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i i Work Plan For Additional Groundwater Assessment 6 Ranch Market 23564 South Santa Fe Road Riverbank California May 10 2001 I . groundwater samples from sand intervals defined by the CPT log Three water samples will be collected from borings CPT-1 and CPT-2 at approximate depths of 35, 50, and 65 feet bgs and in CPT-3 at 35 feet bgs Depth discrete grab groundwater samples will be collected using a modified hydropunch sampler The sampler will be dnven to approximately 35 feet bgs and retracted 3 feet to expose the disposable schedule 20 PVC screen and allow groundwater to enter the hydropunch sampler The depth discrete water sample will be collected by lowering a 3/a" diameter stainless steel bailer through the drive rods to groundwater The groundwater will be balled from the drive rods, decanted from the bailer into 40-m1 VOA vials, and capped Each VOA vial will be checked to insure no bubbles are present, labeled, placed on ice, and transported to the laboratory under a chain-of-custody documentation The dnve rods will be retracted, leaving the disposable drive tip and 4 foot length of PVC well screen in the hole The drive rods and hydropunch sampler will be steam cleaned, equipped with a new drive tip and PVC screen, and driven back into the bore hole to the next sample depth In bonngs CPT-1 and CPT-2, depth discrete water will be collected at 50 and 65 feet bgs using the same methods as described above All downhole drilling equipment will be steam cleaned before dnlling each borehole The Down-hole sampling equipment will be washed in a tn-sodium phosphate or AlconoxTM solution between each sampling effort The soil borings will be tremae grouted back to grade using neat cement Domestic Water Wells Per the RWQCB request, SECOR will monitor depth to bottom in domestic wells DW-3 and DW-4 using a clean steel tape lowered into each well Permission will be obtained from the two property owners prior to accessing each well Water Sample Analyses The depth discrete water samples will be labeled with the well number, placed in an insulated container on ice, and transported under standard chain-of-custody procedures to Kiff Analytical located in Davis, California The water samples will be analyzed for BTEX, TPHg, five oxygenates, and fuel additives 1,2-DCA and EDB using EPA method 8260B Report Preparation A letter report summarizing the results of the groundwater assessment will be prepared and submitted to the RWQCB and the SJCEHD The report will include copies of the CPT logs with a lithologic description, and a summary of the groundwater analytical data The existing cross sections will be updated to include the new data from the three CPT borings Initiation of the proposed work is dependent on RWQCB approval of this work plan, and pre- File Ranch Market\WorkPlan\Rb-CPT Workplan doc