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20 August 2018 AdvancedGeo <br />AGE Project No. 13-2557 Environmental <br />Page 3 of 6 g <br />2.3. SOIL SAMPLE COLLECTION AND ANALYSIS <br />Soil samples will be collected at five-foot intervals beginning at 5 feet bsg in the pilot <br />borings to characterize lithology and define the extent of petroleum hydrocarbon impact. <br />Selected soil samples will be analyzed by a California Environmental Laboratory <br />Accreditation Program (ELAP)-certified laboratory for the following constituents: <br />Total petroleum hydrocarbons as gasoline (TPH-g) in accordance with EPA <br />Method 8015M. <br />Benzene, toluene, ethylbenzene and total xylenes (BTEX) and fuel additives <br />methyl tertiary-butyl ether (MTBE), tertiary-butyl alcohol (TBA), di-isopropyl ether <br />(DIPE), ethyl tertiary-butyl ether (ETBE), tertiary-amyl methyl ether (TAME), 1,2- <br />dibromoethane (EDB), and 1,2-dichloroethane (1,2-DCA) in accordance with EPA <br />Method 8260B. <br />Laboratory reports of soil analysis, testing methods, laboratory quality assurance/quality <br />control (QA/QC) reports, and sample chain of custody documentation will be presented <br />in a report of findings. <br />2.4. MONITORING WELL INSTALLATION, DEVELOPMENT, AND SURVEY <br />All proposed soil borings will be single-completed; six borings will be completed as <br />shallow-screened groundwater monitoring wells and one boring will be completed as a <br />deep-screened groundwater monitoring well. The proposed shallow monitoring wells will <br />be screened between depths of approximately 5 feet and 20 feet bsg; the proposed deep <br />well will be screened between depths of approximately 35 feet and 40 feet bsg. Screened <br />interval depths may vary or be reduced overall according to hydrogeologic conditions <br />encountered while drilling. Following installation, each well will be developed to maximize <br />water flow and minimize the amount of fine-grained sediment drawn into the well during <br />pumping or bailing. The top of each newly installed well casing (well head) will be <br />surveyed to determine its elevation relative to North American Vertical Datum 88. <br />Diagrams of the proposed monitoring well designs are presented in Figures 7 and 8. <br />2.5. GROUNDWATER SAMPLING AND ANALYSIS <br />Following the installation of the new monitoring wells, groundwater monitoring and <br />sampling activities will be conducted at the wells on a quarterly basis for a minimum of <br />one year (four sampling events); monitoring activities will include recording depth to <br />groundwater measurements and collection of groundwater samples for laboratory <br />analysis by an ELAP-certified laboratory for the analytes listed in Section 2.3.