PR0535342 - Laserfiche WebLink

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LFR Inc. collected after completion of excavation activities in this area; instead, groundwater quality was assessed. Photograph 12 depicts the excavation progress during June 2004 and demonstrates the extensive dust control measures used during excavation activities. Details of the excavation activities are provided in the report entitled, "Excavation of Pyrolytic Oil- Affected Soil Including the Construction, Use, and Destruction Photograph 10 of a Temporary Retention Pond at CIWMB staff preparing to use hydraulic lift the Tracy Tire Fire Site, San for soil sampling Joaquin County, California," prepared by LFR and dated February 15, 2006. Generally, during October 2005, approximately 4,000 cubic yards of pyrolytic oil-affected soil was excavated to approximately 3 to 5 feet below the groundwater table. To facilitate excavation, the groundwater table in the excavation area was lowered by pumping water from "dewatering pits" near the excavation area. The extracted water was conveyed to an on-site temporary retention pond. Upon completion of excavation, the excavation area and dewatering pits were backfilled. Analytical results were evaluated and additional excavation was recommended in areas where soil sampling results indicated that concentrations of metals were above background levels. Soil was excavated and additional soil samples were collected until concentrations were below the calculated background concentrations provided in Table 1. Based on evaluation of the confirmation soil sampling results and on observations at the Site, the project objectives were met, and soil containing concentrations of TRPH and/or metals above the cleanup goals was removed from the Site. 5.5 Groundwater Monitoring ` Program 00 LFR prepared a "Work Plan for Photograph 11 Groundwater Monitoring Well and Production Well Installation and Hydraulic lift extended to soil sampling Quarterly Groundwater Monitoring location on cliff face rpt-RA_summ-Nov06-fina1-09025 Page 25