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A S S O C I A T E S I N C excavation. The estimated groundwater flow direction is to the southeast. Proposed boring locations are shown on Figure 2. Groundwater Monitoring Wells Construction Details The three soil borings will be completed as groundwater monitoring wells. The monitoring wells will be constructed of 2-inch inside diameter schedule 40 PVC well screen and casing. A 0.020- inch well screen slot and #2112 mesh sand pack will be used. Neat cement will be used to seal the wells in accordance with California Well Standards (December 1981). To protect the integrity of the wells, locking, water-tight well plugs will be installed on each well and a water-tight wellhead labeled "monitoring well" will be concreted over each well. Proposed well construction details are shown on Figure 3. The top of casing of the new wellheads will be surveyed to assess groundwater gradient and flow direction. All drill cuttings will be stored on site in 55-gallon drums pending laboratory results. Sample Analysis Selected soil samples will be immediately placed on ice and delivered under chain-of-custody documentation to a State-certified laboratory for analysis. Samples will be analyzed for total petroleum hydrocarbons as gasoline (TPHg, EPA Method 8015), total petroleum hydrocarbons as diesel (TPHd, EPA Method 8015), benzene, toluene, ethylbenzene, and xylenes (BTEX, EPA Method 8020), oxygenate fuel additives (EPA Method 8260), and total lead (1LUFT Method). Orr Well Development and Groundwater Sampling Measurement of depth to water in all wells will be completed to evaluate the direction and magnitude of the groundwater gradient beneath the site. The new wells will be developed using surge and bail techniques until the produced water is relatively sediment free. Prior to the collection of groundwater samples, a minimum of three well volumes (casing and sand pack) will be purged. Temperature, pH, water elevation, and electric conductivity will be measured and allowed to stabilize. Water samples will be collected using disposable bailers, one dedicated to each well. Groundwater samples collected from all monitoring wells will be submitted using chain-of- custody record to a State-certified laboratory. Groundwater samples, three total, will be analyzed for TPHg, TPHd, BTEX, oxygenate fuel additives, and total lead. Purge water will be stored in 55-gallon drums approved for hazardous liquid storage pending laboratory analysis. Report Preparation Upon completion of the well installation and development activities, a summary report will be prepared for submittal to PHS/EHD. The report will include a description of all field activities, laboratory analytical results, and well/boring logs. w:1625001reportslwkpweLdoc 3