U.S. Water News Online
ALBUQUERQUE -- Residue from prescription drugs have turned
up in two rivers in New Mexico, and scientists expect to find more as
they test water from other locations.
Estrogen-type drugs were found in the San Juan River in
northwestern New Mexico. Residues of painkillers and seizure medicine
were found in treated wastewater flowing into the Rio Grande near
Only a few samples have been tested so far. No drug residues have
been found in drinking water and officials say there is no solid
evidence of human health risks.
The first results from a statewide study of drug residue in water
were released by the New Mexico Environment and Health departments.
``We know they're probably coming out of the pipe at every sewage
treatment plant,'' said Dennis McQuillan of the New Mexico
But he and David Mills, director of the Scientific Laboratory
Division of the Health Department, said more study is needed before
the scope of the problem is known.
``I don't want to be too alarmist at this point,'' Mills said.
``At this point, it's a research project.''
The drug residues could be getting into rivers several ways.
People who take prescription medicine don't absorb all of it, so some
is excreted and ends up in the sewage system. Unused medicines also
can be flushed down the toilet.
Drugs excreted by livestock and then washed into rivers by runoff
are another potential source, officials said.
Conventional sewage treatment technologies do not completely
remove the drug residues. Other methods, such as activated carbon
filtration or treatment with ultraviolet light, likely would remove
the drugs but could be costly, said Bill Turner, New Mexico's natural
Drug residues could contaminate drinking water wells if the wells
are near a river, he added.
The painkiller Darvon and anti-seizure medication Dilantin were
found in very low levels, varying from 250 to 500 nanograms per liter
of water, in the effluent from the Espanola waste-water treatment
A nanogram in a liter of water is roughly equivalent to one second
out of 32 years, Bouwer said.
Despite the low levels, health experts are concerned about the
potential risks, said John Meyer, head of the chemistry bureau at the
New Mexico Health Department's lab in Albuquerque.
Meyer said the department is in the early stages of testing and
couldn't talk more about specifics.
The drug residues can affect wildlife. The estrogen drugs in San
Juan River were found at levels high enough to cause sexual
disruption in fish, officials said.
While the effects on aquatic life have been documented, there has
been little more than theorizing about the dangers to humans from
drug residue in water.
The New Mexico Health Department is worried about the potential
for antibiotics to get into water sources and create
antibiotic-resistant bacteria. A resistant strain of salmonella was
found in the Rio Grande in southern New Mexico within the past few
years, McQuillan said.
Turner said evidence of caffeine, codeine, cholesterol-lowering
agents, anti-depressants and other drugs in water supplies in other
places has him worried.
As Albuquerque and Santa Fe plan to start diverting water from the
Rio Grande for drinking, Turner said it is time to seriously study
``I don't know what the ultimate solution is,'' he said. ``But I
think the dialogue needs to start.''
The state laboratory is testing for 28 types of pharmaceuticals.
Next year, Mills said he hopes to enhance its technology to enable
tests for antibiotics and other drugs.
Tests of private wells downstream from the Santa Fe sewage
treatment plant and of the Rio Grande at Pilar and Bernalillo turned
up no drugs.
The U.S. Geological Survey is testing water samples from several
states, including samples from Kirtland Air Force Base and White
Sands Missile Range, as part of a national program to assess
contamination from prescription drugs.
New Mexico will continue to collect and test treated sewage
effluent, river water, groundwater and drinking water. McQuillan said
once the state lab works through a backlog of samples, new samples
will be collected from five sites in the middle Rio Grande.
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