Tracking an Invisible Menace

By Doug McGinnis

Hours after a wastewater system failure at Indiana’s largest hog farm dumped 50,000 gallons of raw sewage into a tributary of the state’s most scenic waterway on April 4—the latest in a series of damaging spills at Pohlmann Farms—Wabash student scientists were on the scene. The Indiana Department of Environmental Management (IDEM) responded to the massive fish kill, and TV news carried images of the ecological calamity across the region. But Wabash students were tracking two less visible and more persistent menaces.

For the past two years under the direction of biology professor Shivi Selvaratnam, Maury Raycroft ’03, Andrew Smithka ’03, and Peter Murage ’03 have been sampling Sugar Creek sediment and studying PCB (polychlorinated biphenyl) contamination in the creek and the presence of bacteria that degrades the known carcinogen. Dave Kunberger ’02, Paul Drambarean ’05 and seniors Wes Ket and Marty Dado have been working with Selvaratnam to study the presence and growth of antibiotic-resistant bacteria caused by treated hog waste entering the creek.

It’s hard to imagine more relevant research. Doctors fear that overuse of antibiotics is creating a growing population of bacteria increasingly resistant to medicine’s limited range of antibiotics. At the same time, repairing the damage spread by agricultural run-off to wetlands and waterways has mobilized some of the nation’s largest environmental projects, including those run by Smithsonian Institute ecologist and Wabash alumnus Dennis Whigham ’66. Selvaratnam’s research projects combines these hot environmental topics and puts them under the microscope. The professor/student collaboration is breaking new ground in the state.
“As far as I know, no one else has studied these particular issues in the same way we are,” Selvaratnum says. “IDEM has looked at PCB contamination of Sugar Creek, but not at the microbial community level.”

What they’ve found thus far is alarming. Long before the massive spill, and sampling for one year from three sites—one upstream from the hog farm, one near the farm’s wastewater outlet on Little Sugar Creek, and one farther downstream—the scientists’ results indicated increased numbers of bacteria resistant to antibiotics, with the highest concentration at the site nearest the wastewater outlet. Eighty percent of these bacteria are resistant to multiple antibiotics.

What this means for people and animals in Sugar Creek is speculation, Selvaratnam says—no studies have been done to establish correlation between increased bacteria in the creek and human health problems. But she admits she will not allow her children to play there.

If a human health risk was established, it would be something like this: you accidentally ingest creek water or it makes contact with a skin sore or cut, allowing bacteria into your system.

“Most of these bacteria are fecal pathogens that cause diseases like diarrhea,” the professor says. “If it’s not treatable by antibiotics, you could pick up from Sugar Creek something that’s hard to treat.

“You also have to ask, ‘What are these antibiotic-resistant bacteria doing to other species in the ecosystem?’ They could pose a problem for other organisms, or could transfer their antibiotic resistance to indigenous bacteria.”

And as they work their way through the food chain—a fish ingests the bacteria, a bird eats the fish—the bacteria could be carried far from the petri dish Sugar Creek has become.

This summer, Selvaratnam, [biology professor] Aus Brooks, and their students will study the interaction between the bacteria and algae in the creek.

“The question we haven’t been able to answer is how long these antibiotic resistant bacteria stay around,” Selvaratnam says.

Kier Marshall ’04 is testing one theory—that these bacteria are harbored by algae growing on rocks. The algae may provide suitable habitat for the bacteria to grow and possibly reproduce.

Selvaratnam is submited a paper for publication, and in May she and her students presented their preliminary results at the national meeting of the American Society for Microbiology in Washington, D.C. She also hopes that recent calls from reporters and IDEM will spread word of the potential health hazard of these agricultural practices.

Her goal for the PCB project is more ambitious.

“People know there are PCBs in Sugar Creek—anyone who can read the fish advisory signs along its banks knows that,” Selvaratnam says. She hopes to be able to study how the concentrations of these carcinogens can be reduced.

“I’m hoping in the next year to be able to work with small microcosms—bring samples of the sediment in to the lab, add PCB-degrading bacteria and see what happens.”

“Doing Science”

Whether or not the public responds to Selvaratnam’s research, the benefits for Wabash students have been immediate.

“I wanted to get field experience, to work on something that might help people,” says Raycroft. “I’ve learned a lot. You get a lot of freedom to put your own twist on things.

Dado declares: “You get a chance to screw it up!”

Dado recalls a stretch of two months when he and Ket struggled without any clear results from their experiment. “It forced us to sit down and actually think about what we were doing wrong, and how we could fix it,” Dado says.

“They develop independent thinking,” Selvaratnam says. “And now these guys can troubleshoot, just as scientists do.”

“Doing research, I found out that in science you’ll have some success, but it’s going to be three times more work than you thought it would be,” Raycroft says. “But it’s also more rewarding. When you do a lab for class, it’s all been done before. But with research projects like these, we’re doing something that’s our own, something that can be useful.”

“Being able to do so much here put me far ahead when I applied to graduate school this year,” adds Raycroft, who enters the PhD program at Notre Dame this fall. “They look at the research I’ve done and are impressed.”

Medical school-bound senior Wes Ket, who served an internship at IDEM before his research with Selvaratnum, sees the research broadening the factors he’ll consider when he begins diagnosing patients.

“I’ll certainly be more aware and open to the possibility that environmental influences may be more of a factor in the patients I treat.”

Passing it on

Most scientific studies last for years and engage a steady stream of student researchers, another plus for Wabash students. New researchers must be introduced to the project, and there’s nothing like teaching the next crew to imbed what “veteran” student researchers have learned.

“Maury worked with me for two years, then mentored Wes and Marty, and now they’re all mentoring the next group,” Selvaratnam says. “These “veterans” teach the new guys and the techniques and work with them n the projects. I think that’s an important experience for them. It’s similar to a grad school approach, but it works well for my lab.”

The design of the new science building makes for frequent collaboration, not only between professors and student researchers, but between students and professors working on different projects. This year Selvaratnam, David Polley, and Richard Nelson convened bi-weekly floor meetings on the second floor’s “serendipitous’ space, bringing the professors and student researchers together to talk about their projects, learn about the others’, and exchange ideas.

“These meetings have helped us become a community of learners,” Selveratnum says. “The students feel comfortable seeking help from any of us.”.

“We could never do this in Thomas labs,” Selvaratnam concludes. “The new building creates a space where science students and professors collaborate more freely, where students always have each other to hang out with— a place to talk and be excited about science.”