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1. Introduction
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1.1 Background
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Site Number: |
B4S8 |
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Contract Number: |
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D.O. Number: |
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Action Memo Date: |
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Response Authority: |
CERCLA |
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Response Type: |
Emergency |
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Response Lead: |
EPA |
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Incident Category: |
Removal Action |
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NPL Status: |
Non NPL |
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Operable Unit: |
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Mobilization Date: |
7/11/2012 |
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Start Date: |
7/11/2012 |
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Demob Date: |
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Completion Date: |
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CERCLIS ID: |
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RCRIS ID: |
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ERNS No.: |
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State Notification: |
NC DENR Superfund Section |
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FPN#: |
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Reimbursable Account #: |
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1.1.1 Incident Category
CERCLA - Emergency Response
1.1.2 Site Description
July 10th 2012, NC DENR referred Stony Hill Road TCE Site. Based on sampling results from a sampling event that was conducted by NC DENR in June, a house located on Stony Hill Rd had elevated concentrations of TCE above the Removal Management Level (RML). The RML for TCE is 8 parts per billion (ppb), the Maximum Contaminant Level (MCL) for TCE is 5 ppb.The residential well had TCE levels at 22 ppb.
July 11th, US EPA delivered bottled water to the resident that was identified as having a contaminated well with TCE above the RML. EPA obtained access agreements to conduct well sampling at additional residential properties in the area.
July 12th, US EPA sampled seven (7) residential wells along Stony Hill Rd.
July 13th, US EPA received preliminary data from the lab indicating that three properties; four homes (two homes share one well) have TCE above the RML. US EPA notified residents of results and advised them to not use the water for drinking, cooking, and to limit bathing/showering times to a minimum using a exhaust fan or open window for ventilation to reduce exposure. US EPA had START deliver bottled water to all the impacted homes.
1.1.2.1 Location
Stony Hill Road, Wake Forest, Wake County NC
1.1.2.2 Description of Threat
Residential wells contaminated with TCE above the RML. TCE is a carcinogen; risks of exposure via consumption from drinking water and cooking; risk of exposure via inhalation from showering/bathing.
1.1.3 Preliminary Removal Assessment/Removal Site Inspection Results
On July 10th, NC DENR referred the Stony Hill Road TCE Site to US EPA based on results from a June 2012 sampling event that indicated one resident having a contaminated well with TCE (22 ppb) exceeding the RML.
USEPA sampled homes in the area on July 12th and discovered TCE exceeding RML at three residential properties with four homes (one property has two homes). TCE was detected up to 66 ppb.
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2. Current Activities
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2.1 Operations Section
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2.1.1 Narrative
In August 2005 a resident at 7305 Stony Hill Rd complained of a petroleum odor in his water to Wake County Health Dept. Wake County sampled the well and discovered chlorinated solvents present. Wake County referred the site to NC DENR DWQ's Aquifer Protection Section (APS). The well at 7305 Stony Hill Rd. was abandoned and a neighboring well was utilized to provide water to the resident at 7305 Stony Hill Rd.
NC DENR DWQ transferred the site to NC DENR Inactive Hazardous Waste Section in 2007. Inactive Hazardous Waste Section sampled the area in June 2012 and discovered elevated TCE present at a resident located at 7333 Stony Hill Rd and referred the site to US EPA July 10th 2012.
EPA delivered bottled water to impacted resident on July 11th 2012 and sampled additional residential wells on July 12th. July 13th, based on sample results from the previous day samples; EPA provided bottled water to three additional homes.
On July 16, 2012, the EPA returned to the Site to obtain additional access agreements to expand the sampling area. From July 16 through July 18, 2012 the EPA continued to obtain access agreements from residents in the area. On July 19, 2012, a second round of samples was collected from 11 residences in the area. Of the 11 wells sampled, one well was contaminated above the MCL. Sample results were received on July 20, 2012. One well was found to contain TCE at 7.7 ppb. Bottled water was delivered to the resident immediately upon receipt of the preliminary sample results on July 20, 2012. Two other residences in close proximity had detects of TCE and PCE but were below the MCL. On July 26, 2012 EPA sampled 15 additional wells at the request of the homeowners. EPA received results on July 27, 2012. Of the 15 wells sampled 1 well contained TCE at 4.9 ppb. Because the well was very close to the MCL EPA delivered bottled water. Two additional well samples contained TCE. One well was at 4.9 pre-filter and 2.0 post-filter, the owner was advised that the carbon in his filtration system should be changed to ensure continued efficacy. The other detect was well below MCL at 3.6 ppb. One residence had a trace amount of MTBE at .69 ppb. On August 1, 2012 the remaining 7 residences in the Stone Walls neighborhood were sampled. There was only one detect at .78 TCE in one residential well sample. One additional sample was taken from the Stony Hill Baptist Church community building on Stony Hill Road and August 2, 2012.
On August 14, 2012 EPA held a public meeting at Stony Hill Baptist Church. NC DENR and Wake County attended the meeting along with approximately 30-40 residents from the area. NCDENR gave a brief history of the site and EPA informed the residents of the response actions that EPA has taken and that are being planned including the installation of temporary carbon filters on residences with TCE contamination at or exceeding the RML and with sensitive populations including children or women of childbearing age and the extension of a waterline from a nearby Aqua America operated system down Stony Hill Road to serve the seven homes that are known to be contaminated. EPA answered residents questions regarding the response and NC DENR answered questions regarding the history of the site. On August 17, 2012 EPA installed two chamber activated carbon filtration systems on the only two residences that had TCE at or above RML and sensitive populations.
2.1.2 Response Actions to Date
EPA Obtained Access Agreements
EPA Sampled 40 residential wells
EPA Provided Bottled Water to Impacted Residents
EPA installed carbon filtration systems on 2 homes with sensitive populations
EPA negotiated with Aqua America and NC DENR to extend a waterline from a nearby community water system down Stony Hill Road to serve 7 impacted residences
EPA held a public meeting
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
NC DENR Inactive Hazardous Waste Section suspects the source of contamination is a vapor degreaser that was allegedly used for a short time by Circuit Board Assemblers (CBA) located at 7303 Stony Hill Rd. There was a drain pipe discovered by NC DENR at a cinder block shed located at the rear of the property. EPA is continuing to investigate to identify responsible parties.
2.1.4 Progress Metrics
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Manifest # |
Treatment |
Disposal |
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2.2 Planning Section
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2.2.1 Anticipated Activities
Sample additional wells at owner request.
2.2.1.1 Planned Response Activities
Extend water line from Hasentree water system to serve seven impacted wells on Stony Hill Road.
2.2.1.2 Next Steps
Begin extending the water line.
Analyze feasibility of extending the water line into the Stone Walls neighborhood.
2.2.2 Issues
Additional Sampling needs to be conducted to insure no other exposures exist.
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2.3 Logistics Section
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No information available at this time.
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2.4 Finance Section
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No information available at this time.
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2.5 Other Command Staff
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No information available at this time.
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3. Participating Entities
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3.1 Unified Command
3.2 Cooperating Agencies
Wake County Health Department
NC DENR Inactive Hazardous Waste Section
NC DENR Superfund Section
US EPA ERRB
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4. Personnel On Site
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No information available at this time.
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5. Definition of Terms
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No information available at this time.
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6. Additional sources of information
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No information available at this time.
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7. Situational Reference Materials
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No information available at this time.
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