Fluoride in drinking water

Municipal water suppliers began adding fluoride to the water in the 1940s to improve the dental health of their customers (Gessner, Beller, Middaugh, & Whitford, 1994; Hausen, 2000). Chemical additives that reach the taps in homes has long been controversial. One very good reason for concern for customers of water suppliers that add fluoride to tap water is that suppliers seem to have very inadequate control over the amount of fluoride that flows from the tap.

Simple fluoride poisoning manifests as tingling or numbness in the extremities, nausea, diarrhea, vomiting, and abdominal pain (Gessner et al., 1994).  Since at least the 1980s, assertions of a connection between drinking water fluoridation and bone cancer, particularly among children and adolescents have led to scientific studies, which seem to consistently provide no statistical support for the assertions (Levy & Leclerc, 2012). While Whiting, McDonagh, and Kleijnen (2001) found scientific studies looking at a possible relationship between fluoridation and Down’s Syndrome to be inconclusive, Lowry, Steen, and Rankin (2003), in a study in the north of England, found no statistically significant relationship between fluoridation and congenital defects.

Whether a consumer wants fluoride in their drinking water or not appears to depend on what result the consumer wants. Fluoride, in proper concentrations, does seem to improve dental health. Fluoride may have undesired consequences, but clear support for those assertions seems lacking. However, for consumers who want fluoride removed, whole home filtration using alumina or reverse osmosis are available.


Gessner, B. D., Beller, M., Middaugh, J. P., & Whitford, G. M. (1994). Acute fluoride poisoning from a public water system. The New England Journal of Medicine, 330(2), 95-99.

Hausen, H. W. (2000, October 7). Fluoridation, fractures, and teeth. BMJ: British Medical Journal (International Edition). p. 844.

Levy, M., & Leclerc, B. (2012). Fluoride in drinking water and osteosarcoma incidence rates in the continental united states among children and adolescents. Cancer Epidemiology, 36(2), e83-8. doi:http://dx.doi.org/10.1016/j.canep.2011.11.008

Mahoney, M. C., Nasca, P. C., Burnett, W. S., & Melius, J. M. (1991). Bone Cancer Incidence Rates in New York State: Time Trends and Fluoridated Drinking Water. American Journal Of Public Health, 81(4), 475-479.

Suarez-Almazor, M. E., Flowerdew, G., Saunders, L. D., Soskolne, C. L., & Russell, A. S. (1993). The Fluoridation of Drinking Water and Hip Fracture Hospitalization Rates in Two Canadian Communities. American Journal Of Public Health, 83(5), 689-693.

Whiting, P., McDonagh, M., & Kleijnen, J. (2001). Association of Down’s syndrome and water fluoride level: a systematic review of the evidence. BMC Public Health, 16-8.

Calcium and magnesium in drinking water and human health

Calcium and magnesium are the primary components in water that people associate with hard water. Many people would not notice were it not for the telltale white buildup on faucets and fixtures that people recognize as hard water residue. What you don’t like on your showerheads and faucets is essential for human health.

Water hardness seems to be inversely correlated with heart attacks (myocardial infarctions; Rubenowitz, Axelsson, & Rylander, 1996), specifically the magnesium (Rubenowitz, Axelsson, & Rylander, 1998), rather than the calcium, in the water. Calcium and magnesium, which traditional water softeners replace with sodium and potassium, is necessary for proper functioning of cells, including neuromuscular functions; magnesium activates the enzyme essential to this functioning. The heart is a muscle in humans and other animals and its proper functioning depends on magnesium, which water softeners intentionally remove.

Scientific studies find significant correlation between drinking water and cancer. Water hardness also seems to be inversely correlated with deaths from colon cancer (Yang & Hung, 1998). In this case, the primary benefactor seems to be calcium rather than magnesium in the drinking water. Yang, Chiu, Cheng, Tsai, Hung, and Lin (1999) noted that water hardness is similarly inversely correlated with esophageal cancer mortality.

Scientific research consistently finds benefits to calcium and magnesium in the human diet. For many people, the calcium and magnesium found in their municipally-supplied water in their homes is a primary dietary source. Traditional, ion-exchange water softeners replaces the calcium and magnesium that your body needs, but your fixtures do not, with sodium and potassium, which your cells also need, but which have documented detrimental side effects. A template-assisted crystallization system from Water4 Systems does not remove the calcium and magnesium, but simply converts it into a form that will not, or at least only nominally, build up on a home’s fixtures and surfaces.


Nerbrand, C., Agréus, L., Lenner, R. A., Nyberg, P., & Svärdsudd, K. (2003). The influence of calcium and magnesium in drinking water and diet on cardiovascular risk factors in individuals living in hard and soft water areas with differences in cardiovascular mortality. BMC Public Health, 321-9.

Rubenowitz, E., Axelsson, G., & Rylander, R. (1996). Magnesium in drinking water and death from acute myocardial infarction. American journal of epidemiology, 143(5), 456-462.

Rubenowitz, E., Axelsson, G., & Rylander, R. (1998). Magnesium in drinking water and body magnesium status measured using an oral loading test. Scandinavian Journal Of Clinical & Laboratory Investigation, 58(5), 423-428. doi:10.1080/00365519850186409

Yang, C. Y., Chiu, H. F., Cheng, M. F., Tsai, S. S., Hung, C. F., & Lin, M. C. (1999). Esophageal cancer mortality and total hardness levels in Taiwan’s drinking water. Environmental research, 81(4), 302-308. doi:10.1006/enrs.1999.3991

Yang, C., & Hung, C. (1998). Colon cancer mortality and total hardness levels in Taiwan’s drinking water. Archives of Environmental Contamination and Toxicology, 35(1), 148-151. doi: 10.1007/s002449900362


Low Magnesium and Type 2 Diabetes


Longstreet, Heath, Panaretto, and Vink (2007) observed that native Australians are diagnosed with and die from Type 2 Diabetes in significant numbers.  They reported that clinical data has established a correlation between low magnesium intake and Type 2 Diabetes and between low magnesium levels, hypomagnesaemia, and complications from diabetes.  They examined associations between diabetes and magnesium in the diet and in the drinking water of the Aboriginal and Torres Strait Islander peoples of Australia, in addition to several demographic factors.  They concluded that diets high in magnesium reduced the risk of diabetes by 33-34%.

Longstreet et al. (2007) found a significant correlation between reduced magnesium levels in drinking water and death due to diabetes, when adjusting the mortality figures for age.  They concluded that lower intake and replenishment of magnesium through the drinking water significantly increases the risk of hypomagnesaemia, which significantly increases the risk of Type 2 Diabetes and death from diabetes in the population they studied.  They noted the need for further research before generalizing their findings beyond the indigenous Australian population.

Longstreet et al. (2007) noted that drinking water typically supplies between 6% and 31% of the recommended daily allowance of magnesium.  Ferrandiz et al. (2004), cited by Longstreet et al. (2007), reported a correlation between increased water hardness and reduced chronic disease, including diabetes, but water softening and other water conditioning removes magnesium from the drinking water. Restoring magnesium to the drinking water or supplementation high in magnesium appear to be the alternatives available to adequately replenish the magnesium most commonly lost via perspiration.


Ferrandiz, J., Abellan, J.J., Gomez-Rubio, V., Lopez-Quilez, A., Sanmartin, P., Abellan, C. et al. (2004). Spatial analysis of the relationship between mortality from cardiovascular and cerebrovascular disease and drinking water hardness. Environmental Health Perspectives, 112, 1037-1044.

Longstreet, D., Heath, D., Panaretto, K., Vink, R. (2007). Correlations suggest low magnesium  may lead to higher rates of type 2 diabetes in Indigenous Australians? Rural and Remote Health 7, 843

Disinfection byproducts in drinking water and skin cancer

Karagas, Villanueva, Nieuwenhuijsen, Weisel, Cantor, and Kogevinas (2008), citing Villanueva et al. (2007), noted increasing evidence of increased cancer risk, particularly skin cancers, from absorption of disinfectant byproducts through bathing, showering, and swimming.  Karagas et al. asserted that the increased risk of basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) warranted further study.  The Karagas et al. study sample consisted of 293 SCC cases, 603 BCC cases, and 540 controls in a review of reported trihalomethane  levels in the municipal water supplies associated with the study participants, each of whom was in New Hampshire.


Karagas, M., Villanueva, C., Nieuwenhuijsen, M., Weisel, C., Cantor, K., & Kogevinas, M.  (2008). Disinfection byproducts in drinking water and skin cancer? A hypothesis.  Cancer Causes Control, 19, 547–548. doi: 10.1007/s10552-008-9116-y

Villanueva, C., Cantor, K., Grimalt, J., Castaño-Vinyals, M., Silverman, D., Tardon, A., Garcia-Closas, R., Serra, C., Carrato, A., Rothman, N., Real, P., Dosemeci, M., & Kogevinas, M. (2007). Bladder cancer and exposure to disinfection byproducts in water through ingestion, bathing, showering and swimming in pools: Findings from the Spanish Bladder Cancer Study. American Journal of Epidemiology, 165, 148–156.

Drinking Water and Cancer

Contaminants enter the drinking water supply in one of three ways.  Contaminants may enter the source water.  Contaminants may be added to the water during the treatment process.  The consumer may also add contaminants to the drinking water supply.  Morris (1995) noted that arsenic, asbestos, radon, agricultural chemicals, and hazardous waste are primary concerns, although chlorine and chlorine byproducts receive increased attention as carcinogens.  Arsenic is associated with liver, lung, bladder, and kidney cancers.  The byproducts of chlorination of municipal water supplies may contribute to 5000 bladder cancer cases and 8000 rectal cancer cases annually in the United States alone.  Morris reported no such apparent risks associated with fluoridation.  Morris also noted that the risk of asbestos in drinking water does not appear significant and that radon in drinking water may contribute to 100 cancer cases annually in the United States.  The primary likely source of asbestos in the drinking water is concrete-asbestos pipes in the water distribution system.

DeRouen and Diem (1975) reviewed the concerns raised by the Environmental Defense Fund and the Environmental Protection Agency over the presence of 66 chemicals in the water supply of New Orleans, LA.  The authors noted the increased risk of urinary tract and gastrointestinal cancers related to the presence of the chemicals and encouraged a new primary water supply source or improved purification methods.  Kuzma, Kuzma, and Buncher (1977) wrote of similar concerns over stomach and bladder cancers due to exposure to volatile organic compounds in public water supplies in Ohio.

Morris (1995) noted the increasing concern about biologically active micropollutants or endocrine disrupters.  These compounds may disturb normal intercellular communications and, as a consequence, disrupt certain biological functions.

Morris (1995) reported that the evidence relating volatile organic compounds and hazardous waste in general in drinking water to leukemia seems weak.  Trichlorethylene leaching from plastic liners within concrete pipes seems associated with increased leukemia risk.  Morris observed that chlorination, despite the risks, continues to provide benefits in the water distribution process.  The key for consumers may be to remove the chlorine and chlorine byproducts at the end of the water distribution system, after it enters the home or other point of use.

Koivusalo, Vartiainen, Pukkala, and Jaakkola (1995), studying the presence of certain chlorine byproducts in drinking water in Finland in relation to the certain cancers, concluded that the presence of acidic, mutagenic compounds in drinking water increases risk of lymphomas and pancreatic cancer.  Koivusalo et al. looked at both volatile and non-volatile organic compounds with and without consideration of pH.  Koivusalo et al. expressed specific concern about the presence of 3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone, also known as mutagen X, because its production as chlorine byproduct does not seem to be pH dependent. Koivusalo et al. previously  noted the increased risk of exposure to such compounds for urinary tract and gastrointestinal cancers (Koivusalo, Jaakkola, Varliainen, Hakulinen, Karialainen, Pukkala, &  Tuomisto, 1994).  Mancaş, Vartiainen, Rantakokko, Navrotescu, Diaconu, Mancaş, and Diaconu (2002) did a comparable study in Romania with similar conclusions.

Doyle, Zheng, Cerhan, Hong, Sellers, Kushi, and Folsom (1997) noted, based on a study of postmenopausal women in Iowa, that chlorination of drinking water and exposure to chlorination byproducts appears to increase the likelihood of colon and other cancers in women.

Margel and Fleshner (2011) noted a possible relationship between exposure to estrogen in drinking water supplies and prostate cancer.  The study analyzed data from 87 countries and concluded that oral contraceptive use seems to have a high likelihood of being the source for estrogen in drinking water.


DeRouen, T., & Diem, J. (1975). The New Orleans drinking water controversy: A statistical perspective.  American Journal of Public Health, 65(10), 1060-1062.

Doyle, T., Zheng, W.,  Cerhan, J., Hong, C., Sellers, T., Kushi, L., & Folsom, A. (1997). The association of drinking water source and chlorination by-products with cancer incidence among postmenopausal women in Iowa: A prospective cohort study. American Journal of Public Health, 87(7), 1168-1176.

Koivusalo, M., Jaakkola, J., Varliainen, T., Hakulinen, T., Karialainen, S., Pukkala, E., &  Tuomisto, J. (1994). Drinking water mutagenicity and gastrointestinal and urinary tract cancers: An ecological study in Finland. American Journal of Public Health, 84(8), 1223-1228.

Koivusalo, M., Vartiainen, T., Pukkala, E., & Jaakkola, J. (1995). Drinking water mutagenicity and leukemia, lymphomas, and cancers of the liver, pancreas, and soft tissue. Archives of Environmental Health, 50(4), 269-276

Kuzma, R., Kuzma, C., & Buncher, R. (1977). Ohio drinking water source and cancer rates. American Journal of Public Health, 67(8), 725-729.

Mancaş, G., Vartiainen, T., Rantakokko, P., Navrotescu, T., Diaconu, R., Mancaş, D., & Diaconu, D. (2002). Chemical contaminants in drinking water: Mutagenic and toxic effects. The Journal of Preventive Medicine, 10(3), 63-74.

Margel, D., & Fleshner, N. (2011). Oral contraceptive use is associated with prostate cancer: an ecological study. BMJ Open, 1(2), 1-10. doi:10.1136/bmjopen-2011-000311

Morris, R. (1995). Drinking water and cancer. Environmental Health Perspectives Supplements, 10780475, 8(103), 225-232.

Chlorine and Chlorine By-products in Water Supply

Chlorine began to be introduced into municipal water supplies in Chicago and in Boonton, New Jersey in 1908.  In 1974 and 1975, the first scientific studies classified chlorine by-products as a major contaminant in the nation’s water supplies, yet chlorine remains a additive in approximately 75% of the municipal drinking water supplies in the US.

In 1992, Morris, Audet, Angelillo, Chalmers, and Mosteller (1992) did a widespread analysis of scientific papers and concluded that chlorine by-products presented a 1.15% increase in the risk of bladder, colon, and rectal cancers in humans.  Their study reviewed ten peer-reviewed papers published between 1978 and 1988.


Morris, R., Audet, A.,  Angelillo, I., Chalmers, T.,  & Mosteller, F. (1992).  Chlorination, Chlorination By-products, and Cancer: A Meta-analysis. American Journal of Public Health, 82(7), 955-963.

Pharmaceuticals in the Water Supply

Radjenovic, Petrovic, and Barceló (2007) noted that wastewater treatment plants, which some might assume are helpful in extracting harmful compounds from the water supply, are actually a major source of pharmaceuticals in the water supply.  Radjenovic, Petrovic, and Barceló (2007) identified 31 compounds in the wastewater treatment plant water supply, including microgram per liter concentrations of analgesics and anti-inflammatory drugs such as naproxen, ibuprofen, ketoprofen, diclofenac, and acetaminophen, the antihyperlipoproteinaemic drugs gemfibrozil and bezafibrate, the β-blocker atenolol, and the diuretic hydrochlorothiazide.  Smaller concentrations, on the order of 10-100 nanograms per liter.  Standard removal processes demonstrated a removal efficiency in the range between 65% and 90%.  For some people, the residual pharmaceutical levels may be sufficiently high to express concerns.  Radjenovic, Petrovic, and Barceló (2007) suggested appropriate membrane technologies to remove the residual pharmaceuticals.


Jelena Radjenovic, J., Petrovic, M., & Barceló, D. (2007). Analysis of pharmaceuticals in wastewater and removal using a membrane bioreactor, Anal Bioanal Chem, 387, 1365–1377. doi: 10.1007/s00216-006-0883-6

Solutions for Hard Water

California, Arizona, Nevada, Utah, and New Mexico are all known to have hard fresh water sources, defined as 80 or more milligrams of calcium carbonate per liter of water (see http://water.usgs.gov/owq/hardness‐alkalinity.html).   In fact, few geographic areas of the United States do not have hard water; the lucky ones include New England, most of Oregon, coastal Washington, and a long swath from Eastern Maryland, across the Carolinas and Georgia, and west to Mississippi.  Hard water clogs and damages pipes in the home and in other installations, leaves residue glassware and other household items, damages plumbing fixtures, and dries human skin.

For years, homeowners have responded to hard water by installing salt-based water softeners, which, chemically, are ion exchange systems that add even more salt into the wastewater system.  As some homeowners, and some municipalities, have installed graywater systems in their homes, in an attempt to be more conservative with their water, the high salinity of the recovered water is killing the landscaping.

In addition to the introduction of salts, beyond that found naturally or entering the water supply from agricultural and industrial sources, pharmaceuticals, pesticides, herbicides, cleaning compounds, and chlorine by-products are also an increasing problem in many water supplies.  Municipal water treatment facilities are unable to remove all of these contaminants, so the water we trust to be safe for home and other uses may not be.

Traditional water softening systems exchange sodium ions for the calcium and magnesium ions found in the water supply entering the home.  The resin that holds the sodium prior to the exchange gradually loses its ability to “soften” the water, so the resin needs to be re-charged or replaced.  Recharging the ion exchanger introduces new salts into the wastewater system, either at the residence or at an industrial facility.

A viable alternative is now available in some markets.  This alternative does not use salt to condition the water.  Template-assisted crystallization creates small, nano-crystals of calcium and magnesium salts that, once formed, remain suspended in the water rather than causing scale build-up in pipes, on housewares, and on plumbing fixtures.  Unlike some water conditioning options, a template-assisted crystallization device does not require electricity or backflushing of the system.  The system will require periodic recharging or replacing of the media.  The other selling point of a TAC-based system is that, compared to other salt-free solutions, a TAC-based system is more effective at reducing scale that builds up; any scale that accumulates on fixtures or glassware, as examples, simply wipes off.

Source:  Thomure, T., & Fox, P. (2013). Evaluation of Alternatives to Domestic Ion Exchange Water Softeners, a webinar presented by the WateReuse Research Foundation.