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WELLS FARGO BANK PROPERTY 49 SOUTH WILSON WAY STOCKTON, CALIFORNIA DECEMBER 28, 1.998 Page 2 February 1996, Phase II. Subsurface Investigation A Phase II Subsurface Investigation was performed by Building Analytics in February 1996, to investigate the potential effects of an environmental impact by the former on-site gasoline service station. The following is a summary of the findings from the investigation: • Soil samples were collected from five Geoprobe borings at depths of up to 25 feet below ground surface (bgs). �1. • The soil samples revealed non-detectable concentrations for total petroleum hydrocarbons as gasoline and diesel (TPH-g and TPH-d) and benzene, toluene, ethylbenzene and xylenes (BTEX). E•• • Total recoverable petroleum hydrocarbons (TRPHs) were found at concentrations ranging from 10 parts per nullion (ppm) to 31 ppm, which is well below the Maximum Contaminant Level (MCL) of 100 ppm as set forth by the Regional Water Quality Control Board (RWQCB). ! Based on the above-mentioned analytical results, it was concluded that the on-site soil contamination, although below regulatory action levels, was likely caused by the spilling of waste oil and motor oil at the former on-site gasoline service station. There was no indication of diesel or gasoline contamination. Groundwater was expected at a depth of approximately 60 feet bgs, and was not sampled during this Subsurface Investigation. February 1997, Follow-Up Phase II Subsurface Investigation Building Analytics completed a Follow-up Phase II Subsurface Investigation in February 1997, which included the installation and sampling of three groundwater monitoring wells. } The following is a summary of the findings from the investigation: I 1 • The groundwater flow direction in February 1997 was measured to be to the northeast, with a hydraulic gradient of 0.0025; • TPH-g at levels up to 1,300 ppm, and benzene at levels up to 0.39 ppm, were reported in the soil samples collected from Boring B2, at depths between 35 and 55 feet bgs; • TPH-g and BTEX were not reported in groundwater samples collected from MW- 1 or MW-3; • Benzene was not reported in the groundwater b sbamd from MW-2; • TPH-a (1.6 ppm), eth lbenzene (120 ppm) and, x lens (37 ppm) were re orted in the groundwater sample collected from MW. 2; and j • Methyl-tert-butyl ether (MTBE) was not reported in any of the soil or groundwater samples collected. 4y T Based on the above-mentioned analytical results, it was concluded that soil and f groundwater beneath the site had been impacted by TPH-g and BTEX in the area of groundwater monitoring well MW-2. 1