from Turkey and is investigating building desalination plants.
[ ]On the other hand,
Iraq and
Syria watched with apprehension the construction of the
Atatürk Dam in
Turkey and a projected system of 22 dams on the
Tigris and
Euphrates rivers.
[ ] According to the BBC, the list of 'water-scarce' countries in the region grew steadily from three in 1955 to eight in 1990 with another seven expected to be added within 20 years, including three
Nile nations (the Nile is shared by nine countries).
Water in Asia
 |
Three Gorges Dam, receiving, upstream side, 26 July, 2004. |
In Asia,
Vietnam and
Cambodia are concerned by
China's and
Laos' attempts to control the flux of water. China is also preparing the
Three Gorges Dam project on the
Yangtze River, which would become one of the world's largest dams, causing many social and environmental problems. It also has a project to divert water from the Yangtze to the dwindling
Yellow River, which feeds China's most important farming region.
The
Ganges is disputed between
India and
Bangladesh. The water reserves are being quickly depleted and polluted, while the
glacier feeding the sacred
Hindu river is retreating hundreds of feet each year because of
global warming and
deforestation in the
Himalayas causing subsoil streams flowing into the Ganges river to dry up. Downstream, India controls the flow to Bangladesh with the
Farakka Barrage, 10 km on the Indian side of the border. Until the late 1990s, India used the barrage to divert the river to
Calcutta to stop the city's port drying up during the dry season. This denied Bangladeshi farmers water and
silt, and left the
Sundarban wetlands and
mangrove forests at the river's delta seriously threatened. The two countries have now signed an agreement to share the water more equally. Water quality, however, remains a huge problem, with high levels of
arsenic and untreated sewage in the river water.
[ ]Water in South America
The
Guaranà Aquifer, located between the
Mercosur countries of
Argentina,
Brazil,
Bolivia and
Paraguay, with a volume of about 40000 km³, is an important source of fresh, drinkable water, for all four countries.
Privatisation of water companies
Privatisation of water companies has been contested on several occasions, due to bad quality of the water, increasing prices, etc. In
Bolivia for example, the proposed privatization of water companies by the
IMF were met by
popular protests in Cochabamba in 2000, which ousted
Bechtel, an American engineering firm based in San Francisco.
SUEZ has started retreating from South America, due to similar protests (in
Buenos Aires in
Argentina, as well as in
Santa Fe; in
Córdoba, consumers took to the streets to protest water rate hikes of as much as 500 percent mandated by Suez). In South and Central America, Suez has water concessions in Argentina, Bolivia, Brazil and Mexico. "Bolivian officials fault Suez for not connecting enough households to water lines as mandated by its contract and for charging as much as $455 a connection, or about three times the average monthly salary of an office clerk", according to the
Mercury News.
[ ] South Africa also made moves to privatize water, provoking an outbreak of cholera killing 200.
[ ]Regulating water distribution
Drinking water is often collected at
springs, 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 rainwater and river or lake water. This surface water, however, must be
purified for human consumption. This may involve removal of undissolved substances, dissolved substances and harmful
microbes. Popular methods are
filtering with sand which only removes undissolved material while
chlorination and
boiling kill harmful microbes.
Distillation does all three functions. More advanced techniques exist, such as
reverse osmosis.
Desalination of abundant
ocean or
seawater is a more expensive solution used in coastal
arid climates.
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.
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. As other types of pollution, this does not enter standard accounting of market costs, being conceived as
externalities for which the market can not account for. Thus other people pay the price of this water pollution, while the private firms' profits are not redistributed to the local population victim of this pollution.
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.
Water is considered a purifier in most religions, including
Hinduism,
Christianity,
Islam,
Judaism, and
Shinto. For instance,
baptism in Christian churches is done with water. In addition, a ritual bath in pure water is performed for the dead in many religions including Judaism and Islam. In Islam, the five daily prayers can be done only after completing washing the body with clean water (
wudu). In
Shinto, water is used in almost all rituals to cleanse a person or an area. Water is mentioned in the
Bible 442 times in the
New International Version and 363 times in the
King James Version: 2 Peter 3:5(b) states, "The earth was formed out of water and by water" (NIV).
Water is often believed to have spiritual powers. In
Celtic mythology,
Sulis is the local
goddess of thermal springs; in
Hinduism, the
Ganga is also personified as a goddess, while
Saraswati have been referred to as goddess in
Vedas. Also water is one of the "panch-tatva"s (basic 5 elements, others including
fire,
earth,
space,
air). Alternatively, gods can be patrons of particular springs, rivers, or lakes: for example in
Greek and
Roman mythology,
Peneus was a river god, one of the three thousand
Oceanids.
The
Greek philosopher Empedocles held that water is one of the four
classical elements along with
fire,
earth and
air, and was regarded as the
ylem, or basic substance of the universe. Water was considered cold and moist. In the theory of the four
bodily humors, water was associated with
phlegm.
Water was also one of the
five elements in traditional
Chinese philosophy, along with
earth,
fire,
wood, and
metal.
* OA Jones, JN Lester and N Voulvoulis, Pharmaceuticals: a threat to drinking water?
TRENDS in Biotechnology 23(4): 163, 2005
* Franks, F (Ed), Water, A comprehensive treatise, Plenum Press, New York, 1972-1982
*
Property of Water and Water Steam w Thermodynamic Surface* PH Gleick and associates, The World's Water: The Biennial Report on Freshwater Resources. Island Press, Washington, D.C. (published every two years, beginning in 1998.)
Water as a natural resource
* (Produced every two years;
data available here)
* (Cambridge Middle East Library)
*
Notes
*
Water Conserve - Water Conservation Portal*
UNESCO's World Water Assessment Program*
UNESCO Water Portal*
UNESCO-IHE Institute for Water Education*
UN Water*
European Water Association.
*
Whose right to water Schools resource on water rights
*
United Nations' World Water Development Report*
United Nations GEMS/Water Programme*
The World's Water, data, historical information on conflict*
Phase diagrams of water*
Oceans and Water Issues Page*
Bottled Water vs Tap Water - Tap or Bottled: which is better? This site contains facts about tap and bottled water and compares them.
*
Scientific Facts on Water Disinfectants A faithful summary by GreenFacts of a leading scientific consensus report on Drinking Water Disinfectants published by the International Programme on Chemical Safety of the WHO.
*
World Water Forum*
Water Structure and Behaviour*
WaterAid*
SAHRA—Global Water Newswatch*
Stockholm International Water Institute (SIWI)
*
California Water Impact Network (C-WIN)*
BBC: The water debate*
BBC News (International): The Water Debate*
E the Environmental Magazine piece on bottled water (Oct 2003).
*
International Association for the Properties of Water and Steam*
US Geological Survey: Comprehensive discussion of the water cycle, in many languages*
US Geological Survey: Planetary water volumes*
Why is water blue?*
Water, scientific data (by London South Bank University)*
Water requirements in adults*
Climate change raises markets for environmental technology, drinking water and clean energies*
'Unfreezable water', bound water and water of hydrationzh-yue:æ°´
