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Air Sparging Pilot Test Related Activities Report and Remedial Action Work Plan Former Countryside Market, Stockton, California April 30, 2015 4.3 Injection Test Procedures Data loggers were deployed in wells OBS-1, AS-2 and MW-5 on January 26, 2015 to measure background water level, DO, and ORP in each well prior to initiating air injection into the first test well (AS-1). Injection testing at AS-1 was conducted on January 27, 2015 at three progressively higher injection flow rates. Following the completion of AS testing at AS-1, the data loggers remained deployed in OBS-1 and MW-5 to collect recovery data, and testing at AS-2 was conducted on January 28, 2015 in the same manner as the first test with the exception of the data logger from AS-2 being relocated to AS-1. The data loggers were removed on January 29, 2015. Groundwater was at an average of approximately 99 feet below TOC at the time of testing. Observation wells for AS testing at AS-1 (screened 110 to 115 feet bgs) were as follows: Observation Well Screen Interval (feet-bgs) Distance from AS-1 (feet) Pre-test Depth to Water (feet below TOC) OBS-1 80 to 120 15 99.31 AS-2 110 to 115 20 98.62 MW-5 80 to 100 28 98.79 VW-1 30 to 60 23 NA NA = not applicable Observation wells for AS testing at AS-2 (screened 110 to 115 feet bgs) were as follows: Observation Well Screen Interval (feet-bgs) Distance from AS-2 (feet) ' Pre-test Depth to Water (feet below TOC) OBS-1 80 to 120 7.5 99.31 AS-1 110 to 115 20 99.20 MW-5 80 to 100 42 98.79 VW-1 30 to 60 9 NA NA = not applicable As discussed previously (Section 3.4), the observation wells OBS-1 was constructed with 2-inch schedule 80 PVC, 0.020-inch slot, and a 40-foot screened interval (80 to 120 feet bgs). Injection wells AS-1 and AS-2 were constructed with 2-inch schedule 80 PVC, 0.010-inch slot and a five foot screened interval (110-115 feet bgs). Vapor well VW-1 was constructed with 2-inch schedule 80 PVC, 0.020-inch slot and a 30 foot screened interval (30-60 feet bgs). The data loggers were deployed in wells OBS-1, MW-5 and AS-2 on January 26, 2015 to collect background data prior to initiating air injection into test well AS-1. The Data loggers remained deployed in wells OBS-1 and MW-5 until they were removed on January 29, 2015 in preparation for the start of testing at AS-2. The data logger from AS-2 was relocated into well AS-1 prior to initiating air injection into test well AS-2. Each data logger was set approximately three feet below the groundwater surface. Testing included monitoring the groundwater and vadose zone conditions before, during, and after testing. This included field measurements of observation well head pressure, VOC soil vapor concentration, DO, ORP, and groundwater levels from the observation wells. The injection wells 4-3 The Source Group, Inc.