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USF professor develops way to solve pollution problem at local beach

TAMPA, Fla. – High levels of pollution hit the shores of Ben T. Davis Beach earlier this year and University of South Florida ProfessorValerie (Jody) Harwood from the Department of Integrative Biology was asked to solve the problem. Thanks to microbial source tracking, which Harwood helped develop, she was able to find the source of pollution: a submerged, broken sewer pipe.

“My research deals with pollution by pathogens like sewage and fecal material, so I’m interested in microbial aspects of pollution,” Harwood said. “There is a whole myriad of different influences that can contribute to fecal pollution.”

Harwood devoted 15 years to developing the microbial source tracking (MST) technique, which she explained was like using DNA fingerprinting to figure out what sort of animal or human sources was contributing to fecal contamination.

“Once you find out that a particular microorganism is associated with a particular host, you can use what we call a ‘marker’ for that kind of host,” Harwood explained. “Then we use polymerase chain reaction.”

Harwood explained polymerase chain reaction, or PCR, like a Xeroxing machine for DNA that makes small identical copies. To illustrate, she used the example of searching for human polyomavirus.

“We can use PCR to detect the markers for human polyomavirus in the water,” Harwood said. “Then we can say, ‘Ok, so now we know that some of this contamination is coming from human sources when we find the human polyomavirus.’”

Harwood said Ben T. Davis Beach is partly fixed. The fecal contamination that was traced to a submerged broken sewer pipe has been fixed and the porta-potties that sat next to the edge of the beach have been removed. However, the beach still receives violations of recreational water quality because of storm water.

“Anytime storm water comes into an area, it’s going to carry pollutants with it because it’s washing everything that is collected on the land and into the water,” Harwood said. “The problems aren’t completely solved but they’d have to reengineer their storm water system which would be way more expensive than fixing a pipe and moving porta-potties.”

The methods of microbial source tracking have evolved into this simplistic model of finding microorganisms. But Harwood said the method is still being tweaked until her team can figure out better ways to concentrate the virus and detect it at lower levels.


Filed under:Integrative Biology Arts and Sciences    
Author: Melissa Moreno