Laserfiche WebLink
2400 Airport Way, Stockton, California <br /> Chevron U.S.A. Products Company April 13, 1 <br /> Page4 <br /> 4 <br /> TASK 6: GROUNDWATER MONITORING AND SAMPLING <br /> Groundwater samples will be collected from all site-related groundwater monitoring wells during the <br /> quarterly groundwater monitoring sampling event. At least 24 hours after development of the new <br /> well, all site-related wells will be gauged for depth to water and for the presence of any <br /> separate-phase hydrocarbons with an ORS Interface Probe Well Monitoring System which utilizes a <br /> dual optical/conductivity sensor to distinguish between water and separate-phase petroleum <br /> hydrocarbons. Before groundwater sampling, the wells will be purged of approximately four well <br /> volumes, or until pH, conductivity, and temperature of the purge water have stabilized. <br /> Groundwater samples will be collected using a teflon sampler cleaned and rinsed with an industrial <br /> detergent and distilled water. Prior to collecting the first sample, a distilled water rinsate will be <br /> collected from the rinse water of the sampler as a check of the cleanliness of the sampling <br /> instrument. Distilled water field blanks will be collected to document ambient sampling conditions. <br /> Groundwater samples will be placed in 40-milliliter glass vials with teflon septum caps. Each sample <br /> will be labeled and placed on ice in an insulated container with a chain-of-custody manifest pending <br /> delivery to a state-certified analytical laboratory. <br /> The groundwater samples collected from the groundwater monitoring wells will be analyzed for <br /> BTEX and TPH-G by EPA methods 5030/8020/modified 8015. All water generated during well <br /> development and sampling will be pumped into a DOT-approved purge water trailer and transported <br /> to the Chevron refinery in Richmond, California for recycling. <br /> TASK 7: REPORT PREPARATION <br /> Groundwater Technology will prepare an assessment report summarizing the data collected under <br /> the scope of work detailed above. The report will document the methods and results of the <br /> assessment, summarize laboratory analytical results, and include appropriate maps. <br /> TASK 8: PROJECT SCHEDULE <br /> Groundwater Technology is prepared to begin work on this project within two weeks of work plan <br /> approval by the SJCPHS-EHD. Drilling, soil sampling, and monitoring well development will be <br /> completed within one day. The report will be submitted approximately three weeks after the receipt <br /> of all laboratory analyses results. <br /> GROUNDWATER <br /> =ter---- <br /> r TECHNOLOGY <br />