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14.0 LIGHT, AIR & SPACE CONSTRUCTION ENVIRONMENTAL SERVICES COMPANY State Contractor's License Number 445403 State EPA R.E.A.Number 04072 Office 408-979-0661 Water samples retained for chemical analysis were placed in laboratory prepared clean, 40 ml VOA glass acid-preserved bottles and clean amber glass acid-preserved one-liter bottles sample containers. Samples were collected with minimum headspace, and inverted to check for air bubbles. Upon completion each sample was sealed, labeled, logged onto a chain-of-custody form and then placed in an ice chest on crushed ice, and refrigerated at 4 degrees Centigrade for transport to the laboratory. 4.0 Chemical Analysis Twenty-one soil samples from the exploratory borings and soil stockpile area, and three groundwater samples were analyzed at Torrent Analytical laboratory, Inc., a certified analytical laboratory. The laboratory composited the soil samples in the laboratory. The soil samples and groundwater samples were tested for the following; Total Petroleum hydrocarbons as Gasoline (TPHG) and Diesel (TPHD), Benzene (B), Toluene (T), Ethylbenzene (E), Xylene (X), and Volatile Organic Compounds (VOC), Methyl-tert-butyl-ether (MTBE), and fuel oxygenates tert- Amyl-Methyl-Ether, Ethyl-tert-B utyl-Ether, Di-Isopropyl Ether and Tert-Butyl Alcohol, and 1,2- Dichlorethane and Ethlyene Dibromide, Ethanol and Methanol using EPA Methods 3510/8015, 5030, 8020 and 8260. The laboratory analytical reports are attached and the data present in Tables 2 and 3 below. 5.0 Brief Conceptual Site Model, Well Search and Subsurface Conditions The project site is located near Manteca near the northwestern edge of the San Joaquin Valley and Delta area. Quaternary and Holocene alluvial fan and stream sediments composed of sand, gravel, silt and clay deposited by the San Joaquin River underlie the region. Surficial soils in the region are mapped by the U. S. Department of Agriculture as Arents soil association composed of sandy loam and sandy silts with hardpan forming on low alluvial fans, interfan basins and stream terraces. Arents soils are mapped as being weakly cemented and having moderate to moderately slow permeability. The underlying alluvium at depth may consist of weakly consolidated and irregularly interbedded sand, silt and clay strata. These subsurface alluvial and fluvial strata may be of variable lateral and vertical continuity and extent. Very large groundwater aquifers underlie the Manteca region. These aquifers produce very large quantities of water used for agricultural and municipal drinking sources. The regional groundwater flow is estimated to flow to the west and northwest in this region. Historic pumping has locally drawn down the groundwater levels in the area and may affect the local groundwater flow direction. January 5, 2009 _ Page 5 of 12 MAIN OFFICE • 1707 LITTLE ORCHARD STRP.E-l', Surrc A •SAN JOSE•CA•95125 MAILING ADDRESS•P.O.Box 36303•SAN JOSE•CA•95158-6303•408/979-0661 -4081979.0621 FAX'LAV ONY fit WI..l.r.11q E-MAIL GENERAL AND ENGINEERING CONTRACTOR'HAZARDOUS SUBSTANCE REMOVAL CONTRACTOR'SITE ENVIRONMENTAL ASskssMEN I's WETLAND AND RIPARIAN HABITAT—ASSESSMENT—DESIGN—RESTORATION—CONS"I'RUC't7oN—MITIGATION MONITORING