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I I EZ-SERVE PETROLEUM MARKETING COMPANY OF CALIFORNIA QUARTERLY GROUNDWATER MONITORING PROGRAM SAMPLING AND ANALYSIS PLAN The following sections describe the procedures and protocols followed during this quarterly groundwater monitoring event at the subject site. Depth-to-Water Measurements I Prior to sampling the groundwater monitoring wells, the wells were opened to the atmosphere for approximately one-quarter of one hour, to allow the static water level to adjust to the open barometric pressure The depth-to-groundwater was then be measured, using an oil-water interface probe. The interface probe was lowered slowly until free product or water was encountered. At this 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 corresponds to the thickness of the free product. The total depth of the well was then measured using the same probe. A second check for free-product on top of the water column was made using a disposable bailer. The disposable bailer was lowered into the water to approximately one-half the bailer length The bailer was then removed from the well and a check for the presence of free petroleum product or a product sheen was made. In the event that 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 bottom of well measurements, and the presence or absence of free product, was recorded on the field sampling form In addition, comments regarding the condition of the well and/or containment box were also be noted on the field sampling sheet at this time. Wells observed to contain a product sheen or free product on top of the water column were not be purged or sampled. Groundwater Monitoring Well Purging The depth-to-water and bottom of well measurements were used to calculate the volume of water contained in one well volume. The following values were used to calculate the volume of water contained in the well casing and filter pack surrounding the well Well lime r Qidlons/lin= f t 2-inch 0.16 4-inch 0.65 8-inch filter pack 0.78 10-inch filter pack 1.21 1 r r I I r I I r Ir r r r r r r i r ' v ' I ! I I I ! fk ! I{ f If I Ilr�fi ' rl I Ilf I! l�l{r