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i • 375 West Larch Road,Tracy August 28, 2013 Page 4 ANALYTICAL RESULTS The groundwater samples were transported under chain-of-custody procedures to McCampbell Analytical,a state-certified laboratory in Pittsburg, California. One soil sample from each boring was selected for analysis. The laboratory report and chain of custody form are included as Attachment F. The samples were analyzed for the presence of total petroleum hydrocarbons quantified as gasoline range organics (TPH-grog) and total petroleum hydrocarbons quantified as diesel range organics (TPH-dro) by EPA Method 8015C, benzene,toluene, ethylbenzene,and xylenes(BTEX), methyl tert butyl ether(MTBE), naphthalene, fuel oxygenates, and lead scavengers by EPA method 8060, and total lead by E200.8. No concentrations of TPH-gro, TPH-dro, benzene, toluene, MTBE, naphthalene, fuel oxygenates, lead scavengers, or total lead were detected above the laboratory detection limits. Ethylbenzene and toluene were detected in the groundwater samples collected from B-1 only at concentrations of 2.3 micrograms per liter(Ng/L)and 16 pg/L respectively. Both concentrations are well below the Maximum Concentration Levels (MCL's) set forth by the California Department of Public Health (CDPH). The MCL for toluene is 300 pg/L and for xylenes is 1,750 p/L. CONCLUSIONS AND RECOMMENDATIONS In 1970 two maps indicated a plan to install a 8,000-10,000 gallon fuel tank(unspecified above or below ground)and two fuel dispensers. In 1973 an inspection record indicated that a 1,000 gallon diesel AST was present on the Property illegally and was required to be replaced with a UST. No further information regarding UST's or AST's was found. ERAS scanned the area for the presence of any remaining UST's and none were found. Following approval from the S]CEHD, ERAS advanced three soil borings(B-1 through B-3)on August 15t', 2013 for the collection of groundwater samples in the location of a former fuel tank and dispenser. The samples were analyzed for the presence of TPH-gro, TPH-dro, BTEX, MTBE, oxygenates, naphthalene, lead scavengers, and total lead. The only contaminants detected were ethylbenzene and toluene in the groundwater samples collected from B-1 at concentrations of 2.3 pg/L and 16pg/L respectively, below the MCUs set forth by the CDPH. TPH-gro,TPH-dro,and TPH-oro are methods that compare analytical results to standards for gasoline,diesel and motor oil,respectively. Therefore analytical results are estimates of quantities based on what would be expected for the range of hydrocarbon results for the standard. Gasoline range organics(giro)are those hydrocarbon compounds that are in the range of C6 to CIO,diesel range organics(dro)are those hydrocarbon compounds that are in the range of CIO to C23,and oil range organics(oro)are those hydrocarbon compounds that are in the range of CI8 to C36. There can be overlap in reporting methods as well as identification of compounds that fall within the standard that may not necessarily be derived from gasoline,diesel,or oil.