Here is an excerpt from the Synthetic Organic Contaminants page. (Click on image for larger view.)
I find the "Likely Sources of Contamination" column unsettling. Residue of banned termiticide. Runoff from insecticides. Discharge from chemical factories. Leaching of soil fumigant. I find no comfort in the fact that the levels of contaminants fall within "safe limits."
Heptachlor and chlordane have been banned for decades, and yet are in my water supply in 2013.
2,4-D is directly linked with nervous system damage. Glyphosate, commonly known as Roundup, has been linked to endocrine disruption in frogs as well as people.
With two other pages filled with contaminants such as benzene, styrene, toluene, and PCBs, all unique to modern times, I'm unwilling to assume that all is well with my tap water.
If you're interested in seeing what's in your water, the Environmental Working Group offers this National Drinking Water Database. Earthworks also provides a helpful fact sheet on Understanding Your Water and Air Tests.
Where does this leave us in terms of water filtration? Options abound and are often confusing. Our family currently uses the Berkey water filter shown below.
The best bet is to find raw water from a spring that is gravity-fed. These are more plentiful than you might expect. FindASpring.com offers a helpful database. I was shocked to discover one within 45 minutes of our Arizona home!
As I consider our water company's annual report, the growing controversy surrounding hydraulic fracturing (used to drill for natural gas), and the explosive growth of genetically modified crops, I have to agree with author and marine biologist Rachel Carson that the indiscriminate use of pesticides and other chemicals will have long-term implications.