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a A S S O C I A T E S I N C detected in the groundwater sample collected from soil boring SBI. The January 1998 subsurface investigation results are detailed in ATC's Summary Report for Subsurface Investigation, dated February 4, 1998, In September 1998, ATC supervised the excavation of approximately 70 tons of impacted soil. The soil was transported and disposed of at an appropriate landfill on the same day it was excavated. The excavation was limited on two sides by buildings and overhead lines. Confirmation samples collected from the excavation indicated there was residual contamination remaining. Also in September 1998, ATC supervised the advancement of four soil borings around the former excavation area. Three of the borings were completed as groundwater monitoring wells. Analytical data indicated the soil and groundwater dt the site is impacted with total petroleum hydrocarbons as stoddard solvents (TPHss). The September 1998 subsurface investigation results are detailed in ATC's Summary Report of Soil Excavation and Additional Subsurface Investigation, dated December 3, 1998. On March 23, 2000, an ATC geologist supervised the advancement of one angle soil boring, SB2A, to approximately 32 feet bgs. The boring was advanced at a thirty-degree angle from the vertical, directly under the on-site building, south of the former UST location. Soil samples and a grab groundwater sample were collected. The soil and groundwater samples contained no detectable concentrations of TPHg, TPHd, TPHss, benzene, toluene, ethylbenzene, and xylenes (BTEX), or oxygenate fuel additives. On April 9, 2000, an ATC geologist supervised the installation of one groundwater monitoring well to approximately 39 feet bgs. Soil samples were collected at five-foot intervals. The well was developed and groundwater samples were collected. The soil and groundwater samples contained no detectable concentrations of TPHg, TPHd, TPHss, BTEX, or oxygenate fuel additives. The March and April 2000 subsurface investigation results are detailed in ATC's Summary Report ofAdditional Subsurface Investigation, dated May 16, 2000. SAMPLING ACTIVITIES On December 8, 2000, groundwater samples were collected by ATC Associates personnel from monitoring wells MW1 through MW4. The locations of the monitoring wells are shown on Figure 2. Prior to collection of groundwater samples, the depth to water, pH, electrical conductivity, and temperature were measured in the monitoring wells and recorded. A minimum of three well casing volumes was purged from each well prior to sampling. The wells were allowed to recover and samples were collected from each well using dedicated disposable bailers. Groundwater well purge and sample logs are contained in Attachment 1. The groundwater samples collected from each well were submitted to State-certified Argon Laboratories (ELAP Cert. No. 2358) for chemical analysis of TPHg, TPHd, and TPHss utilizing EPA Method 8015 modified, and BTEX utilizing EPA Method 8020. wa I72951quan1yl4gr-2000.doc 2