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PRETANx CG4SURF��ITE_AssF,ssMENT PORT Shell nil Company 3725 Tracy Boulevard,Tracy,California Delta Project No.40-89-012 Page 11 r Concentrations of BTEX and TPH from soil samples collected from soil borings SB-7, SB-8, and SB-9 were below the deiection limit of 0.002 and 0.2 ppm, respectively. The soil sample analyzed from SB-10 indicated concentrations of BTEX ranged from 0A1 to 0.04 ppm. Concentrations of TPH were at 140.0 ppm and were identified as stoddard solvent. 3-6a2 Location of Existing Under_mund Storaste7anks Four soil borings were drilled near the existing underground storage tanks(SB-1, SB-2, SB-3, and SB-4). A total of four soil samples were collected at depths of I I feet below the ground surface and were sent to the laboratory for chemical analysis of BTEX and TPH. Chemical results are summarized in Table 5 and Iaboratory data sheets are presented in Appendix E. Concentrations of BTEX from soil samples collected from soil borings SB-I through SB-4 were below detection limits. Concentrations of TPH from SB-2 and SB-3 were below detection limits of 0.5 and 0.2 ppm, respectively. Soil samples from SB-I and SB-4 contained concentrations of TPH at 77.0 and 11.0 ppm, respectively,and were identified as stoddard solvent or light petroleum distiilat?. 5amples FromMonitoEin Well Logatign and 5oil Boring B-11 Three soil borings were drilled at well locations MW-I,MW-2, and MW-3 and were converted to monitoring wells. Three soil samples were collected at depths of 6 feet below the ground surface and were sent to the laboratory for chemical analysis of BTEX and TPH. Chemical results are summarized in Table 5 and laboratory data sheets are presented in Appendix E. Concentrations of BTEX and TPH were below the detection limits of 0.002 and 0.2 ppm, respectively. Soil boring SB-I 1 was drilled in order to determine the impact of petroleum hydrocarbons or solvents in front of the service station. One soil sampez was collected at a depth of 6 feet below the ground surface and was sent to the laboratory for chemical analysis of BTEX and TPH. Chemical results are summarized in Table 5,and laboratory data sheets are presented in Appendix E. Concentrations of BTEX and TPH were below the detection limits of 0.002 and 0.2 ppm, respectively. 3.7 Ground Weter-Chemistry On September 26, 1989, each monitoring well was purged by removing seven well casing volumes s. of water from each well(see Section 3.4,Well Development). Ground water samples were collected _-_______________._ _..__...._....... ..........._.__..from each well and sent-to the laboratory for analysis of-BTEXandTPH:-In-addition;the ground--- --...._._.: __...__.... water from monitoring well MW- was analyzed for oil and grease, metals, nitrogen as ammonia, T.... cyanide, fluoride, total organic halogens, formaldehyde, fatty acids, semivolatile organic acids,