HFAC Investigates Airfield Environmental Impacts on Water Resources

Recently, the Hanscom Field Advisory Commission (HFAC) reviewed airfield impacts on local wetlands, wildlife, and water resources as described in Massport’s most recent 2017 environmental report, during its Feb. 16 meeting.

“I think the Massport plan [to protect wetlands, wildlife, and water resources] is generally good, and our role is to watch and make sure they follow it,” Chair Christopher Eliot said.

However, he cautioned, “Aviation requires the use of various toxic chemicals including fuel, anti-icing compounds and firefighting foam,” and added, “There have been instances where local water supplies have been impacted by airport activities. Bedford water was actually shut down.”

Bedford’s natural water resources have always had a tenuous relationship with its airport neighbor.  Hanscom Field’s runways are built atop the ancient lake bed of glacial Lake Concord and the entire airfield is drained by the Shawsheen River and its tributary Elm Brook.  It is surrounded by wetlands and about half of the airfield lies above protected groundwater resources.   In early 1941, as the State planned to take the land for the new airfield by eminent domain, Samuel Hoar, a Concord resident, foreshadowed some of the environmental issues which have since come to pass, protesting, “I can’t believe that this is the only spot available for an airport.  It is 1 ½ miles from the center of Concord and the swamp there has to be drained and the ground filled and leveled.”  (The Boston Globe: “Bedford Airport Proposal” Tuesday, Jan. 7, 1941, Page 6; shared courtesy of John Linz)

In 1984, Bedford’s new Hartwell Road municipal wellfield and treatment plant were shut down after tap water samples showed contamination with VOCs (volatile organic compounds) including benzene and TCE (trichloroethylene). The Town sued the Navy, Raytheon, the Air Force, and Massport after a remedial investigation showed the contamination traced back to Navy/Raytheon facilities bordering the airfield, as well as deep aquifer layers of the airfield itself.  The defendants settled in 1993, paying $4,700,000 to the Town.

In 2014, the Bedford Shawsheen municipal wellfield was closed for several weeks to prevent potential cross-contamination of its groundwater source by the nearby Shawsheen River.  The river had been polluted by jet fuel and PFAS-containing fire-fighting foam after a charter jet failed to achieve lift-off from the runway at Hanscom Field and crashed and burned in the river with the loss of all 7 people on board.  The wellfield at that time supplied 15% of Bedford’s drinking water.  Note:  PFAS are synthetic per- and polyfluorinated substances which the EPA has described as “very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time. There is evidence that exposure to PFAS can lead to adverse human health effects.” See:  https://www.epa.gov/pfas/basic-information-pfas

In 2019, the same wellfield was closed again after detection of PFAS in water samples.  The source of the PFAS contamination is as of yet undetermined.  MWRA now supplies 100% of Bedford’s drinking water.

Eliot also noted that PFAS were discussed during the February Senate confirmation hearing of White House Budget Director nominee, Neera Tanden, who was born and grew up in Bedford.  During the hearing, Senator Gary Peters, D-I, MI, spoke of “the toxic forever chemicals known as PFAS,” and Tanden said she believes PFAS contamination in communities across the country “is an issue for federal concern because of the national scope” and a “real public health concern.”

Emily Mitchell, HFAC and Bedford Select Board member, observed that PFAS detected in airfield groundwater were also discussed during the December 2020 Restoration Advisory Board meeting with the Air Force in Bedford.

Margaret Coppe, HFAC member and representative for the South Lexington Civic Association, noted that a 2003 Massport environmental impact study of deicing chemical usage at Hanscom Field was initiated at the request of HFAC.

“It’s an interesting report, basically saying that everything’s fine.  But the problem I’m having with it is, I don’t know what follow up there has been since 2003,” Coppe said and continued,  “With the changes in the aircraft mix, and in terms of have there been more de-icing events than there were almost 20 years [ago]?”  She suggested HFAC may decide to advise Massport that additional sampling and study is needed.  Coppe also asked for more detail on how Massport tracks and reports the overall usage of de-icing compounds per season at Hanscom Field.

The 2017 Massport Environmental Status and Planning Report (ESPR) for Hanscom Field states that chemical deicers are used on airfield runways and taxiways, salt is applied to roads and parking areas, and a propylene glycol aircraft deicing solution is used by its tenants Jet Aviation, Signature Flight Support, and Rectrix. The report can be seen at https://www.massport.com/media/3182/2017_hanscom_espr_web.pdf

Mitchell added she believes climate change may alter assumptions about wetlands and the lateral extent of flooding in land that borders the airfield if major storm events are becoming more common.

It was also pointed out during the meeting that the 2009 National Pollutant Discharge Elimination System (NPDES) permit granted for Hanscom airfield as described in the ESPR requires only periodic visual inspection of stormwater discharges into the Shawsheen River, which borders the eastern edge of the airfield, and Elm Brook, its tributary which flows along the western edge of the airfield.  Stormwater samples are collected quarterly from 4 of 11 outfall locations and visually inspected for color, clarity, floating solids, settled solids, suspended solids, foam, and oil sheen. They are also smelled to determine whether or not further investigation is needed.  The ESPR notes that no follow-up has ever been recommended since the original 2003 study.

In contrast, the Logan Airport NPDES permit requires Massport to monitor airfield stormwater outflow from October to April for ethylene glycol, propylene glycol, biological oxygen demand, chemical oxygen demand, total ammonia nitrogen, and two toxic additives to deicing agents, nonylphenol and tolyltriazole. (https://www3.epa.gov/region1/npdes/logan/pdfs/finalma0000787permit.pdf)

Logan stormwater discharges are also routinely analyzed for pH, oil and grease, surfactants, benzene, naphthalene, and six other polynuclear aromatic hydrocarbons due to potential toxicity to Boston Harbor aquatic life.

Although Boston Harbor is not used as a drinking water source, Burlington does divert water from the Shawsheen River as part of its drinking water supply.

The Massport community relations representative, Mike Vatalaro, was asked how Massport handles snow disposal on the airfield, since about half of the airfield lies atop protected aquifer and water supply zones.  He was also asked if the State’s December 2020 revised guidelines for snow disposal from paved areas contaminated by salt, sand, and other pollutants will impact Massport snow removal practices.  Vatalaro offered to seek clarification from Massport on its airfield snow disposal policies for Hanscom Field.

Coppe and Mitchell both emphasized they would like HFAC to offer comments early in Massport’s preparation of its next ESPR for Hanscom Field, expected around 2022.  Vatalaro volunteered to find out the timeline for public comments.

Eliot also summarized some of the major environmental issues for local communities to be aware of in his review of the ESPR chapter on Hanscom airfield’s wetlands, wildlife, and water resources as follows:

  • Hanscom Field property encompasses a number of wetlands
  • Massport intends all future building to be done on existing hard surface areas, rather than expand into wetlands
  • Four endangered, threatened, or special concern species live on airport property (Grasshopper Sparrow, Upland Sandpiper, Wood Turtle, and the Northern Long-eared Bat)
  • Trees under approaches to runways must be trimmed periodically for safety, but communities may have concerns about overzealous cutting
  • Conservation commissions in each town have oversight of Massport tree-cutting activities
  • Various fuel and chemical compounds in use at the airfield have the potential to contaminate local water resources
  • A number of areas on the airfield are contaminated (The ESPR shows locations of three old fire-fighting training sites, multiple fuel spills, jet fuel tank sludge, paint waste disposal, and one suspected dump site on the airfield. Much of the contamination has already been remediated by the Air Force and Navy under the Superfund program, but several of the sites will require years or decades of additional remediation.)

Hanscom Field’s environmental impacts on local cultural and historical resources will be discussed at the next HFAC Zoom meeting on Tuesday, March 16 at 7 p.m.  The meeting agenda and login information can be accessed at the HFAC webpage hosted by the Town of Lincoln at https://www.lincolntown.org/AgendaCenter/Hanscom-Field-Airport-Commission-58