‘Forever chemicals’ are polluting the Peconic River. New data makes strongest case yet that former Navy site is to blame.

Man-made “forever chemicals” have been polluting the Peconic River system for years. The chemicals are present in some fish, and they’ve been found in the private water wells of nearby homes.

Clean water advocates have long pointed to the former Northrop-Grumman site in Calverton, which was used for decades by the U.S. Navy contractor to develop and test aircraft, as the source of the pollution. While the Navy has acknowledged on-site groundwater and soil contamination by a variety of substances, it has denied the responsibility for off-site groundwater pollution and refused to clean it up.

But new data and maps released last month by the Navy as part of the cleanup process of the property may change that. It shows groundwater polluted with per- and polyfluoroalkyl substances (PFAS) — a group of synthetic chemicals linked to adverse human health effects like cancer and nicknamed “forever chemicals” because of how slowly they break down over time — migrating off of the former Grumman site in Calverton towards the Peconic River.  

The maps show the contaminated groundwater flowing from Site 2, a 32-acre former firefighting training area at the southern part of the facility, under Swan Pond in Manorville and towards Donahues Pond. Donahues Pond is a part of the Peconic River, while Swan Pond is connected to it through the Peconic Estuary’s watershed. The data was presented during the Jan. 23 Calverton Restoration Advisory Board meeting; Site 2 is currently targeted for remediation efforts, since PFAS is prevalent in a firefighting foam that was used at the site.

New information has prompted the Navy to expand its private drinking water well sampling area. (See map below). If you are within the sampling zone you can make an appointment to sample by calling 800-908-9339.

In addition to testing for PFAS substances in nearby water bodies, Navy officials in charge of the cleanup investigation will now evaluate the fate and transportation of PFAS migration in the environment; perform risk assessments to determine the human health risk and ecological risk of the pollution; and determine chemicals of concern potentially requiring cleanup. 

The Navy has refused calls from Restoration Advisory Board (RAB) members to remediate the pollution while it continues its investigation, said Adrienne Esposito, the executive director of the environmental advocacy group Citizens Campaign for the Environment and a RAB member. 

”To leave it in place to continue to pollute the river and contaminate the fish is unacceptable and criminal,” she said. “And the Navy needs to act — stop stalling, stop dragging their feet.”

“The longer we wait, the more there is to clean up, the more exposure there is to the environment and the public,” Esposito said.

PFAS pollution in the Peconic River prompted the state health department to issue an advisory in May 2023 warning the general public to limit consumption of yellow perch caught between the Peconic Lake dam and Edwards Avenue dam in Calverton to only one meal per month, and for sensitive populations to avoid eating the fish altogether. (Advisories for consuming other kinds of fish in the lake due to the presence of mercury are also in effect.)

Data collected by the Department of Environmental Conservation in 2018 and shared with RiverheadLOCAL shows PFAS substances are already present in fish in Donahues Pond, although there are no health advisories for the pond related to PFAS. (State health advisories for other kinds of fish due to the presence of mercury are also in effect for Donahues Pond. Visit the Department of Health’s website for more information.)  

Additional fish in Peconic Lake/Forge Pond were tested for contaminants in 2021, according to the DEC, which said it is preparing a report on that data. The DEC also collected fish from Swan Pond in 2024 that are being tested, according to the agency.

There is evidence that exposure to PFAS can lead to adverse human health effects, including immune system suppression, increased risk of certain cancers, increased cholesterol levels, reproductive and developmental problems, and reduced vaccine efficacy. Because of those harms, federal and state agencies have set drinking water standards for water supplies containing PFAS.

The area surrounding the Peconic Lake is not within the Navy’s expanded drinking water well sampling area. According to Riverhead Water District Superintendent Frank Mancini, private wells servicing homes closest to the lake have tested for the highest concentrations of PFAS pollution in all of Riverhead Town. 

“If you can’t eat the fish in the Peconic, you don’t need to study that anymore,” Mancini, a RAB member, said in an interview. “It’s a problem. You need to clean it up.”

Mancini, a hydrogeologist, said the PFAS plume from the EPCAL site is “probably” part of the PFAS problems already facing the Peconic River. He noted that Site 2 is in the “same spot” as the plume of volatile organic compounds that impacted the groundwater well at the Peconic River Sportsman’s Club; the sportsman’s club is located to the east of Donahues Pond and was connected to public drinking water after the pollution was discovered.

DEC spokesperson Denis Slattery said in a statement that “Most potential sources [of pollution] identified to date have been on the former NWIRP property. A few smaller off-site locations connected to Navy’s past operation are also being investigated as potential sources. DEC will continue to work with state and federal partners and the community to ensure a comprehensive investigation and cleanup.”

PFAS pollution of the Peconic River and its tributaries could have a wide range of implications for the East End, Joyce Novak, the executive director of the Peconic Estuary Partnership, said in an interview.

“We have aquaculture, we have fisheries. Recreational fishing is a huge economic driver on the East End,” Novak said. “So when we talk about the knock-on effects ecologically into the communities, the possibilities are quite large, and a lot of that information we just don’t have yet.”

Novak said the full impact of PFAS chemicals on the Peconic’s ecosystem is not clear. ”There’s still a lot of things that need to be studied,” she said. “But of course, I have concerns of the knock-on effects into the surrounding lakes and groundwater system and the Peconic River. And of course, all of that is part of the Peconic watershed, so it will all make its way to the bays.”

The Peconic Estuary Partnership is a program under the Environmental Protection Agency’s National Estuary Program, which was established through the Clean Water Act to restore and protect estuaries of national significance, such as the Peconic Estuary. PEP has focused primarily on the effects of nitrogen pollution from septic systems on water quality, Novak said. While it has not looked directly into PFAS pollution’s effects on the estuary, Novak said the program would discuss whether to research the topic next year.

The Comprehensive Conservation Management Plan for the Peconic Estuary, last updated in 2020, says the PEP staff should research the “types, sources, and impacts of toxic contaminants existing in and entering the Peconic Estuary and development of recommendations for reducing toxic contamination.”

While the Navy’s investigation continues, Mancini is trying to get clean water to residents on contaminated private water wells. The water district’s next project is a public water extension to homes on Forge Road in Calverton — just to the east of Peconic Lake — where public wells have tested for PFAS at some of the highest values within the town.