ARCHIVED REPORTS XR0001738 - Laserfiche WebLink

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Quarterly Ground-Water Monitoring June 30, 1989 Beacon Station No. 1-502, Lodi, California AGS 86091-6 April 22, 1987) . At Beacon's request, Applied GeoSystems began quarterly monitoring of the ground water in the wells in January 1988. Four vapor-extraction wells (VW-6 through VW-9) were later installed in the vicinity of the tank cavity to allow mitigation of soil contamination (AGS Report No. 86091-6, August 3, 1988) . The locations of the ground-water monitoring wells and vapor-- extraction wells relative to site facilities are depicted on the Generalized Site Plan (Plate P-2) . A geologist from Applied GeoSystems visited the site on March 3, 1989, to measure the depth to ground water, inspect water samples for subjective evidence of contamination, and purge and sample the five ground-water monitoring wells. Depths to ground water were measured to the nearest 0.01-font in the monitoring wells with a Solinst water-level indicator prior to purging the wells. After the initial water levels were measured, samples of ground water from the air-water interface were collected for subjective analyses by .towering approximately half the length of a clean Teflon bailer past the interface. The bailer was then retrieved and the water samples examined for floating product, sheen, or other subjective evidence of hydrocarbon contamination. No subjective evidence of hydrocarbon contamination was noted in samples from the wells. Results of these and previous subjective analyses are summarized in Table 1. After the subjective analyses, a minimum of 20 gallons (approximately 3 well volumes) of ground water was removed from each well using a submersible pump. That volume was sufficient to allow the pH, conductivity, and temperature of the water to stabilize, The purge water from the wells was temporarily stored onsite in properly labeled, 55-gallon, 17-E steel drums approves: for that use by the Department of Transportation, pending removal by Beacon to their refinery for treatment. Ground-water samples were collected after the wells were allowed to recover to their static water-levels. The ground-water samples were collected by lowering a clean Teflon bailer past the air-water interface. The bailer was then retrieved and the sample transferred to laboratory--cleaned, 40-milliliter glass vials which contained concentrated hydrochloric acid as a preservative. The vials were completely filled to eliminate headspace. Three method blank samples were also collected, but were not analyzed. A Chain of Custody Record was initiated by the field geologist and accompanied the samples to the analytical laboratory. A copy of that record is attached to this letter report. 2 A e �OOSS�`�'!!lS l�/ /% d n y