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Area of Concern 65
Chronology of Actions/Investigations
Year | Month | Action/Results | Action Performed By | Project Number |
Prior to 1966 | Unknown | A concrete pit area in Building 90 that housed a metal vat that contained TCE and PCE. The vat was removed in 1995. | CSSA | NA |
2000 | April | Collected 2 samples from cored area under the vat. Samples analyzed for VOCs and metals. | Parsons ES | DO5068 |
April | CSSA advanced 1 boring at Building 90. Four samples were collected. | CSSA | NA | |
2001 | January - February | Three hundred nineteen soil gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics at AOC-65 and in the vicinity of Building 90. PCE, TCE, cis-1,2-DCE, and trans-1,2-DCE were detected. | Parsons | DO5084 |
March � April | Fourteen soil borings advanced in and around Building 90/AOC 65. | Parsons | DO 5084 | |
August | Groundwater samples collected from monitor wells installed at AOC 65. | CSSA | NA | |
November | Groundwater samples collected from monitor wells installed at AOC 65. | CSSA | NA | |
2002 | August | Interim Removal Action (IRA) completed. Approximately 1,255 cupic yards of soil were excavated from the site. See Final AOC-65 Interim Removal Action Report. | Parsons | NA |
September | Soil Vapor Extraction (SVE) System installed and initiated at AOC-65. Final RCRA Facility Investigation Report submitted to TCEQ. | Parsons | DO5084 | |
2003 | September | AOC-65 Geophysical Summary Report submitted. The purpose of the subsurface geophysical investigation was to delineate structural and stratographic conditions at AOC-65. | Parsons | TO0058 |
2007 | April | SVE system at AOC-65 optimized and expanded with additional vapor extraction wells (VEWs) and regenerative vacuum blowers and updated piping systems. | Parsons | NA |
2011 | April - May | Two steam injection wells (SIWs) and five VEWs were added to the SVE system. | Parsons | NA |
2012
| February | IRA performed to remove contaminated soils and bedrock from beneath a concrete-lined drainage ditch. The ditch was then converted into an infiltration gallery to facilitate an in-situ chemical oxidation (ISCO) treatability study. | Parsons | NA |
August | First ISCO injection. SVE system operations formally terminated at AOC-65 due to its significantly decreased effectiveness. | Parsons | NA | |
2013 | May | Second ISCO injection. | Parsons | NA |
2014 | September | Third ISCO injection. | Parsons | NA |