Site background and enforcement information can be found on Pollution Reports #1, #2, and #3.
On January 7, 2008 excavation began in grids C20, D17-D20, E17-E20, F17-F20, and G17-G20. After clearing up to 24 inches, grids D17, E18, E19, F19, and F17 were found by XRF to have lead concentrations above the screening level. Due to language in the AOC which allows for an excavation limit of 24 inches, Type III samples (as established in the Sampling Plan) were collected for laboratory confirmation from these grids; the grids were then temporarily lined with 30-mil HDPE to prevent runoff.
On January 8-9, exploratory excavations were dug in grids D17, E18, E19, F19, and F17 to determine how much additional material would be removed in order to meet the cleanup goal. It was estimated that an additional excavation of 1 foot to 1.5 feet would be required in some locations, while only 0.5 feet to 1 foot would be require for others. Also on January 9, excavation began in grids I16-I19 and H16-H19.
Excavation was slowed due to rain on January 10 and operations ceased due to extremely wet conditions on January 11.
On January 15, excavation in grid I20 uncovered a concrete vault at approximately 1 foot below grade on the Colter Electric Lot, immediately east of the IMACO property on 22 East Acadia Avenue. The vault is approximately 15 feet wide and 15 feet long with a concrete wall separating it into two long compartments. The vault is approximately 5 feet deep with no top and is filled soil and water. A sheen was observed on the water and much of the soil appeared to be stained black. However, no odor was observed and a disturbance test of the sheen suggested that it may be bacterial in origin. Metal piping of approximately 4 inches in diameter and traveling in the northeast direction was excavated from the vault, but no remaining contents were observed and its purpose could not be determined. The function for this vault is unknown and North Carolina State records provide no indication of its existence or uses based on previous operators. Soil and water samples were collected from the vault and sent off-site for analysis.
EPA and START conducted community interviews on January 15 with residents, housing managers, the NCSA building manager, a city manager rep, and a city fire department rep.
On January 16, EPA contacted the property owner of 22 East Acadia Ave to discuss the discovery of the concrete vault and related actions.
It was determined on January 28 that the last viable metal reclamation facility within a 3 hour radius of the Site would not be accepting the kettle bottoms. As a result, as set forth in the Work Plan, the kettle bottoms will be crushed, treated with TSP directly, and mixed with stockpiles 9, 10, and 11.
On January 29 the RP made the decision regarding grid locations that exceeded the cleanup level at 24 inches, to not remove additional soils in these grids under language in the AOC which allows for limited excavation at 24 inches. The impacted area and concentration of lead in these grids will not constitute a substantial threat when backfilled. Per OSC instruction, the cleanup contractor will place orange polyethylene fencing in the excavation areas where lead is still above the cleanup level prior to backfilling to provide a visual warning barrier in these grids should they be excavated in the future.
Decontamination activities were performed on January 30 at the conclusion of excavation. No work was conducted on January 31 and February 1 while TCLP samples from stockpiles 9, 10 , and 11 await analysis.
- Sampling to determine the aerial and vertical extent of contamination on-site and 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-remvoal state to the maximum extent practicable (ONGOING)
- Load and transport off-site for disposal stockpiles 9, 10, and 11
- Complete all backfilling operations, including seeding and mulching
- Decontaminate and demobilize all equipment
- Repair fencing and patch damages areas of grass in adjacent lots
Analytical results for samples taken from the concrete vault were received on January 28. The samples were analyzed for Metals, VOCs, SVOCs, PCBs, Mercury, as well as Oils and Greases per the landfill’s request. Nearly all compounds were non-detectable, though low levels of lead and barium were found at 0.095mg/L and 1.0mg/L respectively in TCLP analysis. Given these results, it will not be necessary to excavate the soils in the concrete vault, and it will also not be necessary to remove the vault itself. Crews will continue with confirmation sampling and backfilling procedures in Grid I20 as outlined in the Work Plan.
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