ARCHIVED REPORTS XR0000003 - Laserfiche WebLink

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A S S D C I A T E S I N C On September 21, 1998, an ATC geologist supervised the advancement of five soil borings, S137 through SB 11, from 5 to 31 feet bgs Soil samples were collected at five-foot intervals and grab groundwater samples were collected from each boring Samples were analyzed for petroleum hydrocarbons and elevated concentrations of petroleum hydrocarbons were detected in soil and groundwater samples The September 1998 subsurface investigation results are detailed in ATC's Summary Report ofAdditional Subsurface Investigation, dated November 4, 1998 In January 1999, ATC supervised the advancement of three soil borings around the former excavation area The borings were completed as groundwater monitoring wells Analytical data indicated the soil and groundwater at the site are impacted with total petroleum hydrocarbons as diesel (TPHd) and as gasoline (TPHg) The January 1999 subsurface investigation results are detailed in ATC's Summary Report of Additional Subsurface Investigation, dated April 7, 1999 In July 1999, ATC supervised the advancement of two soil borings south and southwest of the former excavation area The borings were completed as groundwater monitoring wells Analytical data indicated the groundwater samples from the new wells were impacted with TPHd The soil samples contained no detectable concentrations of TPHd or TPHg The July 1999 well installation activities are detailed in ATC's Summary Report of Well Installation Activities, dated August 26, 1999 In October 1999, ATC supervised the performance of a 24-hour groundwater pumping test Groundwater was pumped from well MW2 for a period of 24 -hours Depth to water measurements were made in wells MW1, MW2, MW3, and MW4 during the groundwater pumping test The results of the groundwater pumping test are summarized in ATC's Summary Report of Pumping Test and Remedial Investigation Feasibility Study, dated March 20, 2000 SAMPLING ACTIVITIES On July 3, 2002, groundwater samples were collected by ATC Associates personnel from monitoring wells MW1 through MW5 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 Groundwater levels were recorded with an electronic water probe capable of measuring with an accuracy of 0 01 feet 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 with bottom emptying devices to reduce volitilization The groundwater samples collected from the wells were submitted to Argon Laboratories Inc , a state -certified analytical laboratory (ELAP Cert No 2359) for chemical analysis of TPHg and TPHd utilizing EPA method 8015 modified, and benzene, toluene, ethylbenzene, and xylenes (BTEX) utilizing EPA method 8020 Groundwater well purge and sample logs are contained in Attachment 1 w 1130991quartlyl3gr-2002 doc 2