SITE INFORMATION AND CORRESPONDENCE

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ChevronTexaco- Surland omes Project • 06-6102-00-2931-120 April 28,2003 Page 2 SAMPLING AND ANALYSIS PLAN Task 1 —Quarterly Groundwater Monitoring and Reporting The two existing on-site monitoring wells (TW-1 and TW-3) will be sampled and analyzed for a minimum of one quarter. Well locations are shown on Figure 2. Groundwater monitoring wells will be purged and sampled in accordance with the ChevronTexaco Quality Assurance/Quality Control Sample Collection Guidelines, Chevron Old valley Pipeline Sites, California (Geomatrix Consultants, August 2001). Prior to the collection of groundwater samples, water levels will be measured from top of casing at each well. The wells will then be purged of four casing volumes of water, using peristaltic or other pumps. During the purge process, water quality parameters, including pH, specific conductance, and temperature will be measured and recorded. After water- quality parameters stabilized (i.e., a minimum of three consecutive readings with values within 10 percent for each parameter), groundwater samples will be collected. Any groundwater exhibiting a visible petroleum sheen at the time of the sampling event will not be sampled. Groundwater samples will be collected using disposable polyethylene bailers, and decanted into laboratory-provided sample containers. The containers will be labeled, sealed, and placed immediately into ice-filled coolers for transport to the analytical laboratory. Purge water will be placed in labeled, close-topped 55-gallon drums. SAIC will coordinate with Sturgeon & Sons to remove the drums from the site at the end of each sampling day. All drummed purge water will be properly disposed of by ChevronTexaco in accordance with California State and Federal regulations. The groundwater samples will be submitted to Friedman & Bruya of Seattle, Washington, a California certified laboratory, with appropriate chain of custody protocol, for the following chemical analyses: • Benzene, toluene, ethylbenzene, and total xylenes (BTEX, EPA Method 8260); • Total petroleum hydrocarbons quantified as diesel (TPHd, EPA Method 8015 modified); • Polynuclear aromatic hydrocarbons (PAHs, EPA Method 8270) Analyses for TPHd will be performed both with the use of the silica-gel cleanup method and without it. Quarterly Reporting After receiving the chemical analytical results, SAIC will prepare a letter report documenting the quarterly sampling procedures and findings. The letter report will include: • A site plan;