Laserfiche WebLink
ENGINEERING-SCIENCE, INC* � <br /> San Joaquin County <br /> 4 February 1992 <br /> Page 2 <br /> 2) Dilution factors for groundwater samples - None of the groundwater <br /> samples submitted for analysis required dilution prior to analysis. Examination <br /> of the certified analytical reports indicates that a dilution factor of 1 was utilized <br /> for all groundwater sample analyses. <br /> 3) Detection of Toluene in groundwater trip blank - Toluene was detected in the <br /> groundwater trip blank at a concentration of 25 ug/L. The source of the toluene <br /> detected in the trip blank is unknown; however, it does not appear to be due to <br /> laboratory contamination because toluene was not detected in the laboratory <br /> method blank. In addition, it does not appear to be due to contamination in the <br /> field because toluene was not detected in any of the monitoring well samples <br /> collected. <br /> 4) Standards utilized for TPH analysis - the standards utilized for the DTSC <br /> Leaking Underground Fuel Tank (LUFT) Field Manual Method (modified EPA <br /> Method 8015) analysis of TPH by Galson Laboratories are listed as gasoline and <br /> kerosene. These standards should have been listed as gasoline and diesel <br /> according to proper DTSC/LUFT protocol. However, there are many mixtures <br /> of diesel; some of which are chromatographically similar to kerosene (personal <br /> communication between Mr. Neal Siler of ES-Alameda and Mr. Richard Wood <br /> of ES Laboratories, January 30, 1992; personal communication between Neal <br /> Siler of ES-Alameda and Ms. Eva Galson of Galson Laboratories, January 30, <br /> 1992). The kerosene standard used by Galson Laboratories is very similar to <br /> diesel. <br /> Diesel consists primarily of straight-chain hydrocarbons (alkenes and alkanes) <br /> ranging in length from C10 to C23, with C16 and C17 carbon chain length <br /> compounds predominating. The straight-chain hydrocarbons comprising <br /> kerosene have a more restricted carbon chain length range, C10 to C18. <br /> 5) Reported Results - gasoline and kerosene are reported as either not detected <br /> (ND) or as present on the certified analytical laboratory reports. ES personnel <br /> noted this deficiency and requested that Galson Laboratories quantify and report <br /> the results. The quantified results for soil samples are reported in Table 2 of the <br /> "Preliminary Site Investigation Report, Greyhound Terminal Location 8969, <br /> Stockton, California" (attached). <br /> Quantified analytical laboratory results for the groundwater samples are <br /> included in Appendix B of the aforementioned report. <br /> 6) Analysis of Samples - separate aliquots of a sample were utilized for <br /> determining the moisture content and the analysis of TPH and BTEX. The <br /> samples were not dried prior to analysis of TPH and BTEX (personal <br /> communication between Neal Siler of ES-Alameda and Ms. Eva Galson of <br /> Galson Laboratories,January 30, 1992). <br /> 7) Condition of Samples upon arrival at analytical laboratory - Galson <br /> Laboratories did not include comments on either the chain-of-custody records or <br /> the signed laboratory data sheets as to the condition (temperature, suitable <br />