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Manteca-Quarterty Groundwater Monrtona Pae 2 to a California certified laboratory for analysis The analytical soil parameters include total petroleum hydrocarbons (TPH) as gasoline (Modified EPA Method 8015), benzene, toluene, ethylbenzene, and xylene (BTEX) (EPA Method 8020), and total lead (EPA Method 7421) The analytical soil samples were placed in a cooler containing additional frozen blue ice packets, and shipped following chain-of-custody procedures to North Creek Analytical (CLAP # 1267) for analysis The three groundwater monitoring wells were installed approximately ten feet into the groundwater aquifer The well locations, designated at SRK-MW1 through SRK-MW3, are provided on Figure 1 Moist soil conditions were encountered at a depth of 25 feet BGS, while saturated conditions were observed in soil samples collected at 30 feet BGS The screened Minterval consists of 4-inch diameter Schedule 40 PVC casing(0 02 slot) that extends from the end of hole to five feet above the groundwater surface Blank 4-inch diameter Schedule 40 PVC casing extends from the screened interval to the ground surface The sand pack (#2 grade) extends from the bottom of the boring to five feet above the screened interval A pelletized bentonite seal (2 feet thick) lies directly above the sand pack The remainder of the annular space is filled with grout A locking end cap was placed in the top of each casing The wells are protected at the ground surface with flush mounted steel Christy boxes set in concrete On November 24, 1991, five casing volumes of water were purged from each of the monitoring wells (SRK-MW-1 through SRK-MW3) using a 4-inch submersible pump and braided PVC tubing The casing volumes were based on actual static water level measurements made on the day of sampling The submersible pump and braided PVC tubing were cleaned before purging each well by placing the pump in a 55-gallon drum containing non-phosphate soap, and pumping the soapy solution through the tubing After the residue had been flushed from the tubing, the pump and tubing were then flushed with deionized water Approximately 55 gallons were purged from each well and stored on-site in DOT approved closed-top drums No petroleum odors or iridescent sheen were observed in any of the water purged from the monitoring wells The three existing monitoring wells installed by BEI in 1989 were not purged or sampled r 2.0 SCOPE OF SERVICES The scope of work for the Quarterly Groundwater Monitoring includes • Property survey to accurately locate the position and elevation of monitor wells • Purging and sampling the wells according to PHS/EHD guidelines, • Shipping the groundwater samples under correct chain-of-custody procedures to a California licensed Laboratory for analyses • And determining the localized groundwater gradient by measuring the static water level relative to the top of casing 32544 2»0.crtya 22 Steffen Robertson and Kosten