All Wet: How to Identify and Remove Common Water Contaminants
(Page 3 of 4)
July/August 2003
By Lori Tobias
Perchlorate
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Similar to MTBE, perchlorate is a rocket fuel oxidizer. According to Jessica Leibler, a spokesperson for Clean Water Action in San Francisco, companies that make rockets and/or rocket fuel have dumped the chemical into waterways. Perchlorate can cause adverse health effects by blocking the uptake of iodine by the thyroid, and scientists are trying to determine just how detrimental minute amounts of the compound in drinking water are. Fetuses, infants, and children are particularly vulnerable because thyroid hormone is essential for brain development.
Pharmaceuticals
Among the most significant emerging issues affecting our water is the discovery of prescription and over-the-counter drugs in the drinking supply. “Right now, an unlimited amount of pharmaceutical contaminants can stream from a tap without actually being illegal,” says the NRDC’s Olson. “We’re finding traces of drugs in streams, rivers, and lakes because most sewage treatment plants aren’t designed to filter them out. One big source is hog and chicken farms, where animals are treated with huge amounts of antibiotics,” he points out.
A U.S. Geological Survey and National Park Service study of water in Lake Mead and the Las Vegas Wash (a waterway used to transport treated wastewater from the Las Vegas metropolitan area to Lake Mead) detected thirteen compounds in water samples collected between October 2000 and August 2001. The most commonly found compounds included caffeine, carbamazepine (used to treat epilepsy), cotinine (a metabolite of nicotine), and dehydronifedipine (a metabolite of the antianginal Procardia).
Pesticides
In general, pesticides harm the earth and its inhabitants, but when it comes to the truly noxious, atrazine is one of the most insidious. Used primarily on corn crops, atrazine is one of the country’s most widely used pesticides. According to Susan Kegley, staff scientist with Pesticide Action Network, atrazine is particularly troublesome because it’s long lasting and highly water soluble, making it that much more likely to leach into the groundwater. Atrazine has been linked to cancer, miscarriages, stillbirths, and endocrine disruption.
Trihalomethanes
When the chlorine used to disinfect the public water supply comes in contact with organic matter in the water, toxic byproducts occur. Called trihalomethanes (THMs or TTHMs), these chemicals have been linked to cancer, birth defects, and low birth rates. “One of the reasons they’re so insidious,” says Olson, “is you get a significant dosage while showering. In fact, you’re inhaling them.”