ARCHIVED REPORTS XR0011228 - Laserfiche WebLink

Home Browse Search

July 27,2001 Project No 2005-2050-01 page 6 Sand and gravelly sand were logged in each CPT boring from approximately 110 to 120 feet bgs This sand layer is approximately 10 to 35 feet thick onsite and greater than 40 feet thick at offsite boring CPT-7 This sand layer appears to be laterally continuous No sand was encountered below this water bearing zone Cross sections A-A' (Figures 3 and 7) B-B' (Figures 4 and 8) C-C' (Figures 5 and 9) and D-D' (Figures 6 and 10) illustrate interpreted geologic relationships Depth to groundwater in the monitoring wells ranged from 41 70 feet bgs (MW-4) to 43 97 feet bgs (MW-5) on May 18, 2001 Data obtained from MW-12 was not utilized as the well appears to have been compromised during construction Depth to water measurements, well casing elevations, and groundwater elevations for each monitoring well are shown in Table 1 Figure 11 shows groundwater elevation contours (corrected to mean sea level) for monitoring wells with total depths of less than 75 feet bgs (shallow wells) Figure 12 shows groundwater elevation contours for monitoring wells with total depths ranging from 105 to 115 feet bgs (deep wells) The groundwater flow direction in the upper water bearing zone was calculated to be towards the east at a gradient of 0 00057 ft/ft The groundwater flow direction in the lower water bearing zone was calculated to be towards the southeast at a gradient of 0 0005 ft/ft between monitoring wells MW-11 and MW-8 ANALYTICAL RESULTS • Soil and groundwater samples collected during the investigation were forwarded to Alpha Analytical Inc in Sparks, Nevada, a California state-certified analytical laboratory, for chemical analysis Soil and groundwater samples were analyzed for TPHG using USEPA Method SW8015 DHS/LUFT Manual and for benzene, toluene, ethylbenzene, xylenes (BTEX), methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), di-isopropyl ether (DIPE), tertiary amyl methyl ether [TAME], tertiary butyl alcohol [TBA], and 1,2-dichloroethane (1,2-DCA) using USEPA Method SW8260B The waste composite soil sample was analyzed for TPHG using USEPA Method SW8015 DHS/LUFT Manual, for BTEX and MTBE using USEPA Method SW826013, and for total lead using USEPA Method 6010 The soil and groundwater samples collected from boring CPT-1 were analyzed on a 24-hour turn-around-time All other samples were analyzed on a standard turn-around-time Soil analytical results are presented in Table 2 and Certified Analytical Reports with chain-of-custody documentation are presented in Appendix D TPHG, benzene, TBA, and 1,2-DCA concentrations in soil at select CPT boring locations are also shown on cross sections A-A' through D-D' (Figures 3 through 6) The highest concentrations of TPHG, toluene, ethylbenzene, and total xylenes in soil were detected at 100 feet bgs at bonng CPT-1 BTEX were detected at 138 feet bgs at boring CPT-1 (the bottom of the boring) The vertical extent of petroleum hydrocarbon impact to soil was not defined at boring CPT-1 Onsite soil samples were impacted with petroleum hydrocarbons at 95 feet bgs at CPT-8 and at 93, 109, and 113 feet bgs at boring CPT-10 The vertical extent of petroleum hydrocarbon impact to soil was also not defined at boring CPT-10 TPHG C 1Project FileslApache Plastics\ReportslApache Soil&GW 072001 A doc