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OweoSolv, LLC-Groundwater Monitoring for Manan age 2 og 0 lie ��,�a--.�� ►��v:- �� ass-;V rYa: The subject site is located in downtown Lockeford, CA It was previously used as a gasoline service station which housed four pump dispensers with associated 1 piping, three gasoline USTs, and one waste oil UST. Most of the site is covered by asphalt except for the concrete slab under the building and in the vicinity of the former dispenser islands. The site is basically flat and surface drainage flows Rt1o11 the alley way' at the a south end of the property. 17 L1.��3„ �IJJYY47LIl:V L16C J' l VLq kfL�r� w�VY— kuY ar.L'87 V�Y,w��I1L I�1.-�i1 Three (3) wells were purged and sampled in the field QSee Appendix A foT WoN Development Logs). Water levels were measured prior to purging of approximately fifteen (15) gallons from each of the three wells A Slope Indicator water level meter was used to measure the depth to groundwater. The measurements were read to the nearest 100th of an inch. All 1 wells were surveyed by a certified land surveyor for relative elevation and location. Each well was sampled after purging approximately three (3) or more borehole volumes from each well, allowing the water level to recover to at least 80% of the original, static level. The purging was performed by the use of a steel bailer. Temperature, electrical conductivity, and pH were monitored during each purging, so that the three parameters are within a 10% error difference from one 1! another, over three consecutive readings The data was used to verify that water had been removed from well casing storage and that the well water was representative of the aquifer, prior to sampling. Well purge and rinseate water was stored in a 55 gallon ®OT approved drum and was labeled to be transported to a legal point of disposal. GROUNDWATER GRADIENT The groundwater gradient was measured on July 15, 2001 prior to groundwater sampling All groundwater monitoring well locations were surveyed by a certified land surveyor for location and Top of Casing elevations. The groundwater gradient was measured at 0.016 feet/foot to the south (See Figure a for Groundwater Gradient Map). GROUNDWATER SAMPLING Water samples were collected by placing a plastic disposable check valve bailors down the center of each PVC well casing after purging The bailor was lowered to the bottom of the well casing and pulled to the surface to be decanted from the bottom of the bailer by temporarily unplugging the check valve until water flowed freely into the glass sample container. Water samples were contained in 40- milliliter VOA vials for TPH-g, MTBE, BTEX, oxygenates, and lead scavenger analysis The samples were labeled and stored on ice at 4 degrees centigrade until delivered, under chain-of-custody procedures, to McCampbell Analytical, Inc. of Pacheco, California, a State-certified analytical laboratory. All samples were analyzed by appropriate and applicable EPA Methods 8260, 8020 and 8015 Modified 07 2s-2ooa GeoSoly, LLC- Groundwaf+er Monitoring for Nunan Page 2 of 3