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not show any Ethanol although TPHD was 1;100,000 Ug/1 and TFIFI.G 1,700 Ug/l. SA.1C representatives indicated that their sample analysis focus was on the pipeline petroleum source oil and not on petroleum fuels, so direct comparisons are considered preliminary. 11.0 Conclusions and Recommendations WRIGHT performed a soil and groundwater assessment used to locate and install four groundwater monitoring wells. 'rhe assessment revealed subsurface conditions similar to those discussed in the 2003 study where contaminants appeared to have leaked from the former US'r on-site. The shallow aquifer is composed of interbedded sand and silt strata that contain petroleum contaminants. Groundwater samples indicate the shallow aquifer is contaminated to depths of about 25 feet. A thin silt/clay stratum appears to have retarded contaminant penetration to depths of about 25 to 30 Feet. Soil and groundwater contaminants are predominantly TP.FID with some dissolved Methanol and.Ethanol. MTBE was not observed in this study, however .MTBE was observed in 2003. Stained soil was noted in several boreholes and sheen and some separate phase product was present in MW-1 and MW-3. The initial groundwater plot shows a northerly flow direction. Two old pipelines formerly used by Chevron cross the property near the former UST pit. These pipelines were used for decades to ship petroleum to northern refineries according to Chevron representative SAIC. This is a potential contaminant source, as is the former railroad land use that is known to have caused shallow soil contamination in this area. This report provides the initial groundwater monitoring data. The S1C/EHD will need to review and approve the quarterly monitoring program, Wright anticipates that the following chemicals will be included in the quarterly monitoring program; TPHG, TPHD, BTEX, MTBE and related oxygenates, EBD, 1,2-DCA Ethanol and Methanol. Quarterly reports of the groundwater monitoring program will be prepared for submittal. to the City and P1[S/EHD and RWQCB Region 5, in both hard copy, and electronic format for submittal to Geotr'acker. 32.0 Limitations This report has been prepared specifically for the City of Tracy Boyd Service Center Site at 520- 560 North Tracy Boulevard in Tracy, CA and was performed according to the current State and local agency suggested guidance documents for these investigations. The interpretations, conclusions and recommendations made herein are based on the data and analysis for the soil and water samples collected onsite. Conditions of the property can change aver time and the use of this report by third parties is entirely at their own risk. Please note that reports of contamination must be submitted to the agencies in a timely manner, This report has been prepared for use solely of City of Tracy, our Client. This report shall not be relied upon by or transferred to any other party, or used for any other purpose, without the express written authorization of our Client, and Wright Environmental Services, Inc. Page 9 of 14