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mon—mv MEMO Harding Lawson Aswwistes r. borings to avoid cross-contamination. At the completion of drilling, the bor- ings were sealed to..the ground surface with a cement/bentonite grout. Qualitative ground-water saiTples ("grab samples") were collected from Borings 2 through 4; 6, and 7. The borings were extended approximately two feet below the water table, allowed to come to equilibrium overnight, and then were checked for free product. Subsequently, water samples were collected. Upon completion of the borings for Monitoring Wells MW-6, MW-7, and MW-8, we commenced well construction ope;-ations. We installed 2-inch-diameter Schedule 40 PVC well casing at MW-6 and 4-inch-diameter casing at MW-7 and i ! MW-8. The tops of the wells were completed slightly below the ground surface '- and secured with locking metal well.covers. Each well was equipped with a 9 water-tight cap to minimize intrusion of surface water. All wells were installed in accordance with the construction standards outlined in our letter, "Application for Well Permits," dated December 15, 1987, which was V submitted to the SJLHI (Appendix A). These,standards comply with those set by . the California Regional Water: Quality Control Board (RWQCB). Plates 9 through 11 illustrate construction details for the three rr:ew wells. HLA developed MW-6 through MW-8 on.January 5, 1988. The wells were bailed until the water became clear. The bailed water was monitored for phi, conduc- tivity, and temperature. When these parameters stabilized, the wells were sampled with a stainless steel bailer, and-the water was decanted into vola-. -- - the organic analysis (VOA) vials. Water discharged from the wells during , development and puxging was collected and stored in 55-gallon drums for proper rGO-1 ►�: `disposal. Ground-water samples were stored'in a cooled ice chest. Both sail 6