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FOURTH QUARTER 1996 <br /> GROUNDWATER MONITORING REPORT <br /> I FORMER DIAMOND LUMBER - MANTECA <br /> JANUARY, 1997 <br /> I2.2 Monitoring Well Purging <br /> Each sampled well was purged using a submersible pump until at least three equivalent well <br /> 1 volumes of water had been removed and pH, temperature and conductivity measurements had <br /> stabilized All purging and sampling equipment was washed in a tasodium phosphate solution and <br /> rinsed in distilled water prior to each usage to reduce the potential for cross contamination <br /> between wells The pH, temperature and conductivity measurements were recorded on field data <br /> sheets, which are kept in a permanent project file The wells were allowed to stand for a period of <br /> time to equilibrate prior to sampling Groundwater purged from the wells was placed into DOT <br /> approved 55-gallon drums The purge water will be disposed of by pumping into a vacuum truck <br /> and sending it to a recycling facility <br /> 2.3 Groundwater Sampling <br /> Proper sample collection and handling are essential to assure quality data obtained from a sample <br /> Each groundwater sample, therefore,was collected using a new disposable bailer for each well <br /> and placed in the appropriate laboratory prepared containers, using proper protocol The samples <br /> were labeled with the date, time and identifying well number,placed into a cooler at 4° C, and <br /> transported to the laboratory under continuous chain-of-custody (COC) documentation The <br /> laboratory reports and COC documentation are included in Appendix B <br /> 1 2.4 Groundwater Analyses <br /> Analyses of the sampled groundwater were performed by Sierra Laboratories, Inc (Sierra), a <br /> California certified laboratory Samples were analyzed in accordance with state guidelines and <br /> EPA protocols <br /> 3.4 SUMMARY AND CONCLUSIONS <br /> 1 3.1 Results of Groundwater Laboratory Analyses <br /> rTPH G and BTEX were detected in five of the eight wells sampled (BEI-MW 1, BEI-MW2, BEI- <br /> MW3, SRK-MW2, and MW-8-P) TPH G was reported at concentrations ranging from non- <br /> detect 1n SRK-MW1, SRK-MW3, MW-7-P, and MW-8-P to 41,000 micrograms per liter (µg/1) <br /> in BEI-MW3 Benzene was reported at concentrations ranging from non-detect in SRK-MW 1, <br /> SRK-MW3 and MW-7-P to 8,000 µg/1 in BEI-MW3 Both offsite wells were non-detect for <br /> TPH, and low to non-detect for BTEX constituents The laboratory results for this sampling <br /> event are presented on Figure 3 and in Table 2 <br /> 2 <br />