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r , Expedited Cleanup of Underground Tank Pit Wright conducted further limited assessment of the open tank pit area in an attempt to minimize future potential contaminant impacts to the new parking lot as required by the City of Tracy. As a result, a cleanup effort was performed in the tank pit area to remove contaminated soil while the pit area was open as directed by City officials. A site map of sample locations can be found in Figure 2. On December 6, 2001 Wright over-excavated areas of obvious contamination down to the level of groundwater which was approximately 14.0 feet from surface level. Wright removed approximately 8.58 tons of contaminated soil and disposed of the material at a State approved facility permitted to accept such waste. Tonnage reports of disposed material can be found in Attachment B. Upon completion of the over-excavation, groundwater was allowed to flood the excavation pit and samples were-collected. Wright collected 2 (1) liter amber jars of groundwater for sampling. Wright also collected one grab soil sample for confirmation of removal of contaminated materials. Analytical results of groundwater impact with chain-of-custody can be found in Attachment C. All samples labeled, logged onto chain- of-custody hain- ofcustody forms and were placed in an ice chest on crushed ice where they were transported to a State approved laboratory for analysis. After samples were collected and upon PHS-EHD approval and supervision the excavation pit was backfilled, compacted and restored to rough grade. Clean imported backfill was brought in to replace the UST volume and excavated contaminated soil. Chemical Analysis Soil and groundwater samples were analyzed for Total Petroleum Hydrocarbons as gasoline and diesel (TPHG, TPHD), BTEX and Fuel Oxygenates using EPA methods 8015, 3510, 8020, 8260 and 6040B respectively. As requested by the County in their approval letter dated December 4, 2001, only soil was tested for total lead using EPA method 6010B. A summary of these results is presented in Table 1 and Table 2. Conclusions Wright has completed its interim cleanup remediation of the above referenced site under PHS-EHD approval and supervision. It is Wright's opinion that a majority of the contaminated soil has been removed on the basis of field observations and laboratory data. Analysis of our confinnation samples (both soil and groundwater) displayed results of none detected. The concentrations of lead observed in the samples appear typical for the geology of the region. - Wright's interpretation of the data is that groundwater in the tank pit vicinity was not affected. Analysis of groundwater samples showed contaminants of concern were not detected (Attachment C). At this time Wright believes that most of the contamination has Page 2.