The drugs we take for diabetes, depression and birth control are ending up in the nation's waterways. The amounts are small, but no one can say they're safe. Ilsa Setziol, of member station KPCC reports aquatic animals may be the most at risk.
CURWOOD: If your municipal water supply comes from nearby river, chances are that every sip you take includes a very dilute cocktail of drugs, made up of everything from heart medicines to birth control pills. Four out of five streams recently sampled by the U.S. Geological Survey contained trace amounts of pharmaceuticals and other manmade chemicals. The study highlights a dichotomy of today's science. New technology can detect just a few molecules of a chemical in a sample, but their impact on public health is unclear. Still, some municipalities aren't taking any chances when it comes to using water directly recycled from sewage. Ilsa Setziol of member station KPCC has our report:
SETZIOL: The Geological Survey found more than 80 different drugs and household chemicals in streams and rivers across the nation. Most of the streams they studied were polluted by multiple chemicals.
BUXTON: We found acetaminophen. It's a drug that we often take to reduce fevers.
SETZIOL: Herb Buxton is co-author of the study.
BUXTON: We found it in about a quarter of the streams that we sampled. Another compound that we found quite frequently was a common insect repellant. Caffeine was found in about 70 percent of the samples. Some of the other compounds we found were ibuprofen. We also found things like cardiac-related medicines, antacids - very common drugs used in our day-to-day lives.
SETZIOL: How do drugs get into sewers? Just the way you might think. They survive digestion and coast right into the toilet. Some of these compounds do break down in sewage treatment, even though it wasn't designed to handle them, but many don't. Feces from farm animals can contain drugs like antibiotics and can wash into waterways. Scientists are only beginning to understand which of these compounds might end up in the environment. Christian Daughton is a scientist with the U.S. EPA's National Exposure Lab in Las Vegas. He says the new study is a good start, but we still have very little data on the thousands of drugs and household chemicals that could wind up in our waterways.
DAUGHTON: Most of the drugs that we know occur in the environment, there's really not much known about their potential toxicological effects. And for those that we do have some idea as to what effects could occur, we really don't know whether they occur in the environment.
SETZIOL: Daughton says because the amounts of individual compounds they're finding are small, scientists don't think they pose a human health problem. But they need to know a lot more before they're sure.
DAUGHTON: So it's impossible to say that there isn't a concern with respect to human exposure, especially if there were exposure to many different drugs simultaneously, and one were drinking a lot of water, or if the exposure were during a critical developmental period, for example, for a fetus or infant.
SETZIOL: The chemical concentrations that have been found in drinking water are even smaller than those in streams. In short, Daughton says, his concern is not so much for humans.
DAUGHTON: The major exposure potential is to aquatic organisms. It's lower for humans, simply because humans are exposed to water less than aquatic organisms are. And aquatic organisms, it's hard for them to avoid exposure because they exist in water their entire lives, through multi-generations.
SETZIOL: Also, most chemicals that are designed for human use haven't been studied in aquatic animals.
[SOUND OF BUBBLING WATER]
SETZIOL: But there's one kind that has. At the University of California, Riverside, Daniel Schlenk is researching estrogens in wastewater. The lab looks like a typical science classroom. It's filled with familiar instruments like beakers and Ph meters. But Schlenk is using brand new techniques that allow him to analyze tiny concentrations of chemicals. He peers into one of several small aquaria filled with tiny silver and gold Japanese fish called medaka.
SCHLENK: We use the fish to sort of tell us what types of compounds that act like estrogens are in the water.
SETZIOL: Schlenk says even after it's processed by the sewage treatment plants, wastewater contains estrogens - estrogen produced naturally by women's bodies and estrogen from birth control pills. There are also compounds that act like estrogen when they break down in the environment.
SCHLENK: In the United Kingdom, studies have indicated that there have been reproductive alterations, primarily feminization of specific fish populations, primarily caused by estrogens in wastewater. They went out and placed cages with animals in those particular receiving streams and found that the male fish or juvenile fish that they put in there behaved more like females.
SETZIOL: In tests he and colleagues have conducted in the U.S., male fish exposed to wastewater flowing into the Hudson and a small stream in Mississippi began to produce egg yolk proteins that are normally only found in female fish. Water districts around the country are starting to pay attention to this research, especially in communities that reuse wastewater. Perhaps nowhere is the interest as strong as in Orange County, California.
[SOUND OF MACHINERY]
SETZIOL: Where they're planning the largest wastewater-to-drinking water project in the country. At the water district plant, General Manager Bill Mills stands amidst a maze of large pipes and tanks.
MILLS: We're designing this system over here, which is the Cadillac of all treatment systems.
SETZIOL: Mills says pharmaceuticals will be removed in the second of a four-step process, reverse osmosis. He points to a cluster of 30-foot long pipes.
MILLS: Each of these units, or elements, as we call them, consists of a flat sheet of a membrane that is rolled around a center tube. Water is introduced at one end under a pressure around a hundred pounds per square inch, and is forced through the surface of the membrane.
SETZIOL: The pharmaceuticals are left behind because they're too big to fit through the filter's tiny pores. This system is similar to reverse osmosis units that many southern Californians have installed under their sinks. Then the water passes under ultraviolet light and is treated with hydrogen peroxide. Finally, it percolates into ground water basins. Several scientists agree that this process should produce drinking water that's very safe. But the EPA's Christian Daughton says reverse osmosis generates its own salty, polluted waste.
DAUGHTON: You have to keep in mind that the brine has to be discharged somewhere. And it might be further treated, but eventually that ends up being discharged to the surface water environment.
SETZIOL: And that's another reason why Daughton says people should act on this emerging issue. Physicians should be careful not to over-prescribe medications, and the public shouldn't flush unused drugs down the toilet. For Living on Earth, I'm Ilsa Setziol in Los Angeles.
CURWOOD: Coming up, a major oil company hits emission reduction targets for the Kyoto Protocol eight years ahead of schedule. You're listening to Living on Earth.
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