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Drinking Water

Drinking water

Drinking water is water that is intended to be drunk by humans. Water of sufficient quality to serve as drinking water is called potable water whether it is used as such or not. Although most fresh water sources are drinkable by humans, they can be a disease vector or cause long-term health problems if they do not meet certain water quality guidelines. Most nations have water quality regulations for water sold as drinking water, although these are often not strictly enforced outside of the developed world. Virtually all municipal water systems deliver a single quality of water, whether it is to be used for drinking, washing or landscape irrigation. irrigation 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).

External links

- [http://www.epa.gov/ebtpages/watedrinkingwater.html US Environmental Protection Agency Drinking water page]
- [http://www.awwa.org/ American Water Works Association] for professionals in water production and distribution and other water fields.
- [http://www.geocities.com/tapvsbottled/ Tap Water Vs Bottled Water] - Interesting site providing facts about tap and bottled water.
- [http://www.emagazine.com/september-october_2003/0903feat1.html E the Environmental Magazine piece on bottled water] (Oct 2003).
- [http://www.workplacefairness.org/index.php?page=envwhistleblowers] - Rights of environmental whistleblowers in US under Safe Drinking Water Act.
- [http://www.dwi.gov.uk The Drinking Water Inspectorate] - The drinking water regulator in England and Wales.
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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 (from the Old English word wæter; c.f German "Wasser", from PIE
- wod-or, "water") is a tasteless, odorless, and nearly colorless (it has a slight hint of blue) substance in its pure form that is essential to all known forms of life and is known also as the most universal solvent. Water is an abundant substance on Earth. It exists in many places and forms. It appears mostly in the oceans and polar ice caps, but also as clouds, rain water, rivers, freshwater aquifers, and sea ice. On the planet, water is continuously moving through the cycle involving evaporation, precipitation, and runoff to the sea. Water fit for human consumption is called potable water. This natural resource is becoming more scarce in certain places as human population in those places increases, and its availability is a major social and economic concern.

Molecular properties

Forms of water

potable water] Water takes many different shapes on earth: water vapor and clouds in the sky, waves and icebergs in the sea, glaciers in the mountain, 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.

Water in biology

From a biological standpoint, water has many distinct properties that are critical for the proliferation of life that set it apart from other substances. Water carries out this role by allowing organic compounds to react in ways that ultimately allows replication. It is a good solvent and has a high surface tension, and thus allows organic compounds and living things to be transported in it. Fresh water has its greatest density at 4°C, then becoming less dense as it freezes or heats up from this point. As a stable, polar molecule prevalent in the atmosphere, it plays an important atmospheric role as an absorber of infrared radiation, crucial in the atmospheric greenhouse effect without of which, the average surface temperature would be −18° Celsius. Water also has an unusually high specific heat, which plays many roles in regulating global and regional climate, such as the Gulf Stream climate, allowing life to survive. Water is a very good solvent, chemically not unlike ammonia, and dissolves many types of substances, such as various salts and sugar, and facilitates their chemical interaction, which aids complex metabolisms. Some substances, however, do not mix well with water, including oils and other hydrophobic substances. Cell membranes, composed of lipids and proteins, take advantage of this property to carefully control interactions between their contents and external chemicals. This is facilitated somewhat by the surface tension of water. Water drops are stable due to the high surface tension of water caused by the strong intermolecular forces called cohesive forces. 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. This property plays a key role in plant transpiration. A simple but environmentally important and unique property of water is that its common solid form, ice, floats on the liquid. This solid phase is less dense than 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 more dense than the liquid form. Fresh water is most dense at 4°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. Life on earth has evolved with and adapted itself to the important features of water. The existence of abundant liquid, vapor and solid forms of water on Earth has been an important factor in the abundant colonization of Earth's various environments by life-forms adapted to those varying and often extreme conditions. Civilizations have historically flourished around rivers and major waterways; Mesopotamia, the so-called cradle of civilization, is situated between two major rivers. Large metropolises like London, 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.

Astronomical position of Earth and impact on its water

Mesopotamia The coexistence of the solid, liquid, and gaseous phases of water on Earth is vital to the origin, evolution, and continued existence of life on Earth. However, if the Earth's location in the solar system were even marginally closer 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 provides 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). According to the solar nebula model of the solar system's formation, Earth's mass may be largely due to its distance from the Sun. The distance between Earth and the Sun and the combination of solar radiation received and the greenhouse effect of the atmosphere ensures that its surface is neither too cold nor too hot for liquid water. If Earth were more distant, 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. In the former case, the low albedo of oceans would cause Earth to absorb more solar energy. In the second case, a runaway greenhouse effect and inhospitable conditions similar to Venus would result. 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 solar flux, 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.

Human uses of water

Gaia hypothesis 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) 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 men[http://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. 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.

Water as a precious resource

:See water resources for information about fresh water supplies. fresh water Because of the growth of world population and other factors, the availability of drinking water per capita is shrinking. The issue of water shortage can be solved through more production, better distribution and less waste of it. 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. 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. 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.

Regulating water distribution

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. 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 pollutor. 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.

The impact of water on human culture

Water is considered a purifier in most religions, including 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 daily Salah can only be done after ablution (Wodoo), that is, washing parts of the body in clean water. In Shinto, water is used in almost all rituals to cleanse a person or an area. 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. Alternatively, gods can be patrons of particular springs, river 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 stuff of the universe. Water was considered cold and moist. In the theory of the four bodily humours, water was associated with phlegm. Water was also one of the Five Elements in traditional Chinese philosophy, along with earth, fire, wood, and metal. A common misconception about water is that it is a powerful conductor of electricity. Any electrical properties observable in water are due to the ions of mineral salts and carbon dioxide dissolved in it. Water does self-ionize (two water molecules become one hydroxide anion and one hydronium cation), but only at a very slight, almost immeasurable level. Pure water can also be electrolized into oxygen and hydrogen gases but without any dissolved ions, this is a very slow process and thus very little current is conducted. Many bottled water companies exploit another common misconception, advertising both purity and taste, even though pure water is tasteless.

External links

- [http://www.lsbu.ac.uk/water/phase.html Phase diagrams of water]
- [http://www.publicforuminstitute.org/issues/oceans/index.htm Oceans and Water Issues Page]
- [http://www.greenfacts.org/water-disinfectants/index.htm 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.
- [http://www.hkc22.com/residentialwater.html Residential water problems and markets] Study paper from Helmut Kaiser Consultancy
- [http://www.hkc22.com/watermarketsworldwide.html Water markets worldwide] Study paper from Helmut Kaiser Consultancy
- [http://www.worldwaterforum.org/ World Water Forum]
- [http://www.unesco.org/water/wwap/ World Water Assessment Program]
- [http://unesdoc.unesco.org/images/0012/001295/129556e.pdf United Nations' World Water Development Report]
- [http://www.gemswater.org/ United Nations GEMS/Water Programme]
- [http://www.lsbu.ac.uk/water/ Water Structure and Behaviour]
- [http://www.wateraid.org/ WaterAid]
- [http://www.sahra.arizona.edu/newswatch/ SAHRA—Global Water Newswatch]
- [http://www.siwi.org/ Stockholm International Water Institute] (SIWI)
- [http://www.c-win.org/ California Water Impact Network (C-WIN)]
- [http://news.bbc.co.uk/2/hi/science/nature/3752590.stm BBC: The water debate]
- [http://www.geocities.com/tapvsbottled/ Tap Water Vs Bottled Water] - Interesting site providing facts about tap and bottled water.
- [http://www.emagazine.com/september-october_2003/0903feat1.html E the Environmental Magazine piece on bottled water] (Oct 2003).
- [http://www.iapws.org/ International Association for the Properties of Water and Steam]
- [http://ga.water.usgs.gov/edu/watercycle.html US Geological Survey: Comprehensive discussion of the water cycle, in many languages]
- [http://www.dartmouth.edu/~etrnsfer/water.htm Why is water blue?]
- [http://www.water.org.uk/home/resources-and-links/water-for-health/ask-about/adults Water requirements in adults]
- [http://www.hkc22.com/environmentaltechnology.html/ Climate change raises markets for environmental technology, drinking water and clean energies]

References

- OA Jones, JN Lester and N Voulvoulis, Pharmaceuticals: a threat to drinking water? TRENDS in Biotechnology 23(4): 163, 2005
- Category:Beverages Category:Hydrology Category:Materials Category:Natural resources Category:Nutrition zh-min-nan:Chúi als:Wasser ko:물 ja:水 ms:Air simple:Water th:น้ำ

Drinking

Drinking is the act of consuming a liquid through the mouth. Water is required for many of the body's physiological processes, and excess or decreased water intake is associated with health problems. "Drinking" may refer specifically to alcoholism depending on the context in which the term is used. alcoholism

Physiology

A daily intake of 1-2 liters of water is required for the normal physiological functioning of the body, depending on the ambient weather conditions. The absolute minimum over the long term is about 1.6 liters (600 ml for urine, 200 ml for fecal losses, and 800 ml for losses via the skin and lungs). This includes water contained in food (i.e. it is not necessary to drink 1-2 liters of water a day). The sensation caused by dehydration of the body is called "thirst". The sensation of thirst is a dry feeling in the back of the throat and an intense desire to drink fluids. Thirst is regulated by the hypothalamus in response to subtle changes in the body's electrolyte levels, and also as a result of changes in the volume of blood circulating.

Role in disease

Polydipsia is the medical term for consumption of large quantities of water and may be a sign of various diseases (diabetes mellitus, diabetes insipidus, and some psychiatric conditions). Much of the world's disease is caused by the lack of clean drinking water. Lack of water in the diet will eventually cause death by hypernatremia and dehydration, particularly when sweating consumes much of the body water. It is also possible to overhydrate, which sometimes happens with athletes who consume too much water, thereby diluting the concentration of salts in the body.

Vessels

Drinking vessels include glasses, cups, bottles, canteens, or even bowls in some cases. Fewer skills are required for drinking from a baby bottle or a cup with a lid with nozzle. Therefore these are useful for small children and people with some disabilities. If eating and drinking is not possible, alternatives are enteral nutrition and parenteral nutrition.

Alcohol

"Drinking" is also used as a euphemism for the consumption of alcoholic beverages, with the word thirst being the corresponding euphemism used by alcoholics for craving alcohol-containing liquids. Category:Drinking culture ja:飲む

Disease

A disease is any abnormal condition of the body or mind that causes discomfort, dysfunction, or distress to the person affected or those in contact with the person. Sometimes the term is used broadly to include injuries, disabilities, syndromes, symptoms, deviant behaviors, and atypical variations of structure and function, while in other contexts these may be considered distinguishable categories. Pathology is the study of diseases. The subject of systematic classification of diseases is referred to as nosology. The broader body of knowledge about diseases and their treatments is medicine.

Syndromes, illness and disease

Medical usage sometimes distinguishes a disease, which has a known specific cause or causes (called its etiology), from a syndrome, which is a collection of signs or symptoms that occur together. However, many conditions have been identified, yet continue to be referred to as "syndromes". Furthermore, numerous conditions of unknown etiology are referred to as "diseases" in many contexts. Illness, although often used to mean disease, can also refer to a person's perception of their health, regardless of whether they in fact have a disease. A person without any disease may feel unhealthy and believe he has an illness. Another person may feel healthy and believe he does not have an illness even though he may have a disease such as dangerously high blood pressure which may lead to a fatal heart attack or stroke.

Transmission of disease

Some diseases, such as influenza, are contagious or infectious, and can be transmitted by any of a variety of mechanisms, including droplets from coughs and sneezes, by bites of insects or other vectors, from contaminated water or food, etc. Other diseases, such as cancer and heart disease are not considered to be due to infection, although micro-organisms may play a role.

Social significance of disease

The identification of a condition as a disease, rather than as simply a variation of human structure or function, can have significant social or economic implications. The controversial recognitions as diseases of post-traumatic stress disorder, also known as "shell shock"; repetitive motion injury or repetitive stress injury (RSI); and Gulf War syndrome has had a number of positive and negative effects on the financial and other responsibilities of governments, corporations and institutions towards individuals, as well as on the individuals themselves. The social implication of viewing aging as a disease could be profound, though this classification is not yet widespread. A condition may be considered to be a disease in some cultures or eras but not in others. Oppositional-defiant disorder, attention-deficit hyperactivity disorder, and, increasingly, obesity are conditions considered to be diseases in the United States and Canada today, but were not so-considered decades ago and are not so-considered in some other countries. Conversely, the number of people in the West who consider homosexuality to be a disease became widespread in the 20th century but has been decreasing in the last two decades. To consider a condition to be a disease can sometimes involve a negative social value judgement. Lepers were a group of afflicted individuals who were historically shunned and the term "leper" still evokes social stigma. Fear of disease can still be a widespread social phenomena, though not all diseases evoke extreme social stigma.

Other uses of the term

In biology, disease refers to any abnormal condition of an organism that impairs function. The term disease is often used metaphorically for disordered, dysfunctional, or distressing conditions of other things, as in disease of society.

External links

- [http://www.nlm.nih.gov/medlineplus/healthtopics.html Health Topics], MedlinePlus descriptions of most diseases, with access to current research articles.
- [http://www.cdc.gov/health/default.htm Center for Disease Control Health Topics A-Z], fact sheets about many common diseases
- [http://rarediseases.about.com/ Rare/Orphan Diseases]
- [http://www.national-health.org/rarediseases/ National Organization for Rare Disorders] Extensive, useful information on rare diseases.
- [http://www.merck.com/pubs/mmanual/sections.htm The Merck Manual], detailed description of most diseases, freely searchable online. Category:Diseases Category:Medical terms als:Krankheit zh-min-nan:Pīⁿ ms:Penyakit ja:病気 simple:Disease th:โรค

Water quality

To most people not professionally involved in water quality issues, water is either drinkable (technically potable) or contains potentially harmful or toxic substances. However, the vast majority of surface water on the planet is neither potable nor toxic. This remains true even if we eliminate from consideration the more than 97% of the earth's water found in the oceans (sea water)—too salty to drink. Another general perception of water quality is that of a simple property that tells whether water is polluted or not. In fact, water quality is a very complex subject, in part because water is a complex medium intrinsically tied to the ecology of the entire planet. Interest by individuals and volunteer groups in making local water quality observations is high, and an understanding of the basic chemistry of many water quality parameters is an essential first step to making good measurements. Most citizens harbor great concern over the purity of their drinking water, but there is far more to water quality than water treatment for human consumption. In point of fact, purification of drinking water is really a different, although obviously related, subject altogether. Many people in the world live where community water purification is simply not a reality. For these people, water quality, even for drinking purposes, relates directly to the local stream, lake, or groundwater. Thus, at its heart, water quality is about preserving uses. Not only use of water as a consumable product, but all other uses such as wildlife habitat, irrigation, swimming, fishing, rafting, and boating—any or all of which can be adversely impacted by water quality degradation. Of course, industrial uses are also important, and industries are always interested in the quality and quantity of water available to them. Statements to the effect that "uses must be preserved" are included within water quality regulations because they provide for broad interpretation of water quality results, while preserving the ultimate goal of the regulations. Technical measures of water quality—that is, the values obtained when making water quality measurements—are always subject to interpretation from multiple perspectives. Is it reasonable to expect a river to be pristine in a landscape that no longer is? If a river has always carried sediment, is it polluted even if the cause is not man induced? Can water quality be maintained when water quantity can not? The questions that arise from consideration of water quality relative to human uses of the water become more complex when consideration must be given to conditions required to sustain aquatic biota. Yet inherent in the concept of preserving uses is a mandate that waterways must be much more than conduits for a fluid we might want to drink, fill our swimming pool with, or carry our wastes out of town.

Measurement of water quality

The complexity of water quality as a subject is reflected in the many types of measurements of water quality. These measurements include (from simple and basic to more complex):
- Conductivity (also see salinity)
- Dissolved Oxygen (DO)
- pH
- Color of water
- Taste and odour
- Turbidity
- Total suspended solids (TSS)
- Chemical oxygen demand (COD)
- Biochemical oxygen demand (BOD)
- Fecal coliform bacteria (e.g. Escherichia coli)
- Nutrients (fertilizers)
- Dissolved metals
- Dissolved organics The simple measurements (towards the top in the listing above) are those that can be made with an instrument, in most cases in the field (in situ). The more complex or difficult measurements are those that come from analytical methods, typically requiring a water sample to be collected, preserved, and later analyzed in a laboratory setting. These latter measurements can be expensive and it is always important to understand in advance the reason(s) for making any particular measurement. Also, because the number of substances that could be present in a water sample runs to the millions, it is not possible to reasonably establish what all might be in a particular sample without a very large budget. If the logic of this fact is difficult to grasp, the inefficiency should be obvious: to satisfy such a request, a laboratory would have to charge for determining the more that 99% of possibilities that are NOT present in the sample to discover the minutely less than 1% that are. One effective way to improve water quality in a farm pond is to get more oxygen in the water. AERATION is often done by sending compressed air to an air diffuser at the bottom of the pond. The deep water rises to the surface and the water molecules grab oxygen from the atmosphere. As the pond water circulates, soon the oxygen levels in the water from top to bottom increase. Thus, aeration adds oxygen to the water and improves water quality.

External link

- World Health Organization [http://www.who.int/water_sanitation_health/dwq/gdwq3/en/ water quality guidelines]
- U.S. National Water Quality Monitoring Council (NWQMC) [http://water.usgs.gov/wicp/acwi/monitoring/]
- European Environment Agency [http://reports.eea.eu.int/92-9167-023-5/en/tab_content_RLR]
- USGS [http://water.usgs.gov/nawqa]
- U.S. Environmental Protection Agency [http://www.epa.gov/owow/monitoring]
- U.S. National Agricultural Library [http://www.nal.usda.gov/wqic] Category:Chemical oceanography Quality

Landscape

Landscape can mean:
- The layout of a land area, particularly with respect to its appearance and character. A landscape includes such elements as landforms, bodies of water, flora and fauna, and lighting and weather conditions (the natural elements), as well as human presence and human-built elements (the cultural elements or built environment). See also Landscape Architecture, Landscape Ecology and Landscape Engineering, Landscape Planning, Landscape Design.
- A depiction of a landscape in a painting or photograph. See Landscape painting.
- The orientation of a rectangular page, painting or other graphic, denoting that the longer axis is horizontal. (So named because landscape paintings usually have this orientation.) When the long axis is vertical, it is termed portrait.
- In String Theory, it is used to refer to the Anthropic landscape. Related terms:
- Hardscape
- Seascape
- Skyscape
- Cloudscape
- Moonscape
- In Sonic Art, the Soundscape
- Landscape is also a play by Harold Pinter ja:景観

Safe Drinking Water Act

The Safe Drinking Water Act was an act passed by Congress on December 16, 1974. It is the main federal law that ensures safe drinking water for Americans. With this act, EPA is allowed to set the standards for drinking water quality and oversees all of the states, localities, and water suppliers who implement these standards.

Whistleblower

A whistleblower is an employee, former employee, or member of an organization who reports misconduct to people or entities that have the power to take corrective action. Generally the misconduct is a violation of law, rule, regulation and/or a direct threat to public interest -- fraud, health, safety violations, and corruption are just a few examples. For instance, Jeffrey Wigand is a well-known whistleblower in the United States for his role in the Big Tobacco scandal, revealing that executives of the companies knew that cigarettes were addictive and that they added other carcinogenic ingredients to the cigarettes. Whistleblowers are most often employees of businesses, but are also commonly employees of government agencies. Contrary to popular belief, not only the most severe cases of corporate or governmental misconduct that results in substantial public harm precipitate a whistleblowing. While these instances are the most newsworthy and the type most portrayed in popular culture, any kind of misconduct may initiate the whistleblowing process and the vast majority of cases are based on relatively minor misconduct. The most common type of whistleblowers are internal whistleblowers, who are whistleblowers that report misconduct to another employee or superior within the company or agency of their work. Contrasting this, external whistleblowers report misconduct to outside persons or entities. In these cases, depending on the severity and nature of the wrong-doing, whistleblowers will usually report the misconduct to lawyers, the media, law enforcement or watchdog agencies, or to other local, state, or federal agencies. If the disclosure is specifically prohibited by law or is specifically required by executive order to be kept secret in the interest of national defense the reporting by a whistleblower might constitute treason. Role-prescribed whistleblowing, for example whistleblowing done by quality control personnel or internal auditors, does not necessarily constitute whistleblowing in the traditional sense, chiefly because their reporting of misconduct is mandated.

Reactions to whistleblowing

Perceptions of whistleblowing vary widely. Some perceive whistleblowers as selfless martyrs for public interest and organizational accountability, while others view them as "snitches", solely pursuing personal glory and fame. Because the majority of cases are very low-profile and receive little or no media attention and because whistleblowers who do report significant misconduct are usually put in some form of danger or persecution, the latter view is generally less held. Persecution of whistleblowers has become a serious issue in many parts of the world. Although whistleblowers are often protected under law from employer retaliation, there have been many cases where punishment for whistleblowing has occurred. As a reaction to this many private organizations have formed whistleblower legal defense funds or support groups to assist whistleblowers; one such example in the UK is Public Concern at Work. Depending on the circumstances, it is not uncommon for whistleblowers to be ostracized by their co-workers, discriminated against by future potential employers, or even fired from their organization.

Whistleblower law

Legal protection for whistleblowing varies from country to country. In the UK, the Public Interest Disclosure Act 1998 provides a framework of legal protection for individuals who disclose information so as to expose malpractice and matters of similar concern. In the vernacular, it protects whistleblowers from victimisation and dismissal. In the United States, legal protections vary according to the subject matter of the whistleblowing, and sometimes the state in which the case arises. In passing the 2002 Sarbanes-Oxley Act, the Senate Judiciary Committee found that whistleblower protections were dependent on the "patchwork and vagaries" of varying state statutes. (Congressional Record p. S7412; S. Rep. No. 107-146, 107th Cong., 2d Session 19 (2002).) Still, a wide variety of federal and state laws protect employees who call attention to violations, help with enforcement proceedings, or refuse to obey unlawful directions. The patchwork of laws means that victims of retaliation need to be alert to the laws at issue to determine the deadlines and means for making proper complaints. Some deadlines are as short as 10 days (for Arizona State Employees to file a "Prohibited Personnel Practice" Complaint before the Arizona State Personnel Board; and Ohio public employees to file appeals with the State Personnel Board of Review). It is 30 days for environmental whistleblowers to make a written complaint to the Occupational Safety and Health Administration [OSHA]. Federal employees complaining of discrimination, retaliation or other violations of the civil rights laws have 45 days to make a written complaint to their agency's equal employment opportunity (EEO) officer. Airline workers and corporate fraud whistleblowers have 90 days to make their complaint to OSHA. Nuclear whistleblowers and truck drivers have 180 days to make complaints to OSHA. Victimes of retaliation against union organizing and other concerted activities to improve working conditions have 180 days to make complaints to the National Labor Relations Board (NLRB). Private sector employees have either 180 or 300 days to make complaints to the federal Equal Employment Opportunity Commission (EEOC) (depending on whether their state has a "deferral" agency) for discrimination claims on the basis of race, gender, age, national origin or religion. Those who face retaliation for seeking minimum wages or overtime have either two or three years to file a civil lawsuit, depending on whether the court finds the violation was "willful." Those who report a false claim against the federal government, and suffer adverse employment actions as a result, may have up to six years (depending on state law) to file a civil suit for remedies under the U.S. False Claims Act (FCA). 31 U.S.C. § 3730(h). Under a "qui tam" provision, the "original source" for the report may be entitled to a percentage of what the government recovers from the offenders. However, the "original source" must also be the first to file a federal civil complaint for recovery of the federal funds fraudulently obtained, and must avoid publicizing the claim of fraud until the U.S. Justice Department decides whether to prosecute the claim itself. Such "qui tam" lawsuits must be filed under seal, using special procedures to keep the claim from becoming public until the federal government makes its decision on direct prosecution. Federal employees benefit from the Whistleblower Protection Act (5 U.S.C. § 1221(e)), and the No Fear Act (which made individual agencies directly responsible for the economic sanctions of unlawful retaliation). The Military Whistleblower Protection Act (10 U.S.C. § 1034), protects the right of members of the armed services to communicate with any member of Congress (even if copies of the communication are sent to others). The Hope Scholar Ship in Georgia is the only incentive to report corporate, government, or religious crimes. This scholarship provides four years of free tutition to a tech school or University in Georgia for children of whistleblowers or those researching corporate crime. :For more information about how whistleblowers can file an initial complaint, see External links

Famous whistleblowers

- Daniel Ellsberg - a former State Department analyst who leaked the Pentagon Papers in 1971, a secret account of the Vietnam War and its pretexts to The New York Times, which revealed endemic practices of deception by previous administrations, and contributed to the erosion of public support for the war.
- W. Mark Felt, (aka Deep Throat) - until very recently, a secret informant who in 1972 leaked information about United States President Richard Nixon's involvement in Watergate. The scandal would eventually lead to the resignation of the president, and prison terms for White House Chief of Staff H. R. Haldeman and presidential adviser John Ehrlichman.
- Mordechai Vanunu - an Israeli former nuclear technician who revealed details of Israel's nuclear weapons program to the British press in 1986. He was subsequently lured to Rome by an American Mossad agent, abducted and smuggled to Israel, where he was tried behind closed doors and convicted of treason. After 18 years in prison, more than 11 years of which were served in solitary confinement, Vanunu was released from prison in 2004.
- Cynthia Cooper of Worldcom and Sherron Watkins of Enron, who exposed corporate financial scandals, and Coleen Rowley of the FBI, who later outlined the agency's slow action prior to the September 11, 2001 attacks. The three were selected as Time's People of the Year in 2002.
- Katharine Gun - a former employee of Government Communications Headquarters (GCHQ), a British intelligence agency who in 2003 leaked top-secret information to the press concerning illegal activities by the United States and the United Kingdom in their push for the 2003 invasion of Iraq.
- Joseph Darby - a member of the United States military police who in 2004 first alerted the U.S. military command of prisoner abuse in the Abu Ghraib prison, in Abu Ghraib, Iraq.
- Samuel Provance - a system administrator for Military Intelligence at the Abu Ghraib prison, who publicly revealed the role of interrogators in the abuses, as well the general effort to cover-up the Abu Ghraib prisoner abuse itself.
- Christoph Meili - a night guard at a Swiss bank. He discovered that his employer was destroying records of savings by Holocaust victims, which the bank was required to return to heirs of the victims. After the Swiss authorities sought to arrest Meili, he was given political asylum in the United States.
- Walter DeNino - a student who questioned Eric Poehlman's integrity
- Paul van Buitenen - who accused European Commission members of corruption.
- Jeffrey Wigand - former executive of Brown & Williamson who exposed his company's practice of intentionally manipulating the effect of nicotine in cigarettes on the CBS news program 60 Minutes.
- Bunnatine "Bunny" H. Greenhouse - former chief civilian contracting officer for the United States Army Corps of Engineers exposed illegality in the no-bid contracts for reconstruction in Iraq by a Halliburton subsidiary.[http://www.whistleblowers.org/html/greenhouse_fund.htm][http://www.washingtonpost.com/wp-dyn/content/article/2005/10/18/AR2005101801796_pf.html]
- Allan Cutler-The first whistle-blower on the Canadian Adscam or Sponsorship Scandal Without WB protection, he was fired by Canadian government.

Resources

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External links

- [http://www.whistleblower.org US Government Accountability Project]
- [http://www.pogo.org Project On Government Oversight (POGO)]
- [http://www.whistleblowers.org/ National Whistleblower Center]
- [http://www.ellsberg.net/truthtellingproject.html The Truth-Telling Project] - Project formed by whistleblowers Daniel Ellsberg and Katharine Gun
- [http://www.pcaw.co.uk/index.html Public Concern at Work] - the leading UK authority on Public Disclosure
- [http://www.legislation.hmso.gov.uk/acts/acts1998/19980023.htm Public Interest Disclosure Act 1998] from Her Majesty's Stationery Office
- [http://www.workplacefairness.org/index.php?page=envwhistleblowers Workplace Fairness FAQ for environmental whistleblowers]
- [http://www.taterenner.com/whistleblowers.htm Tate & Renner article on whistleblowers under US federal law]
- [http://www.whistleblowerlaws.com Whistleblower Employee Protection Website]
- [http://www.euabc.com/index.phtml?word_id=962 Whistleblowers in the EU]
- [http://www.ifex.org International Freedom of Expression Exchange]
- [http://www.NSWBC.org National Security Whistleblowers Coalition] Source for many and varied articles
- Category:Dissent Category:Politics Category:Political corruption

Occupational Safety and Health Administration

The United States Occupational Safety and Health Administration (OSHA) was created by Congress under the Occupational Safety and Health Act, signed by President Richard M. Nixon,on December 29, 1970. Its mission is to prevent work-related injuries, illnesses, and deaths by issuing and enforcing rules (called standards) for workplace safety and health. This same act also created the National Institute for Occupational Safety and Health (NIOSH) as a research agency whose purpose is to determine the major types of hazards in the workplace and ways of controlling them. The agency is currently run by Deputy Assistant Secretary of Labor for Occupational Safety and Health Jonathan Snare. OSHA's statutory authority extends to most nongovernmental workplaces where there are employees. State and local government workers are excluded from Federal coverage, however, states operating their own state workplace safety and health programs under plans approved by the U.S. Department of Labor cover most private sector workers and are also required to extend their coverage to public sector (state and local government) workers in the state. Section 2 (11) of the OSH Act encourages states to develop and operate their own state OSH programs. OSHA regulations [29 CFR Part 1956] also permit states without approved plans to develop plans that cover only public sector workers. In these states, private sector employment remains under Federal OSHA jurisdiction. Twenty-two states and territories operate plans covering both the public and private sectors and four states - Connecticut, New Jersey, New York and the Virgin Islands - operate public employee only plans. OSHA was widely criticized in its early years for confusing, burdensome regulations. A good deal of the early conflict came about because of arbitrary and inconsistent enforcement during OSHA's early years. In addition, businesses were expected to retrofit guards and other safety devices on existing equipment and to implement other hazard controls, often at considerable expense, to bring them in line with then-current best safety practices. Other requirements of effective safety programs, such as training, communication, and documentation were seen as even more difficult and expensive. With time, manufacturers of industrial equipment have included OSHA-compliant safety features on new machinery. Enforcement has become more consistent across jurisdictions, and some of the more outdated or irrelevant rules have been repealed or are not enforced. During the Carter administration, OSHA, under the leadership of University of Cincinnati toxicologist Eula Bingham, began to concentrate more on health hazards, such as toxic chemicals. With the Reagan and Bush I administration came efforts to weaken OSHA enforcement and rulemaking, although several important rules were issued including hazard communication (right to know about chemical exposures) and blood-borne pathogens (to protect workers against illnesses such as hepatitis and AIDS). The Clinton administration began a reorganization of OSHA's approach, focusing more on "stakeholder" satisfaction through compliance assistance. When the Republicans took over Congress in 1994, one of their main goals was weakening some of the agency's ability to issue standards. Republican bills were stopped by the Democratic minority and moderate Republicans, but other legislation passed, such as the [http://www.osha.gov/dcsp/smallbusiness/sbrefa.html Small Business Regulatory Enforcement Fairness Act of 1996] and the Congressional Review Act. In 2000, OSHA issued the ergonomics standard after ten years of study and struggles with a Republican-controlled Congress that was unconvinced that additional government regularion was the right way to address the issue of ergonomic injuries to American workers. Ergonomic injuries (also known as musculoskeletal injuries) such as back injuries and carpal tunnel syndrome, account for 1/3 of all serious injuries suffered by American workers. The Republican-controlled Congress [http://www.nsc.org/issues/ergo/backinring.htm repealed the standard] in March 2001 and the repeal bill was one of the first major pieces of legislation signed by the newly elected George W. Bush. The Bush administration replaced the process of issuing mandatory regulations with voluntary "Alliances" and put additional resources into other, previously existing voluntary programs. In 2004, the General Accounting Office issued a [http://www.gao.gov/new.items/d04378.pdf report] questioning the effectiveness of these programs and warning that their planned growth threatened to take resources away from OSHA's enforcement budget. The real debate about OSHA regulations and enforcement policies revolves around the cost of regulations and enforcement, versus the actual benefit in reduced worker injury. Here are some of the major changes in industrial safety brought about by OSHA: # Guards on all moving parts - By 1970, there were guards to prevent inadvertent contact with most moving parts that were accessible in the normal course of operation. With OSHA, use of guards was expanded to cover essentially all parts where contact is possible. # Permissible exposure levels (PEL) - Maximum concentrations of chemicals stipulated by law for chemicals and dusts. They cover only around 600 chemicals and most are based on research from the 1950's and 1960's # Personal protective equipment (PPE) - broader use of respirators, gloves, coveralls, and other protective equipment when handling hazardous chemicals; goggles, faceshields, ear protection in typical industrial environments # Lockout/tagout - In the 1980s, requirements for locking out energy sources in an "off" condition when performing repairs or maintenance # Confined space - In the 1990s, specific requirements for air sampling and use of a "buddy system" when working inside tanks, manholes, pits, bins, and similar enclosed areas # Hazard Communication ([http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10099 HazCom]) - Also known as the "Right to Know" standard, it was issued as 29CFR1910.1200 in November 25, 1983 (48 FR 53280, requires developing and communicating information on the hazards of chemical products used in the workplace. # Process Safety Management ([http://www.osha.gov/SLTC/processsafetymanagement/ PSM]) - Issued in 1992 as 29CFR1910.119 in an attempt to reduce large scale industrial accidents. Although enforcement of the standard has been spotty, compliance with this regulation has been proven to reduce chemical and refinery accidents and its principles have become widely accepted by the petrochemical industry.

External links

- [http://www.osha.gov OSHA website]
- [http://www.legalarchiver.org/osh.htm Full text of the OSH Act]
- [http://www.cdc.gov/niosh/homepage.html National Institute for Occupational Safety and Health]
- [http://spewingforth.blogspot.com Confined Space] is a weblog that covers workplace safety and health issues. Category:OSHA Category:United States Department of Labor Category:Safety organizations category:Standards organizations

Water purification

Water purification, or drinking water treatment, is the process of removing contaminants from surface water or groundwater to make it safe and palatable for human consumption. A wide variety of technologies may be used, depending on the raw water source, contaminants present, standards to be met, and available finances.

Sources of drinking water

Water to be used in public or private water supplies can be drawn from a variety of sources. Different sources of raw water demand different treatment methods to render it fit for human consumption. #Deep groundwater - The water emerging from some deep groundwaters may have fallen as rain many decades or even hundreds of years ago. Soil and rock layers will have naturally filtered the groundwater to a high degree of clarity even before it is pumped to the treatment plant. Such water may emerge as springs, artesian springs, or may be extracted from boreholes or wells. Deep groundwater is generally of very high bacteriological quality but may be rich in dissolved solids especially carbonates and sulphates of calcium and magnesium. Depending on the strata through which the water has flowed, other ions may also be present including chloride, and bi-carbonate and there may be a requirement to reduce the iron or manganese content of this water to make it pleasant for drinking, cooking, and laundry use. Disinfection is also required. Where groundwater recharge is practised, such groundwaters should be graded as being equivalent to lowland surface waters for treatment purposes. #Shallow groundwaters - water emerging from shallow groundwaters are usually abstracted from wells or boreholes and the bacteriological quality can be variable depending on the nature of the catchment. A variety of soluble materials may be present including potentially toxic metals such as zinc or copper. In parts of Bangladesh, many shallow ground water sources are contaminated with unacceptably high levels of arsenic. #Upland lakes and reservoirs - typically located in the headwaters of rivers systems, upland reservoirs are usually sited above any human habitation and may be surrounded by some form of protection zone to restrict the opportunities for contamination. Bacteria and pathogen levels are usually low but some bacteria, protozoa and algae will be present. Where upland are forested or are peaty, humic acids can colour the water brown. Many upland sources have low pH which requires adjustment before the water is put into supply. #Rivers, canals and low-land reservoirs - lowland surface waters will have a significant bacterial load and may also contain algae, suspended solids and a variety of dissolved constituents

Water treatment methods

#Screening - A municipal surface water treatment plant must first screen or sieve out large objects such as trash and leaves. The tighter the mesh of the sieve, the smaller the particles must be to pass through. Filtering is not sufficient to completely purify water, but it is often a necessary first step, since such particles can interfere with the more thorough purification methods. #Storage- Water from rivers may also be stored in bankside reservoirs for periods between a few days and many months to allow natural biological purification to take place. This is especially important if treatment is to be by slow sand filters. The filtered water is then treated to remove any microscopic organisms including protozoa and bacteria. This is generally followed by a disinfection stage to eliminate any residual bacteria and viruses. For waters that are particularly difficult to treat such as from catchments with intensive agriculture, both physical and biological treatment methods may be combined. #Flocculation - The water is treated with small volumes of appropriate chemicals which will form a chemical floc which entraps particles. The most common flocculent chemicals are metal salts such as aluminium sulfate, ferric sulfate, or ferric chloride. Flocculation can be enhanced by adjusting the pH and alkalinity with acid, lime, and/or carbon dioxide. Polymers are also used in addition to, or in place of, metal salts at some plants. #Rapid Sand Filters - The use of rapid sand filters is the most common form of physical treatment of water. Passing flocculated water through a sand filter strains out the floc and the particles trapped within it. Where taste and odour may be a problem (organo-leptic impacts), the sand filter may include a layer of activated carbon to remove the taste and odour. Sand filters become clogged with floc after a period in use and they are then backwashed or pressure washed to remove the floc. This backwash water is run into special settling tanks so that the floc can precipitate out and is then disposed of as waste material. In some countries this may be used as a soil conditioner. #Slow Sand Filters - Where land and space are available, water may be treated in slow sand filter beds. These rely on biological treatment processes for their action rather than physical filtration. Slow sand filters are carefully constructed using graded layers of sand with the coarsest at the base and the finest at the top. Drains buried at the base of the filter convey treated water away for disinfection. When a new slow sand filter bed is brought into use, raw water is carefully decanted onto the filter material until a water depth of 1 to 3m is achieved, dependant on the size of the filter bed. The water passing through the filter for the first few hours is recirculated through the filter and not put into supply. Within a few hours, a biological film comprised of bacteria, protozoa, fungi, and algae builds on the surface of the sand. This is the Schmutzdecke layer and it is this layer that removes all the impurities. An effective slow sand filter may remain in service for many weeks or even months if the pre-treatment is well designed and produces an excellent quality of water which physical methods of treatment rarely achieve. #Disinfection - The finished water is then disinfected with chlorine gas, chloramine, sodium hypochlorite, chlorine dioxide, ozone, or ultraviolet light, before it is pumped into the distribution system of water mains and storage tanks on its way to consumers. Some plants also pre-chlorinate their raw water influent after the screening phase to reduce the incidence of biological films in the treatment cycle. They may also pre-chlorinate to oxidize and precipitate out dissolved iron and manganese from the water, in order to prevent unsightly iron (orange) and manganese (black) stains in the consumer's sink. Water utilities may choose to further boost chlorine levels (termed re-chlorinating) in the distribution system to counteract any pathogens that may occur. Bleach may be used for emergency disinfection at the rate of 2 drops of 5% bleach per liter or quart of clear water according to a treatment table in the following US EPA document [http://www.epa.gov/safewater/faq/emerg.html Emergency Disinfection]. Many environmental and cost considerations affect the siting and design of water purification plants. Groundwater is cheaper to treat, but aquifers once depleted can take thousands of years to recharge. Surface water sources must be carefully monitored for the presence of unusual types or levels of contaminants. The treatment plant itself must be kept secure from vandalism or terrorism and the presence of large quantities of dangerous chemicals mandates special training for workers and emergency personnel. The facility must responsibly dispose of its settled and filtered solids and prevent them from contaminating the treatment components or the source waters. All facilities disinfect finished water, but the exact method of disinfection can be controversial, and the costs and benefits of different methods must be evaluated.

Other water purification techniques

Other popular methods for purifying water, especially for local private supplies are listed below. In some countries some of these methods are also used for large scale municipal supply. Particularly important are distillation (de-salination of sea-water) and reverse osmosis # Boiling: Water is heated to its boiling point long enough to inactivate or kill microorganisms that normally live in water at room temperature. Near sea level, bring the water to a vigorous rolling boil for at least one minute. At high altitudes (greater than a kilometer or a mile) boil for three minutes. Source: [http://www.epa.gov/safewater/faq/emerg.html US EPA] In areas where the water is "hard" (that is, containing dissolved calcium salts), boiling decomposes the bicarbonate ion, resulting in some (but not all) of the dissolved calcium being precipitated in the form of calcium carbonate. This is the so-called "fur" that builds up on kettle elements, etc., in hard water areas. With the exception of calcium, boiling does not remove solutes of higher boiling point than water, and in fact increases their concentration (due to some water being lost as vapour). # Carbon filtering: Charcoal, a form of carbon with a high surface area due to its mode of preparation, adsorbs many compounds, including some toxic compounds. Water is passed through activated charcoal to remove such contaminants. This method is most commonly used in household water filters and fish tanks. Household filters for drinking water sometimes also contain silver, trace amounts of silver ions having a bactericidal effect. There are two types of carbon filtering. One is granular charcoal which is not very effective for removing many contaminants such has mercury, volitle organic chemicals(this is the most prevalent contaminant found in drinking water and is also not removed by reverse osmosis or distillation), asbestos, pesticides, disinfection by product (trihalomethanes), mtbe, pcbs etc.. A better for of carbon filtering is the use of a sub-micron solid block carbon filter which will remove all of the contaminants listed above. To find out if a particular product will take out all of those contaminants or to compare any products go to the National Sanitation Foundation at nsf.org and check under the health rating no 53, or check the California Health Certificate that comes with most filters. # Distilling: Distillation involves boiling the water to produce water vapour. The water vapour then rises to a cooled surface where it can condense back into a liquid and be collected. Because the solutes are not normally vaporized, they remain in the boiling solution. Even distillation does not completely purify water, because of contaminants with similar boiling points and droplets of unvaporized liquid carried with the steam. However, 99.9% pure water can be obtained by distillation. # Reverse osmosis: Mechanical pressure is applied to an impure solution to force pure water through a semi-permeable membrane. The term is reverse osmosis, because normal osmosis would result in pure water moving in the other direction to dilute the impurities. Reverse osmosis is theoretically the most thorough method of large-scale water purification available, although perfect semi-permeable membranes are difficult to create. # Ion exchange: Most common ion exchange systems use a zeolite resin bed and simply replace unwanted Ca²⁺ and Mg²⁺ ions with benign (soap friendly) Na⁺ or K⁺ ions. This is the common water softener. A more rigorous type of ion exchange swaps H⁺ ions for unwanted cations and hydroxide (OH^-) ions for unwanted anions. The result is H⁺ + OH^- → H₂O. This system is recharged with hydrochloric acid and sodium hydroxide, respectively. The result is essentially deionized water. # Electrodeionization: Water is passed between a positive electrode and a negative electrode. Ion selective membranes allow the positive ions to separate from the water toward the negative electrode and the negative ions toward the positive electrode. High purity de-ionized water results. The water is usually passed through a reverse osmosis unit first to remove nonionic organic contaminants. # Water conditioning: This is a method of reducing the effects of hard water. Hardness salts are deposited in water systems subject to heating because the decomposition of bicarbonate ions creates carbonate ions which crystalise out of the saturated solution of calcium or magnesium carbonate. Water with high concentrations of hardness salts can be treated with soda ash (Sodium carbonate) which precipitates out the excess salts, through the common ion effect, as calcium carbonate of very high purity. The preciptated calcium carbonate is traditionally sold to the manufacturers of toothpaste. #Plumbo-solvency reduction: In areas with naturally acidic waters of low conductivity (i.e surface rainfall in upland mountains of igneous rocks), the water is capable of dissolving lead from any lead pipes that it is carried in. The addition of small quantities of phosphate ion and increasing the pH slightly both assist in greatly reducing plumbo-solvency by creating insoluble lead salts on the inner surfaces of the pipes.

Portable water purification

Portable drinking water systems or chemical additives are available for hiking, camping, and travel in remote areas. Portable pump filters are commercially available with ceramic filters that will filter 5000 to 50,000 liters per cartridge. Some also utilize activated charcoal filtering. Chemical additives include chlorine dioxide or iodine solutions. Iodine, in solution, crystallized, or in tablets, is added to water. The iodine kills off many, but not all, of the most common pathogens that may be present in natural fresh water sources such as lakes, rivers, and streams. Carrying iodine for water purification is a lightweight but imperfect solution for those in need of field purification of drinking water. There are kits available in camping stores that include a iodine pill and a second pill that will remove the iodine taste from the water after it has been disinfected. Chlorine bleach can also be used as an emergency measure. The correct amount is dropped into the water, then it is covered for 30 minutes or 1 hour. After this it may be left open to reduce the chlorine smell and taste. Guidelines are available online for safe and effective use of bleach. [http://www.epa.gov/safewater/faq/emerg.html], [http://www.bchealthguide.org/healthfiles/hfile49b.stm] Neither chlorine (e.g. bleach) nor iodine alone is considered effective against Cryptosporidium, and they are limited in effectiveness against Giardia. (Chlorine is slightly better than iodine against Giardia. [http://www.epa.gov/safewater/faq/emerg.html], [http://www.bchealthguide.org/healthfiles/hfile49b.stm] SODIS (Solar Water Disinfection): Microbes are destroyed through temperature and UVA radiation, provided by the Sun. Water is placed in a transparent plastic bottle, which is oxygenated by shaking, followed by topping-up. It is placed on tile or metal for six hours in full sun, which raises the temperature and gives an extended dose of solar radiation, killing any microbes that may be present. The combination of the two provides a simple method of disinfection for tropical developing countries.

External links

- [http://www.hkc22.com/waterdisinfection.html Helmut Kaiser Consultancy water study]
- [http://www.cdc.gov/travel/food-drink-risks.htm CDC information on water purification techniques when travelling]
- [http://www.water-treatment.org.uk Water Treatment Information - UK]
- [http://www.epa.gov/safewater/faq/emerg.html Emergency Disinfection of Drinking Water] (US EPA)
- [http://www-cie.iarc.fr/htdocs/monographs/vol52/01-water.htm Chlorinated Drinking Water] (IARC Monograph)
- [http://ntp.niehs.nih.gov/ntp/htdocs/LT_rpts/tr392.pdf NTP Study Report TR-392: Chlorinated & Chloraminated Water] (US NIH)
- [http://www.isracast.com/tech_news/240805_tech.htm New UV Disinfection method] - An article
- [http://www.endfatigue.com chronic fatigue and fibromyalgia site] ja:浄水器 category:Drinking water

Water resources

Water resources are sources of water that are useful or potentially useful to humans. It is important because it is needed for life to exist. Many uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water. Only 3% of water on the Earth is fresh water, and over two thirds of this is frozen in glaciers and polar ice caps. Water demand already exceeds supply in many parts of the world, and many more areas are expected to experience this imbalance in the near future. The framework for allocating water resources to water users (where such a framework exists) is known as water rights.

Water and Conflict

Water and resources have rarely been sources of conflict. This fact has lead security experts to ignore the relationship between water and security. There is in fact a long history related to water and conflict. The use of water systems as weapons is just one of them.

Sources of Fresh Water

Surface Water

water rights Surface water is water in a river, lake or fresh water wetland. Surface water is naturally replenished by precipitation and naturally lost through discharge to the oceans, evaporation and sub-surface seepage. Although the sole natural input to any surface water system is precipitation within its watershed, the total quantity of water in that system at any given time is also dependent on many other factors. These factors include storage capacity in lakes, wetlands and artificial reservoirs, the permeability of the soil beneath these storage bodies, the runoff characteristics of the land in the watershed, the timing of the precipitation and local evaporation rates. All of these factors also affect the proportions of water lost through discharge to the oceans, evaporation and sub-surface seepage. Human activities can have a large impact on these factors. Humans often increase storage capacity by constructing reservoirs and decrease it by draining wetlands. Humans often increase runoff quantities and velocities by paving areas and channelizing stream flow. The total quantity of water available at any given time is an important consideration. Some human water users have an intermittent need for water. For example, many farms require large quantities of water in the spring, and no water at all in the winter. To supply such a farm with water, a surface water system may require a large storage capacity to collect water throughout the year and release it in a short period of time. Other users have a continuous need for water, such as a power plant that requires water for cooling. To supply such a power plant with water, a surface water system only needs enough storage capacity to fill in when average stream flow is below the power plant's need. Nevertheless, over the long term the average rate of precipitation within an watershed is the upper bound for average consumption of natural surface water from that watershed. Natural surface water can be augmented by importing surface water from another watershed through a canal or pipeline. It can also be artificially augmented from any of the other sources listed here, however in practice the quantities are negligible. Humans can also cause surface water to be "lost" (i.e. become unusable) through pollution.

Sub-Surface Water

pollution Sub-Surface water, or groundwater, is fresh water located in the pore space of soil and rocks. It is also water that is flowing within aquifers below the water table. Sometimes it is useful to make a distinction between sub-surface water that is closely associated with surface water and deep sub-surface water in an aquifer (sometimes called "fossil water"). Sub-surface water can be thought of in the same terms as surface water: inputs, outputs and storage. The critical difference is that for sub-surface water, storage is generally much larger compared to inputs than it is for surface water. This difference makes it easy for humans to use sub-surface water unsustainably for a long time without severe consequences. Nevertheless, over the long term the average rate of seepage above a sub-surface water source is the upper bound for average consumption of water from that source. The natural input to sub-surface water is seepage from surface water. The natural outputs from sub-surface water are springs and seepage to the oceans. If the surface water source is also subject to substantial evaporation, a sub-surface water source may become saline. This situation can occur naturally under endorheic bodies of water, or artificially under irrigated farmland. In coastal areas, human use of a sub-surface water source may cause the direction of seepage to ocean to reverse which can also cause salinization. Humans can also cause sub-surface water to be "lost" (i.e. become unusable) through pollution. Humans can increase the input to a sub-surface water source by building reservoirs or detention ponds. Water in the ground are in sections called aquifers. Rain rolls down and comes into these. Normally an aquifer is near to the equilibrium in its water content. The water content of an aquifier normally depens on the grain sizes. This means that the rate of extraction may be limited by poor permiability.

Desalinization

Desalinization is an artificial process by which saline water (generally ocean water) is converted to fresh water. The most common desalinization processes are distillation and reverse osmosis. Desalinization is currently very expensive, and is only practical to generate water for household use in arid areas.

Frozen Water

arid] Several schemes have been proposed to make use of icebergs as a water source, however to date this has only been done for novelty purposes. Glacier runoff is considered to be surface water.

Threats to Fresh Water

There are many things that are a threat to the Earths freash water supply. Here are a few of them.

Climate Change

Climate change will cause changes to the water because there will be more rainfall in some parts and less in others. It would also causes major droughts during the summer. It also means that high tempratures and lower water flows provide the perfect growth conditions for a toxic algae which forms through the process of eutrophication. Climate change could also mean an increase in demand for farm irrigation, garden sprinklers and perhaps even swimming pools.

Depletion of Aquifiers

Since competition for water is growing, underground aquifiers are becoming depleted. This is mainly due to irrigation by groundwater. Millions of small pumps are currently taking water out of aquifers to irrigate crops. Irrigation in dry areas such as India is supplied by groundwater.

Pollution and Water Protection

India Water pollution is one of the many concerns of the world today. World governments have strived to find solutions to eliminate this problem. One of these suggestions is the Kyoto Protocol. Many programs strive to protect our water resources. They are usually funded by donations from people who are generous.

Uses of Fresh Water

Uses of fresh water can be categorized as consumptive and non-consumptive (sometimes called "renewable"). A use of water is consumptive if that water is not immediately available for another use. Losses to sub-surface seepage and evaporation are considered consumptive, as is water incorporated into a product (such as farm produce). Water that can be treated and returned as surface water, such as sewage, is generally considered non-consumptive.

Agricultural

sewage] It is estimated that 70% of world-wide water use is for irrigation. In some areas of the world irrigation is necessary to grow any crop at all, in other areas it permits more profitable crops to be grown or enhances crop yield. Various irrigation methods involve different trade-offs between crop yield, water consumption and capital cost of equipment and structures. Another trade-off that is often insufficiently considered is salinization of sub-surface water. Aquaculture is a small but growing agricultural use of water. Freshwater commercial fisheries may also be considered as agricultural uses of water, but have generally been assigned a lower priority than irrigation (see Aral Sea and Pyramid Lake). Most people believe that irrigation wastes enormous quantities of water but if we be more efficient with irrigation, water would be made available for more than agriculture. The first people who grew plants needed to learn three tasks. They were how to put specific plants in an area, how to prevent weeds from growing and how to make them flourish. How ever in dry climates plants needed water. Since most of the water was salt water, there had to be enough water to flush out the salt. In well drained areas flushing occurs naturally.

Industrial

Pyramid Lake] It is estimated that 15% of world-wide water use is industrial. Major industrial users include power plants which use water for cooling or as a power source (i.e. hydroelectric plants), ore and oil refineries which use water in chemical processes, and manufacturing plants which use water as a solvent. The portion of industrial water usage that is consumptive varies widely, but as a whole is lower than agricultural use.

Household

oil It is estimated that 15% of world-wide water use is for household purposes. These include drinking water, cleaning water, sewage and landscape irrigation. Landscape irrigation is a major concern because it can cause the flooding of residential basements. Most household water is treated and returned to surface water systems, with the exception of water used for irrigation. Household water use is therefore less consumptive than agricultural or industrial uses.

Recreation

residential Water has a lot of recreational value. Recreational water use is a very small but growing percentage of total water use. Recreational water use is mostly tied to reservoirs. If a reservoir is kept fuller than it would otherwise be for recreation, then the water retained could be categorized as recreational usage. Release of water from a few reservoirs is also timed to enhance whitewater boating, which also could be considered a recreational usage. Other examples are anglers, water skiers, nature enthusiasts and swimmers. Recreational usage is non-consumptive. However it may reduce the availability of water for other users at specific times and places. For example, water retained in a reservoir to allow boating in the late summer is not available to farmers during the spring planting season. Water released for whitewater rafting may not be available for hydroelectric generation during the time of peak electrical demand.

Environmental

whitewater Explicit environmental water use is also a very small but growing percentage of total water use. Environmental water usage includes artificial wetlands, artificial lakes intended to create wildlife habitat, fish ladders around dams, and water releases from reservoirs timed to help fish spawn. Like recreational usage, environmental usage is non-consumptive but may reduce the availability of water for other users at specific times and places. For example, water release from a reservoir to help fish spawn may not be available to farms upstream.

World Water, Supply and Distribution

dam Food and water are two basic human needs. As the picture shows in 2025 much of the water will belong to the rich countries of the world and the poorer countries will suffer. By 2025 much of the worlds popualtion will live in urban and peri-urban areas.This means that the people and industries in these areas will be using a large share of the Earths water. Much of this water to supply these areas will come from irrigation.

Refrences/Sources

- [http://water.usgs.gov/ Water Resources of the United States]
- [http://www.iwra.siu.edu/ International Water Resources Association]
- [http://www.cwra.org/ Canadian Water Resoures Association]
- [http://www.awra.org/ American Water Resoures Association]
- [http://ag.arizona.edu/AZWATER/ Water Resource Research Center]
- [http://www.environment-agency.gov.uk/yourenv/639312/641094/642206/642375/642736/?lang=_e "Threats to water resources"] by the Environment Agency
- [http://www.geology.ucdavis.edu/~cowen/~GEL115/115CH17oldirrigation.html Ancient Irrigation] from the University of California, Geology Department
- [http://www.geology.ucdavis.edu/~cowen/~GEL115/115CH18miningwater.html Mining Water] from the University of California, Geology Department
- [http://www.worldwater.org/data.html The World's Water]
- [http://www.uleth.ca/vft/Oldman_River/WaterUses.html Uses for Water...]
- [http://www.galileo.org/schools/crowther/science/blueplanet/future.html Future Sources of Fresh Water]
- [http://www.iwmi.cgiar.org/pubs/WWVisn/WWSDHtml.htm World Water Supply and Demand: 1995 to 2025] from the International Water Management Institute

Bottled water

Bottled water is drinking water, usually spring water or mineral water, or simply water that has been treated, and is sold in a sealed portable bottle. The worldwide bottled water industry is worth an estimated $22bn annually. For health reasons, it is preferred in areas where the water is either too polluted or infested, but nowadays, bottled water is becoming increasingly favoured over tap water because it usually contains far less fluoride and chlorine, which are often included in tap water during processing. See fluoridation and chlorination. As with many heavily marketed products, there may be a certain snob value to some of the more expensive brands of bottled water. In a somewhat ironic twist, many brands are marketed focusing on both the taste and the purity of the water; however, pure water has no taste.

Bottled water sources

The most common types of bottled water are the following:
- mineral water - spring water that has a higher mineral content
- purified water - surface or underground water that has been treated for human consumption
- spa water - water taken from a spa
- carbonated water (sparkling) - treated with carbon dioxide to make it bubbly