ARCHIVED REPORTS XR0001736 - Laserfiche WebLink

Home Browse Search

• Quarterly Ground-Water Monitoring March 8, 2989 Beacon station No. 1-502, Lodi, California AGS 86091-6 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, dated August 3, 1988) . The locations of the ground-water monitoring wells and vapor-extraction wells relative to site facilities are depicted on the Ge.ieralized Site Plan (Plate P--2) . A geologist from our office was present at the site on December 6, 1988, 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-foot 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-fluid interface were collected for subjective analyses by lowering 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 was noted in samples from the wells. Results of these and previous subjective analyses are summarized in Table 1. After the subjective analyses, ground-water samples for laboratory analyses were taken from each of the ground-water monitoring wells. A minimum of 46 gallons (approximately 3 well volumes) of ground water was removed from each well using a submersible pump. That volume was sufficient to allow the physical parameters of the water (pH, conductivity and temperature) to stabilize. The purge water from the wells was temporarily stored onsite in properly labeled, 55-gallon Department of Transportation 17-E steel drums, pending removal by Beacon to their refinery for subsequent treatment. Ground-water: samples were taken 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 in which concentrated hydrochloric acid was added as a preservative. The vials were c-ompletely filled, thereby eliminating 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. The ground-grater samples were sent to Applied GeoSystems' analytical laboratory in Fremont, California (California 2 Aoe�1,61e1' 011SPI MMI - - __J -