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samples 2, 3, and 5 Analytical results of soil samples 1 and 4 detected up to 3 500 milligrams per kilogram (mg/kg) total petioleuni hydrocarbons (TPH) as diesel fuel (TPH-d) and 5,100 mg/kg TPH as jet fuel (TPH-I) An Unauthorized Release Form (No 90-U 11) was completed and submitted to the San Joaquin County Public Health Services, Enviromnental Health Department (PHS-EHD) on January 31, 1990 Following the UST removal, several investigations were conducted to assess the limits of the petroleum-impacted soil The results of the investigations characterized the majority of the contanination was limited to the soils adjacent to the former excavation Three groundwater monitoring wells were installed (as shown on Figure 3) at the AASF in 1993 to assess the condition of aroundwatei beneath the former USTs, and have been monitored six tunes to date 4 TPH was last detected in the wells in 1996 Detections of the aromatic hydrocarbons benzene, toluene, ethylbenzene and total xylene isomers (BTEX), and the fuel oxygenate methyl tertiary butyl ether (MTBE) have been infrequent, with maxiimurm concentrations of benzene (0 014 milligrams per liter [mg/L]) and MTBE (0 00149 mg/L) detected in 1996 During the last monitoring event in March 2000 benzene and total xylene concentrations of 0 0011 mg/L and 0 0017 mg/L, respectively, were detected in well MAV-1, MTBE and petioleurn hydrocarbons were not detected The analytical results for this and historical sampling events aie presented in Table 1 Six monitoring events over a period of seven years suggest that groundwater has not been actionably impacted by the release of jet fuel from the fonrier USTs and that detections of trace concentiations of the constituents of concern are ephemeral In April 2002, a minae fuel spill comprising approximately five gallons of jet fuel occurred near the northern edge of the conciete pad o-%,eilying the former UST location The CANG excavated and removed a small quantity of soil (less than one cubic yard) in the inunediate area of the spill 1.12 CSMS In March 2000, 1 630 mg/kg of TPH as hydiaulic oil was detected in soil at a depth of ten feet bgs in the pressure/steam wash bay of the CSMS shop area In addition., unknown objects potentially causing uplift of pavement in the vehicle storage area east of the CSMS building (see Figure 4) have been detected by geophysical, remote sensing inethods The locations of the objects are apparently directly below the area of greatest pavement uplift at each of the two areas The objects, or features, are non-metallic To assess the impact of surface runoff to an unlined ditch draining vehicle and equipment storage areas located in the northeastern portion of the CSMS area, east of the CSMS and Armory buildings ten shallow borings and surface sample locations, B-15b & c, and B-16a,b,c through B-18a.b,c, were used to collect soil and soil vapor samples The locations of the ditch and areas of runoff are presented in Figure 4 Composited surface samples contained motor oil-weight petroleum hydrocarbon concentrations ranging from 76 mg/kg to 475 mg/kg, and concentrations of zinc rangmg from. 218 mg/kg to 912 mg/kg One coimposited sample contained a lead concentration of 175 mg/kg 104700 4766 2WOSSEPT2004