Drinking water supplies, contamination

As a result of volatilization, significantly elevated indoor air levels of trichloroethylene can occur in homes that use water supplies contaminated with trichloroethylene (Andelman 1985a). The transfer of trichloroethylene from shower water to air in one study had a mean efficiency of 61% which was independent of water temperature (McKone and Knezovich 1991). The study authors concluded that showering for 10 minutes in water contaminated with trichloroethylene could result in a daily exposure by inhalation comparable to that expected by drinking contaminated tap water. Another study using a model shower system found that, in addition to shower spray, shower water collecting around the drain could be an important source of volatilized trichloroethylene, and the fraction volatilized could be affected by spray drop size and flow rate (Giardino et al. 1992). 

Cyanide contamination creates special public information problems, e.g. it is difficult to explain why cyanide is not included in the current drinking water standards but that aquatic organisms are affected at relatively low cyanide concentration. There is confusion on whether fresh water standards are based on free or complexed cyanides. Fortunately, the provision of a permanent drinking water supply to each affected household removed risk assessment as a major issue. 

Can easily be used without explosives (e.g., contaminating drinking water supplies)... 

Kim D-H, Lee S-K, Chun B-Y, et al. 1994. Illness associated with contamination of drinking water supplies with phenol. J Korean Med Sci 9 218-223. 

P 21.6 Is There a Danger that the Drinking-Water Supply System of a City is Affected by Air Contaminants ... 

Safety IS the PRACTICAL CERTAINTY that injury will not result from a substance when used in the quantity and in the manner proposed for its use (I). The goal of all public health and water authorities is to assure that public drinking water supplies are safe, pure, and wholesome in the broadest sense, that is, free from contamination by substances of possible health concern as well as free from adulterants that would detract from the water quality and reduce acceptance by consumers. Not only should public water supplies be safe, but they should be perceived to be safe. 

A review committee set up under the auspices of the North Atlantic Treaty Organization in 1979 listed 744 chemical contaminants that had been identified in the drinking water of 14 countries (I). Since then, more have been found. However, it has been estimated that more than 80 of the total organic carbon in the drinking water still remains uncharacterized. This growing number of organic chemicals identified in drinking water supplies led to public concern and debate about the potential risks to health. 

Table I. Concentration of Contaminants in Canadian Drinking Water Supplies...

Trichloroethylene (TCE) is the most prevalent organic contaminant of drinking water supplies in the United States. Air stripping, the once conventional treatment method, is now largely disallowed. Extensive efforts have been made to develop bacterial systems to remove TCE from water. Efforts to obtain bacteria that... 

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