Protein key to PCB removal
The problem with PCBs – what keeps them persistent in the environment – is their chlorine content. The chlorine prevents naturally occurring bacteria in the soil from producing a protein that breaks down hydrocarbon molecules, including PCBs.
Scientists have thus far been unsuccessful in finding an answer to this chlorine challenge. Now Chris Young, founder of the California-based company BioTech Restorations, thinks he may have found it.
Mr. Young figured out how to synthesize the protein that allows bacteria the ability to break down PCB molecules.
This protein is the key to BioTech’s PCB removal method. When treating a contaminated site, BioTech implants this protein into the soil, which then gives bacteria back their ability to naturally break down chlorinated chemicals.
“When PCBs are not broken down, the bacteria have received a stop signal from the PCB breakdown,” Dr. Peter deFur, president of the consulting firm Environmental Stewardship Concepts, explained to an audience of interested community members and local environmental leaders gathered at First Congregational Church in Great Barrington, MA on Sept.17. “This method administers a protein which changes that signal to continue breaking down PCBs.”
While BioTech’s method won’t eliminate all dredging, Tim Gray, executive director of the Housatonic River Initiative (HRI), explained that the dredges used would be less invasive, smaller GPS-controlled machines.
High success rate
Housatonic River Initiative first discovered BioTech Restorations about three years ago when the company got approval to started doing PCB removal at several sites in California. Mr. Gray noticed that BioTech was working to remove the same type of PCBs found in the Housatonic, and thought that perhaps it could be done here. “It made sense to us that if these guys could clean PCBs on a site, we may be able to catapult this cleanup decision into the future,” he said.
The BioTech method has already been used to remove chlorine-based pesticides from the Borello site in California, and as Gray described, “When they were done treating the site, California EPA said it was so clean you can build residential houses on the site.”
Closer to home, another promising result has come out of testing the method on a local site. Last winter BioTech did a lab testing on dioxin-contaminated soil from the Log Home site in Great Barrington. Test results have indicated very high, nearly unheard of removal percentages, in the range of 98 to 100 percent. Dioxins, as Dr. deFur explained, are more resistant to breakdown than PCBs, and therefore are much harder to remove. “Dioxins are a bigger problem than PCBs and the success rate here is something I’ve never seen anything like, and I’ve been working on them for 20 years,” he said.
Planning a pilot test
BioTech is confident in their method, so confident that the company is willing to invest its own money in doing a pilot test on contaminated sediment and soil from the Housatonic River.
“Free is free, and it’s a no-brainer that we don’t at least give them a couple acres and say ‘show us what you can do,’” said Mr. Gray.
He said BioTech plans to submit a request to the EPA to collect over a hundred soil samples from PCB-impacted upland soil in the river.
Currently the EPA is waiting for BioTech to send them this request in the form of a quality assurance project plan – essentially a document that outlines BioTech’s method, how the company plans to implement it, and how the company will know if it works or not.
According to EPA’s Jim Murphy, the agency’s Team Leader for the New England region, the EPA is interested in BioTech. “We’ve been clear we’d really like to work with them,” Mr. Murphy said during the Sept.17 meeting.
Setting a precedent
Mr. Gray pointed out that if BioTech method proves successful on the Housatonic, this cleanup case would set a precedent for future PCB removal scenarios elsewhere.
“It’s my belief that if BioTech actually did work, and we found that we’ve cleaned this river in a more effective way and a way that catapults us into the future, we could be a model for the country if not the world, as far as cleaning up a river,” said Mr. Gray.
That would be no small distinction, considering the scope of PCB contaminated waterways that exist nationwide. As Dr. deFur mentioned, there are about 2.3 million acres of lakes and ponds in the U.S. that are contaminated with PCBs, and 775 square miles of PCB-contaminated estuaries, along with about 1,000 contaminated river segments. “We face a huge problem,” he said.
Will BioTech’s PCB removal method be the solution?
“We’re not saying we absolutely know it works, we’re just saying this is the best stuff we’ve seen in all the years of studying it,” said Mr. Gray. “We’re feeling this may be our last great hope for the Housatonic River, and let’s try it.”