See previous POLREP
Site operations resumed on January 5, 2010, following a holiday break. Upon return to the Site, ERRS conducted snow removal in the command post area.
ERRS segregated and secured the first area of stockpiled soil, which is estimated to be 1,700 yards; analytical data from the stockpile was 107 mg/L TCLP, and the soil is considered "hazardous". ERRS received 3 bids for T&D of this stockpile. The lowest bidder will collect a sample from the stockpile on Site to qualify their price; the percentage of debris in the stockpiled soils will have to be determined for an accurate T&D rate. ERRS will then award the subcontract to the lowest bidder.
ERRS continued excavation at the western end of the Site. ERRS constructed an additional area for stockpiling of this excavated soil. START utilized XRF equipment to determine lead concentrations ranging from 3,256 to 21,264 ppm in these excavated soils.
Respiratory protection is still being utilized in the hot zone areas as an additional precaution, due to the presence of high lead concentrations in the excavation areas. START will continue to monitor the particulate levels in the hot zone; a determination to downgrade PPE may occur when the lead concentrations become lower in the Site soils.
START continued to collect particulate data from the western, eastern, and southern perimters of the Site to ensure that minimal dusts are migrating from the Site during operations. However, due to snow and wet conditions on the Site, these instruments could only be run for one of the five work-days. The maximum concentration of migrating dust from the Site during this operational period was 39.4 ug/m3.
Analytical data from the December 17, 2009, sampling event verified that the remaining soils on the surface of the lower road contain lead in concentrations ranging from 868 to 2,650 ppm. The OSC will make a determination of future actions in this area.
Interested parties may view added recent pictures in the Images section of the website: www.epaosc.org/twincities.
1. Remove contaminated sediment from Beaver Creek such that average concentrations along the entire length of the Site do not exceed 91.3 mg/kg lead and 1 mg/kg PCB;
2. Prepare Site for permanent erosions controls by grading and/or removal of soil and debris. Preparing the Site for surface for the permanent erosion controls may require removing or covering soil and debris with lead over 1,000 mg/kg and PCBs over 25 mg/kg such that soil at the surface contains lead less than 1000 mg/kg and PCBs less than 25 mg/kg:
3. Install permanent erosion controls that intend to protect the integrity of the response action and minimize the erosion of the installed cover;
5. Sample and consolidate or otherwise prepare the soils and sediments removed for appropriate off-Site disposal pursuant to Section 121(d)(3) of CERCLA and 40 CFR 300.440;
6. Dispose of off-Site all soils and sediments removed in accordance with Section 121(d)(3) of CERCLA and 40 CFR 300.440.
Continue excavation of designated areas.
Continue coordination with local and state officials.
1. Concentrations of lead in Site soils were determined up to 149,000 mg/kg.
2. Concentrations of lead in Site sediments were determined up to 677 mg/kg.
3. Concentrations of PCBs in Site soils were determined up to 66 mg/kg.
4. Concentrations of PCBs in Site sediments were determined up to 2 mg/kg.
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