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Di Salvo-Lathrop M W I Report June 28, 1995 Paee-4- The soil samples were delivered under chain-of-custody procedures to GeoAnalytical Laboratories, Inc., in Modesto, California, within 24 hours of sample collection. The results of soil sample analyses are discussed in Section 7.1. 3.2 Monitor Well Construction The monitor well was constructed with 2-inch I.D., Schedule 40, flush-threaded, 0.020 machine-slotted PVC screen extending from a depth of approximately 18.5 feet to 10.5 feet bgs. A flush PVC bottom cap was placed at the bottom of the well screen. Blank PVC casing was installed above the well screen up to-the ground surface. The well casing was delivered to the site in the manufacturer's original packaging, removed from the packaging and immediately installed in the monitor well. No glue or solvents were used in construction of the well. A sand pack of 2/12 Lonestar sand was placed in the annular space from the total depth to approximately 10 feet bgs. Bentonite pellets were placed from approximately 10 feet to 7.5 feet bgs to insure that a protective sea] was present at least one foot below the fill material. The bentonite was hydrated using potable water and allowed to set for approximately 30 minutes. A surface seal of neat cement containing five percent bentonite by weight was poured into the annular space from the top of the bentonite seal to the ground surface. A water-tight traffic box was installed at the -mound surface. The well was secured with a locking, water-tight cap and a keyed padlock. The well construction diagram is included with the geologic log. The L log for MW 1 is in Appendix B. 3.3 Field Observations Fill material was encountered from the ground surface to a depth of approximately 9 feet bgs during the installation of MW 1. Native soil was present below a depth of 9 feet. The native soil consisted of silty sand from 9 to 10.5 feet, fine to coarse sand from 10,5 to 16 feet and silt from 16 feet to 18.5 feet. Field observations and screening with the OVA indicated no evidence of petroleum hydrocarbons in the soil samples collected at 1 I feet and 13 feet bgs. No other samples were available for OVA measurements. 4.4 MONITOR WELL DEVELOPMENT On June 5, 1995, Condor personnel were on site to develop MWI. The well was developed by surge and pump methods until the discharge water was free of sediment, clear to the unaided eye and the electrical conductivity, pH, and temperature of the water stabilized. Approximately 20-gallons of water were purged from MWL All well-development equipment was cleaned prior to use as described in Section 3.1. The purge +r. `� CONDOR