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t d Pombo Property Subsurface Investigation All sampling equipment including the stainless steel Geoprobe® screen point, pump, bailer, and cables, used by sampling personnel, will be disassembled, if appropriate, and steam-cleaned prior to commencement. of sampling. These procedures will also be followed between ach well, sampling point, and at the end of the sampling day. De-ionized or organic-free water (also provided by the laboratory) will then be introduced into the pump or bailer as a final stage of cleaning. This water will then be a pumped or gently poured into sample vial to be used as pump or bailer blanks. Thes blanks will be tested only if their corresponding samples are found to contain contaminants. Immediately prior to sampling, water levels and well depth measurements will be taken in all wells at the site. Each well will be evacuated using a stainless steel bladder pump, which does not introduce air into the water column, or a Teflon bailer. The pH, temperature, and electrical conductivity of the water will be monitored as the well is evacuated. These parameters will be noted on a field log. Instruments calibrated to known standards will be used to monitor these parameters. At least 5 well volumes will be evacuated from each well, and more, if necessary, until the above parameters have stabilized. Wells that are de- watered before evacuation of 5 well volumes has been accomplished will be sampled upon 80 percent recovery of the i itial water level. The wells or other sampling points will be sampled in order o the least to the most contaminated, as best known or estimated. The samples will be pumped from a stainless steel bladder pump or carefully poured from a Teflon bailer into clean glass vials with Teflon-lined screw caps and half gallon plastic containers provided by the laboratory. Care will be taken to ensure that no air space exists in the vials by inverting to check for bubbles and re-samplilng if necessary. The groundwater samples will be analyzed or extracted within 14 days according to their EPA methods. The samples shall be analyzed for Total Petroleum Hydrocarbons (gasoline), BTX&E (Benzene, Toluene, Xylene, and Ethyl Benzene) and the Oxygenated compounds Jy EPA Method 8260. Analysis will be conducted by GeoAnalytical Laboratories. The minimum detection limits used for each analyte will be .0005 mg/l for B X&E, 0.001 mg/l for the Oxygenated compounds (0.010 for tertiary-Butanol), and 0.05 mg/l for diesel and gasoline. Prepared by: v� .pb,01157 E�pirgs: Michael"kioberdanz, REA, California Registered Environmental Assessor 402157 �TdF cA�;f�� California Registered Environmental Health Specialist #4783 6