August 10, 2004 — Scientists in Great Britain have found levels of a common antidepressant in the water. It begs the question: What about the drinking water in the U.S.? Should we be concerned?

The exact quantity of the antidepressant Prozac — found in river systems and groundwater used for drinking — was not specified. However, the British report says that it could be potentially toxic.

Similar problems have been discovered both with prescription and nonprescription drugs in the U.S. and throughout Europe, albeit at low levels. Many have questioned whether even low levels of these medications could affect human health and reproduction.

The First Report

In 2002, the U.S. Geological Survey (USGS) released the first study of pharmaceuticals, hormones, and other organic wastewater-related chemicals in streams across the nation. Most sites were downstream of urban and farming areas where wastewater is known or suspected to enter streams.

The study showed that:

• Pharmaceuticals, hormones, and other organic wastewater-related chemicals have been detected at very low concentrations in streams across the U.S.
• Many of the chemicals examined (81 of 95) do not have drinking-water standards or health advisories. Measured concentrations of compounds that do have standards or criteria rarely exceeded any of them.
• Among the chemicals detected were: human and veterinary drugs (including antibiotics), natural and synthetic hormones, detergents, plasticizers, insecticides, and fire retardants.
• Some of the compounds most frequently detected include: coprostanol (a fecal steroid), N-N-diethyltoluamide (an insect repellant), caffeine, triclosan (an antimicrobial disinfectant), tri (2-chloroethyl) phosphate (a fire retardant), and 4-nonylphenol (a detergent by-product).
• 38 chemicals were found in a single water sample.

This week, an update on that report will be released, says Herb Buxton, coordinator of the United States Geological Survey’s Toxic Substances Hydrology Program.

The news is not good: “The compounds we use in small amounts can get significantly concentrated because of how we handle wastewater,” Buxton tells WebMD. “Our filtration systems aren’t built to treat these kinds of chemicals — organic chemicals. We need more sophisticated technology to filter them.”

Most problematic, Buxton says, is whether antibiotics in the environment cause antibiotic resistance. Also, could natural human hormones as well as synthetic hormones (birth control pills, hormone supplements, and estrogen-like compounds such as detergents) affect fertility?

His data will be used by the American Waterworks Association, the EPA, the FDA, and other agencies to address those questions.

What’s Being Done?

The main problem is outdated water treatment systems. “There are a bunch of systems out there, they are probably effective to some degree, but they’re probably not completely effective,” says Ephraim King, JD, director of standards and risk management in the EPA’s Office of Water.

“Each city, each town has some kind of treatment system in place,” he tells WebMD. “But that system will vary according to the contaminants they’re trying to address, and the system’s age. … The filtering systems may not be capable of removing certain chemicals like pharmaceuticals.”

Disposal of unwanted medications is part of the problem, King says. “People are well advised not to flush them down the toilet or down a drain. Then it goes through a sewer system and eventually gets back into the environment. Inevitably there’s a lot of dilution, but people are well advised not to put it down the toilet in the first place.”

The EPA, the National Drinking Water Advisory Council, and the National Academy of Science are assembling a list of potential contaminants to be studied. “We want to be sure we’ve got as much information as we possibly can on the health risks that may be posed,” King tells WebMD.

Effects on Humans May Vary

“The core problem is — there’s nothing really in the design of most treatment plants to take this stuff out,” says Robert Morris, MD, PhD, an environmental health consultant and professor at Tufts University. “This is a truly daunting problem. Treatment systems were all initially designed to get rid of bacteria and viruses. They have filters and use chlorine, but that doesn’t do a whole lot to get rid of chemical contaminants.”

Whether these water contaminants have effects on humans is still an open question, Morris tells WebMD. “The presumption has been that the stuff gets so diluted that it won’t cause a problem. Whether or not that’s true is another issue. People used to think that about microbes and bacteria, and discovered they were pretty wrong about that.”

The effect may vary from town to town. “This stuff is coming out of sewage treatment plants. The [size of] the plant, the amount that’s coming out of it, and the size of the river or lake determine the concentration of chemicals in drinking water. So it’s going to vary a lot. It may be that specific regions of the country have a worse problem.”

So what are the effects over a lifetime — or during particularly vulnerable stages such as pregnancy? “We don’t really know,” Morris says. “There’s evidence that concentrations coming out of treatment plants have an effect on things living in the water. They’re obviously going to get the highest exposure. Whether the lower exposure has an effect on humans, we don’t know.”

Should We Drink Bottled Water?

Bottled water is “an expensive solution, and it produces a lot of plastic that needs be disposed,” Morris says. “I don’t see that as an ideal solution.”

If a woman is pregnant or trying to get pregnant, that’s the time to be most careful — drink bottled or filtered water, he advises. “That’s especially true if your water is coming from a major river system or water source that has a lot of sewage treatment plants going into it. That’s where you have to be concerned.”

A healthy adult won’t likely feel major effects from these drugs, adds Morris. “But boy, I’d like to see us gather more data on this. The list of chemicals being produced is huge. The mixture coming down these waterways contains many, many chemicals. We don’t know how they interact. We don’t know their total effect. I don’t want to scare people. There’s no cause for panic. But certainly there is more cause for getting more information.”