ARCHIVED REPORTS_XR0003144 - Laserfiche WebLink

Home Browse Search

Project No 034-98081 Page No 4 positive PID readings were noted in any of the other boreholes Additionally, no hydrocarbon odors or oily sheen were associated with the six water samples collected 52 Groundwater Depth and Recharge Rate Groundwater was first encountered at depths of approximately 34 to 38 feet bgs in boreholes B-2 through B-7 Groundwater recharge rate near the water table was somewhat slow in four of six boreholes, hindering attempts to sample using Hydropunch® methods and requiring overdrillmg to approximately ' 40 feet bgs Recharge rates into boreholes were increased using by overdrilling and depth to groundwater tended to stabilize at approximately 34 feet bgs within 30 to 60 minutes of first groundwater encounter 53 Analytical Results The results of chemical analysis of selected soil samples and groundwater are presented in Tables I and 11, respectively Samples where analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX) and for total petroleum hydrocarbons as gasoline (TPH-G) by EPA Methods 802113 and 8015M, respectively Methyl tertiary butyl ether(MTBE) was also analyzed by Method 5030 in one groundwater sample One confirmation sample was also analyzed for volatile organic constituents using EPA Method 8260A Complete analytical reports may be found in Appendix D 60 DISCUSSION 61 Soil Profile and Groundwater Recharge Properties As noted on the boring logs in Appendix C and borehole locations (Figure 2), the soil profile varies somewhat substantially over lateral distances of less than 100 feet Within the current groundwater table interval, moderate to highly plastic clays (CL and CH) predominated although extensive silt was encountered throughout that depth range in borehole B-6 Thin (0 75 - 2 5 inches thick) sand lenses (classified as SP) were observed in samples of clay retrieved from boreholes B-2 and B-3, however, no such lenses were observed in samples from other boreholes Because of their limited thickness, it is possible sand lenses exist at the remaining borehole locations but were not intercepted in samples collected Observations of soil cuttings produced while drilling and pulling auger from boreholes B-4 through B-7, however, showed no evidence of sand lenses being encountered during drilling as was the instance with boreholes B-2 and B-3 KRAZAN & ASSOCIATES, INC Offices Serving the Western United States 3498081 SGS