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------------- <br /> .,r. 06 February 2001 <br /> AGE-NC Project No. 95-0118 <br /> Page 3 of 7 <br /> The dissolved hydrocarbon concentrations have decreased to below analytical detection <br /> limits. This decrease is attributed to the vapor extraction and air sparging activities at the site. <br /> Three consecutive sampling events have demonstrate no residual dissolved contamination <br /> in ground water samples collected at the site. <br /> 2.0. PROCEDURES <br /> Monitoring and sampling were performed in accordance with guidelines.established by the Central <br /> 1 Valley Regional Water Quality Control Board(CVRWQCB) and by the San Joaquin County Public <br /> Health Services - Environmental Health Division (PHS-EHD) for subsurface investigation of <br /> underground storage tank sites and in accordance with the procedures included in the PHS-EHD- <br /> <i <br /> approved Remedial Action Work Plan Addendum for corrective action prepared by AGE, dated 14 <br /> January 1998. <br /> 2.1. MONITORING OF SVE AND COLLECTION OF SOIL VAPOR SAMPLES <br /> For the past three months (November 2000 through January 200 1) a vacuum blower capable of <br /> extracting approximately 20 cfm operated continually at the site. The system has been monitored <br /> I monthly to measure flow rate of extracted soil vapor using a Dwyer differential pressure flow meter <br /> .J and to measure organic vapor concentrations in the extracted vapor stream entering the blower <br /> (influent stream), using an organic vapor meter equipped with a photo-ionization detector (PID: <br /> 1 Thermo Environmental 580A, 10.0eV, calibrated to isobutylene). <br /> Vapor samples were collected on 27 November and 21 December 2000 and on 23 January 2001 from <br /> the influent streams using a Tedlar bag. The'sample was labeled, placed in an ice chest and <br /> J1 transported under chain-of-custody to McCampbell Analytical Inc. 'of Pacheco (MAI). The samples <br /> were analyzed for: <br /> J • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> i <br /> Method 8015 Modified; <br /> =i <br /> • Volatile aromatic compounds-benzene,toluene,ethylbenzene and total xylenes(BTEX)and <br /> methyl-tertiary butyl ether(MTBE) in accordance with EPA Method 8020 and <br /> • Oxygenated fuel additives - di-isopropyl ether (D1PE), ethyl tertiary butyl ether (ETBE), <br /> MTBE, tertiary butyl alcohol (TBA) and tertiary amyl methyl.ether (TAME), methanol, <br /> ethanol, ethyl-dibromide(EDB) and 1,2-dichloroethane(1,2-DCA)in accordance with EPA <br /> Method 8260 Modified. <br /> _;� Advanced GeoEnvironmental,Inc. <br />