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9 S E C O R <br /> Mr. Dana Thurman <br /> June 16, 2004 <br /> Page 2 <br /> ' A record search at local agencies was conducted for the Site which indicated that no records were found. <br /> There is no evidence of prior development at the Site. No records were found during the local agency <br /> records search that indicates a potential environmental concern for the Site. However, one <br /> environmental soil sampling report was completed for the Site in 2001 in preparation for proposed station <br /> development activities. <br /> A Limited Initial Site Assessment Report dated February 2, 2001 was prepared for the San Joaquin <br /> Environmental Health Division that documents the sampling and laboratory analysis of five soil borings <br /> advanced under the direction of Kobmacher Engineering Inc. (KEI). On November 15,2000, five soil <br /> ' borings (SB-1 through SB-5)were advanced at the Site to a maximum depth of 26.5 feet below ground <br /> surface (bgs). Groundwater was not encountered during boring advancement activities. SECOR staff <br /> was onsite to collect soil samples for laboratory analysis. Soil samples were analyzed for total petroleum <br /> hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, and total xylenes (BTEX <br /> compounds), and the fuel oxygenates tert-butyl alcohol (TBA), methyl-tert butyl ether (MTBE), di- <br /> isopropyl ether(DIPE),ethyl-tert-butyl ether(ETBE),tert-amyl methyl ether(TAME),methanol,ethanol, <br /> 1,2- dichloroethane (1,2 DCA) and ethylene dibromide (1,2 DBA). The analytical report indicates that <br /> none of the above compounds exceeded laboratory reporting limits. <br /> A review of historical aerial photographs and topographic maps showed the property has been <br /> vacant/undeveloped and agricultural land since at least 1916. Because of this agricultural use,pesticides <br /> may have historically been used at the Site. <br /> Based on the findings of the Phase I investigation, SECOR concludes the following: <br /> • Based on the topographic gradient, groundwater flow direction is assumed to be to the north. <br /> 1 • Well data obtained from the EDR database report indicated that depth to groundwater at a well <br /> approximately 1/3-mile southwest of the Site ranged from approximately 43 to 56 feet bgs. <br /> 1 • The Site is currently vacant, undeveloped land. No evidence of current or past Site use(other than <br /> former agricultural use)was observed. <br /> • No potential sources of off-site contamination were listed within 1-mile of the Site that would likely <br /> ' impact soil and/or groundwater quality beneath the Site. <br /> • Analytical soil reports indicate that no petroleum hydrocarbon compounds were detected above <br /> ' laboratory reporting limits in 2000. <br /> • There were no environmental concerns identified in relation to the Site, with the exception of the <br /> former agricultural use of the Site. Based on this finding, SECOR recommended shallow soil <br /> sampling to determine if residual pesticides are present at the Site. <br /> During a May 10, 2004 telephone call, SECOR recommended to Chevron that shallow soil samples <br /> ' should be collected and analyzed for pesticides since agricultural activity was previously conducted at the <br /> Site. Chevron concurred with SECOR's recommendation and on June 4,2004,four shallow soil samples <br /> (BA-1 through BA-4)were collected from the Site. <br /> ' Laboratory reports indicate that no pesticide compounds (EPA Method 8081A) were detected in soil <br /> above laboratory reporting limits except for pp-dichlorodiphenyl dichloroethylene (pp-DDE). Three soil <br /> samples contained reportable levels of pp-DDE (a breakdown product of DDT <br /> SECOR International Incorporated <br />