Scientists Getting to Point of Pollution

Walk along the banks of the Savannah River. Fish the
Chattahoochee. Swim in the Flint. Chances are you’ll see a sign
warning of the potential risk due to pollution. Pollution
threatens the quality of water and the health of people all over
the state. But often, it’s not easy to determine exactly where
that pollution is coming from.



Feces in water typically comes from leaking septic tanks,
agricultural runoff or animal droppings. If water
contains feces, it could also contain disease-producing bacteria
or viruses that can exist in the feces. These diseases include
typhoid fever and hepatitis A.



The maximum amount of pollution a body of water can have without
violating state water-quality standards is called the Total
Maximum Daily Load. Fecal pollution is a major contributor to
TMDLs for Georgia watersheds.



Most fecal pollution comes from nonpoint sources. So far, there
has been no proven way to know where or from what animal it came.
And if you can’t locate the problem, you can’t fix it.



Water Detective

But new research may help regulatory agencies pinpoint sources of
fecal pollution and clean up one of Georgia’s most valuable
resources.



Peter Hartel is an associate professor of crop and soil science
in the University of Georgia College of Agricultural and
Environmental Sciences. For the past two years, he’s been an
environmental detective.



Hartel uses a type of DNA fingerprinting that can tell what
animal caused the fecal pollution of a specific watershed.



Using a process called ribotyping, Hartel can make a DNA
fingerprint, a series of distinct bands, of the Escherichia coli.
This bacterium is found in all warm-blooded animal feces.



A few years ago, scientists believed E. coli was the same in all
animals. But it’s not. Different animals have different
types.



“Dog E. coli is found only in dogs. Human E. coli is found only
in humans. The same with cows and poultry,” Hartel said. “We’re
not sure why that is right now. But we know they’re
different.”



After you have a library of the distinct E. coli fingerprints of
various animals, the rest, in theory, is easy, Hartel said.



You can monitor and take samples of a watershed, isolate the
different E. coli found in the water and compare that to the
library of animal samples. That will tell you what animal feces
are in the water, Hartel said.



Building the Library

When Hartel began his research, there was little information on
ribotyping to identify pollution sources in water. He’s changing
that.



So far, his E. coli fingerprint library has samples from several
Georgia animals, including beef cattle, swine, poultry and Canada
geese. But he needs more.



“There has to be an established library to compare and identify
samples against,” Hartel said. “The more extensive the source
library, the greater the likelihood of obtaining matches.”

“This is cutting-edge science,” said UGA CAES water quality
coordinator Bill Segars. “The possibilities for using (this)
method to identify nonpoint pollution sources could revolutionize
water management around the world. This ribotyping data
collection is a sound, scientifically based tool.”



Other states are also using ribotyping to better understand
pollution, said Alan Hallum, chief of the water protection branch
of the Georgia Environmental Protection Division. But Georgia
could lead the way.



If there is a public health problem in a watershed, Hallum said,
this test could better target what needs to be done in the
watershed to correct the problem as quickly and as economically
as possible.



“I would like to have, from a state regulatory standpoint, a way
to know we’re not spending money unnecessarily,” Hallum said.
“This (test) allows the stakeholders in a watershed to do a
best-management approach to fixing a problem.”