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-- -- -�--- eoCag uaC7echnus Inc ---- ---- —- - - -- - - - - - --- - — ------ ------ Page 4�'- - - - -- — -- — <br /> Groundwater Momtonng Report <br /> Project No 425 2 <br /> February 1,2001 <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 /> their movement and insure their integrity <br /> During the December 22, 1999 event, Carol Oz of SJC PHS/EHD decided it was no longer <br /> necessary to sample the domestic well located at 1600"B" Durham Ferry Road, as this well <br /> was non-detect during the September 1999 sampling <br /> 13 Laboratory Analyses <br /> The groundwater samples collected on December 27, 2000 were delivered to Sherwood <br /> Labs (Department of Health Services Certification No 1400), of Hilmar, California, for <br /> analysis <br /> The samples were analyzed using the following methods <br /> • EPA method 602 — BTEX <br /> ® EPA method 602 —MTBE <br /> o EPA method 5030/8015(m) - TPH-Gasoline <br /> The detection limits for the above analyses are listed in Table 4 of Appendix A and the lab <br /> data is presented in Appendix B <br /> 1 <br /> 2.0 FINDINGS AND DISCUSSION <br />+� The laboratory analytical data from the December 27, 2000 monitoring event shows that <br /> TPH-G & BTEX compounds have been detected in the following monitoring wells MW-1, <br /> MW-2, MW-4 and MW-5 <br /> The results from the latest rounds of sampling are comparable with the results from the <br /> previous monitoring events The following observations are made <br /> • Horizontal groundwater gradients are currently towards the NE <br /> • Vertical groundwater gradients are dominated by upward moving water, typically in the <br /> low pumping season <br /> • TPH-G concentrations in MW-1 and MW-2 continue to fluctuate See Figures 4 & 5 <br /> for graph of Benzene and TPH-G versus time <br /> • Wells MW-4 and MW-5 contaminant concentrations exhibit a stable trend <br /> • Wells MW-102 and MW-202 did not contain contaminant concentrations above the <br /> laboratory reporting limits <br /> • All three of the domestic wells were non-detect for the December 2000 event <br /> i <br />