Questions raised over Bay Shore plume 'fixes'

In a report that raises new questions about an expensive and widely used toxic-groundwater treatment system in Bay Shore, a preliminary government study found evidence that pumping oxygen into a mile-long plume can create compounds that are potentially just as toxic.

Scientists at the U.S. Geological Survey, who presented the early results at a toxicology conference in Portland, Ore., this week, stressed that amounts of the new toxins, called oxy-PAH's, were small and that test results were "provisional and subject to revision."

Nevertheless, the findings represent the first time the toxins, which are produced by oxygen-injection systems intended to encourage microbes to consume plumes, have ever been positively detected in treated groundwater samples, scientists say. The new toxins are not detectable using current conventional tests.

National Grid has spent tens of millions of dollars cleaning up the former LILCO-owned gas-making plant in Bay Shore and the plumes it created for about a century until 1973.

Large amounts of toxic soil have been excavated and oxygen-pumping systems have been installed at hundreds of points south of Union Boulevard near Fifth Avenue, and officials agree that the systems appear to be working. Three separate plumes underlie dozens of homes, an elementary school, a gym and other public places.

National Grid Wednesday night declined to comment, referring questions to the state Department of Environmental Conservation, which is overseeing the cleanup.

The DEC responded by pointing to an e-mail sent to Newsday last week in which it says it "has seen no evidence that undesired byproducts have been created during this degradation process, and has no reason to believe that they will be."

Wednesday, the DEC stood by the statement, adding only, "We look forward to reviewing the information collected by USGS."

Suffolk County Health Services, which commissioned the USGS study, has raised questions since 2006 about the oxygen treatment method, including that the method could release toxins into the air.

"Confirmation of the presence of oxy-PAHs in groundwater has been an important first step in understanding the full range of environmental effects" of sites treated with oxygen, an abstract of the USGS paper says.

Ron Paulsen, a hydrogeologist for Suffolk, noted that while the new toxin amounts were low, so were the original toxin levels of the plume from which they derived. Analysis of further samples is expected in coming weeks.

"We're still trying to figure out if this is something we need to stop everything and take a harder look at," he said, adding, "We can't make a judgment on whether they are harmful or not" until more results are available.

Paulsen stressed that the oxygen-pumping systems otherwise appear to be working in Bay Shore and that the preliminary USGS results do not yet raise "big alarms."

Residents who generally applauded the oxygen treatment systems as signs of progress were left with new questions.

"I'm not an engineer, but is that the best or the surest way to do it?" said Geraldine Coupe, 71, who lives with her daughter at a home on Lanier Lane. "Are there other ways to get rid of the plume? We don't know."

Robert Nicholoson, a chemical engineer who is among a group of property owners suing National Grid, said even preliminary positive results of oxy-PAH's raise questions about claims of success in treating the plume.

"For them to say they're having this great success, it seems to me like a lot of spin," he said.

One problem in understanding the new results is that the budget for Suffolk and USGS to test for the toxins is about to run out. Some $50,000 in county and federal money funded the early tests, but there is no follow-up budget, officials said.