[Home]
Final Phytoremediation Treatability Study
Appendix A - Chronology of Actions/Investigation at SWMU B-20
| Year | Month | Action/Results | Action | Project |
| 1946- 1987 | NA | B-20 area (approximately 33.5 acres) was used periodically for ordnance OB/OD activities. On an unknown date, sand and spent ammunition from the practice firing building at CSSA were disposed of at the B-21 area, which is immediately adjacent to B-20. | CSSA | NA |
| 1993 | June | A Compliance Order was issued for the B-20 site for unpermitted treatment of hazardous waste and for failure to have a closure plan. | EPA | NA |
| 1994 | January | Preliminary samples were collected from the B-20 area to provide an estimation of the nature and extent of contamination for environmental investigation planning purposes. | RRAD | NA |
|
| March | Partial Facility Closure Plan for B-20 (ES, 1994) closure/remedial investigation was submitted to EPA Region VI and TNRCC. | Parsons ES | Order 126 |
|
| November- December | First phase of closure/remedial investigation was conducted at B-20. UXO was cleared from within the original site boundary, and geophysical surveys were conducted to identify anomalies in craters. Total of 812 UXO items removed. Surface soil, subsurface soil, surface water, and sediment were sampled and analyzed for metals and explosives. Surface water and sediment samples were also analyzed for VOCs. Barium, cadmium, lead, and mercury levels exceeded RRS1. | Parsons ES | Order 126 |
| 1995 | June | Final Remedial Investigation Report (Parsons ES, 1995a) for B‑20 submitted. Report recommended additional sampling and UXO clearing activities. | Parsons ES | Order 126 |
| 1995 | September | Amendment to Project Plans (Parsons ES, 1995b) submitted to regulatory agencies for second phase of sampling. Second phase of remedial investigation conducted. Subsurface soils sampled near three first phase RI borings to determine if metals failed SPLP test. Surface soils sampled in south-central portion of site to better delineate extent of metals contamination. | Parsons ES | Order 126 |
| Year | Month | Action/Results | Action | Project |
| 1995 | October | USFWS sent a letter of concurrence for planned vegetation clearing activities at the B-20 site. | USFWS | NA |
| 1995 | December | Second Amendment to Project Plans (Parsons ES, 1995c) submitted to regulatory agencies. | Parsons ES | Order 126 |
| 1996 | January - March | Field activities conducted, including vegetation clearing to facilitate UXO identification, systematic sweep of surface for UXO with magnetometers within original site and perimeter, excavation and removal of buried UXO in craters, excavation and removal of buried UXO in northern 5 acres of site, and collection and disposal of scrap metal scattered over the surface of the site. | Parsons ES | Order 126 |
|
| January | All UXO items found on site to date (365 items) were detonated after receiving approval from TNRCC on January 29. | CSSA | Order 126 |
|
| May | UXO items identified since January 31 (447 items) were detonated on site. | ||
|
| June | Addendum to the Remedial Investigation Report (Parsons ES, 1996b) submitted. Report recommended additional UXO clearing activities. | Parsons ES | Order 126 |
| 1997 | January | Third Amendment to Project Plans for Remedial Investigation submitted. | Parsons ES | RL33 |
|
| January-September | East extension to B-20 was cleared of vegetation and systematically swept for UXO. Soils from northern 5-6 acres of the site were sifted to remove UXO and metal scrap. | Parsons ES | RL33 |
|
| March-April | Phytoremediation, soil washing, and stabilization bench-scale treatability studies conducted. | Parsons ES | RL33 |
| 1999 | April | EPA Memorandum indicated analytical results obtained from ITS are not usable for closure or compliance. | EPA | NA |