Contaminated Drinking Water May Increase Risk For Cancer

ElDoubleVee, that polluted water guess is a good one. I was working on something about diabetes (arsenic in water is linked to type 2 diabetes) and stumbled across this:¹

It shows contamination of well water by Volatile Organic Compounds (VOCs). "VOCs come from a wide variety of sources, including gasoline, plastics, paints, dyes, solvents, adhesives, insecticides, and spot removers."

This study only tested 2401 wells, between 1991 and 2002. A pittance, since "about 400,000 new wells are drilled every year." Of those 2401:

"65% had detectable levels of VOCs, and 1% had levels above the EPA [limit]."

Exposure to VOCs is a known risk factor for cancer: EPA: Drinking water Contaminants.

So, except for California and the Northwest, there does seem to be a gross correlation between this and the map of colon cancer rates in my previous post.
________
This doesn't let public water off the hook. Municipal water is chlorinated to kill microorganisms. Byproducts of chlorination include a group of compounds called trihalomethanes:

"Studies conducted at NIEHS have shown that administration of certain trihalomethanes, by-products of water chlorination, and several brominated chemicals cause colorectal cancer in experimental animals. Epidemiologic studies now suggest a link between the consumption of chlorinated water and increased human risk for colorectal cancer."
- Trihalomethanes and Colorectal Cancer, and Trihalomethanes and Other Environmental Factors That Contribute to Colorectal Cancer, Environmental health Perspective, 1994.

Yep, that water guess has merit.
________¹ VOCs Turn Up in Well Water: Sensitive Measure Reveals Groundwater Contaminant, Environmental Health Perspectives, 2007.