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Rally's Stockton Work Plan 11 Project No. 91349.A STANDARD OPERATING PROCEDURES FOR WATER SAMPLING SOP 1 Ground water monitoring wells are to be DEVELOPED within 48 hours of completion. Well Development follows the drilling of the well and cleans the screen and well of drill cuttings and silt. Approximately 10 times the volume of water in the casing should be withdrawn, if possible. Water can be withdrawn from the well by means of a bailer or a pump. If the aquifer is slow to recharge, development continues until recharge is too slow to practically continue. SOP 2 All development water should be stored in drums pending sample analytical results. SOP 3 Immediately prior to purging (SOP 4), the standing water level (SWL) in the well casing is recorded. SOP 4 Purging of the ground water will be conducted prior to sampling. When purging is done with a bailer, the first time the bailer is dropped into the well, care should be taken to allow the bailer to descend into the water until it is only half submerged. Upon extraction, the bailer should be inspected for floating product. If floating product is seen, the thickness should be noted and recorded. SOP 5 Prior to water sampling, each well shall be purged by bailing or pumping a minimum of four casing volumes, or until the discharge water indicates stabilization of temperature, eH and pH. If the well is evacuated before four casing volumes are removed, or stabilization is achieved, the sample should be taken when the water level in the well recovers to 80% of its initial level. Stabilized water temperature and pH, plus observations of water quality, shall be recorded. SOP 6 All water which is pumped or bailed from a monitoring well while purging for sampling should be placed in barrels while awaiting analysis results. SOP 7 Use only vials properly washed and baked, available from and prepared by the laboratory conducting the analyses.