Laserfiche WebLink
1 <br /> Unit, a dual-rod sampling techruque which enabled collection of undisturbed soil samples at the <br /> 1 desired depths The bonngs were advanced to the capillary fringe at depths of between 8 and 10 <br /> feet bgs Descriptions of the material encountered and photoionization (PID) readings are <br /> presented on the stratigraphic logs located in Appendix I <br /> Two soil samples were collected from each confirmation boring The deepest sample from <br /> 1 bonngs CB-2, CB-3, CB-4 and CB-5 were submitted to Argon Laboratories of Modesto, <br /> California (DOHS Lab No 1873) for analysis of TPHg and BTEX by EPA Methods 8015/8020, <br /> 1 and TPHd by EPA Method 8015 A copy of the chain of custody is presented in Appendix III <br /> Soil encountered during advancement of the confirmation borings was mostly silty clay, except in <br /> boring CB-1 where sandy backfill material was encountered <br /> 1 No petroleum hydrocarbon compounds were detected in any of the samples analyzed Copies of <br /> laboratory reports are located in Appendix III <br /> The estimated lateral extent of residual TPHd remainingin the soil from 5 feet to 9 feet b s is <br /> g <br /> 1 presented on Figure 3 <br /> 4.2 Groundwater Conditions <br /> 1 Currently, no groundwater degradation exists at the site Petroleum hydrocarbon constituents <br /> have not been present in groundwater samples collected from wells MW2 and MW3 for the last <br /> six sampling rounds (October 14, 1992, January 13, April 27, July 27, and October 1, 1993, and <br /> January 5, 1994) <br /> 1 <br /> Episodes of degradation to the groundwater which occurred during high water levels have been <br /> 1 extremely minimal and temporary, occurring only twice in the sampling history of wells MW2 and <br /> MW3 During July 1991 BTEX and TPHg were present in well MW2 at or near the detection <br /> limits (0 5 to 0 6 ppb and 54 ppb, respectively) and in well MW3 ethylbenzene and xylenes were <br /> 1 present at levels slightly higher than the detection limits (1 4 ppb and 0 7 ppb, respectively) <br /> During the July 1992 monitoring episode, TPHg was detected at 120 ppb and xylenes were <br /> detected at 18 ppb in well MW2 <br /> w 1967311mporu\Ciosurc doc 6 <br /> • <br /> 1 <br /> Sian <br />