Harbor Sludge Might Hold Means to Clean The Anacostia River

"They don't fall apart in the environment," said Joel Baker, a professor at the University of Maryland Center for Environmental Science. "They don't fall apart in humans."

In the Anacostia, which is heavily contaminated with PCBs from industrial work at the Washington Navy Yard and other sites, people are trying to bury the problem. Sections of river bottom have been covered with materials designed to keep the pollutants in place.

"Unless you dredge it up," which is very expensive, "there's no other way," said Monir Chowdhury of the District's Department of the Environment.

Sowers, the University of Maryland researcher, has spent years looking for another way. He needed to look in an extremely polluted place, in the hopes of finding a creature that was well-adapted to living in poison.

Sowers didn't have to look far. His lab sits on a pier extending into the dark, trashy waters of the Baltimore Harbor. Which is like a coral expert having an office on the Great Barrier Reef.

"I just go out the back door," Sowers said.

Using samples of that black harbor mud, Sowers and his team eventually found a very small -- as in eight-millionths of an inch wide -- lemon-shaped microbe that can break down certain PCBs. What it does is something like breathing, for a single-celled creature without any lungs.

"Instead of using oxygen, they're using PCBs," Sowers said. At the end of this process, the microbe has stripped one of the chlorine atoms out of the PCB molecule, making the chemical more vulnerable to other creatures that might break it down completely.

So, eventually, they might clean up Baltimore's problem on their own, but the time scale for that is probably decades, at the least, Sowers said. The amount of PCBs in the harbor has decreased sharply in the past 30 years, he said, but some of that is probably because of contaminated mud being washed out or removed through dredging.

In that time, Sowers said, the same microbe has been found all over the world, including in the Anacostia. His theory is that these microbes had evolved to rely on some PCB-like chemical that was in the environment naturally and then took to PCBs when humans started dumping them in.

Now, Sowers said, he would like to supercharge the reproduction of this creature and others like it, so they might be injected en masse into a place such as the Anacostia. He is experimenting with ways to do that, looking at adding other chemicals the microbes rely on to grow. Still, he said, it could be years before that goal is reached.

Thinking ahead, Sowers said, he cannot foresee any danger that these cleanup microbes might become a problem when PCBs are gone.

"Once they're done eating the PCBs, essentially they're going to stop living," he said.

In the meantime, Sowers said, he has been fielding requests from researchers in other cities, whose local muck does not measure up to the Baltimore brand. He bottles it up and ships it off.

"It's good stuff," Sowers said.