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J Work Plan for Groundwater Extraction Well Installation March 15, 1993 Southland Site No. 20304, 455 Grant Line Road, Tracy, CA 3 f grade with 1 foot of bentonite followed by a neat-cement grout containing 95 pounds of, Portland Type 1/II Cement to 5 gallons of clean water. The wellhead will be protected by a watertight locking cap and a traffic-rated street box with a watertight bolted lid until construction of the groundwater extraction system begins, at which time an appropriate accessible vault will be installed. A typical groundwater extraction well construction diagram is presented in Attachment 3. If an aquitard greater than 5 feet thick is observed below the water table in the extraction well boring, the boring will be sealed to the top of the aquitard with neat cement using a tremie pipe before setting the extraction well. k TASK 3: WELL DEVELOPMENT, SURVEYING, AND GROUNDWATER EXTRACTION Approximately 48 hours after installation, the recovery well will be rig developed using a combination of surging and balling to remove fine-grain sediments from the well and filter pack. Water from the development process will be retained on site In labeled Department of Transportation (DOT)- approved 55-gallon drums pending proper disposal. Approximately 24 hours after development, the water table will be monitored to measure static levels and the thickness of separate phase product, if present. The water-table level will be measured using an QRS Environmental Equipment INTERFACE PROBE'" Well Monitoring System, which consists of a dual optical sensor and electrical conductivity probe, that distinguishes between water and petroleum products. The top-of-casing (TOC) and horizontal position of the well will be surveyed relative to the established benchmark. The survey data will be used with the depth-to- water measurements to calculate Water-table elevation in the extraction well and to estimate the local groundwater flow direction and gradient. TASK 4: WELL PURGING, WATER SAMPLING, AND ANALYSIS Groundwater samples from the extraction well will be collected during the quarterly groundwater monitoring and sampling events conducted after installation of the well. After groundwater monitoring, 3 to 5 well-casing volumes of water will be removed from the well before sampling. A log will be maintained by the field technician that includes observations and measurements of pH, temperature, and conductivity values for the water purged. Groundwater Technology personnel will then collect groundwater samples from the extraction well. Each water sample will be analyzed for BTEX, TPH-G, TPM-D using the EPA-approved methods noted above. The work will be conducted according to Groundwater Technology's SOPs (Attachment 2). Purge water from the extraction well will be stored on site in properly labeled DOT-approved 55-gallon drums pending receipt of the groundwater sample analyses results. WP3767A1.SLL 'r _ GROUNDWATER �n__ TwiNOLOGY, INC.