Laserfiche WebLink
Geofogica(Technics Inc. <br /> G&B Equipment Page 3 <br /> Groundwater Monitoring Report <br /> Project No.336.2 <br /> Aril 25, 1997 <br /> A chain of custody document, listing all samples collected and their intended analyses, <br /> accompanied the samples from field to the laboratory, thereby providing a means to track <br /> i their movement and insure their integrity. <br /> 1.3 Laboratory Analyses <br /> I <br /> The groundwater samples collected on March 28, 1997 were delivered to Sherwood Lab <br /> (Department of Health Services Certification No. 1400), of Hilmar, California, for analysis. <br /> The samples were analyzed using the following methods: <br /> • method 602 - benzene, toluene, ethylbenzene, total xylene (BTEX) <br /> • method m8015/LU1 T-total volatile hydrocarbons as gasoline (TPH-G). <br /> The detection limits for the above analyses are listed in Table 2 of Appendix A and the lab <br /> data is presented in Appendix B. <br /> 1 <br /> 2.0 FINDINGS AND DISCUSSION <br /> The laboratory results for this sampling event are suspect. MW-3 is now showing <br /> contamination by BTEX and TPH-G and MW-1 is non-detect, except for a minimal amount <br /> ..._ of Toluene. In the past MW-1 has always tested positive for the above compounds while <br /> MW-3 has been non-detect. In conversations with Sherwood Laboratory it became clear that <br /> the field labeling method was inadequate which probably caused samples to be misidentified. <br /> Most likely the sample from MW-1 was identified as MW-3 and vise-versa. MW-2 may also <br /> have been misidentified so all results from this event should be treated with caution before <br /> using them to draw any conclusions. <br /> 3.0 CONCLUSIONS AND RECOMMENDATIONS <br /> ' Despite the suspect data, several tentative conclusions can be drawn. If the sample from <br /> MW-1 and MW-3 were switched, then MW-3 may have a small concentration of Toluene, <br /> 2.0 ug/L, see results under MW-1. If the sample integrity was not violated other then <br /> N switching identification, the overall concentration of both BTEX and TPH-G decreased <br /> i- approximately one order of magnitude. The values reported are the lowest seen in the four <br /> sampling events. These possible trends will be confirmed or refuted by further sampling. <br /> i <br />