Jan 19, 2022, 7:22 am


EPA Identifier: 110009302174
CERCLIS ID: 110009302174
40.8878, -73.17477


Create Date: 01-MAR-00
Update Date: 01-JUL-09
Final Date: 19990119

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Programs: {CERCLIS}
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Site Summary:
Federal Register Notice:  January 19, 1999 (PDF) (8 pp, 179K, About PDF)

Conditions at Proposal (September 29, 1998): The Smithtown Ground Water Contamination site is a contaminated ground water plume located in the Town of Smithtown, Suffolk County, New York. The area is encompassed by the Villages of Nissequogue and Head of the Harbor, and by the Hamlet of St. James. Homes in this area use private wells for potable water supply and septic systems for sanitary waste water disposal. At this time, the area affected by the contaminated plume is not serviced by a public water supply. The site is situated south of the Stony Brook Harbor and east of the Nissequogue River.

On October 9, 1997, the U.S. Environmental Protection Agency (EPA) received a written request from the New York State Department of Environmental Conservation (NYSDEC) requesting assistance in funding alternative water supplies for residences affected by contaminated ground water. Attached to this request was a private well sampling survey prepared by the Suffolk County Department of Health Services (SCDHS), which presented drinking water survey results for 34 private wells in the area. Analytical data from this survey indicated that several wells were contaminated with volatile organic compounds (VOCs), primarily tetrachloroethylene (PCE).

Throughout 1997 and 1998, the SCDHS collected samples from approximately 150 homes throughout the Villages of Head of the Harbor and Nissequogue, and the Hamlet of St. James. Analytical results from these data indicated that 23 residences were contaminated with PCE at concentrations exceeding the State and Federal maximum contaminant level (MCL) of 5 parts per billion (ppb). Four of these residences had PCE concentrations exceeding EPA's Removal Action Level (RAL) of 70 ppb.

SCDHS has investigated several current and former commercial/industrial facilities (located east of the site) in the area in order to identify sources of the contaminated ground water plume. These investigations included the installation and subsequent sampling of test wells downgradient of these facilities. Based on a review of analytical data from this sampling, the source or sources of the ground water contamination have not been determined.

An observed release of PCE to ground water is documented by the chemical analyses of ground water samples collected from private drinking water wells. In April 1998, EPA sampled 295 homes in the area in an effort to determine the extent of PCE contamination. Samples were analyzed according to EPA Method 524.2 for specific VOCs. Analytical results from this sampling event indicated the presence of PCE in 33 residential wells at concentrations above the MCL. The RAL for PCE was exceeded in six of these wells. Levels of PCE below the MCL (i.e., 1-5 ppb) were detected throughout the study. In addition to PCE, low levels of other VOCs, including breakdown products of PCE, were detected in private wells sampled by EPA and SCDHS. All of these wells are screened in the upper glacial or Magothy aquifers, which are interconnected and evaluated as the aquifer of concern.

As a result of the analytical results generated during the April 1998 sampling event, EPA began the delivery of bottled water to four of the six residences contaminated above the RAL with PCE. The other two residences had already had installed granular activated carbon (GAC) treatment systems. In June 1998, EPA expanded the delivery of bottled water to homes where the MCL for PCE or its breakdown products was exceeded and whose residents were interested in receiving bottled water. On July 23, 1998, an EPA Action Memorandum was signed, authorizing Removal Action activities to be conducted at the site: For homes where the MCL is exceeded and where public water is available, EPA will provide the service connection to the public water supply. For homes where the MCL is exceeded and public water is not available, EPA will provide a GAC treatment system. Bottled water delivery will continue until these actions are completed.

Institutional Controls:
Media Where IC Applies
(Multiple entries where more than one pathway is impacted)
Restriction Type Instrument
expand Ground Water
Prohibit Ground Water Well Installation/Construction
New York Environmental Conservation Law Section 15-1527: Permit required for certain wells in Long Island counties. 1. No person or public corporation shall hereafter install or operate any new or additional wells in the counties of Kings, Queens, Nassau or Suffolk to withdraw water from underground sources for any purpose or purposes whatsoever where the installed pumping capacity of any such new well or wells singly or in the aggregate, or the total installed pumping capacity of old and new wells on or for use on one property is in excess of forty-five gallons a minute without a permit pursuant to this title.
The link to this document is currently unavailable. Please contact the regional contacts listed for more information.
Document Effective, Implementation  September 30, 2004 

Gloria Sosa , RPM
Ground Water
Prohibit Ground Water Well Installation/Construction
The Record of Decision (ROD) included existing Suffolk County Department of Health Services (SCDHS) regulations as the necessary institutional controls during the period of restoration of the groundwater to drinking water standards. SCDHS regulations require new residences and businesses to connect to public water supplies whenever public water mains are reasonably available. Where such mains are not available, the SCDHS regulations require proposed wells for new residences and businesses be tested for water quality prior to use and provide treatment, if necessary. The remedy included the construction of public water mains to allow for all potentially effected residences to be hooked up to the public supply. At the time USEPA found that construction of the water mains was completed, the SCDHS regulations were in place and Suffolk County was expected to adequately enforce its regulations for at least as long as the groundwater was impacted by site-related contamination.
The link to this document is currently unavailable. Please contact the regional contacts listed for more information.
Document Effective, Implementation  September 29, 2006 

Gloria Sosa , RPM