About pharmaceuticals in water
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7/5/2009 - 7/5/09
As one of five participating entities in the recent, free, well-testing program conducted by the New Mexico Environment Department, we were privy to some interesting inquiries about the testing protocol. The objectives of the program are to improve our knowledge of local groundwater chemistry and ultimately to be able to map the distribution of natural and manmade contaminants in the local aquifers.
One of the most unusual questions posed to me was whether or not we would be testing for pharmaceuticals. The answer is "No." In early, 2008, the Associated Press released the results of a five-month study revealing trace amounts of pharmaceuticals in public drinking-water systems. Albuquerque was one of the few major cities where test results were negative, and Santa Fe water was not tested. The AP report was a reiteration of facts that have been known for decades, but detection by modern analytical methods of very minor levels of pharmaceuticals, coupled with an increase in prescription drug usage, caused a resurgence of interest in the subject.
PPCPs (pharmaceuticals and personal-care products) are classed as bioactive chemicals because they have an effect on living tissue. PPCPs include prescription, over-the-counter, and veterinary drugs; and fragrances, cosmetics, sunscreen agents, nutraceuticals, biopharmaceuticals, and growth-enhancing chemicals used in agribusiness.
Pharmaceuticals enter wastewater streams because medications are only partially absorbed by the body and the residues are excreted. Another contributing action is when people flush unused medications down toilets and they enter wastewater treatment plants and eventually flow to our streams and rivers. There are no federal or state regulations for the discharge of PPCPs from wastewater treatment plants. Just last month, the river conservation group Amigos Bravos reported evidence of traces (parts per trillion) of drugs in irrigation ditches off the Rio Grande in Bernalillo County. There are no definitive studies showing long-term human health effects from pharmaceuticals at the levels being detected.
Concerns have been raised about the possible entry of PPCPs from the Rio Grande at the Buckman Direct Diversion Project. Potential issues are discussed in the independent consultant's report on contaminant removal. City water, by statute, will comply with the Safe Drinking Water Act, which does not govern PPCPs. There are also no maximum contamination levels for pharmaceuticals under New Mexico's Drinking Water Regulations.
Private, domestic well-owners are on their own to monitor their water quality. There are some useful indirect markers. Nitrate, which is commonly an indicator of septic intrusion into a well-water supply, is a possible indicator of a pathway for other contaminants (such as PPCPs). The EPA recommends testing annually for nitrate.
Excellent sources for learning more about PPCPs include the websites of the EPA, the National Sanitation Foundation International, and the Water Quality Association. In a recent article in the Journal of the American Water Works Association, the authors noted that, in addition to its myriad other capabilities, reverse osmosis removes more than 90 percent of steroids, antibiotics, antidepressants, anti-inflammatory drugs, and antimicrobials.
Stephen Wiman has a background in earth science (Ph.D. in geology) and is the owner of Good Water Company in Santa Fe. He may be reached at 505-471-9036 and skwiman@goodwatercompany.com.
