Library: Reports: Cleanup: WT

Pre-excavation sampling of the abandoned lagoon was conducted from May 21, 1998 to June 16, 1998 in accordance with the May 5,1998 Field Sampling Plan, Volume XIII. Fifty 25 ft. x 25 ft. full or partial grids of the fifty-three originally described in Section 2.2 of the sampling plan were sampled. The three grids not sampled were B7, B12 and D13. Grids B7 and B12 are only partial grids and will be included in the excavation of adjoining grids. Based on a more accurate location of the 39 inch sewer pipe with respect to the abandoned lagoon grid system, grid D13 is actually on the east side of the sewer pipe. The sewer pipe forms the eastern boundary of the abandoned lagoon.

In addition, 14 grid locations from the 1996 Alternative Evaluation Report (AER) were sampled deeper as described in Section 2.3 of the Field Sampling Plan.

A total of 172 soil samples (including duplicates) were submitted for PCB analysis. These analytical results and data from the AER are presented in Figure 1, Preexcavation Results.

Sample location ALBP-5 was sampled to the depth specified by the USEPA. However additional samples could not be obtained deeper to determine a clean elevation. Sample retrieval was not possible due to wet soil conditions. A clean elevation will be determined as part of the post-excavation sampling.

Upon reviewing the data, it was determined that C3 will need to be sampled deeper once the excavation begins due to contamination below one foot in D3. The additional sampling is based on the procedures that were developed in response to the EPA's comments to the May 5, 1998 abandoned lagoon work plan. This procedure is contained in the May 28, 1998 CBS letter to the Consent Decree parties' addressing all the comments on the May 5, 1998 work plan.

Using this pre-excavation data and the data from the AER, the excavation requirements have been determined for each grid in the abandoned lagoon. The initial excavation depths for the affected grids are presented graphically in revised Figure 3, Initial Excavation Depths. This figure replaces Figure 3, Preliminary Excavation Depths, included in the May 5, 1998 Field Sampling Plan. An initial excavated volume of approximately 5,000 cubic yards is identified in this revised Figure 3. Post-excavation sampling will be conducted as described in Section 2.4 of the May 5, 1998 Field Sampling Plan in each grid that is excavated. Based on the postexcavation sampling additional material may be removed to meet the clean criteria.

Mobilization for remediation of the abandoned lagoon is scheduled for mid to late July.