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Mr. Jay Utal 9 • <br /> Nextbay Properties, LLC - 2 - 24 October 2012 <br /> pg/L of TPH as diesel (TPHd), 190,000 pg/L of TPH as motor oil (TPHmo), and 8.1 pg/L <br /> of 1,2,4-trimethylbenzene. <br /> Based on these results, TERRASEARCH excavated an area 23 feet by 24 feet by 8 feet <br /> deep of impacted soil beneath the AST. Approximately 314 tons of petroleum <br /> contaminated soil was excavated from the area beneath the former diesel AST. <br /> Confirmation samples collected from the sidewalls and bottom of the excavation were <br /> non-detect for petroleum hydrocarbon constituents. Groundwater was not encountered <br /> and was estimated to be approximately two feet beneath the bottom of the excavation. <br /> To evaluate the extent of groundwater impact beneath the former excavation, additional <br /> grab groundwater samples need to be collected, and based on the results, groundwater <br /> monitoring wells may need to be installed. In addition, a visual reconnaissance of the <br /> site and surrounding perimeter properties needs to be conducted to assess if any <br /> additional groundwater wells (domestic, agricultural) are located in the rural area. <br /> Please submit a work plan to install a sufficient number of soil borings and collect soil <br /> and grab groundwater samples to characterize any remaining hydrocarbon impacts at <br /> the site. The samples should be analyzed for TPHg, TPHd, TPHmo, benzene, toluene, <br /> ethylbenzene and xylenes, PCBS, and volatile organic compounds including <br /> naphthalene. In addition please conduct a visual well search of the site and <br /> surrounding properties, if any wells are found, please collect groundwater samples and <br /> analyze them for the aforementioned constituents of concern. <br /> Please submit the requested work plan by 19 November 2012. If you have questions <br /> please contact me at (916) 464-4696, or via email, at pvellinesewaterboards.ca.gov. <br /> f t%2 <br /> Pat Vellines, P.G. <br /> Engineering Geologist <br /> cc: Mr. Harlin Knoll, San Joaquin County Environmental Management Department, <br /> Stockton <br /> Mr. Morgan Johnson, ENGEO, Inc., Rocklin <br />