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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 |