This fact sheet addresses community health concerns associated with groundwater and the Massachusetts Military Reservation (MMR). Terms identified in bold are defined in the glossary.

The MMR is located on the upper western portion of Cape Cod. It covers approximately 34 square miles and includes portions of the towns of Bourne, Mashpee, and Sandwich, and Falmouth. The MMR sits over the recharge area for the sole source aquifer on which the towns rely for their drinking water supply. The aquifer, referred to as the Sagamore Lens, is a valuable water supply resource.

The military has used fuels, solvents and other chemicals at MMR for more than 60 years. Some of these materials spilled on the ground. As these materials filter through the sandy Cape Cod soil, they may dissolve and encounter groundwater. This can result in a groundwater plume (plume). There are several known plumes originating from the MMR; many have moved beyond the base boundary. The Air Force, U.S. Environmental Protection Agency (EPA), and the Massachusetts Department of Environmental Protection (DEP) are developing and implementing community-based solutions for cleanup of groundwater contamination at or emanating from the MMR.

WHO USES THE GROUNDWATER?

The four towns of Bourne, Falmouth, Mashpee, and Sandwich, as well as the MMR base, use the groundwater as their public water supply. Additionally, numerous private well users in the four towns rely on the groundwater for drinking, other domestic uses, and irrigation.

IS THE WATER FROM PUBLIC WATER SUPPLIES SAFE TO DRINK?

Yes. The water from the towns of Bourne, Falmouth, Mashpee, and Sandwich, as well as the MMR base is safe to drink. As with all public water supplies, these sources are regulated by the MassDEP and are tested regularly.

WHAT IS A GROUNDWATER PLUME?

A groundwater plume is a body of groundwater containing contaminants which exceed federal and state safe drinking water standards. Contaminated water can result when fuels, solvents or other potential contaminants are spilled or released. When these materials filter through the sandy Cape Cod soil, they may dissolve and encounter groundwater, or the water table, where soil is saturated with water. As the groundwater moves, the contaminants may be carried with it, creating a groundwater plume (Figure 1).

WHAT ARE THE PRIMARY CONTAMINANTS IN THE GROUNDWATER PLUMES AT MMR?

Contaminants frequently found in the MMR plumes are volatile organic compounds (VOCs). Examples include solvents used in metal degreasing such as tetrachloroethylene (PCE), trichloroethylene (TCE), and carbon tetra-chloride (CCl4), as well as fuel constituents and an aviation gasoline additive, ethylene dibromide (EDB).

Figure 1

IF MY PRIVATE WELL IS NEAR AN MMR PLUME, IS THE WATER SAFE TO DRINK?

Most of the private wells in the area draw water from a shallow depth or zone in the upper portion of the aquifer. This zone, generally less than 80 feet below ground surface, should produce safe drinking water. Most of the plumes associated with the MMR are deep¾as much as 100 to 200 feet below the ground surface.

AFCEE conducts a residential well sampling program for private wells in the vicinity of the MMR plumes. The EPA and MassDEP monitor this program. AFCEE has and will take action to provide an alternate water supply when needed.

If you have questions about whether your well should be tested and for what, contact your local Board of Health, County Health Department, or the Installation Restoration Program (IRP) office at MMR.

HOW MAY THE PUBLIC AND THE ENVIRONMENT BE AT RISK FROM THE CONTAMINANTS IN THE GROUNDWATER AT AND AROUND THE MMR?

In order for there to be a risk, there must first be an exposure to the contaminant. The magnitude of the risk to one's health depends on the level and duration of exposure, the toxicity of the particular contaminant, the concentration of the contaminant, and various personal factors. The fact sheet "Understanding Exposure" in this series provides more information about exposure.

The major potential health risk at and around the MMR is from drinking contaminated groundwater. However, most residences around the base are connected to town water. For those residences not connected to town water and located in an area that might be potentially at risk, the Air Force conducts a private well sampling program.

The fact sheet "Ecological Risk Assessment" provides more information about potential impacts to the environment.

FOR MORE INFORMATION

GLOSSARY

aquifer: an underground geological formation, where the soil is saturated with water, containing usable amounts of groundwater that can supply wells and springs.

carbon tetrachloride (CCl4): a clear, man-made liquid with a sweet odor, used in propellants for aerosol cans, the production of refrigerator coolants, as an industrial degreasing agent and cleaning fluid, in fire extinguishers, and in laundry spot removers.

concentration: the relative amount of a substance mixed with another substance such as water, air, or soil.

contaminants: substances that pollute the air, water, soil, or food.

drinking water standards: the maximum concentration of a given contaminant allowed in a public drinking water supply under state and federal regulations. Also referred to as maximum contaminant levels (MCLs).

ethylene dibromide (EDB): a man-made additive that was formerly used in aviation gasoline to control the build-up of lead in engines.

exposure: the contact of an organism (humans, in the case of a health risk assessment) with a chemical or physical agent

groundwater plume: a concentration of contaminants in groundwater exceeding safe drinking water standards, usually originating from a distinct source. The size and shape of a groundwater plume is confirmed by multiple samples from multiple wells.

recharge area: an area of land where there is a net annual transfer of water from the surface to groundwater; where rainwater soaks through the earth to reach an aquifer.

tetrachloroethylene (PCE): a man-made solvent commonly used for metal degreasing and in dry cleaning clothes; also known as perchloroethylene

toxicity: the actual or potential harmful effects of chemicals on living organisms and ecosystems. The amount of chemical required to produce harmful effects varies widely with the nature of the substance and the amount of exposure to it.

trichloroethylene (TCE): a man-made solvent used to dissolve or disperse another substance such as oil, and is often used in metal degreasing.

volatile organic compounds (VOCs): organic compounds such as PCE and TCE that readily evaporate to the atmosphere.

water table: the upper limit of the ground wholly saturated with water.

FOR ADDITIONAL INFORMATION

Additional information about the cleanup program at the MMR is available on the program’s website (http://www.mmr.org). The website includes a variety of information, including technical documents, meetings agendas and summaries, maps, glossaries, weekly reports, and news releases. It also includes links to other websites, including those of EPA Region 1, DEP, DPH, and ATSDR.

In addition, five local libraries house information repositories for the cleanup program. The libraries are:

The Administrative Record, which is a public record of all documents used in decision-making, is available for review at the Falmouth Public Library or by contacting the IRP Office at (508) 968-4678.

This fact sheet was developed through a collaborative effort of the Air Force Center for Environmental Excellence (AFCEE), U.S. Environmental Protection Agency (EPA), U.S. Agency for Toxic Substances and Disease Registry (ATSDR), Massachusetts Department of Environmental Protection (DEP), Massachusetts Department of Public Health (DPH), Joint Program Office (JPO), and local officials.