A recent Associated Press investigation found that pharmaceuticals were detected in tap water supplies of at least 41 million Americans.

While utilities maintain that their water is safe, follow-up questions were posed to two experts: Purnendu "Sandy" Dasgupta, chairman of the department of chemistry and biochemistry at the University of Texas at Arlington, and Alicia Diehl, team leader in the public drinking water section at the Texas Commission on Environmental Quality in Austin.

What can or should consumers do to protect themselves from pharmaceuticals in water?

Dr. Diehl: The least expensive, most effective method to remove organic chemicals from water for home use is with a carbon filter, such as a Brita filter or equivalent.

Dr. Dasgupta: The present state of knowledge we have is very sketchy. One must understand that present instruments can detect very minute quantities of substances, and all the results I have seen to date for U.S. drinking water do not indicate that the levels are enough to be of concern.

Do we know if bottled water is any safer?

Dr. Diehl: No. If anything, more questions arise with bottled water, since plasticizers may leach out of plastic into the bottled water.

Dr. Dasgupta: Some bottled water is just municipal tap water from some place. That's clearly not any better. Others are ultraviolet-sterilized. Such a step will degrade most pharmaceuticals.

Does it appear that new regulations might be necessary to keep pharmaceuticals out of drinking water?

Dr. Diehl: The U.S. Environmental Protection Agency will consider regulating pharmaceuticals or other chemicals of human origin using their standard scientific protocol. This involves determining whether the chemicals occur frequently enough to be of nationwide concern, and scientifically determining what levels of the chemicals may cause an adverse health effect. Based on this protocol, EPA will make a decision to regulate or not regulate these chemicals.

Dr. Dasgupta: A few pharmaceuticals are already on the EPA's unregulated contaminant monitoring list. If the levels approach anywhere near those of concern, obviously they will need to be regulated.

What kinds of research might shed more light on the nature of this risk?

Dr. Diehl: The EPA will review human epidemiological data and animal studies in determining the risk to human health.

Dr. Dasgupta: Standard toxicologic lifecycle studies at low levels of drugs on organisms and aquatic life, and routine monitoring.

Do we know how this risk might compare to other environmental health risks?

Dr. Diehl: At this point, the risk is not quantifiable. Therefore it is not possible to compare it with other risks – either from the environment or from drinking water.

Dr. Dasgupta: My personal opinion is that it is relatively low. We do not do as much water recycling as some places in Europe, and in general these levels are too low to be of concern. I have not seen the latest results on the Dallas-Fort Worth drinking water area. I would be far more concerned if our water was not properly disinfected.

Jake Batsell