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November 1990 -C3- M88168D l D I � sleeve and two end caps were cleaned between each use with a nonphosphate detergent solution and rinsed with potable water, and air dried to prevent cross- contamination. Prior to the collection of each sample, the sampling equipment was decontaminated using a nonphosphate detergent wash, followed by a tap water rinse, and two distilled water rinses. The sampling sleeves were decontaminated prior- to initiating the assessment using the same protocol described above. MONITORING WELL CONSTRUCTION i MW-1 was drilled to a depth of 80 feet bgs. The monitoring well was completed as a 4-inch-diameter ground water monitoring well pursuant to the i California Administrative Code, Title 23, Subchapter 16, Article 4, Section 2647. The details of the well construction are shown in Table C-1 - Monitoring Well I Construction Summary. The monitoring well (MW-1) consists of 4-inch-diameter, Schedule 40 PVC pipe set to a depth of 80 feet bgs. The 4-inch-diameter well screen is machine slotted into four columns of 0.020-inch horizontal cuts. The perforated interval extends to the bottom of the well from 40 feet bgs and is overlain by � 40 feet of 4-inch-diameter Schedule 40 blank riser casing. The gravel pack consists of No. 3 Monterey Sand which was poured into the annular space surrounding the perforated interval from the well bottom to a depth of 38 feet bgs. A 5-foot-thick bentonite seal was placed above the gravel pack and the remainder of the annular space consists of a cement/bentonite seal. The wellhead was secured and protected with a traffic-rated utility vault constructed slightly above the existing grade as to provide for positive surface drainage. An as- built diagram of the monitoring well is presented in Appendix A. GROUND WATER SAMPLING A ground water sample was collected from within the hollow stem auger at DH-2 from a depth of 90 feet bgs. The ground water sample was collected in a 3-foot-long, 1.5-inch-diameter disposable bailer. The water sample was I J ' transferred into 40-m1 VOA vials (two per sample) and a 1-liter amber bottle, i .