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• • �CAMBRIA trace gas analyzer in soil samples collected from 10 feet below grade (fbg) from three of the four soil borings The source of the hydrocarbons was not identified During November 1985 all three USTs were removed and replaced with three 10,000 gallon double-walled fiberglass tanks in the same location Canome Engineers, Inc collected soil samples from beneath the USTs and water samples from the bottom of the excavation Laboratory analysis of these samples indicated total petroleum hydrocarbons (TPH) were present in soil at concentrations up to 40 parts per million (ppm) and in groundwater at concentrations up to 0 7 ppm The source of these hydrocarbons was not identified During August and September 1990 Delta Environmental Consultants, Inc (Delta) drilled and sampled 12 soil borings and converted three of the borings to monitoring wells (MW-1, MW- 2, and MW-3) TPH was detected in soil samples from three of the 12 borings at concentrations as high as 140 ppm and benzene was detected in only one boring at a concentration of 001 ppm TPH and benzene were not detected in groundwater samples collected from the three monitoring wells These findings are documented in Delta's November 22, 1989 Pretank Closure Assessment Report During May 1990, three 10,000 gallon USTs were removed from the site DeltaP erformed soil sampling activities associated with the UST removal Delta directed overexcavation activities in the vicinity of the eastern fuel dispensers removing soil containing greater than 10 ppm TPH or BTEX (benzene, toluene, ethylbenzene, and xylenes) These activities are documented in Delta's November 28, 1990 Preliminary Report and Tank Closure Report During July 1990 wells MW-1, MW-2, and MW-3 were damaged during site remodeling activities and were subsequently properly destroyed These wells were replaced in August 1990 by wells MW-]A, MW-2A, and MW-3A These three wells have been sampled on a quarterly bans since they were installed Depth to groundwater at this site has ranged from approximately 7 5 to 1 1 fbg The predominant groundwater flow direction is to the northeast Cambria issued a Sensitive Receptor Survey in November 1999 for the subject site Well records obtained from the California Department of Water Resources identified ten water wells within 2,000 feet of the site The closest water supply well was at the Chevron station, adjacent to the subject site The existence of this well is questionable since we were unable to • locate it during a field visit Additionally, the Chevron site appears to be served by the city water supply since there is a water meter located in the sidewalk adjacent to the site 0813 2