Further tests for Yaphank composting site

Investigators looking into puzzlingly high radioactivity levels in groundwater near a Yaphank compost facility will embark on a new round of tests this week, officials said.

State and county workers will sample soil, groundwater and compost at Long Island Compost's Great Gardens transfer station on Horseblock Road, where the contaminated plume, discovered in 2009, is thought to have originated. Investigators will sink wells at the property's western border to check if the pollution could have come from another location off-site.

They'll also test other Suffolk compost sites to determine if radioactivity and high levels of manganese -- the other pollutant in the Yaphank plume -- could be generated by the composting process itself.

If so, the state may have to consider new ways to manage compost sites that are more protective of groundwater, said Peter Scully, regional director for the state Department of Environmental Conservation.

Yard waste makes up about 20 percent of Long Island's garbage, and composting diverts much of that material from landfills, he said.

Measures to protect groundwater could include installing systems to filter runoff from compost piles, said Jean Bonhotal, associate director of the Waste Management Institute at Cornell University in Ithaca.

Still, she said it was highly unlikely that compost itself was the source of the radioactivity.

"It wouldn't have come from leaves and yard waste," Bonhotal said Monday. "We test lots of that, and if there was high exposure to radiation from an outside source, that's the only way it could have ended up there."

Last year, tests of the Yaphank plume, which has already contaminated a nearby private well, showed radioactivity levels that exceeded state drinking water standards and were higher than is typical in local groundwater.

Water from wells on Horseblock Road had gross alpha concentrations of up to 58.4 picocuries per liter, according to a Suffolk Health Department memo. The state standard for such radionuclides, which indicate the breakdown of radioactive material such as radium or strontium, is 15 picocuries per liter. Samples taken from compost itself at Great Gardens showed lower levels of radioactivity.

Long Island Compost president and chief executive Charles Vigliotti said a consultant hired by his firm had found radioactive isotopes in finished compost produced by Islip Town at "similar" levels to those found in compost at Great Gardens.

"We're all somewhat taken aback," he said. "The first thing I would like to know is how is this entering our environment?"