Drinking water

From Wikipedia, the free encyclopedia

  (Redirected from Potable water)
Jump to: navigation, search
 This article may require cleanup to meet Wikipedia's quality standards.
Please improve this article if you can. (November 2007)
The introduction to this article may be too long. Please help improve the introduction by moving some material from it into the body of the article according to the suggestions at Wikipedia's lead section guidelines.
Please discuss this issue on the talk page and read the layout guide to make sure the section will include all essential details.
Tap water
Tap 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 sources are utilized 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 in less developed countries, primarily arising from industrial contamination and pollution. As of the year 2000, 27 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 can 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. [2] Within 30 days of any retaliation, a whistleblower can file a complaint with the Occupational Safety and Health Administration (OSHA).

Contents

[edit] Metabolism

Main article: Fluid balance

Water is necessary for all life on Earth. 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. Water is essential for the growth and maintenance of our bodies, as it is involved in a number of biological processes.

[edit] Requirement

Reference daily intake for water is 3.7 l/day for human males aged 19-30 years. Food contributes with 0,5–1 l and the metabolism of protein, fat and carbohydrates generates another 0.25–0.4 l[3]. Thus, a person needs to drink another 2-3 l/day of water. These assumptions are limited by the condition of the subject, including personal health, physical exercise, but also temperature and humidity. For a long term functional urinary tract about 1-2 l have to be produced per day (300-400 ml/urination, or ~4 urinations/day) and the according intake has to be sustained depending on the environmental conditions.

[edit] Access to drinking water

Drinking water vending machines in Thailand. One liter of purified water is sold (into the customer's own bottle) for 1 baht
Drinking water vending machines in Thailand. One liter of purified water is sold (into the customer's own bottle) for 1 baht

Earth's surface consists of 70% water. Water is available almost everywhere if proper methods are used to get it. 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.

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 United Nations' 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 3 billion people did not have access to adequate sanitation facilities. (For details see data on the website of the Joint Monitoring Program (JMP) on water and sanitation of WHO and UNICEF.)

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.

The access to safe drinking water to the populations in several countries is listed below.[4]

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.

Only forty-six percent of people in Africa have safe drinking water.
Only forty-six percent of people in Africa have safe drinking water.

Many other countries also lack in the amount of safe drinking water that they need to survive. Some of the countries have less than twenty percent of the population that has access to safe drinking water. For example in Africa, with more than seven hundred million people, only forty-six percent of people have safe drinking water. The more populous Asia Pacific region with over three billion people, eighty percent of whom with access to drinking water, still leaves some six hundred and twenty seven million people without access to safe drinking water.[1]

The lack of water and the lack of hygiene is one of the biggest problems that many poor countries have encountered in progressing their way of life. The problem has reached such endemic proportions that 2.2 million deaths per annum occur from unsanitary water - ninety percent of these are children under the age of five. [2] One program developed to help people gain access to safe drinking water is the Water Aid program. Working in 17 countries to help provide water, Water Aid is useful in helping the sanitation and hygiene education to some of the world's poorest people.[3]

[edit] Drinking water quality monitoring

 Please help improve this article by expanding this section.
See talk page for details. Please remove this message once the section has been expanded.

Parameters for drinking water quality typically fall under two categories: chemical/physical and bacteriological. Chemical/physical parameters include heavy metals, total suspended solids (TSS), and turbidity. Bacteriological parameters include total coliform and fecal coliform.

Chemical parameters tend to pose more of a chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and arsenic may have a more immediate impact. Physical parameters affect the aesthetics and taste of the drinking water and may complicate the treatment of bacteria, viruses, and pathogens.

Originally, fecal contamination was determined with the presence of coliform bacteria, a convenient marker for a class of harmful fecal pathogens. The presence of fecal coliforms (like E. Coli) serves as an indication of contamination by sewage. Bacteriological parameters are typically of greatest concern because of their immediate health risk.

[edit] See also

 Water Portal

[edit] References

  1. ^ I.A. Shiklomanov, Appraisal and Assessment of World Water Resources, Water International 25(1): 11-32 (2000)
  2. ^ 42 U.S.C. 300j-9(i)
  3. ^ Swedish DFA
  4. ^ Safe Drinking Water (UNICEF website article)

[edit] External links

Wikimedia Commons has media related to:
This article or section includes a list of references or external links, but its sources remain unclear because it lacks in-text citations.
You can improve this article by introducing more precise citations.


Retrieved from "http://en.wikipedia.org/wiki/Drinking_water"
Personal tools