ARCHIVED REPORTS_XR0007734 - Laserfiche WebLink

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construction procedures are presented in Appendix C Further details on well construction specifications are presented in the drilling logs SOIL ANALYSES During drilling of each borehole, soil samples were collected at 5 or 10-foot intervals for geologic logging and laboratory analysis Soil samples were screened in the field for hydrocarbon emissions using an organic vapor analyzer (OVA) Based on the OVA readings and visual/olfactory observations, a total of 68 soil samples were selected for laboratory analysis of TPH and BTEX by EPA method 8015/8020 The samples were analyzed by Orange Coast Analytical and American Analytics, both state certified laboratories Procedures used for soil sampling are presented in Appendix C Results of lab analysis indicate soil samples from six well locations at the site contained greater than 1,000 mg/kg TPH These well locations appear to be clustered in three separate areas The • first area is located along the west side of the property near the pump island and former western underground tank Soil samples from this area contained TPH concentrations up to 4,100 mg/kg as found in sample TB4-10 The area is further defined by well locations MW5 and TB6, which also had elevated contaminant levels The second area is located near the center and to the east of the former tank cluster as defined by wells TB7, TB 12, and MW2 Soil samples in this area contained up to 5,300 mg/kg TPH as found in sample TB7-20 The third area is interpreted to be an isolated zone around bonng/well TB3 This area had up to 5,700 mg/kg TPH as found at 30 feet below grade This location was the site of an unidentified subsurface fiberglass pipe that was discovered during site reconstruction The pipe was approximately 2-inches in diameter and appeared to run from the cashier's booth area north towards Harding Way There are no known uses for this pipe, but moderate hydrocarbon odors were noted in the surrounding soil Page 6 ft _