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Smithtown Ground Water Contamination

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Printable Version (PDF) (43 K, 2 pp)

Site Description

The Smithtown Ground Water Contamination site is an area of contaminated groundwater which has impacted drinking water in the Town of Smithtown in a location that includes the Villages of Nissequogue and Head of the Harbor and the Hamlet of St. James. There are approximately 500 homes in the immediate vicinity of the Site. Many homes in Smithtown use private wells for a potable water supply and septic systems for sanitary waste disposal. The Site is situated south of Stony Brook Harbor and east of the Nissequogue River. While the Site is located in a residential area, active commercial areas are located within one mile to the east and south.

Current Site Status and Cleanup Actions to Date

  • In April 1998, EPA collected samples from 295 private wells to delineate the extent of perchloroethylene (PCE) contamination. Based on the analytical data, a total of 35 residential wells were identified as contaminated with PCE (or its breakdown products) at concentrations above the federal maximum contaminant level (MCL) of 5 parts per billion (ppb). The Removal Action Level (RAL) of 70 ppb for PCE was exceeded in six homes.
  • Based on the results of well water samples, EPA initiated a Superfund Removal Action to supply bottled water to homes with wells contaminated above the MCLs. These actions were taken to protect the health of the public until a more permanent solution can be implemented.
  • In the fall and winter of 1998 - 1999 EPA took further action. Where a public water supply was available, the impacted residences were connected. At homes where water mains were not available, EPA installed individual carbon treatment systems (PDF) (532 K, 2 pp) or upgraded existing household treatment systems to EPA specifications.
  • EPA conducted a Remedial Investigation/Feasibility Study (RI/FS) to determine the nature and extent of the contamination at the Site and develop remedial alternatives to address the contamination. EPA observed sporadic and isolated pockets of groundwater contaminated with volatile organic compounds (VOCs), particularly PCE. No contiguous groundwater plume was detected. The RI was not able to determine the source(s) of the VOC contamination detected in the groundwater. During the Remedial Investigation (RI), four additional residential wells were identified as contaminated above the MCL. Those homes were connected to the public water supply.
  • EPA signed a Record of Decision (ROD) in September 2004 which selected a remedy of providing an alternate water supply to homes currently and potentially impacted by groundwater contaminated by VOCs, particularly PCE, by connecting these homes to the municipal water supply. Approximately 200 homes are within the area of potential contamination designated in the ROD. In addition, the remedy includes long-term groundwater and surface water monitoring and the implementation of institutional controls to restrict use of contaminated groundwater.
  • The work to connect residences within the area designated in the ROD to water mains began in November 2005.

Current Funding Status

  • To date, EPA has spent approximately $3.7 million for RI/FS work conducted at this site.
  • EPA has funded the Region 2 ERRS contract with $2,.9 million to perform the remedy selected in the 2005 ROD.

For more information on the projects at this site, please read the Smithtown Ground Water Contamination Fact Sheet (PDF) (70 K, 3 pp) on the Region 2 Superfund Web site.

Key Accomplishments

  • EPA has addressed 39 private wells with PCE levels above or equal to the EPA MCL by connecting the well owners to the public water supply or installing a water treatment system in individual properties where public water mains are not available.
  • A ROD was signed in September 2004 to address approximately 200 homes within the area of potential contamination designated in the ROD.


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