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01 March 1999 AGE-NC Project No. 95-0103 Page 3 of 8 Two soil gas/vapor samples were collected on 30 December 1998. The soil gas/vapor samples were collected in Tedlar bags from the influent stream. The samples were collected with a vacuum pump. The samples were labeled,placed in a cool ice chest and transported under chain-of-custody to MAI. The samples were analyzed for: • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA method 8015 Modified and • Volatile aromatic compounds (benzene,toluene, ethyl-benzene and total xylenes: BTEX) in accordance with EPA method 8020. Based on the low concentrations of BTEX extracted over the previous quarters,the catalytic oxidizer remained off-line from the extraction system. The change in the design has been implemented to reduce the overall cost of the extraction operation and maintain costs for extraction on the site. The soil-vapor concentrations have been measured with an OVM and analyzed to confirm the reduced concentrations of vapor emissions. 3.0. FINDINGS Field measurements and laboratory reports are presented below and in Tables 1 through 5. Copies of the field measurements and laboratory reports are included in Appendices A, B and C. 3.1. RELATIVE GROUNDWATER ELEVATION .. Ground water elevation increased approximately 0.02 feet between September and December 1998. The upper surface of the saturated zone on the site appears has a depression on the northern portion of the property (Figure 3) near wells MW-1 and MW-3; a ground water high was noted in the vicinity of monitoring well MW-4. Ground water flow on the site is toward MW-1, and may shift toward the east from MW-1. 3.2. ANALYTICAL RESULTS OF GROUND WATER SAMPLES 3.2.1. Chemical Analysis TPH-g was detected in samples from wells MW-1, MW-3, MW-4 and vapor well VE-6 at concentrations of 1,300 micrograms per liter (µgll), 7,500 ug1l, 4,800 µgll and 3,200 µg/l, �. respectively. Advanced GeoEnvironmcntat,Inc.