The risk of source water contamination is becoming increasingly prevalent!
Contamination cause by municipal water treatment methods
Besides the four regulated trihalomethanes, the EPA regulates five other contaminants in a family of chemicals known as haloacetic acids -- monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid (EPA 2012b). The current EPA legal limit for these five chemicals is 60 parts per billion.
While there have been relatively few epidemiological studies on the potential health effects of haloacetic acids, there is evidence suggesting that exposure to these chemicals during the second and third trimesters of pregnancy may be linked to intrauterine growth retardation and low birth weight (Levallois 2012, Hinckley 2005; Porter 2005).
Haloacetic acids have been classified by the EPA as possibly carcinogenic to humans because of evidence of carcinogenicity in animals. According to the EPA, long-term consumption of water that contains haloacetic acid concentrations in excess the legal limit of 60 parts per billion is associated with an increased risk of cancer (EPA 2002). A technical bulletin released by the Oregon Department of Human Services in 2004 warned that long-term exposure to haloacetic acids at or above 60 parts per billion may cause injury to the brain, nerves, liver, kidneys, eyes and reproductive systems.
Some studies point to concerns with specific haloacetic acids. Dibromoacetic acid has been shown to disturb the balance of the intestinal tract and to cause disease, especially in people with weakened immune systems (Rusin 1997). This particular haloacetic acid compound is toxic to the sperm of adult rats at concentrations as low as 10 parts per billion. At high doses, it has caused a range of neurological problems in test animals, including awkward gait, tremors and immovable hind limbs (Linder 1995). Two members of the haloacetic acid family -- dichloroacetic acid and trichloroacetic acid -- have been shown to cause severe skin and eye irritations in humans (NTP 2005).
People who's source water is municipal water are at risk.
A number of processes are utilized in municipal water treatment can result in the introduction of contaminants into the drinking water supply. Studies have shown that there are more than 600 unwanted chemicals created by the interaction of water treatment disinfectants and pollutants in source water (Barlow 2004, Richardson 1998, 1999a, 1999b, 2003). Most of these water treatment contaminants have not been studied in depth. Among them: haloacetonitriles, halo aldehydes, halo ketones, halohydroxyfuranones, haloquinones, aldehydes, haloacetamides, halonitriles, halonitromethanes, nitrosamines, organic N-chloramines, iodoacids, ketones and carboxylic acids (Bond 2011, Bull 2011, EWG 2001, Plewa 2004, Yang 2012). Some of these compounds are suspected carcinogens (Bull 2011). Notably, scientists believe that hundreds more water treatment contaminants are present in drinking water but have not yet been identified (Barlow 2004).