Some surface waters and associated wetlands near a Seacoast Superfund site have an “unacceptable added risk” from accidental ingestion, according to a new risk assessment from the Environmental Protection Agency (EPA).
In the risk evaluation dated in September for a number of PFAS chemicals, the EPA determined there was “an unacceptable added risk” from accidental ingestion of surface water “from Berrys Brook, Little River, and associated wetlands near the Coakley Landfill Superfund Site.” It found an incremental lifetime cancer risk level and a non-cancer hazard index higher than EPA targets.
“The levels of contaminants in surface water really haven’t changed since we started testing for them,” said Richard “Skip” Hull, a remedial project manager for the EPA. “What has changed is more and more research on these contaminants, specifically PFAS compounds and the understanding of the toxicity levels, and so that has changed over time, and when that happens, we’ve revisited the risk evaluations and updated them.”
The EPA is requiring the Coakley Landfill Group — which represents the municipalities and solid waste generators and transporters identified as potentially responsible parties — to post several signs, in addition to existing ones, where the public may come in contact with the waters. “Contaminants associated with the Coakley Landfill Superfund Site have been detected in surface waters in this area,” the signs must read at a minimum, plus relevant contact information. “Avoid contact with surface water.”
The EPA is also “evaluating what long-term measures would be most effective to reduce contaminant migration to surface water at the site and to protect human health from exposure to contaminants in surface water,” the agency said in a fact sheet for the public.
PFAS chemicals have been linked to harmful health effects such as high cholesterol, weakened immune systems, decreased fertility, increased blood pressure in pregnant women, developmental problems in children, and prostate, kidney and testicular cancers.
The chemicals break down at an extraordinarily slow place in the environment. There are thousands of varieties of the man-made chemicals; in its screening, the EPA focused on six. PFAS are widely used in consumer and industrial products, and they are so ubiquitous that they can be found in the blood of almost all humans.
Coakley Landfill, located in Greenland and North Hampton in Rockingham County, has been a point of concern for decades. It collected industrial and municipal waste from the early 1970s to the ‘80s; then, for several years, it received incinerator residue from a facility on Pease Air Force Base, according to the Department of Environmental Services. It was added to the National Priorities List in 1983, the list of sites identified by the EPA because of their risk or release of harmful substances.
In 2016, PFAS and 1,4-dioxane — identified by the EPA as a likely human carcinogen — were found in groundwater and surface water and the site. The contaminants were also found in some private wells, according to the EPA, spurring an ongoing monitoring program.
This spring, the EPA updated its toxicity values for two types of PFAS chemicals, PFOA and PFOS, leading to recalculations of the site-specific screening levels at the Coakley Landfill.
Understanding the data
The Coakley Landfill Group collected samples “from wetland areas that form the headwaters for Berrys Brook and Little River, from within Berrys Brook and Little River, and from the leachate seep located at the northwest corner of the landfill,” according to the EPA fact sheet.
The highest of those values from all of the locations was used to determine whether the EPA would conduct a risk evaluation of a particular PFAS chemical. “As you can imagine, the highest values are from the locations that are closest to the landfill,” Hull said. In its risk screening and evaluation, the EPA looked at three rounds of surface water data from June 2023, this January, and this June, with each of these rounds testing for six PFAS chemicals.
This map shows where the Coakley Landfill Group collects surface water samples. (Provided by the EPA)
The highest values for each chemical — called the “maximum concentration” — were compared to site-specific screening levels, which are not enforceable standards but instead used as a baseline for the EPA to decide whether a further investigation is needed. Essentially, if the maximum concentration was higher than the site-specific screening level, the EPA did a risk assessment.
Four PFAS chemicals — PFOA, PFOS, PFNA, and PFDA — exceeded those site-specific screening numbers in at least one sampling round. Some of these figures were far in excess of the screening levels, according to the EPA document from Sept. 4 outlining the screening and risk assessment results.
In the most recent June round, the maximum concentration of PFOA was 318 nanograms per liter; anything over 0.25 ng/L would have triggered an assessment. (A nanogram is one billionth of a gram.)
For PFOS, the maximum concentration was 795 ng/L; the site-specific screening level is 10.1 ng/L. And for PFDA, the maximum concentration was 222 ng/L; anything over 0.203 ng/L would have caused the EPA to take a further look.
In June 2023, the maximum concentration of PFNA was 360 ng/L; its site-specific screening level is 256 ng/L. It did not exceed those screening levels in subsequent rounds of testing this January and June, but it was still evaluated for risk along with the other chemicals found to have exceeded the screening levels.
Those risk calculations found that the total incremental lifetime cancer risk of PFOA and PFOS exceeded the EPA target cancer risk range. (“No cancer toxicity values are currently available for PFNA or PFDA,” the document said.) The combined non-cancer hazard index for the four PFAS chemicals was a value of 43; the EPA has a target limit of 1.
The hazard index is found by adding the non-cancer hazard quotients for each of the chemicals; hazard quotient estimates “represent the risk of health effects other than cancer from exposure to contaminants,” according to the document.
The risk estimates include exposure through ingestion and skin contact. “There is currently insufficient toxicity data to estimate risk from inhalation exposure to PFAS,” the document said.
To determine risk, the EPA made a number of assumptions: It was calculated for a child recreator who was exposed one hour per day, 45 days a year for six years.
‘Kids play in there’
Mindi Messmer, a scientist and former state representative who sits on a subcommittee for the Superfund site, said many members of the public who interact with these waters have no idea about the contamination.
“People bike through there, kids play in there, they walk through there,” Messmer said of the rail trail near Coakley. “I’ve literally watched kids in boots standing in water over there and throwing rocks into it, skipping rocks and things.”
The Coakley Landfill Group monitors certain private wells on an ongoing basis; in May, it tested 13. Two — which have had treatment systems since 2018 — exceeded the state ambient groundwater quality standards for PFOA and 1,4-dioxane, according to the public fact sheet. Another well, which exceeded standards for PFOA, “has been taken offline and will be connected to municipal water,” according to the EPA.
One well, for the first time, exceeded the state standard for PFOA, but a resampling showed results below the standard, according to the EPA. The Department of Environmental Services informed private well owners within 500 feet.
The Coakley Landfill Group will continue to “investigate the interaction between surface water and groundwater and the relative contribution of contaminants migrating” from the site, and it has “increased sampling of surface water, stormwater runoff from the landfill cap, and shallow groundwater that is discharging to surface water,” according to the fact sheet. That sampling will be used to address the migration of contaminants and “protect human health from exposure to contaminants in surface water.”
Messmer said the recent EPA action constitutes part of a major victory. At the same time, much work remains to address the contamination and safeguard public health and the environment.
“It represents a really concerning health risk, which is something we’ve been concerned about for years,” Messmer said.
This story was originally produced by the New Hampshire Bulletin, an independent local newsroom that allows NH Business Review and other outlets to republish its reporting.
