Are Our Medicines Tainting the Environment?
June 2, 2000 -- To those schooled in the ways of water purification, it
makes perfect sense. But it's a fair bet many Americans will find distressing
the notion that residues from therapeutic drugs may be afloat in the nation's
drinking water sources -- and that they could be coming from sewage.
Italian researchers discovered that might be the case in their country. They
found a variety of drugs showing up in river water and sediment, and a few even
drifting into sources of drinking water -- in all cases, just tiny
concentrations. The results of their research appear in the British medical
journal The Lancet and confirm studies done elsewhere in Europe during
the past 10 years.
Perhaps the most striking thing about the latest research is that about half
of the 16 drugs the researchers tested for shared a single characteristic:
excretion from the human body in an unchanged form, which could mean they came
from sewage. Other drugs that were included in the analysis are known to
undergo breakdown in the body; their presence in the water supply suggests
possible additional sources for the pollution -- improper disposal, for
Either way, the results suggest that the widespread use of therapeutic drugs
isn't being lost on the environment, though experts say it's not clear what it
all means. "My personal opinion is that any risk to humans is much less
than for aquatic [plants and animals]," says Christian Daughton, PhD, chief
of the Environmental Protection Agency's National Exposure Research Laboratory
in Las Vegas. "There's practically nothing known about what can happen with
aquatic life. Is it possible they are having an effect, but we're really not
noticing it at this time?"
In other words, are drug residues causing subtle, but potentially
devastating, effects on marine life? One example of a drug that might have such
effects is verapamil. Daughton says the drug, used for cardiovascular ailments
in humans, might harm the primary line of defense that some organisms have
against water pollutants. Similar drugs might also affect animals' sperm
viability, he says, while the class of antidepressants that includes Prozac has
actually been found to increase spawning.
Daughton says some might ask: Aren't drug residues degradable? "Sure,
they might be," he says. "But you're constantly introducing them. So
these aquatic organisms are exposed 24 hours a day to these chemicals for their
entire life span."
And even very small amounts of some drugs might make a difference, experts
say. "The interesting thing about pharmaceuticals is that sewage treatment
plants don't do anything to remove them," says Bob Morris, MD, PhD, an
environmental epidemiologist and associate professor in the department of
family medicine and community health at Tufts University in Boston. "And
second, these are chemicals specially designed to have an effect on humans at
low levels -- and that's what makes this story interesting."