This fact sheet addresses community concerns associated with risk assessment for the Massachusetts Military Reservation (MMR). Terms identified in bold are defined in the glossary.

Living near a Superfund site, such as MMR, raises concerns about health and safety for many community residents. Risk is the likelihood that people or the environment may experience adverse effects as a result of their contact with, or exposure to, contamination. The risk assessment is one tool used by the U.S. Environmental Protection Agency (EPA), Massachusetts Department of Environmental Protection (DEP), and Air Force Center for Environmental Excellence (AFCEE) to address health and environmentally related concerns during the investigation and cleanup process at the MMR. The objective of a risk assessment is to characterize potential current and future risks to human health and the environment posed by contaminants on and or migrating from MMR.

A risk assessment evaluates and usually quantifies the risks to human health and the environment posed by contaminants found at MMR sites. This is done by:

• Identifying the contaminants of concern
• Identifying the human health and ecological effects associated with these contaminants
• Determining the level and manner in which exposure may occur
• Integrating the results of the three previous steps to determine the magnitude of risks to people and the environment at or near MMR

With this information, EPA, DEP, and AFCEE are able to develop a cleanup plan that addresses the specific health and ecological risks associated with the MMR.

WHAT IS THE PURPOSE OF A RISK ASSESSMENT?

A risk assessment is conducted to document the risk of particular chemicals to health and the environment, considering the toxicity of the chemical and the potential for exposure to it. For areas where the risk is determined to be unacceptable, the risk assessment provides the basis for cleanup actions. The most important risks are then addressed to reduce those risks to be protective of human health and the environment.

WHO CONDUCTS HUMAN HEALTH AND ECOLOGICAL RISK ASSESSMENTS AT MMR?

AFCEE (with federal and state oversight), the DEP, or the EPA may conduct a risk assessment. AFCEE works with the EPA and MassDEP to collect the necessary data required in the risk assessment. Risk assessments at MMR are done following Federal and State risk assessment guidances.

HOW IS RISK ASSESSMENT USED AT MMR?

There are approximately 79 sites associated with MMR that require some level of risk assessment. The results of a risk assessment help to determine whether cleanup action will be undertaken and identify the acceptable cleanup levels at that site. It also may be used to predict the potential health risks and ecological impacts, if any, of implementing different types of cleanup options.

WHAT TYPES OF RISKS ARE EVALUATED IN AN MMR RISK ASSESSMENT?

As in all risk assessments, human health risk is evaluated in terms of cancer and non-cancer effects such as liver and kidney damage or fertility problems. Cancer risks are estimated as a probability, or chance, that a person would develop cancer over his or her lifetime as a result of exposure to the contaminants at MMR. For example, a risk of "one in one million" means that if one million people were exposed to the contamination at MMR for their lifetimes, at most one additional case of cancer would be expected to occur as a result of their exposure. Non-cancer hazard potential is presented as a ratio of the predicted exposure compared to a safe level. This is termed a hazard index. Ecological risk assessment evaluates risk to organisms, species, and food chains.

WHAT ARE SOME LIMITATIONS OF A RISK ASSESSMENT AND IS IT REALLY PROTECTIVE?

Risk assessment is not an exact science, but rather uses the best available data on what is occurring, or could occur, and applies scientific judgment to calculate statistically the likelihood of exposure to the contaminants. There are many sources of uncertainty in a risk assessment. Exposure is predicted based on assumptions about how people or different species living near MMR might come into contact with the contaminants. It is not known, for many of the contaminants, if the health effects seen in laboratory animals will be the same for people or other animals. There is also a lack of complete understanding of several aspects of risk assessment, such as how a contaminant affects an individual's or animal's well being or how it moves through the air, water, or ground. To deal with the various uncertainties, regulators use conservative assumptions to make sure that their decisions protect the health of the MMR community and surrounding environment.

DOES "NO EXPOSURE" MEAN "NO RISK"?

If there is no possibility of exposure to contaminants, and there is no reason to believe that there will be in the future, the contaminants do not pose a risk to human health or the environment. Living near MMR does not automatically place a person at risk. Risk depends on the type of contaminants present, the concentration, and the pathway by which people are exposed to them.

WILL A RISK ASSESSMENT TELL ME WHAT MY RISKS ARE?

A risk assessment does not tell an individual his or her specific risks, because it is not possible to account for the unique exposures that a person may encounter daily. Therefore, the assessment estimates risk for the high exposure group. Not everyone around MMR will be part of the high exposure group. The risk assessment is done to be very conservative and is designed to protect the community as a whole, as well as the individual.

GLOSSARY

contaminants: any substance that diminishes the quality of air, water, soil, or food
  
hazard index: a numerical comparison between an expected contaminant level and a known safe level to measure the potential for non-cancer health effects in humans and animals
 
high exposure group: EPA uses estimates of exposure for individuals, and uses the highest exposure they reasonably might expect to occur. Many people will have less exposure than the high exposure group.

pathway: the route by which a contaminant travels from the source area to reach a receptor (humans, birds, etc.)
  
risk: measure of the chance that adverse impacts to life, health, or the environment may occur

FOR MORE INFORMATION

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.