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5608 N PERSHING AVE PAGE 12 TPH as gasoline and.BTEX at detection limits of 50 ppb and 0.5 ppb,respectively,except for 160 ppb TPH as gasoline and 0.8 ppb toluene in MW#8,3.9 ppb xylene in MW#4A,and 1.5 ppb benzene in MW#2A. This was the first groundwater sampling event after the over-excavation activities. Several of the monitoring wells had received damage from the equipment during the over-excavation work. 09-13-93 Monitoring wells MW#8 and MW#9 destroyed this date. No odors or soil discoloration noted during the overdrilling process. As these were deeper wells, no soil samples were obtained during the destruction. 10-14-93 PHS/EHD receives results of the soil samples obtained from the destruction of the monitoring wells,MW#1 (from 33'BGS),MW#2 (from 38' BGS),MW#3 (from 33' BGS), and MW#6 (from 34' BGS). All showed nondetect for TPH as gasoline and BTEX at detection limits of 1.0 ppm and 0.005 ppm, respectively, except for 0.017 ppm total xylene detected in MW#6. 12-20-93 PHS/EHD receives letter report from RP discussing an estimate of residual soil contamination remaining at the site. 1994 letter to RP requesting a revised estimate on remaining hydrocarbon mass _ HD sends L g 0105-94 PHS/EHD q based on an area previously documented to be impacted with hydrocarbons. 04-04-94 PHS/EHD receives a letter report from RP with a revised estimate of residual hydrocarbon mass for the site. The calculated conservative estimate for TPH as gasoline remaining at the site is 11.5 pounds or 1.9 gallons. 04-04-94 PHS/EHD receives the quarterly monitoring report for water sampling at the site in December 1993. The depth to water for the three remaining wells were 35.29' BGS for MW#4A, 34.51' BGS for MW#10 and 34.96'BGS for MW#11. MW#4A, now situated in a planter,showed a higher groundwater elevation that in the past. This may be due to being irrigated regularly. When used to determine groundwater � ted in a planter area which is g Iota p flow for the site,it skews the direction to the north northwest,inconsistent with all past data _ showing a north northeast flow direction. All water sample results showed nondetect for TP14 as gasoline and BTEX at detection limits of 50 ppb and 0.5 ppb,respectively,except for 0.5 ppb toluene in MW#10. Toluene was also, however, detected in the travel blank at 0.7 ppb. 04-22-93 PHS/EHD receives a faxed copy of groundwater sample results from the 03-25-94 sampling event. All three MWs show TPH as gasoline and BTEX at <50 ppb, 1.1 ppb, 1.1 ppb, <0.5 ppb,and 2.5 ppb, respectively, for MW#4A, <50 ppb, <0.5 ppb,0.7 ppb, <0.5 ppb,and 0.7 I� ppb, respectively, for MW#10, and 50 ppb, 0.8 ppb, 1.1 ppb, <0.5 ppb, and 1.5 ppb, respectively, for MW#11. 1i i i i i -