TANSTAAFL!

Byproduct of water disinfection process found to be highly toxic

15 Sep 2004

A recently discovered disinfection byproduct (DBP) found in U.S. drinking water treated with chloramines is the most toxic ever found, says a scientist at the University of Illinois at Urbana-Champaign who tested samples on mammalian cells.

Water in the United States has to be treated with a chemical to disinfect it. That is, to keep bacteria from growing in it before it can get to the consumer.

We've been using chlorine in water for about a century now, and it works pretty well. But it produces byproducts, including trihalomethanes (THMs) which hit the news a couple of years ago as possibly causing miscarriages.

There are other chemicals that have been used to disinfect, or sanitize, or sterilize water. These include chlorine dioxide (used, you may recall, to kill anthrax spores in the Capitol back in 2001-2002), chloramine, and ozone. Each of these chemicals has its good points and bad points.

The linked article points out that all these chemicals cause byproducts to form. In the case of chlorine, we know what about half of those byproducts are. Compare this with knowing about a third of the byproducts that arise from chlorine dioxide, a sixth of those caused by chloramine, and a twelfth of those caused by ozone.

In all cases, we know the toxicity of only three in ten of these chemical byproducts.

My hunch: The risk of disease or toxicity from each of the chemicals used to treat water will probably turn out to be about equal. Changing from one chemical to another may decrease your risk of kidney cancer, but it will increase your risk of something else, like leukemia. You're not going to find a water treatment that has no risk at all.

Oh, and the possibility of skipping the disinfection step altogether? Maybe we could forget about treating the water, and not generate the byproducts in the first place? Well, they've tried that. The byproduct of not disinfecting is called "typhoid" and it kills more people, faster, than disinfection by-products do.