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Water covers 71% of the earth's surface and is vital to all known forms of life. More than two billion people still lack access to clean, safe water. Less than 1 percent of the earth’s freshwater is accessible to us. Unsafe water kills more people each year than war and all other forms of violence combined. Meanwhile, our drinkable water sources are finite and without action, the challenges will only increase by 2030, when global demand for freshwater is expected to be one-third greater than it is now. 


Municipal water (tapwater) varies greatly in its purity, chemical constitution, pH, and molecular qualities. Bottled waters (filtered, distilled, spring, and others) also vary greatly in their properties. Much debate exists as to the best drinking water and various purification systems.


For more information on drinking water quality and recently discovered properties of water visit here.

The availability of safe drinking water is essential for health and well-being of humans and animals all over the world. Traditionally, microbiological quality of drinking water has attracted the most attention and this is still an ongoing issue in a large part of the world. The provision of safe drinking water, with respect to pathogens since the second half of the nineteenth century, has virtually eliminated the spread of infectious waterborne diseases, such as typhoid fever and cholera in most countries. However, during the last few decades, attention towards chemical contamination in ground and surface water has grown together with the knowledge of these toxic chemical compounds and their detrimental health effects.


Water contaminants are introduced by all kinds of human activities, such as agriculture, shipping, industry, and use of chemicals in households. Some of the chemicals affecting human health are the presence of toxic metals such as arsenic, lead, cadmium, mercury, copper, etc., as well as hundreds, if not thousands, of petrochemicals, chlorinated solvents, pesticides, nitrates and even pharmaceuticals. The toxic chemical fluoride is also intentionally added to water, as is chlorine.


Clearly, the agricultural sector is not only the biggest consumer of global freshwater resources, with farming and livestock production using about 70 percent of the earth’s surface water supplies, but it is also a serious water polluter. Around the world, agriculture is the leading cause of water degradation. In the United States, agricultural pollution is the top source of contamination in rivers and streams, the second-biggest source in wetlands, and the third main source in lakes. It is also a major contributor of contamination to estuaries and groundwater. Pesticides, such as herbicides, fungicides, insecticides, plant growth regulators, bactericides, and defoliants have been a topic of concern for surface water quality for decades. Every time it rains, fertilizers, pesticides, and animal waste from farms and livestock operations wash nutrients and pathogens into our waterways. Nutrient pollution, caused by excess nitrogen and phosphorus in water or air, is the number-one threat to water quality worldwide and can cause algal blooms, a toxic soup of blue-green algae that can be harmful to people and wildlife.


Industry, mining and wastewater are also responsible for contaminating water with heavy metals and hundreds of chemicals. Several toxic industrially solvents are regularly detected in surface waters. Many of these contaminants are poisonous to aquatic life, often reducing an organism’s life span and ability to reproduce and make their way up the food chain as predator eats prey. That is how tuna and other big fish accumulate high quantities of toxins, such as mercury.


The U.S. Environmental Protection Agency (EPA) has set standards for more than 80 contaminants that may occur in drinking water and pose a risk to human health. The contaminants fall into two groups (acute and chronic) according to the health effects that they cause. 


Acute effects occur within hours or days of the time that a person consumes a contaminant. People can suffer acute health effects from almost any contaminant if they are exposed to extraordinarily high levels (as in the case of a spill). In drinking water, microbes, such as bacteria and viruses, are the contaminants with the greatest chance of reaching levels high enough to cause acute health effects. Most people’s bodies can fight off these microbial contaminants the way they fight off germs, and these acute contaminants typically do not have permanent effects. Nonetheless, when high enough levels occur, they can make people ill, and can be dangerous or deadly for a person whose immune system is already weakened.


Chronic effects occur after people consume a contaminant at levels over EPA’s safety standards over the course of many years. The drinking water contaminants that can have chronic effects include chemicals (such as disinfection byproducts, solvents and pesticides), radionuclides (such as uranium, radium), and toxic elements (such as arsenic, mercury and lead).

Examples of these chronic effects include cancer, liver or kidney problems, or reproductive difficulties.


The Safe Drinking Water Act of 1974, as amended, includes requirements for the Environmental Protection Agency (EPA) to set standards for only 83 specific contaminants. The limited selection is based on the potential for causing adverse health effects and for known or potential occurrence in drinking water. 

The following water treatment technologies are effective in reducing arsenic from drinking water:

1. Activated alumina filters
2.Anion exchange
4. Reverse Osmosis
6. Iron Oxide Filters

General Information

Bove, Frank, Youn Shim, and Perri Zeitz. "Drinking water contaminants and adverse pregnancy outcomes: a review." Environmental health perspectives 110, no. suppl 1 (2002): 61-74.

Daughton, Christian G. "Non-regulated water contaminants: emerging research." Environmental Impact Assessment Review 24, no. 7-8 (2004): 711-732.

Grabow, W. O. K. "Waterborne diseases: Update on water quality assessment and control." Water Sa 22, no. 2 (1996): 193-202.

IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, World Health Organization, and International Agency for Research on Cancer. Some drinking-water disinfectants and contaminants, including arsenic. Vol. 84. IARC, 2004.

Medema, Gertjan J., Pierre Payment, Alain Dufour, W. Robertson, M. Waite, P. Hunter, R. Kirby, and Y. Andersson. "Safe drinking water: an ongoing challenge." Assessing Microbial Safety of Drinking Water 11 (2003).

Vodela, J. K., S. D. Lenz, J. A. Renden, W. H. McElhenney, and B. W. Kemppainen. "Drinking water contaminants (arsenic, cadmium, lead, benzene, and trichloroethylene). 2. Effects on reproductive performance, egg quality, and embryo toxicity in broiler breeders." Poultry science 76, no. 11 (1997): 1493-1500.


Waterborne arsenic is a major cause of disease in many parts of the world including the Indian sub-continent—particularly Bangladesh and Bengal—South America, and the Far East. Many wells in North America are contaminated with arsenic. It has been associated with skin, lung, and bladder cancers, vascular diseases, hypertension, diabetes and birth defects. A primary source of arsenic in drinking water wells is from water flowing through arsenic-rich rocks and soil. It can be further released into the environment through natural activities such as volcanic action and forest fires, as well as through human actions. Arsenic is used in paints, dyes, metals, drugs, soaps, and semiconductors. Agricultural applications, mining, and smelting also contribute to arsenic releases in the environment. These can enter the groundwater system by gradually moving with the flow of groundwater from rains, melting of snow, etc. Testing water for arsenic in areas where arsenic is a concern is an important strategy for private water well owners to safeguard the health and well-being of their family.


Hopenhayn, Claudia, Catterina Ferreccio, Steven R. Browning, Bin Huang, Cecilia Peralta, Herman Gibb, and Irva Hertz-Picciotto. "Arsenic exposure from drinking water and birth weight." Epidemiology (2003): 593-602.


In order to frack, an enormous amount of water is mixed with various toxic chemical compounds to create frack fluid. This frack fluid is further contaminated by the heavy metals and radioactive elements that exist naturally in the shale. A significant portion of the frack fluid returns to the surface, where it can spill or be dumped into rivers and streams. Underground water supplies can also be contaminated by fracking, through migration of gas and frack fluid underground.

Some of the chemicals that comprise frack fluid are highly toxic and cancer causing, like Benzene, Toluene, 2-butoxyethanol (a main ingredient to anti-freeze and oil dispersants), and heavy metals. The Endocrine Disruptor Exchange identified 353 chemicals used in fracking, many of which can cause cancer and other serious health effects, even in small doses. Once the frack fluid mixture is injected into the ground it can also pick up or entrain further contaminants, like radium, a cancer-causing radioactive particle found deep within the Marcellus and other shales.  Radium has a half-life of over 1,000 years and is produced from Uranium, which has a much longer half-life.  


Gordalla, Birgit C., Ulrich Ewers, and Fritz H. Frimmel. "Hydraulic fracturing: a toxicological threat for groundwater and drinking-water?Environmental earth sciences 70, no. 8 (2013): 3875-3893.

Holzman, David C. "Methane found in well water near fracking sites." (2011): a289-a289.


Kuwayama, Yusuke, Sheila Olmstead, and Alan Krupnick. "Water quality and quantity impacts of hydraulic fracturing." Current Sustainable/Renewable Energy Reports 2, no. 1 (2015): 17-24.

Myers, Tom. "Potential contaminant pathways from hydraulically fractured shale to aquifers." Groundwater 50, no. 6 (2012): 872-882.


Osborn, Stephen G., Avner Vengosh, Nathaniel R. Warner, and Robert B. Jackson. "Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing." proceedings of the National Academy of Sciences 108, no. 20 (2011): 8172-8176.

Rozell, Daniel J., and Sheldon J. Reaven. "Water pollution risk associated with natural gas extraction from the Marcellus Shale." Risk Analysis: An International Journal 32, no. 8 (2012): 1382-1393.


 Willow, Anna J., and Sara Wylie. "Politics, ecology, and the new anthropology of energy: exploring the emerging frontiers of hydraulic fracking." Journal of Political Ecology 21, no. 1 (2014): 222-236.


Lead is a toxic metal that is harmful to human health; there is NO safe level for lead exposure. Lead can enter drinking water when plumbing materials that contain lead corrode, especially where the water has high acidity or low mineral content that corrodes pipes and fixtures. The most common sources of lead in drinking water are lead pipes, faucets, and fixtures. In homes with lead pipes that connect the home to the water main, also known as lead services lines, these pipes are typically the most significant source of lead in the water.  Lead pipes are more likely to be found in older cities and homes built before 1986.  Among homes without lead service lines, the most common problem is with brass or chrome-plated brass faucets and plumbing with lead solder.


Young children, infants, and fetuses are particularly vulnerable to lead because the physical and behavioral effects of lead occur at lower exposure levels in children than in adults. A dose of lead that would have little effect on an adult can have a significant effect on a child. In children, low levels of exposure have been linked to damage to the central and peripheral nervous system, learning disabilities, shorter stature, impaired hearing, and impaired formation and function of blood cells.


Elfland, Carolyn, Paolo Scardina, and Marc Edwards. "Lead‐contaminated water from brass plumbing devices in new buildings." Journal‐American Water Works Association 102, no. 11 (2010): 66-76.

Fertmann, Regina, Stefan Hentschel, Dorothee Dengler, Ulrich Janßen, and Annette Lommel. "Lead exposure by drinking water: an epidemiologial study in Hamburg, Germany." International journal of hygiene and environmental health 207, no. 3 (2004): 235-244.

Renner, Rebecca. "Out of plumb: when water treatment causes lead contamination." (2009): A542-A547.

Zietz, Björn P., Jessica Laß, Roland Suchenwirth, and Hartmut Dunkelberg. "Lead in drinking water as a public health challenge." Environmental health perspectives 118, no. 4 (2010): A154-A155.


Pharmaceuticals and their metabolites can reach water bodies through sewage systems, industrial discharges, effluents from sewage treatment plants (STPs), aquaculture, and livestock farming. Pharmaceuticals include a hundred substances which are very different in regards to chemical–physical properties and environmental behavior, although they may have strong biochemical activities. Their presence in the aquatic environment and impact on aquatic biota and on human health have not yet been studied adequately. Experimental evidence indicates that pharmaceuticals may cause harmful effects, such as morphological, metabolic and sex alterations on aquatic species, and induction of antibiotic resistance in aquatic pathogenic microorganisms.

Barnes, Kimberlee K., Dana W. Kolpin, Edward T. Furlong, Steven D. Zaugg, Michael T. Meyer, and Larry B. Barber. "A national reconnaissance of pharmaceuticals and other organic wastewater contaminants in the United States—I) Groundwater." Science of the total environment 402, no. 2-3 (2008): 192-200.


Benotti, Mark J., Rebecca A. Trenholm, Brett J. Vanderford, Janie C. Holady, Benjamin D. Stanford, and Shane A. Snyder. "Pharmaceuticals and endocrine disrupting compounds in US drinking water." Environmental science & technology 43, no. 3 (2009): 597-603.

Buser, Hans-Rudolf, Markus D. Müller, and Norbert Theobald. "Occurrence of the pharmaceutical drug clofibric acid and the herbicide mecoprop in various Swiss lakes and in the North Sea." Environmental Science & Technology 32, no. 1 (1998): 188-192.

Fent, Karl, Anna A. Weston, and Daniel Caminada. "Ecotoxicology of human pharmaceuticals." Aquatic toxicology 76, no. 2 (2006): 122-159.

Gilbert, Natasha. "Drug waste harms fish." Nature 476, no. 7360 (2011): 265.

Kidd, Karen A., Paul J. Blanchfield, Kenneth H. Mills, Vince P. Palace, Robert E. Evans, James M. Lazorchak, and Robert W. Flick. "Collapse of a fish population after exposure to a synthetic estrogen." Proceedings of the National Academy of Sciences 104, no. 21 (2007): 8897-8901.

Kolpin, Dana W., Edward T. Furlong, Michael T. Meyer, E. Michael Thurman, Steven D. Zaugg, Larry B. Barber, and Herbert T. Buxton. "Pharmaceuticals, hormones, and other organic wastewater contaminants in US streams, 1999− 2000: A national reconnaissance." Environmental science & technology 36, no. 6 (2002): 1202-1211.

Snyder, Shane A., and Mark J. Benotti. "Endocrine disruptors and pharmaceuticals: implications for water sustainability." 

Water Science and Technology 61, no. 1 (2010): 145-154.


Volatile Organic Chemicals (VOC)

The U.S. Environmental Protection Agency reported that the presence of elevated VOC concentrations in drinking water may be a concern to human health because some VOCs are carcinogens and/or may adversely affect the liver, kidneys, spleen, and stomach, as well as the nervous, circulatory, reproductive, immune, cardiovascular, and respiratory systems. Some VOCs may affect cognitive abilities, balance, and coordination, and some are eye, skin, and/or throat irritants.

Andelman, Julian B. "Inhalation exposure in the home to volatile organic contaminants of drinking water." Science of the Total Environment 47 (1985): 443-460.

Barbash, Jack, and Paul V. Roberts. "Volatile organic chemical contamination of groundwater resources in the US." Journal (Water Pollution Control Federation) 58, no. 5 (1986): 343-348.

Brown, Halina Szejnwald, Donna R. Bishop, and Carol A. Rowan. "The role of skin absorption as a route of exposure for volatile organic compounds (VOCs) in drinking water." American journal of public health 74, no. 5 (1984): 479-484.

Fagliano, Jerry, Michael Berry, Frank Bove, and Thomas Burke. "Drinking water contamination and the incidence of leukemia: an ecologic study." American journal of public health 80, no. 10 (1990): 1209-1212.

Giger, W., and Ch Schaffner. "Groundwater pollution by volatile organic chemicals." In Studies in environmental science, vol. 17, pp. 517-522. Elsevier, 1981.

Kavcar, Pınar, Mustafa Odabasi, Mehmet Kitis, Fikret Inal, and Sait C. Sofuoglu. "Occurrence, oral exposure and risk assessment of volatile organic compounds in drinking water for Izmir." Water Research 40, no. 17 (2006): 3219-3230.

Little, John C. "Comment on" Human exposure to volatile organic compounds in household tap water: the indoor inhalation pathway"." Environmental science & technology 26, no. 4 (1992): 836-837.

Wallace, L. A. "Human exposure and body burden for chloroform and other trihalomethanes." Critical reviews in environmental science and technology 27, no. 2 (1997): 113-194.

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