Common Contaminants in Your Drinking Water

Materials dissolved in water: Inorganic Compounds - Compounds that typically do not contain the element Carbon. They can become dissolved in water from natural sources or as the result of human activity.

Dissolved gases (oxygen, carbon dioxide, nitrogen, radon, methane, hydrogen sulfide, etc.) - no appreciable health effects, except for hydrogen sulfide and dissolved radioactive gases like radon. Both methane and hydrogen sulfide can be inflammable. Carbon dioxide dissolved in water creates carbonic acid - a weak acid that gives carbonated water its "bite" and plays an important role in the weathering of limestone and other carbonate rocks. Caverns are a product of eons of erosion by carbonic acid laced water.

Metal and metalloid positive ions - (aluminum, arsenic {MCL=0.05}, lead {MCL=0.015}, mercury {MCL=0.002}, calcium, magnesium, sodium, potassium, zinc, copper {MCL=1.3}, etc.) Some of these ions (lead, mercury, and arsenic) are dangerous at extremely low concentrations and can be introduced into drinking water either though natural processes or as a result of human activity. Other ions in this group (for example, calcium, magnesium, sodium, and potassium) are essential to human health - in the correct amounts. Calcium and magnesium are interesting ions. Although their presence in drinking water is actually a health benefit, they are the prime culprits in most hard water, and are considered undesirable contaminants by those who must live with scaly deposits of calcium carbonate on their faucets (and in their pipes and water heaters) or who can not get their soap to lather.

Negative ions - (fluoride {MCL=4.0}, chloride, nitrate {MCL=10.0}, nitrite {MCL=1.0}, phosphate, sulfate, carbonate, cyanide {MCL=0.2}) As with the positive ions, some of these negative ions are necessary to life in proper concentrations (chloride and carbonate), others can be dangerous to health at moderate concentrations (nitrates and nitrites - look at the ingredients in the next slice of ham, bacon, or hot dog you eat), and others are dangerous at even small concentrations (cyanide).Some, like fluoride, have raised quite a controversy over its safety as an additive (in many areas) to drinking water in an effort to lessen tooth decay, particularly in children.

Radon - Radon is a radioactive gas that comes from the natural breakdown (radioactive decay) of radium, which is a decay product of uranium. The primary source of radon in homes is from the underlying soil and bedrock. However, an additional source could be the water supply, particularly if the house is served by a private well or a small community water system.

Organic Compounds - These compounds all contain the element Carbon. Although there are many exceptions, naturally occurring organic compounds (sugars, proteins, alcohol's, etc.) are synthesized in the cells of living organisms, or like raw petroleum and coal, formed by natural processes acting on the organic chemicals of once living organisms.

Synthetic Organic Chemicals - Organic chemicals can also be synthesized in laboratories and by chemical companies. A growing number of these synthetic organic compounds are being produced. They can include pesticides used in agriculture, plastics, synthetic fabrics, dyes, gasoline additives like MTBE, solvents like carbon tetrachloride {MCL=0.005}, and many other chemicals. Many synthetic organic chemicals, like benzene {MCL=0.005} carbon tetrachloride, and vinyl chloride {MCL=0.002}, vaporize easily in air and are grouped under the category of volatile organic chemicals (VOCs). Methyl tertiary butyl ether (MTBE) is a common synthetic organic chemical used for a number of years as a gasoline additive.

Water purification

From Wikipedia, the free encyclopedia

Water purification is the process of removing contaminants and other harmful microorganisms from a raw water source. The goal is to produce water for a specific purpose with a treatment profile designed to limit the inclusion of specific materials; most water is purified for human consumption (drinking water). Water purification may also be designed for a variety of other purposes, including to meet the requirements of medical, pharmacology, chemical and industrial applications. Methods include, but are not limited to: ultraviolet light, filtration, water softening, reverse osmosis, ultrafiltration, deionization and powdered activated carbon treatment.

Water purification may remove: particulate sand; suspended particles of organic material; parasites, Giardia; Cryptosporidium; bacteria; algae; viruses; fungi; minerals such as calcium, silica, and magnesium; and toxic metals like lead, copper, and chromium. Some purification may be elective in the purification process, including smell (hydrogen sulfide remediation), taste (mineral extraction), and appearance (iron incapsulation).

Governments usually dictate the standards for drinking water quality. These standards will require minimum / maximum set points of contaminants and the inclusion of control elements that produce drinking water. Quality standards in many countries require specific amounts of disinfectant (such as chlorine) in the water after it leaves the water treatment plant (WTP), to reduce the risk of re-contamination while the water is in the distribution system.

It is not possible to tell whether water is safe to drink just by looking at it. Simple procedures such as boiling or the use of a household activated carbon filter are not sufficient for treating all the possible contaminants that may be present in water from an unknown source. Even natural spring water - considered safe for all practical purposes in the 1800s - must now be tested before determining what kind of treatment, if any, is needed. Chemical analysis, while expensive, is the only way to obtain the information necessary for deciding on method of purification.

According to a 2007 World Health Organization report, 1.1 billion people lack access to an improved drinking water supply, 88% of the 4 billion annual cases of diarrheal disease are attributed to unsafe water and inadequate sanitation and hygiene, and 1.8 million people die from diarrheal diseases each year. The WHO estimates that 94% of these diarrheal cases are preventable through modifications to the environment, including through access to safe water.[1] Simple techniques for treating water at home, such as chlorination, filters, and solar disinfection, and storing it in safe containers could save a huge number of lives each year.[2]