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11 E-Z SERVE PETROLEUM MARUFTING COMPANY OF CALIFORNIA QUARTERLY GROUNDWATER MONITORING PROGRAM SAMPLING AND ANALYSIS PLAN I The following sections describe the procedures and protocols followed during this quarterly groundwater monitoring event at the subject site Depth-To-Water Measurements Prior to sampling the groundwater monitoring wells, the wells were opened to the atmosphere for approximately one-quarter of one hour, allowing the static water level well to adjust to the open barometric pressure The depth-to-groundwater was then measured, using an oil-water interface probe The interface probe was lowered slowly until free product or water was encountered At that point, the mark on the interface probe wire was read to the nearest 0 01 feet at the permanent reference point on the top of the well casing If free product was encountered, the probe was lowered until water was encountered The difference between the two depths corresponded to the thickness of the free product The total depth of the well was then measured using the same probe If the presence of free product was questionable, a second check for free-product was make using a disposable bailer The disposable banter was lowered into the water to approximately one-half the bailer length The bailer was then removed from the well and checked for the presence of free petroleum product or a product sheen . In the event a dedicated bailer or purge tubing existed in the well, the dedicated equipment was removed prior to sampling, and temporarily stored in a clean plastic garbage bag The depth-to-water and total depth measurements, and the presence or absence of free product, were recorded on the field sampling forms In addition, comments regarding the condition of the well and/or containment box were also noted on the field sampling sheet at that tune Wells observed to contain a product sheen or free product on top of the water column were purged but not sampled Groundwater Monitoring Well Purging The depth-to-water and bottom of well measurements were used to calculate the volume of purge water contained in one well volume The minimum purge volume was calculated to be three tunes the total well volume Once the minimum purge volume had been calculated, purging was started Purging was conducted using either a centrifugal pump connected to a dedicated Waterra® pump, a 2-inch diameter submersible pump, a bladder pump, or a disposable polyethylene bailer The type of equipment used to purge each well was selected based on the depth to water, the anticipated purge rate, the amount of sediment expected to be contained in the well, and the historical sampling records for each well The specific piece of equipment used was recorded on the Groundwater Sample Collection Record Temperature, pq and specific conductance of the purge water was monitored I during the purging process at regular intervals Purging was ceased when the monitored parameters stabilized (three consecutive reading not varying by more than 10-percent) and a minimum of three well volumes had been purged In the event a well dried out during purging, the well was allowed to recover to 80-percent of its I onguW well volume, or for 8-hours,whichever,was less, prior to collecting a groundwater sample ' I I I , ' I e SII I I' `I �I III � I II I 110 1 1