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i Y Ms. Dot Lofstrom Page 4 of 6 • Soil and rinsate generated during drilling activities was placed into DOT approved 55-gallon drums. Both waste streams are currently stored on site pending characterization for proper disposal. 2.3 Well Construction Well MW2 was screened from 25 feet bgs to 40 feet bgs as per PHS/EHD instructions. The well was constructed of 2-inch diameter, Schedule 40 PVC casing and 0.010-inch slot screen. The filter pack consisted of 17 feet of 2112 silica sand. The annular seal contained 2 feet of bentonite overlain by a 5% bentonite/neat cement grout. The well was completed to the ground surface with a traffic-rated, flush- mount well box cemented in place and a locking well cap. The boring/well construction log for MW2 is included in Attachment A. 4 Well Development and Groundwater Sampling 2. p p g On August 28, 2001, a Ground Zero technician surveyed and tied in well MW2 casing elevation, developed well MW2, monitored water levels in wells MW 1 and MW2 and collected groundwater samples from wells MW 1 and MW2. Prior to well development, depth to groundwater was measured in each well and subtracted from the surveyed wellhead elevation to determine groundwater elevation. Groundwater elevations in wells MW 1 and MW2 were 16.16 and 16.14 feet below mean sea level, respectively. Well MW 1 was purged of 3.5 well casing volumes, and well MW2 was developed by surging and pumping until turbidity was minimized. During well development and purging, temperature, pH, and electrical conductivity parameters were measured and allowed to stabilize prior to groundwater sample collection. Groundwater samples were collected from wells MW 1 and MW2 after physical parameter stabilization, and water recovery of at least 80% of pre-purge levels. Samples were placed in an ice chest at a temperature of 4°C and submitted to Argon under chain of custody protocol. The samples were analyzed for the presence of oxygenate gasoline additives, EDB, 1,2 DCA, TPHg and BTEX. Groundwater purged from the wells was placed into labeled DOT approved 55-gallon drums, which are currently stored on site pending disposal. Groundwater elevations are summarized in Table 1. Field notes, well development and purge logs are included in Attachment B. 3.0 RESULTS 3.1 Subsurface Conditions Soil sampling began at a depth of 20 feet bgs in boring MW2. From 20 to 21.5125 feet bgs, soil was classified as lean clay. Underlying the lean clay, a five-ten foot thick bed of well graded sand was found, and from 31.5135 feet bgs fine grained soils classified as silt, and silty clay extended to 41.5 feet bgs the maximum depth explored. Groundwater was first found at a depth of approximately 33 feet.