Dec 10, 2008

USGS Study Shows Chemicals Remain in Drinking Water After Treatment

Low levels of about 130 manmade chemicals not removed by treatment processes

Following a U.S. Geological Survey (USGS) study showing that man-made chemicals remained in two-thirds of the publicly treated water that was tested, the Water Quality Association (WQA) is encouraging consumers to educate themselves on possible solutions.

According to a report by the USGS, low levels of about 130 manmade chemicals were not removed by public treatment processes. The USGS examined water from nine selected rivers used as sources for public water systems. Tests were conducted before and after public treatment processes. Testing sites included the White River in Indiana; Elm Fork Trinity River in Texas; Potomac River in Maryland; Neuse River in North Carolina; Chattahoochee River in Georgia; Running Gutter Brook in Massachusetts; Clackamas River in Oregon; Truckee River in Nevada; and Cache La Poudre in Colorado.

The most commonly detected chemicals in the source water were herbicides, disinfection byproducts and fragrances. Most of the chemicals found were at levels equivalent to one thimble of water in an Olympic-sized pool.

"Low level detection does not necessarily indicate a concern to human health, but rather indicates what types of chemicals we can expect to find in different areas of the country," said Gregory Delzer USGS lead scientist.

WQA offers an online fact sheet with answers to the issue of chemicals in water, available at

Filtering systems in the home provide the highest technologies available for treatment of drinking water, according to Joseph Harrison, technical director of WQA. Less than 2% of all water consumed is ingested by humans, making these point-of-use systems the most cost-effective and environmentally friendly.

While utilities are required to meet safety standards set by the U.S. EPA, home filtering systems act as a final contaminant barrier and can further purify water for drinking, Harrison said. While specific product performance standards have not yet been developed for every chemical, many point-of-use technologies have proven effective for emerging contaminants.