Drinking water

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Drinking water
Drinking water
Mineral Water
Mineral Water

Drinking water is water that is intended to be ingested by humans. Water of sufficient quality to serve as drinking water is termed potable water whether it is used as such or not. Although many fresh water sources are utilised by humans, some contain disease vectors or pathogens and cause long-term health problems if they do not meet certain water quality guidelines. Water that is not harmful for human beings is sometimes called safe water, water which is not contaminated to the extent of being unhealthy. The available supply of drinking water is an important criterion of carrying capacity, the population level that can be supported by planet Earth.

As of the year 2006 (and pre-existing for at least three decades), there is a substantial shortfall in availability of potable water, primarily arising from overpopulation in lesser developed countries. As of the year 2000, 37 percent of the populations of lesser developed countries did not have access to safe drinking water[1]. Implications for disease propagation are significant. Many nations have water quality regulations for water sold as drinking water, although these are often not strictly enforced outside of the developed world. The World Health Organization sets international standards for drinking water. A broad classification of drinking water safety worldwide could be found in Safe Water for International Travelers.

Typically water supply networks deliver a single quality of water, whether it is to be used for drinking, washing or landscape irrigation; one counterexample is urban China, where drinking water can be optionally delivered by a separate tap. In the United States, public drinking water is governed by the Safe Drinking Water Act (SDWA). Among other provisions, it protects the right of employees to report potential violations. 42 U.S.C. 300j-9(i). Within 30 days of any retaliation, a whistleblower can file a complaint with the Occupational Safety and Health Administration (OSHA).

The standard test for bacterial contamination is a laboratory analysis of coliform bacteria, a convenient marker for a class of harmful fecal pathogens. The presence of fecal coliforms (like Escherichia coli) serves as an indication of contamination by sewage.

Contents

[edit] Metabolism

Water is essential for all life on Earth, including mammals and mankind. Humans can survive for several weeks without food, but for only a few days without water. A constant supply is needed to replenish the fluids lost through normal physiological activities, such as respiration, sweating and urination. Water generated from the biochemical metabolism of nutrients provides a significant proportion of the daily water requirements for some arthropods and desert animals, but provides only a small fraction of a human's necessary intake. There are a variety of trace elements present in virtually all potable water, some of which play a role in metabolism; for example sodium, potassium and chloride are common chemicals found in very small amounts in most waters, and these elements play a role (not necessarily major) in body metabolism. Other elements such as fluoride, while beneficial in low concentrations, can cause dental problems and other issues when present at high levels.

[edit] Access to drinking water

As a country’s economy becomes stronger (as its GNP per capita or PPP rise) a larger percentage of its people tend to have access to drinking water and sanitation. Access to drinking water is measured by the number of people who have a reasonable means of getting an adequate amount of water that is safe for drinking, washing, and essential household activities, expressed as a percentage of the total population.

It reflects the health of a country’s people and the country’s capacity to collect, clean, and distribute water to consumers. According to the World Health Organization (WHO) more than one billion people in low and middle-income countries lack access to safe water for drinking, personal hygiene and domestic use. These numbers represent more than 20 percent of the world’s people. In addition, close to 2 billion people did not have access to adequate sanitation facilities.

While the occurrence of waterborne diseases in developed countries is generally low due to a generally good system of water treatment, distribution and monitoring, waterborne diseases are among the leading causes of morbidity and mortality in low- and middle-income countries, frequently called developing countries.

According to the United Nations over 1.1 billion people are currently without safe drinking water. For details see data on the website of the Joint Monitoring Program (JMP) on water and sanitation of WHO and UNICEF.

The access to safe drinking water to the populations in several countries is listed below.[2]

Table 2: Percentage of population with access to safe drinking water
Country %   Country %   Country %   Country %
Albania 97   Algeria 89   Azerbaijan 78   Brazil 87
Chile 93   Cuba 91   Egypt 97   Iraq 85
Iran 92   Mexico 88   Morocco 80   Peru 80
Syria 80   Sudan 67   South Africa 86   Turkey 82
Tunisia 80   Venezuela 83   Zimbabwe 83      

The main reason for poor access to safe water is the inability to finance and to adequately maintain the necessary infrastructure. Overpopulation and scarcity of water resources are contributing factors in some locations, but the share of drinking water use in global water use as well as in water use in most countries is minimal (see under water resources), so that this is not the key limiting factor to access to safe water.

Common places to find safe drinking water after a disaster are

  • Water heater
  • Household water pipes
  • Back of the toilet tank

[edit] Drinking water quality monitoring

The standard test for bacterial contamination is a laboratory analysis of coliform bacteria, a convenient marker for a class of harmful fecal pathogens. The presence of fecal coliforms (like Escherichia coli) serves as an indication of contamination by sewage.

[edit] Drinking water quality legislation

[edit] United States

In the United States, public drinking water is governed by the Safe Drinking Water Act (SDWA). Among other provisions, it protects the right of employees to report potential violations. 42 U.S.C. 300j-9(i). Within 30 days of any retaliation, a whistleblower can file a complaint with the Occupational Safety and Health Administration (OSHA).

Municipalities throughout the US - from the largest cities to the smallest towns - sometimes fail to meet EPA standards. The EPA may fine the jurisdiction responsible for the violation, but this does not always motivate the municipality to take corrective action. In such cases, non-compliance with SEPA may continue for many months or years after the initial violation. This could result from the fact that the city simply doesn't have the financial resources necessary to replace aging water pipes or upgrade their purification equipment. In rare cases, the source water used by the municipality could be so polluted that water purification processes can't do an adequate job. This can occur when a town is downstream from a large sewage treatment plant or large-scale agricultural operations. Citizens who live in such places - especially young children, the elderly, or people of any age with autoimmune deficiencies - may suffer serious health complications as a long-term result of drinking water from their own taps.

[edit] See also

Portal:Water
 Water Portal

[edit] References

  1. ^ I.A. Shiklomanov, Appraisal and Assessment of World Water Resources, Water International 25(1): 11-32 (2000)
  2. ^ Safe Drinking Water (UNICEF website article)

[edit] External links

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