Dr. Clif Cleaveland, Commentary

We finish yard chores or a workout, turn on the tap and fill a glass of cool water to drink. We trust that this water will be safe, and in most of America it is.

While drought has focused much of our attention upon quantities of drinking water, recent reports by The Associated Press highlight issues of water quality. Writer Jeff Dunn and colleagues reported earlier this month studies of prescription drugs in urban drinking water.

In an interview on public television, Mr. Dunn reported that tap water in 25 of 28 cities tested positive for pharmaceuticals. The study further reported that only 24 of 62 water systems surveyed included tests for pharmaceutical chemicals.

The AP report focused upon Philadelphia, where traces of 56 prescription drugs were detected in the city’s water supply. The drugs represented human and veterinary preparations. Some of the veterinary drugs are not approved for human use.

The list included antibiotics such as Cipro and Chloramphenical, anti-inflammatory drugs, high blood pressure and cardiac drugs, and a number of psychiatric medications. Individual drugs were present in trace amounts, sometimes as little as a few parts per trillion. Dissolving a 500 milligram Tylenol tablet in 100 million gallons of water would create a drug concentration in this range so these are ultra-minute quantities.

No one knows if these trace pharmaceutical contaminants pose a risk to our health. Currently, the U.S. Environmental Protection Agency which sets the standards for drinking water has no regulations for monitoring or removing drugs. Most drugs enter our water supply by human and animal excretion. Unknown quantities of medications are flushed down our toilets. Hospitals and clinics lack any uniform standards for disposal of many of their drugs.

Because EPA monitors manufacturers for discharge of chemicals used in manufacturing drugs but not drugs themselves, it is unclear if this is an important source of water contamination.

Further complicating this issue is the presence of drug-like compounds in such natural substances as soy beans, root vegetables, and coffee grounds. The impact of these trace contaminants is unclear. Their removal would be complex, very expensive, and of uncertain benefit.

I could find no definitive information that trace amounts of drugs could cause or aggravate allergies. Nor could I determine if trace amounts of antibiotics could lead to more drug-resistant microbes.

To find out about our community’s drinking water, I contacted John Watson, who is president of Tennessee American Water Company. I learned that our water, which is pumped from the Tennessee River, makes its first stop in large sedimentation basins where larger particles and aquatic life are removed with the aid of coagulants.

Chlorine is added to kill micro-organisms. A series of filters, which include granular and powdered activated carbon, remove metals and man-made chemicals. I was particularly reassured by the use of activated carbon — a powerful absorbent of many compounds.

Home purification systems employ carbon filtration or reverse osmosis. The latter systems are expensive and do not assure removal of trace amounts of chemicals. I would consider these if I depended upon water from a well or from a water system of uncertain standards. Boiling water will kill microbes but not remove chemical contaminants.

Bottled water presents a wide spectrum of choices. Some brands are little more than bottled tap water of uncertain origin. Some brands are treated by reverse osmosis. The problem with bottled waters concerns chemicals that may leach from the plastic container into the water.

These include bis-phenol A and phthalates, which have known toxicities for human health. Plastic bottles create a severe litter problem as well.

Congress promises hearings on tap-water quality and safety. Meanwhile, the EPA pursues research to permit identification of more drugs and personal care products in our drinking water. Because the EPA is such a vital protector of our water and air adequate funding and political independence are vital for the agency. Some components of government simply cannot be downsized.

Contact Clif Cleaveland at cleaveland1000@comcast.net.