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Environmental Assessment Report 2 • San Joaquin Catholic Cemetery,Cemetery!_ane and Harding Way,Stockton,CA June 29, 1995 split-spoon sampler, lined with three 2-inch-diameter by 6-inch-long brass sample tubes The sampler was driven 18 inches ahead of the augers at each sample point Soil samples were field screened for hydrocarbon vapors using a photo-ionization detector(PID) Soil was logged using the Unified Soil Classification System by a Groundwater Technology field geologist working under the supervision of a California registered geologist(Appendix B) One sample tube from each 5-foot interval was sealed, labeled and placed on ice in an insulated container for transport under chain-of-custody manifest to Sequoia Analytical (Sequoia), a California state-certified analytical lab in Sacramento Based on PID readings and depth to first groundwater observed in each of the deeper borings, 10 soil samples were selected for laboratory analysis (Table 1) Samples were analyzed for benzene, toluene, ethylbenzene and total xylenes (BTEX), and total petroleum hydrocarbons-as-gasoline (TPH-G), using U S Environmental Protecbon Agency(EPA) methods 5030!8020/modified 8015 24 Soil Vapor Extraction Well Installation On April 18, 19 and 20, 1995 A nested extraction well was installed in each of bonngs VW-1 and VW-2, and a single extraction well in each of borings VW-3 and VW-4 Two extraction wells were constructed of 2-inch-diameter schedule 40 PVC blank casing and 0 020-inch slot well screen with flush threads The nested wells consist of a shallow extraction well screened from 8 to 28 feet BGS, and a deep extraction well screened from 35 to 70 feet BGS A#3-sand filter pack was installed in the annulus from the bottom of each borehole to 2 feet above the top of screen of the deeper well, and overlain by a deep well seal consisting of a 4 5-feet thick layer of bentonite The shallow well was installed on top of the deep well seal, and a#3-sand filter pack was installed in the annulus of the shallow well from the top of the deep well seal to 2 feet above the top of screen of the shallow well A 2-feet thick layer of bentonite was deposited over this shallow filter pack, followed by neat cement (grout)to ground surface Each single extraction well consists of a shallow well screened from approximately 10 to 30 feet BGS A#3-sand filter pack was installed in the annulus from the bottom of each borehole to 2 feet above the top of the well screen, followed by a well seal consisting of a 2-feet thick bentonite layer overlain by neat cement(grout)to ground surface Each well was secured by a locking expandable well cap and fitted with a traffic-rated well box set in concrete Details of well construction are presented in the drilling logs (Appendix B) Figures 2 and 3 show the location of the vapor extraction wells on site • S.ICCEAR rptlMac 171 'ETIV GROUNDWATER ��❑ TECHNOIAGY I