State officials have ordered a new battery of tests around a toxic plume in Bay Shore after rising groundwater revealed unacceptable levels of toxins at a home with a newly installed sump pump.
National Grid, which is responsible for cleaning the former manufactured gas site, has already installed a series of water- and air-treatment systems at the affected home, according to the owner, who asked that his name not be used to avoid alarming his neighbors. National Grid confirmed it is working "to resolve an issue" at the home.
The state Department of Environmental Conservation, which has ordered National Grid to sample all wells on the westernmost of several plumes, last month said the mediation it has overseen in Bay Shore has reduced groundwater plumes.
"The shallow groundwater plume used to be a concern but is almost entirely gone because treatment systems have been quite effective," spokeswoman Lisa King said. DEC and other state officials have been meeting with Bay Shore residents this week to explain the new tests, and address a series of odor complaints that officials have said are not related to the plume.
The impacted homeowner said he first noticed strong smells in his house and yard in December, after installing a new sump-pump system in the fall. The system draws water from below the basement floor and pumps it into the yard to prevent seepage into the home. With groundwater levels rising in December, the system began pumping -- and emitting a smell "that would hit you like a ton of bricks," he said.
After water testing showed high levels of toxins, he said, National Grid installed a water filtration system in his yard that includes a tank and several 55-gallon drums to remove the toxins. A separate air-filtration system draws air from the sump-pump system away from the basement and up through a pipe away from the home. Both systems, he said, are "working beautifully," and National Grid has offered to replace a brick patio and layers of soil impacted by the discharged water.
Among the higher toxin levels detected, he said, was naphthalene in concentrations between 15 and 25 times allowable levels. Naphthalene is a byproduct associated with former manufactured gas plant sites.
In a letter to another Bay Shore homeowner last week, the state DEC said it ordered National Grid to conduct a "comprehensive sampling of all the water-table monitoring wells" in the westernmost of four groundwater plumes. The test includes "all wells that sample shallow groundwater," including water that "could infiltrate people's basements during periods of high groundwater levels," according to a copy of the letter shown to Newsday.
The Bay Shore site is one of hundreds across the state that heated coal and other fuels to create a vaporous gas for use in heating and cooking before the era of natural gas. The so-called manufactured gas sites have left a legacy of toxins in their former locations.Since December, 43 Bay Shore residents have filed suit against National Grid seeking to recoup the value of their homes lost as a result of the plume and efforts to clean it up. Their attorney, Irving Like, said the new work at the Bay Shore home "indicates that there are pathways of exposure" above the plume.
National Grid acknowledged new work at the site. "National Grid has been contacted by a Bay Shore homeowner to resolve an issue on his property and we will continue to assist the homeowner and the agencies in addressing this issue," spokeswoman Wendy Ladd said in a statement. DEC officials were in the neighborhood this week to explain to neighbors what is happening at the home, and to address other odor complaints, neighbors said.