Public health officials have identified a potential new threat to Long Island's groundwater from an unlikely source: rotting grass cuttings, leaves and other natural debris.
The state Department of Environmental Conservation recently reported that facilities that process "vegetative waste," such as commercial composting operations, appear to be causing elevated levels of manganese in groundwater.
"It definitely is a new universe of stuff to evaluate and manage," said Walter Dawydiak, acting director of environmental quality for Suffolk County's Department of Health Services. "These are not numbers typically seen in groundwater samples."
Manganese levels reached 49,000 parts per billion in one well in Yaphank tested by the county. The drinking water standard is 300 parts per billion.
Next year, Suffolk plans to expand the investigation to groundwater near other composting sites.
Aquifers are the sole source of water for Long Island's nearly 3 million residents.
Water districts treat public supplies to meet or exceed state and federal standards for safety. But environmental activists and public health officials say the supply already faces a variety of threats from toxic waste, nitrogen in sewage, fertilizer and farms, and saltwater incursion.
State and county investigations into water quality near Long Island Compost in Yaphank in 2009 found the first evidence of elevated manganese levels in groundwater. Researchers thought it was specific to operations at the largest composting operation in the county.
Sites, wells testedBut Suffolk's Department of Health Services has found similar water quality problems near other composting facilities.
Suffolk began testing groundwater at 12 sites in 2010 and is awaiting results from some of its monitoring wells, which stretch from Farmingdale to Speonk.
The county also identified, from DEC lists, another 78 locations where composting may be occurring. In 2014, the county plans to study about 10 of those sites where private wells are nearby.
"There's a need to monitor and manage this better," Dawydiak said of the possible impact of composting operations on groundwater.
Manganese is a naturally occurring element and a key component of a healthy diet, but can lead to health problems if ingested at high levels.
"We need some of it to be healthy, but we don't want to get too much of it," said Amy . . . Juchatz, an environmental toxicologist in Suffolk's health department.
How much manganese represents overexposure varies. "It would really all depend on how much you're exposed to, how long you're exposed to it and how much you get as part of your diet," Juchatz said.
The DEC is in discussions with Stony Brook University about developing a research project to study how the breakdown of trees, leaves and grass clippings impact groundwater, agency spokeswoman Lori Severino said in statement.
The state also may revise the permits that are issued to compost facilities, she said.
Long Island Compost plans to invest $50 million in its Horseblock Road property as part of a settlement agreement signed in June with the DEC over odor, dust and noise complaints, company president and chief executive Charles Vigliotti said.
"We were taken somewhat aback by the findings of the groundwater investigation," Vigliotti said. "Heavy metals have never been detected in any meaningful way in the material and that includes manganese."
Much of the 62-acre facility will be enclosed and a process known as an anaerobic digester will turn clippings into compost in an air-locked environment. The methane gas created will be converted into compressed natural gas to fuel equipment and the company's fleet of 10 trucks. A groundwater monitoring plan will also be created.
'The tipping point'"I guess the groundwater issue was the tipping point because we probably moved from debatable nuisance to something that needs to be seriously addressed," Vigliotti said.
With much of the operations modernized and indoors, the chances of groundwater contamination are reduced, said Adrienne Esposito, executive director of Citizens Campaign for the Environment. After being at odds with Vigliotti over the operation, she said she supports the improvements he plans to make and hopes for them to become a permit requirement for all compost operations.
"This means, unequivocally, DEC needs to change the storage regulations and these materials need to be on an impervious surface and covered," she said.