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 hours.
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 wildlife.
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 swab.
``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,'' Jorgenson said.
But getting some samples are easier to get than others, Jorgenson said.
``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.
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