In a University of Illinois Prairie Research Institute (PRI)
study, researchers collected 58 water samples from eight springs
and five cave streams in southwestern Illinois in 2014 and 2015.
Hormones were detected in only 23 percent of groundwater
samples, but medications and personal care products were
detected in 89 percent of samples, according to Walt Kelly, head
of the Groundwater Science section at the Illinois State Water
The study location was in karst terrain, which is notable for
caves, sinkholes, and smaller openings in the land surface
through which contaminants can readily enter underground streams
and springs. The hilly landscape outside of the St. Louis
metropolitan area contains numerous small farms and has become a
draw for rural residential development.
Karst groundwater is different from other types in that water
moves more quickly from the surface and is easily contaminated
by leaking sewage systems, fertilizers, livestock manure, road
salt runoff, and garbage and trash discards in sinkholes.
“Water lines for drinking water are linked from towns to rural
homes, but often there are no city sewer lines servicing rural
homes, so private septic systems are installed for each
property,” Kelly said. “State regulations require that septic
tanks must be inspected at a minimum of every three years to
prevent leakage, but that doesn't always happen because
inspections are expensive.”
Most water samples were significantly contaminated by bacteria,
particularly from humans, hogs, and cattle. Sewage systems also
leak pharmaceuticals and other products. From analyses performed
by Wei Zheng and Laurel Dodgen, environmental chemists at the
Illinois Sustainable Technology Center, PRI, the two most common
products found in streams and springs were triclocarbans, used
in antibiotic soaps and found in 81 percent of samples, and the
cardiovascular drug gemfibrozil, found in 57 percent of samples.
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Contaminant levels were well below human dosages, but even low
levels may affect aquatic organisms, according to Steve Taylor,
conservation biologist in the Illinois Natural History Survey,
PRI. Of concern are endangered species living in caves, such as
the Indiana bat and the Illinois Cave amphipod.
Many questions related to groundwater contaminants are still unanswered,
including the interaction among the different substances, the actual effects of
the contaminants, and whether the contaminants have been a problem for decades
since the technology to detect many of these compounds in low levels in the
environment has only been available for about 10 years, Kelly said.
“The largest concern is the effect of hormones,” Kelly said. “They don’t persist
as long as other compounds found in groundwater, but they can cause a lot of
damage to fish and possibly other animals.”
Previous recommendations for disposing of medications were to flush them down
the drain or into the sewage system. New recommendations encourage taking unused
drugs to collection facilities in communities. See www.unwantedmeds.org for
proper disposal information and locations of take-back programs.
This study was funded by PRI and the National Great Rivers Research and
Education Center, and is published in the journal Science of the Total