From September 2006 through May 2007, the U.S. Environmental Protection Agency (USEPA) conducted a removal action at the HCC that involved the excavation, transportation and disposal of the pesticide-contaminated soils underneath a deteriorating asphalt cap. In September of 2007 the USEPA conducted a removal assessment and a structural inspection of the Mixing Plant Building (MPB) in preparation for the final phase of the Removal Action.
The final phase will consist of demolishing the MPB, removal of debris associated with the demolition, removal of the foundation, testing soils underneath the MPB for the presence of pesticide contamination, disposal of contaminated soils and finally site restoration.
Demolition activities have been completed. The Mixing Plant Building has been demolished and approximately 1900 cubic yards of construction debris has been transported and disposed of at the Rio Grande Valley Landfill in Donna, TX. The debris was characterized as Class I non-hazardous waste.
Approximately 800 cubic yards of soils excavated from underneath the building were sampled and shipped off as non-hazardous wastes.
Approximately 200 cubic yards of soil remaining were sampled and characterized as hazardous due to elevated concentrations of Heptachlor. These soils will be sent for incineration at a permitted hazardous waste facility.
The area underneath the MPB to be sampled was laid out into 10 grids from which a 9 point composite soil sample was collected from each grid. Soil sampling has been conducted at all 10 Grids. Analytical results from Grids 1-7 indicated the presence of several pesticides, however all results were below the Protective Concentration Limits (PCL's) as set forth in the Texas Risk Reduction Program (TRRP) by the State of Texas for a commercial/industrial site. Grids 1-7 have been restored.
Results from Grid 8 indicated elevated concentrations of both Alpha BHC and Beta BHC above PCL's. Additional excavation was conducted and the grid was re-sampled. Results were below PCL's and Grid #8 has been restored.
Analytical results for Grids 9&10 exceeded PCL's for Heptachlor and Toxaphene. The grids were excavated and re-sampled. The results were below PCL's and Grids 9&10 have been restored.
Backfilling and levelling low lying areas around the site continues and a soil erosion control mat will be installed around the perimeter of the site to help prevent washout during a rainfall event.
Air monitoring and air sampling activities continue at the site.
Complete T&D of all stockpiled soils.
Complete levelling and grading of site with backfill material.
Take down fence and install silt mat to help prevent soil erosion.
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