Site background and enforcement information can be found on Pollution Reports #1, #2, and #3.
On December 10, 2007 the City of Winston-Salem Utilities Division arrived on-site to cut and cap the new sewer line installed by HEPACO that flows down to the main sewer system which runs parallel to the unnamed tributary at the south border of the site.
On December 11, excavation in grids G24 and G25 on the Colter Electric lot was completed and the soil from these grids was treated. Contamination of petroleum products was suspected in these grids based on a strong odor during initial excavation, debris in the grid field, and past use of the site as a used car lot (see POLREP #6). Samples from the excavated soil were analyzed for VOCs, SVOCs, PCBs, Metals, Organics, Oils, and Greases. Results were received on December 4 and showed no sign of contamination or elevated levels of hazardous substances. BFI CMS Landfill reviewed these results and confirmed that they would present no issue for disposal at their facility.
On December 12, stockpile 4 was loaded and transported off-site for disposal. The total volume required 24 loads for an estimated 400 total tons.
On December 13 and 14, excavation of the debris pile continued on grids J17-J19, L17-L19 and H17-H19. Debris, such as rubber, is being found at depths of up to 8 feet and XRF readings confirm lead levels ranging from 10,000ppm to 100,000ppm. Debris is being mixed with the excavated soil and treated appropriately. Excavation in the debris pile is continuing up to and below the original soil surface rather than the debris pile surface.
Backfill activities were completed on the Colter Electric lot between December 10 and 13. A crusher run stone surface is being added to the lot in lieu of topsoil due to the equipment storage and large vehicle traffic; this surface is being applied in addition to an amount of fill dirt required to bring the surface back to its original grade.
On December 17 and 18, backfilling in residential properties on the west side of the IMACO property were completed.
On December 20, analytical results from treated stockpile 6 revealed TCLP lead content of 5.0ppm, equal to the regulatory limit for hazardous waste. As a result, additional TSP was added to stockpile 6, which was retreated on December 21 then re-sampled for TCLP analysis.
On December 21, stockpile 5 was loaded and transported off-site for disposal. The total volume required 20 loads for an estimated 350 total tons.
HEPACO dug several test pits in the debris pile to determine the remaining extent of the debris area. The debris is spread over an area of approximately 50 feet long and 6 feet wide, it is piled at an average depth of 8 feet (total volume of approximately 90-100 cubic yards).
No work was conducted between December 22 and January 2. The site was secured and crews were demobilized from the area for this time period.
Sample results for stockpile 6 were received on January 2, 2008 with all levels within regulatory disposal limits.
On January 3, stockpile 6 was loaded and transported off-site for disposal. The total volume required 20 loads for an estimated 350 total tons.
On January 4, excavation began on soils near the truck entrance and decontamination area on the west side of the IMACO building. When excavation has completed in this area, backfill will be postponed so that cross contamination does not occur during loading and mixing operations. In the meantime, these grids will be lined with a 30-mil polyethylene sheeting.
- Sampling to determine the aerial and vertical extent of contamination on-site and on adjacent properties (COMPLETE)
- All soils and sediments on-site and on adjacent properties which are contaminated above RALs shall be excavated (ONGOING)
- All waste streams shall be disposed of by appropriate measures as determined by the disposal profile (ONGOING)
- Restore areas which are disturbed by the removal action to their pre-removal state to the maximum extent practicable (ONGOING)
- Treat with TSP, load, and transport off-site for disposal of the seventh stockpile
- Transport slag material off-site for recycling or crush and treat slag material on-site for disposal
- Remove slag and soils from mound near SW corner of GMAC building
- Continue excavation of debris pile at SE corner of IMACO property
- Continue other excavation, backfill and restoration activities
Sample analysis has determined that soils in the Colter Electric yard are not contaminated with hazardous substances other than previously identified lead. The odor that was detected upon initial excavation of grids G24 and G25 has not been observed since the week of that excavation, and PID/FID readings during that time did not detect elevated levels of VOCs. Also, no visual contamination was confirmed, the State of North Carolina could not confirm any record of underground storage tanks on the property, and buried debris within these grids (tubing and concrete) provided no indication that a source of contamination was present. HEPACO will backfill the excavated grids according to the same standard as the remaining.
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