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SUD Boyett Petroleum October 23, 1998 419 South Main Street, Manteca, California Page 3 Underground Storage Tank Preliminary Investigation-RDF j The laboratory samples were collected in 40 ml VOA vials with Teflon-lined screw caps. Care was taken to ensure that no head space existed in the vials by inverting to check for bubbles and re-sampling if necessary. The samples were analyzed or extracted within fourteen days according to their EPA methods. The groundwater samples collected at SB-1 and SB-2 at eighteen (18) feet were analyzed using EPA method 5330/LUFT for total Petroleum Hydrocarbons as Gasoline, and EPA method 602 for BTX&E and MTBE. Chain of Custody records were maintained at all times (Appendix C). i ' 3.4 Analytical Results i The soil sample analysis indicated no detectable levels of Petroleum Hydrocarbons as Gasoline or BTXE in the six (6) soil samples collected from the borings. No detectable levels of MTBE were found in any of the soil samples except those samples labeled SB-1@16' and SB-2@16'. The samples SB-1@16' and SB- 2@16' contained levels of MTBE at 600 ug/Kg and 4,700 ug/Kg, respectively. Table 1 of the report provides a tabular summary of the soil analytical data. The composite sample from the stockpile (SP-1,2) was "ND" (none detected) for all r analytes. Table 2 of the report provides a tabular summary of the stockpiled soil analytical data. Laboratory Certificates of Analysis and Chain of Custody are ' found in Appendix C of this report along with the Chematographs. The groundwater sample analysis indicated that no detectable levels of Petroleum ' Hydrocarbons as Gasoline or BTX&E were present in the two samples, SB-1 Water @ 18' and SB-2 Water @ 18'. MTBE was found in both of the samples at levels of 47,000 ug/L and 6,700 ug/L, for SB-1 Water @ 18' and SB-2 Water @ ' 18', respectively. Table 3 of this report provides a tabular summary of the groundwater analytical data. Laboratory Certificates of Analysis and Chain of Custody are found in Appendix C of this report along with the Chematographs. 4.0 Conclusions and Recommendations Based on the preliminary data developed during this scope of work, WHF has made the ' following conclusions: • Soil contamination in the form of MTBE exists only in the water bearing zone ai si2duCn (16) LGCL ueluw gmund ievei (u.g.i.). There is no coniaminau from the surface to approximately eleven(11) feet b.g.l. 1 R' 5