SITE INFORMATION AND CORRESPONDENCE

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Ms.Amy Terrell ERM-West,Inc. 18 Much 2011 Page 4 The depth to groundwater and the total depth of the well will be measured in each monitoring well,with minimal disturbance to the water column. Water will then be pumped from the middle of the screened interval at a low rate to minimize drawdown and disturbance of the water-bearing zone. Groundwater parameters (pH, temperature, specific conductivity, dissolved oxygen,and oxidation/reduction potential)will be frequently monitored until parameter stabilization is reached (+ 0.1 standard unit, + 1 degree Celsius, + 10 percent,+ 10 percent,and + 20 millivolts for the above-listed parameters,respectively). The water level will be checked periodically to make sure that drawdown of the water column is minimal. Groundwater samples will be collected through the flow tubing after parameter stabilization,and the final water level will be recorded after sample collection. Monitoring well groundwater samples will be analyzed for the following parameters: • Antimony, arsenic, barium,nickel, and vanadium by USEPA Methods 6010/7471A; • Ammonia(as nitrogen)by USEPA Method 350.3; and • Chloride,sulfate (as SO4), and nitrate(as nitrogen)by USEPA Method 300.0. Purged groundwater will be temporarily contained on site in 55-gallon drums pending characterization and disposal. SAMPLE SHIPMENT, TRACKING,AND QUALITYASSURANCE1 QUALITY CONTROL PROCEDURES All samples will be collected in clean, appropriately preserved, laboratory-supplied containers. The samples will be labeled and stored in cooled ice chests until delivered to a California-certified analytical laboratory. Chain-of-custody documentation will be completed for the collected samples and will accompany these samples to the laboratory. Duplicate samples will be collected at the rate of 10 percent of the total number of collected samples for both soil and groundwater.