EPA Scientist Weighs Emerging Contaminants

Christian Daughton, a scientist for the Environmental Protection Agency, talks to Tony Cox about the EPA's changing response to new classes of environmental contamination.

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FARAI CHIDEYA, host:

For more on the story, NPR's Tony Cox spoke with Christian Daughton. He's a scientist with the Environmental Protection Agency's Office of Research and Development. Daughton says emerging contaminants first hit the scene in the 1970s in Europe, but most scientists didn't pay much attention until recently.

Mr. CHRISTIAN DAUGHTON (Office of Research and Development, U.S. Environmental Protection Agency): It's been more widely known in Europe than it was in the U.S., and it was really in the mid-1990s that I began raising attention to this in the U.S., resulting in a 1999 review articles that I published. The major issue has to do with the presence of active pharmaceutical ingredients in waterways because the concern really is that of exposure of aquatic life to these bioactive chemicals.

COX: What kinds of drugs are you finding most often in these waterways?

Mr. DAUGHTON: Well, the ones that tend to be found most often really fall into two classes. Those which are used most often such as the non-steroidal anti-inflammatory that people take so often, such as ibuprofen, and the ones that resist our metabolism; that is, they get excreted unchanged, and then when they enter sewage treatment plants. They tend to not get degraded their either. so those are ones that also will persist in having measurable presence in waterways.

However, it's important to point out that the concentrations of these chemicals in waterways are extremely low, many orders of magnitude lower than therapeutic doses.

COX: What is the impact?

Mr. DAUGHTON: This all is an issue involving exposure, and pharmaceuticals are just one tiny class of chemicals that occur in our environment that have biological effects. There are naturally occurring chemicals that are synthesized by plants and microorganisms, and there are also the anthropogenic chemicals, the ones that we make, manufacture that end up in our waterways. And when you consider the very vast numbers of all these chemicals, it's hard to single out any one small group of chemicals as being responsible for any particular type of effect.

COX: So we know that there are trace amounts. We don't know what the impact on the human population of these trace amounts in the waterways is at the moment, but there is enough there to warrant at least a closer look at what the possible impact could be.

Mr. DAUGHTON: We actually need to know more about the types of pharmaceuticals and personal care products that occur at these minute concentrations because the analytical studies are very difficult to perform at such low concentrations. So we probably have an idea of an unknown fraction of these chemicals that actually occur. The issue, really, is one of people being exposed to something that they ordinarily would never get during (unintelligible), that is perhaps fetal exposure or pregnant mothers, for example.

COX: I think you've answered the question partly for me, but I want to put it to you once again so that we are crystally clear. Is this dangerous?

Mr. DAUGHTON: It's impossible for anyone to really venture a guess on that right now. The body of evidence, however, shows there really isn't much to be concerned about with respect to human exposures. The concern really is one of aquatic exposure and what's happening in our waterways. But then again, it's not just these chemicals that we need to be concerned about, it's any type of chemicals that's introduced to the waterways.

COX: Christian Daughton is a scientist at the Environmental Protection Agency. He joined us by phone from Las Vegas. Christian, thank you very much for the information.

Mr. DAUGHTON: You're very welcome.

CHIDEYA: Again, that was NPR's Tony Cox. The EPA and other government agencies recently released guidelines for consumers. They recommend combining prescription drugs with household trash like coffee grounds or kitty litter before throwing them away. They also suggest flushing prescription drugs down the toilet only if instructed. Instead, try returning your unused drugs to the pharmacy's recycling locations.

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CHIDEYA: And just ahead, saying no to sex-ed funding and another weekly staff song pick. And you know it's hot.

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