U.S. Water News Online
SIOUX FALLS, S.D. -- A graduate student at South Dakota
State University is collecting animal manure from around the state in
an effort to compile a database of profiles of local bacteria.
By matching bacteria from samples of contaminated water to the DNA
database, Erick Jorgenson hopes the state Department of Environment
and Natural Resources will be able to determine the source of the
animal fecal contamination.
New technology has made it possible to conduct what scientists
call ``bacterial source tracking.'' By finding the likely source of
bacteria, the technique will help clean up streams and rivers which
are currently unfit for swimming and other recreational use. It also
might help improve drinking water and wildlife habitats.
``The states are clamoring for a method to track these sources,''
said Nels Troelstrup, Jorgenson's professor at South Dakota State.
But before the high-tech gene machines can do their job, Jorgenson
must finish the low-tech work of collecting fresh animal manure.
Fecal coliform bacteria live in the organs and feces of humans and
other mammals and can sicken people who swim in contaminated water.
Every summer, several beaches and swimming areas across the South
Dakota are declared unsafe because of fecal coliform. The elevated
levels usually follow a heavy rain and last only a few days or a few
But more than a third of the 1,014 swimmable miles of South Dakota
streams and rivers consistently exceed the state limit for fecal
coliform. That is down from the late 1990s, however, when more than
690 miles were contaminated.
More than 100 miles of the lower Big Sioux River are contaminated.
Waste from livestock is a likely culprit, but a method to separate
cattle contamination from hog contamination, for example, would help
officials target pollution sources.
In western South Dakota, researchers are concerned that fecal
coliform could contaminate drinking water in wells.
Tracing the contamination could also lead to sources of other
kinds of pollution, such as nutrients that can harm fish and
Several states are compiling databases of local bugs, but South
Dakota's effort has an advantage. The Public Health Laboratory
recently built a state-of-the-art DNA lab.
``It's really exciting to be a part of something brand-new for the
whole state,'' Jorgenson said. ``Hopefully, it will set the standard
for the Midw est.''
But to do that, Jorgenson must finish his unsavory collecting
expeditions. He must track down a few hundred steaming piles of
manure from cows, pigs, poultry, sheep, cats and dogs.
Fortunately, he only needs to collect a small sample on a cotton
``It doesn't have to be right out of the oven, but as long as it's
soft and I can stick the swab in there, it does a pretty good job,''
But getting some samples are easier to get than others, Jorgenson
``Pigs are tough. They go to the bathroom only so many times,'' he
said. At the Western Junior Livestock Show, for example, ``I waited
around the whole day to get pig samples.''
The only real danger comes from human waste samples, which
Jorgenson gets from wastewater treatment plants.
``The wastewater is probably the trickiest because of the viruses,
hepatitis, whatever can be in there. So you've got to be very
careful,'' he said.
Return to the
U.S. Water News Archives page
Return to the U.S. Water
Use a comma to separate e-mail addresses:
Hi, I thought you might like to read this article.