PFAS Drinking Water Well Sampling

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The Department of Navy is requesting permission to sample private drinking water wells within designated areas near NSA Mechanicsburg for certain per- and poly-fluoroalkyl substances, commonly known as PFAS.

For the Dept. of the Navy’s offbase PFAS private well sampling program, 55 wells have been sampled to date, with 54 of the 55 results below the U.S. EPA health advisory levels for PFOS and PFOA.

The Dept. of the Navy will continue to make sampling of private wells available through the end of September.


Property owners with a private drinking water well within the designated sampling area may request sampling by calling 1-833-426-7267.

Properties that have drinking water provided by Pennsylvania American Water Company (PA American) or Suez Water Company (Suez) do not need to be sampled.


Naval Support Activity Mechanicsburg

NSA Mechanicsburg is located in Central Pennsylvania at the eastern boundary of Mechanicsburg, in Hampden Township, Cumberland County. The facility is readily accessible from a number of highways and railroads. NSA Mechanicsburg, Figure 1, occupies nearly 824 acres of land, of which the largest portion (30 percent) is designated as grounds for storage

Presently NSA Mechanicsburg serves approximately 4,300 civilian, military and industry partners assigned to over 40 tenant activities or commands. The largest of these are: NAVSUP Weapons Systems Supply (formerly NAVICP), with approximately 1,000 personnel; the NAVSUP Business Systems Center (formerly NAVSISA), with approximately 500 personnel and NAVSUP headquarters, with a complement of approximately 300 personnel.

Areas for PFAS Drinking Water Well Sampling

The Navy is requesting permission to sample private drinking water wells within designated areas near NSA Mechanicsburg for certain per- and poly-fluoroalkyl substances, commonly known as PFAS.

PFAS are a family of thousands of different chemicals which have been widely used in industrial and consumer products since the 1950s. The Navy developed a proactive policy to address past releases of PFAS at installations nationwide, as several PFAS are now of emerging public health concern to the Navy, U.S. Environmental Protection Agency (EPA), state regulatory agencies, and the general public. The EPA has issued a lifetime health advisory for two commonly used and studied PFAS, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).

The most common Navy activity that could have resulted in the historical release of PFOS, PFOA, and other PFAS to the environment is the use of fire-fighting foam (specifically aqueous film forming foam or AFFF) for testing, training, firefighting, and other life-saving emergency responses. PFAS compounds may be present in the soil and/or groundwater at NSA Mechanicsburg as a result of historical firefighting training and response activities using the AFFF firefighting foam. Because of this historical use, there is potential for PFOS, PFOA, and other PFAS to be in the groundwater on base, and also be present in nearby private drinking water wells that are located in the direction that the groundwater flows away from the base. The designated sampling area, as shown in Figure 2, was selected because of the proximity to NSA Mechanicsburg and the general groundwater flow direction.

Records indicate the majority of residents in the sampling area purchase their drinking water from Pennsylvania American Water Company (PA American) or Suez Water Company (Suez), but a limited number of properties use or may be using a private well for their drinking water. The Navy is not requesting to sample water from residents in the designated off-base sampling areas who receive their drinking water from PA American or Suez as your water is tested prior to distribution. Homeowners should contact PA American or Suez Water with any questions regarding treatment and testing of your drinking water.

The EPA’s health advisories provide information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. EPA's health advisories are non-enforceable and non-regulatory and provide technical information to states agencies and other public health officials on health effects, analytical methodologies, and treatment technologies associated with drinking water contamination. The EPA lifetime health advisory level is 70 parts per trillion (ppt) in drinking water for the combined value of PFOS and PFOA.

Figure 2: Designated Sampling Area

NSA Mechanicsburg Actions Based on Drinking Water Sampling Results

If PFOS/PFOA are found at or below the EPA lifetime health advisory level of 70 ppt in a drinking water sample, then no further action is needed at this time. The Navy will evaluate all results, and additional sampling may be requested in the future.

If PFOS/PFOA are found in a private drinking water well sample above the EPA lifetime health advisory level of 70 ppt, the Navy will provide alternate water (likely bottled water) for drinking and cooking until a long-term solution can be put in place.


Per-and Polyfluoroalkyl Substances

PFAS are chemicals used in many consumer products to prevent stains, and repel water, oil, and grease. Commercial and consumer products containing or degrading to these compounds were first introduced in the 1950s. They were used in a variety of products such as for the treatment of upholstered furniture fabric and carpets, in nonstick cookware, floor wax, the lining of food containers/packaging and fire-fighting foam. PFAS are now present virtually everywhere in the world because of the large amounts that have been manufactured and used by international consumers and industry. Once these compounds are released to the environment, they break down very slowly.

PFAS are chemicals of emerging concern, which have no Safe Drinking Water Act regulatory standards or routine water quality testing requirements. The EPA is currently studying PFAS to determine if national regulation is needed. Studies by the EPA, the Agency for Toxic Substances and Disease Registry (ATSDR), and others indicate that exposure to PFAS may cause elevated serum cholesterol levels and developmental effects to fetuses during pregnancy (e.g., low birth weight, accelerated puberty, skeletal variations) or to breastfed infants. Individual states are also conducting their own evaluations and may establish their own drinking water standards or environmental cleanup requirements.

Navy use of PFAS

While PFAS have been used in a variety of products and substances world-wide, the most common historical Navy use has been in fire-fighting foam (specifically aqueous film forming foam or AFFF) used for testing, training, firefighting, and other life-saving emergency responses. The Navy is working on identifying a new formulation for fire-fighting foam that does not contain PFOS and PFOA, but will still meet critical fire-suppression and ultimately life-saving properties. Until this formulation is approved and products are available, the Navy has taken steps to prevent or minimize additional release of fire-fighting foam to the environment. These specific actions and others implemented by the Navy to PFAS concerns are explained in the Navy Policy section.

Identification of PFAS at NSA Mechanicsburg

The Navy first evaluated the need for an off-base drinking water investigation at NSA Mechanicsburg in summer 2016 in response to a new Navy policy (DASN (E), 20 June 2016). This policy required a review of existing environmental restoration database information to identify sites with drinking water sources within 1-mile in the direction of the groundwater flow away from known or potential releases of PFAS. Off-base drinking water investigations were conducted starting in October 2017 for sites meeting this criteria. No known sites on NSA Mechanicsburg met the policy criteria in initial review. However, the Navy did not stop with these initial sites. Across the country, the Navy has been conducting base-wide evaluations to identify additional potential PFAS releases. These evaluations are being conducted under the federal cleanup program which meets the requirements of, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Following CERCLA, the Navy’s installation-wide assessments are called preliminary assessments/site inspections (PA/SI), and their purpose is to verify, validate, and update the inventory of PFAS release sites for further investigation and cleanup.

The recent base-wide review for NSA Mechanicsburg identified the following 11 locations where PFAS-related operations, use, or storage potentially occurred and additional investigation is needed to determine if a release occurred. These are listed in the following table, and locations are shown on Figure 3.

Figure 3: Potential PFAS Site Locations

The Navy’s priority with PFAS investigations is to identify and eliminate drinking water exposures above the EPA’s lifetime health advisory level. To protect our neighbors, the Navy is not waiting until all on-base investigations under CERCLA are complete at NSA Mechanicsburg to confirm if a release occurred. We are conducting the off-base drinking water investigation first, based on newly identified locations where a potential PFAS release may have occurred. The designated sampling area selected near NSA Mechanicsburg lies in the direction that the groundwater flows off-base, away from these 11 sites where additional investigation is needed. The Navy has identified private drinking water wells for sampling within the designated area, shown on Figure 2.

PFAS Regulatory History

PFOA Stewardship Program

In 2006, EPA initiated the 2010/2015 PFOA Stewardship Program in which eight major companies in the United States committed to reduce facility emissions and product contents of PFOA and related chemicals on a global basis by 95% no later than 2010, and to work toward eliminating emissions and product content of these chemicals by 2015. All U.S. companies have met the program goals. To meet the program goals, most companies stopped the manufacture and import of long-chained PFAS, and then transitioned to alternative chemicals. On January 21, 2015, EPA proposed a Significant New Use Rule under the Toxics Substances Control Act to require manufacturers (including importers) of PFOA- and PFOA-related chemicals to notify EPA at least 90 days before starting or resuming new uses of these chemicals in any process.

Unregulated Contaminant Monitoring Rule (UCMR)

The USEPA issued the Third Unregulated Contaminant Monitoring Rule (UCMR3) in May 2012. The UCMR3 required monitoring, between 2013 and 2015, for 30 substances at all large public water systems (PWSs) serving more than 10,000 people and 800 representative PWSs serving 10,000 or fewer people. Six PFAS compounds were included in the UCMR3 contaminant list. Of these 6 PFAS, EPA issued health advisory levels for only two, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). The UCMR3 results found these two chemicals were present in less than 1% of the nearly 5,000 public water systems that sampled per UCMR3.

In December 2016, the EPA issued the fourth Unregulated Contaminant Monitoring Rule (UCMR4). UCMR4 requires all large PWSs serving more than 10,000 people and 800 representative PWSs serving 10,000 or fewer people to sample for 30 chemicals between 2018 – 2020. There are no PFAS included on the UCMR4 list of contaminants that require sampling and analysis.

EPA Lifetime Health Advisories

In May 2016, the EPA Office of Water issued a drinking water lifetime health advisory for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Health advisories are not enforceable, regulatory levels; rather they are levels that provide Americans, including sensitive populations, with a margin of protection from a lifetime of exposure to PFOA and PFOS in drinking water. The health advisory is 70 parts per trillion (ppt) for PFOA and 70 ppt for PFOS. When both PFOA and PFOS are found in drinking water, the combined concentrations of PFOA and PFOS should be compared with the 70 ppt health advisory level.

PFAS Navy Policy

Department of the Navy, Office of the Assistant Secretary (Environment) [DASN (E)] Policy Memo, 21 Oct 2014

The Navy issued a policy requiring on-base drinking water sampling for PFOA and PFOS for bases where groundwater was used as drinking water and PFAS could have been released nearby in the past. Installations that were not required to sample finished drinking water under UCMR3 that produce drinking water from on-installation groundwater sources and have an identified or suspected PFAS release within approximately 1-mile upgradient to the drinking water source were also required to sample their finished drinking water by December 2015.

Chief of Naval Operations (CNO) Policy Memo, 14 Sept 2015

Similar to the October 2014 DASN (E) policy memo, this memo related to testing on-base drinking water. However, this memo also specified that if levels of PFOS and/or PFOA in drinking water exceeded the then current EPA health advisory (i.e., the 2009 provisional short-term health advisories), then alternative drinking water must be supplied until the PFOA and/or PFOS levels were reduced to below the EPA health advisories.

Office of the Assistance Secretary of Defense (ASD) Policy Memo, 10 Jun 2016

This Department of Defense (DoD) policy memo specified that decisions regarding drinking water should be based on the lifetime health advisories issued by EPA's Office of Water in May 2016, rather than the now outdated provisional short-term health advisories issued in 2009.

DASN (E) Policy Memo, 14 Jun 2016

This policy expanded the sampling PFOA and PFOS at all Navy installations where such sampling was not previously completed under EPA’s UCMR3 or the Navy’s October 2014 policy. This memo also specified that for instances where an installation’s drinking water is purchased from a public water system, but wasn't tested under UCMR3, that the installation must sample the finished drinking water and provide alternative water if the PFOA and/or PFOS levels in drinking water exceed the EPA lifetime health advisory levels. Additionally, this policy included reporting requirements to the DASN (E) office for all PFOA and/or PFOS drinking water results.

DASN (E) Policy Memo, 17 June 2016

This policy defines the DON’s intention to remove, dispose, and replace legacy AFFF that contains PFOS and/or PFOA once environmentally suitable substitutes are identified and certified to meet DoD’s performance requirements. This policy directs the following actions be taken until suitable replacements are certified:

  • Immediately cease the uncontrolled environmental release of AFFF for shoreside installations, with the exception of emergency responses.
  • Update and implement Navy and Marine Corps firefighting system requirements, as needed, to ensure fire and emergency service vehicles and equipment at Navy installations and facilities are tested and certified in a manner that does not allow the release of AFFF to the environment.
  • By the end of FY2017 (September 30, 2017), remove and dispose of uninstalled PFOS-containing AFFF in drums and cans from local stored supplies for shore installations and ships to prevent future environmental releases.

DASN (E) Policy Memo, 20 Jun 2016

This policy required Navy to identify and prioritize sites for investigation if drinking water resources, on- or off-installation, are thought to be vulnerable to PFOA/PFOS contamination from past Navy/Marine Corps PFAS releases. The primary mechanism to identify potential PFAS release sites, was review of existing Navy environmental restoration databases. Sites with drinking water sources within 1-mile downgradient from known or potential releases of PFAS were assigned the highest priority. This policy directed the sampling of off-base drinking water at these high priority (Priority 1) sites be completed by September 30, 2017.


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