AnGlerS In the MId-1990S Were the fIrSt to notice something odd about the fish in lake Mead near las Vegas, nV — some of which had both male and female sex organs. u.S. national park Service
personnel appealed to Shane Snyder for help. the university of
arizona professor and co-director of the arizona laboratory for
emerging Contaminants had been developing bioassays to screen
for chemicals in water. Snyder discovered that the fish were affected
by synthetic estrogen from birth-control pills. he traced the estrogen upstream to las Vegas, where women on the pill unknowingly
threatened fish in lake Mead every time they flushed the toilet.
like most drugs, birth-control pills are only partly metabolized
in the body; what’s left is excreted in urine and feces. human
waste is piped to and treated in sewage treatment plants. Solids
left after treatment are used as fertilizer, and the effluent is
released into streams. treatment removes some, but certainly
not all, drugs.
Snyder’s discovery inspired a flurry of research. Scientists
wanted to know the types and quantities of drugs that escape
into waterways, what effects they
have on aquatic life, and how the
effects could be minimized. they also
wondered about the fate of pharmaceuticals beyond the river or lake. as
rivers flow into reservoirs that provide
drinking water., water treatement
plants remove bacteria and other
contaminants. researchers wondered
whether the treatment plants were
also removing pharmaceuticals, or
were the drugs seeping into the water
we drink? Shane Snyder
James c. Davis, southern nevaDa water authority, las veGas
est is antidepressants, which are very common and persistent in
waterways. “We knew that [the brain chemical] serotonin, which a
number of these drugs modulate, is common across a wide range
of species,” said denver-based uSGS researcher edward furlong.
as reported in the journal Environmental Toxicology and
Chemistry, furlong found that min-
nows exposed to four popular anti-
depressants lost their instinct to avoid
predators. researchers speculated that
such an effect could threaten the spe-
cies’ ability to survive in a water body
tainted by antidepressants. “We’re try-
ing to figure out what the implications
are,” furlong said.
a recent discovery was that the
toilet isn’t the only major source of
drugs in wastewater. researchers
Ilene ruhoy, director of the Institute
for environmental Medicine at Touro University in nevada,
and Christian daughton of the u.S. environmental protection
agency’s national exposure research laboratory in las Vegas,
reported at the spring 2010 aCS national meeting that pharmaceuticals also enter the waste stream through bathing, showering,
and laundering. Many are topical
products used to treat such problems
as acne, fungal infections, and burns.
others are medications that are swallowed and excreted in perspiration.
“It’s very difficult to determine the
precise source of any identified pharmaceutical compound in water studies,” ruhoy said. “But it’s reasonable
to assume [topical products] may
prove to be a significant one.”
courtesy of ilene ruhoycourtesy of eric vance, us epa
Drugs go with the flow
A first step was assessing just how commonly pharmaceuticals
occur in waterways. In 1999 and 2000, the u.S. Geological
Survey (uSGS) sampled water from 139 streams in 30 states.
eighty percent were contaminated with pharmaceuticals and
other compounds, including insecticides and fire retardants.
drugs found included many of the most widely used antihistamines, antidepressants, antibiotics, and pain medications.
“We’ve identified more than
100 pharmaceuticals [in u.S.
waterways],” Snyder said. one
drug class of particular inter-