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Thursday, 5 June 2008

Chlorine Disinfection ByProducts (CDBPs)

As the name says, these potentially and possibly carcinogenic chemicals, both small and large, are produced as a result of chlorine that is used in chlorination reacting with dissolved organic matter (DOM, the stuff that gives some water a yellow-brown colour) in natural waters. In my neck of the woods, Newfoundland and Labrador, it is a real problem, some communities have values of the most well studied group, trihalomethanes (which contain chloroform), at 800 parts per billion (ppb), this is 8x greater than the Canadian Drinking Water Guideline. The actual mass/volume consumed may not seem like alot, but one should realize the amount of water consumed over a week, month, or year. I should mention that this problem is not just a Newfoundland and Labrador thing, it is in most places that use chlorine as a form of chlorination and researchers think that there are over 500 different compounds produced. We could simply stop using chlorination, but the untreated water may cause sickness from bacterial growth. Other forms of disinfection are available, but these are not as simple and cheep as chlorination, or have a residual effect, and some such as ozonation also produce toxic byproducts. The question is, what should we do?