Prozac in Drinking Water? Likely So
Water Treatment Plants Not Designed to Get Rid of Medications
WebMD News Archive
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The main problem is outdated water treatment systems.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."