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LIGHT, AIR & SPACE CONSTRUCTION <br /> ENVIRONMENTAL SERVICES COMPANY <br /> ' State Contmetor's License Number 445403 <br /> State EPA R.E.A.Number 04072 <br /> Office 408-979-0661 <br /> ' Water samples retained for chemical analysis were placed in laboratory prepared clean, 40 ml <br /> VOA glass acid-preserved bottles and clean amber glass acid-preserved one-liter bottles sample <br /> ' containers. Samples were collected with minimum headspace, and inverted to check for air <br /> bubbles. Upon completion each sample was sealed, labeled, logged onto a chain-of-custody <br /> form and then placed in an ice chest on crushed ice, and refrigerated at 4 degrees Centigrade for <br /> ' transport to the laboratory. <br /> 4.0 Chemical Analysis <br /> Twenty-one soil samples from the exploratory borings and soil stockpile area, and three <br /> ' groundwater samples were analyzed at Torrent Analytical laboratory, Inc., a certified analytical <br /> laboratory. The laboratory composited the soil samples in the laboratory. The soil samples and <br /> groundwater samples were tested for the following; Total Petroleum hydrocarbons as Gasoline <br /> ' (TPHG) and Diesel (TPHD), Benzene (B), Toluene (T), Ethylbenzene (E), Xylene (X), and <br /> Volatile Organic Compounds (VOC), Methyl-tert-butyl-ether (MTBE), and fuel oxygenates tert- <br /> Amyl-Methyl-Ether, Ethyl-tert-Butyl-Ether, Di-Isopropyl Ether and Tert-Butyl Alcohol, and 1,2- <br /> ' Dichlorethane and Ethlyene Dibromide, Ethanol and Methanol using EPA Methods 3510/8015, <br /> 5030, 8020 and 8260. The laboratory analytical reports are attached and the data present in <br /> Tables 2 and 3 below. <br /> 5.0 Brief Conceptual Site Model,Well Search and Subsurface Conditions <br /> The project site is located near Manteca near the northwestern edge of the San Joaquin Valley <br /> and Delta area. Quaternary and Holocene alluvial fan and stream sediments composed of sand, <br /> ' gravel, silt and clay deposited by the San Joaquin River underlie the region. Surficial soils in the <br /> region are mapped by the U. S. Department of Agriculture as Arents soil association composed <br /> of sandy loam and sandy silts with hardpan forming on low alluvial fans, interfan basins and <br /> ' stream terraces. Arents soils are mapped as being weakly cemented and having moderate to <br /> moderately slow permeability. The underlying alluvium at depth may consist of weakly <br /> consolidated and irregularly interbedded sand, silt and clay strata. These subsurface alluvial and <br /> fluvial strata may be of variable lateral and vertical continuity and extent. <br /> Very large groundwater aquifers underlie the Manteca region. These aquifers produce very large <br /> ' quantities of water used for agricultural and municipal drinking sources. The regional <br /> groundwater flow is estimated to flow to the west and northwest in this region. Historic <br /> pumping has locally drawn down the groundwater levels in the area and may affect the local <br /> ' groundwater flww direction. <br /> ' January 5 2009 Page 5 of 12 <br /> MAIN OFFICE • 1707 LITTLE ORCHARD STREET, SUITE A • SAN JOSE•CA•95125 <br /> MAILING ADDRESS•P.O.Box 36303•SAN JOSE•CA•95158-6303 •408/979-0661 •408/979-0621 FAX•I..�Sc,aS 14 A,IL"I M E-MAB. <br /> ' GENERAL AND ENGINEERING CONTRACTOR'HAZARBOUSSUBSTANCE REMOVAL CONTRACTOR'SITE ENVIRONmEN-AAL ASSESSMENTS <br /> WETLAND AND RIPARIAN HABrrAT-ASSE smENT-DESIGN-RESTORATION-CONSTRUC'r1ON-MITIGATION MONITORING <br />