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t Additsonal 501 and Groundwater investigation Report Canepa s Car Wash(Park Street) July 12,2004 Page 1] approximate depths of 52 to 60 feet, 74 to 85 feet, 102 and 125 feet, and 140 to 150 feet bgs Drilling ' activities will be performed under the supervision of a Condor geologist in accordance with the provisions of the SJCEHD and City of Stockton permits ' Drill cuttings from the monitoring well bonngs will be logged in accordance with the Unified Soil Classification System (USCS) Descriptions of soil types encountered will be recorded on the boring logs Soil samples will not be collected for laboratory analyses Details of the well construction will be ' noted on the geologic log, including the depth intervals of the screen, sand pack, and seals and notes on the quantity and types of materials added dunng well construction All down-hole drilling equipment will be steam-cleaned prior to use The drill cuttings and steam cleaning effluent will be placed in DOT- approved 55-gallon drums, sealed, labeled, and left on site pending laboratory analyses Disposal of hazardous materials, if any, will be the responsibility of Canepa's Car Wash 7 4 MONITORING WELL DEVELOPMENT, SURVEY, AND SAMPLING At least 48 hours following well construction, the monitoring wells will be developed by surging and bailing the groundwater in the wells until the discharge water is relatively free of sediment The monitoring wells will be purged until the temperature, electrical conductivity, and pH of the water has stabilized All well-development equipment will be cleaned prior to use by washing in a solution of laboratory-grade, non-phosphate detergent and deionized water, and double rinsing with deionized water The purge water discharged from the well during development will be containerized in 55-gallon drums, sealed, labeled, and left on site to await disposal pending results of laboratory analysis • Following installation of the monitoring wells, the location and elevation of the well collars will be surveyed relative to the other site monitoring wells to integrate them into the existing EDF datum The well collars will be surveyed with a vertical accuracy of 0 01 foot and horizontal accuracy of 1 0 foot The measuring points for water-level measurement will be marked on the well collars Groundwater samples will be collected at least 48 hours following development of the monitoring wells Prior to sample collection, the static water level in each discrete screened water-bearing zone will be measured to the nearest 0 01-foot with a battery-operated, water level meter The monitoring wells will be purged until the temperature, electrical conductivity, and pH of the water has stabilized The purge I water from the well will be containerized in 55-gallon drums and left on site pending analytical results of the groundwater samples The groundwater samples will be transferred to laboratory-supplied containers Each container will be labeled for sample identification and placed in a cooler with ice Upon completion I of the fieldwork, the groundwater samples will be delivered under chain-of-custody procedures to a State-certified laboratory for analyses The groundwater samples collected from the monitoring wells will be analyzed for TPH-G by EPA Method 8015M and BTEX and gasoline additives/oxygenates by EPA Method 8260B The additives/oxygenates will include ethanol, TBA, MTBE,D1PE, ETBE,TAME, and 1,2-DCA 7 5 REPORTING Following completion of the fieldwork and evaluation of the laboratory analytical data, a report will be prepared for submittal to the SJCEHD and the CRWQCB describing the results of the investigation At a minimum the report will include (1) a discussion of the site history, (2) a description of the fieldwork conducted at the site, (3) the laboratory results, (4) a scaled site plan, (5) drilling logs, (6) conclusions, and (7) recommendations to CONDOR