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1. Introduction
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1.1 Background
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Site Number: |
A7W2 |
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Contract Number: |
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D.O. Number: |
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Action Memo Date: |
7/21/2010 |
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Response Authority: |
CERCLA |
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Response Type: |
Time-Critical |
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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: |
8/16/2010 |
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Start Date: |
8/16/2010 |
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Demob Date: |
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Completion Date: |
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CERCLIS ID: |
MON000706143 |
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RCRIS ID: |
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ERNS No.: |
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State Notification: |
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FPN#: |
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Reimbursable Account #: |
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1.1.1 Site Description
In March 2010, the Missouri Department of Natural Resources (MDNR) Public Drinking Water Branch (PDWB) found trichloroethylene (TCE) in two non-community wells and an irrigation well on the western edge of Rogersville, Missouri. MDNR’s Superfund Section initiated a combined Preliminary Assessment/Site Investigation (PA/SI) integrated Removal Site Evaluation (RSE) on March 24, 2010. Initial sampling events found 13 of the 100 wells sampled have detectable concentrations of TCE. Five drinking water wells within that sampling group had TCE concentrations above the maximum contaminant level (MCL) of 5 parts per billion (ppb). The source of the TCE release is unknown at this time. MDNR requested EPA to provide alternate water supply to the households drinking contaminated water. EPA currently plans to continue the well water and source assessment work at the site.
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2. Current Activities
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2.1 Operations Section
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2.1.1 Narrative
The week of August 16, 2010, EPA installed 5 water treatment systems in private residences with TCE concentrations above the MCL. Analytical results of post treatment water samples indicate the systems are effective in removing TCE. Sampling to identify other impacted wells found one additional drinking water well with TCE, but the TCE concentration was below the MCL.
During the week of October 4, 2010 EPA sampled 51 private drinking water wells. There were no detections of TCE in these samples.
During the week of December 13, 2010, EPA in cooperation with MDNR, Greene County Resource Management and the Natural Resource Conservation Service (NRCS) plugged a well with high concentrations of TCE to protect groundwater resources. These same agencies also oversaw the constructioin of a new drinking water well at the same location. No TCE was detected in the new well. Also during this week, 65 well water samples were collected from previously unsampled wells and wells where TCE was previously detected. All treatment systems are effectively removing TCE from the groundwater. One additional well was found to have TCE below the MCL. This well is located in the same general area as wells previously found to have TCE contamination.
EPA sampled 25 wells the week of February 21, 2011. No new wells were found to have detectable concentrations of TCE.
This site is being considered for the Natioinal Priorities List (NPL).
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
The source of the contamination has not been determined, but sampling efforts to find the source will continue.
2.1.4 Progress Metrics
| Residential Drinking Water Well Sampling |
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| Wells Sampled |
TCE Detections |
Wells Above MCL |
Wells Left to Sample |
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| 235 |
14 |
5 |
265 |
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2.2 Planning Section
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2.2.1 Anticipated Activities
EPA will continue to sample wells in the area. To date, about 235 of the 500 wells within a four mile radius of the initial area of detection have been sampled.
2.2.1.1 Planned Response Activities
EPA will continue to install water treatment systems on residential drinking water wells with concentrations of TCE that exceed the MCL. Additonal source sampling and a dye trace study are planned for April 2011.
2.2.1.2 Next Steps
This site is being considered for the National Priorities List (NPL).
2.2.2 Issues
The feasibility of extending municipal water lines to residences with TCE concentrations exceeding the MCL is being studied.
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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
Missouri Department of Natural Resources
Greene County
Agency for Toxic Substances and Disease Registry
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4. Personnel On Site
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Emergency Response and Removal Services (ERRS) Contractor Response Manager Dave Brinkmeyer
Superfund Technical Assistance and Response Team (START) Contractor Project Manager Tom Scroggins
Greene County Resource Management-Danny Tavares
Plumbing Contractor
Well Plugging Contractor
Well Drilling Contractor
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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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