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Ms. Anne P. Conner 7 10/9/2007 Pacific Gas&Electric Company parameters [dissolved oxygen (DO), pH, oxidation reduction potential (ORP), temperature, and turbidity] will be monitored at 2 to 10 minute intervals. Purging will continue until the parameters are stable, as indicated by three consecutive readings differing by less than 10 percent. If DO drops to below 1.0 milligrams per liter (mg/L) then +/- 0.3 mg/L will be used as the standard. Upon stabilization of water quality parameters, a total of five groundwater samples (one from each piezometer) and one duplicate sample will be collected and analyzed for the following constituents: • Alkalinity— EPA method 310 • Inorganic Anions (Br, Cl, F, NO3/NO2, SO4) — EPA method 300.1 • Nitrogen as Ammonia — EPA method 350.1 • Total Phosphate — EPA method 365.2 • Total and Dissolved Metals— EPA method 6010/6020 • Total Dissolved Solids (TDS)— EPA method 160.1 Total and dissolved metals will include Al, B, Ba, Ca, K, Mg, Mn, and Na. Collected samples will be placed in coolers with ice until shipment. Additionally, ferrous iron and sulfide will be analyzed in the field for each groundwater sample through the use of Hach TM field test kits. 3.3 Intermediate/Deep Zone Groundwater Sampling Intermediate/deep zone groundwater sampling will be completed at three locations as shown on Figure 1-2. Direct push or another effective drilling technology will be used to advance a HydroPunch® groundwater sample collection rod to specified sample depths. Groundwater samples will be collected, if possible, from depths of 40, 50, 60, 70, 80, 90, and 100 feet bgs at each sample location. Pursuant to SOP EI-GS009, Standards for Direct Push Groundwater Sampling (Shaw, 2007b), or equivalent, the HydroPunch® screen shall be protected such that is not exposed to pore fluid and particles from non- target depths. Upon achieving the designated target interval, the protective cover will be retracted and the length of the screen exposed, thus allowing pore water to flow into the chamber. Dependent upon site conditions, either a peristaltic pump, or the HydroPunch®sample collection chamber, will be used to collect groundwater grab samples. An attempt will be made to collect samples from each sample depth interval. However, it is likely that layers of low permeability soils exist within the intermediate zone and that groundwater recharge into the HydroPunch® chamber may not be sufficient for sample analyte volume requirements. Attempts will be made to collect the groundwater samples from each sample interval, although it is recognized that this might not always be possible. Furthermore, due to the relatively large quantity of samples proposed, a maximum period of 60 minutes will be allocated for sample collection at each specified depth. A maximum of 21 samples and two duplicates will be collected. Samples will be analyzed for the following constituents: • Alkalinity— EPA method 310