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i !15 7-Eleven/Stockton 8 November 1990 The Groundwater Gradient Maps for July, August, and W September 1990 (Figures 4, 5, and 6) , represent the interpreted groundwater-table elevations beneath the site for each of the three months in this reporting period. The regional groundwater- gradient direction remains to the east, as reported in the past. The gradient magnitude has fallen from C.003 foot-per-foot (ft/ft) to 0.0018 ft/ft since the last reporting period. Monitoring well MW-4, which had previously contained separate-phase hydrocarbons (free product) , remained dry during this reporting period. No other free product was observed. Monitoring well MW-4 was last reported as containing separate- phase hydrocarbons (free product) in January 1986. Since that time, the well was reported as having no free product. The well has generally been reported as dry since June of 1989 with the exception of the January 12, 1990, monitoring round. Similarly, during this reporting period, the well was found to be dry. Vapor Extraction Technology has used well MW-4 as an extraction point since August 1990. Results from Vapor Extraction Technology's work are described in their 01 Quarterly Progress �. Reports", the latest is dated October 3, 1990. GROUNDWA2'ER SAMPLING AND ANALYSES Sampling of the operational groundwater-monitoring wells, pumping wells PW-1, PW-2, and PW-3, and nearby domestic wells was performed during this reporting period. Since wells PW-1, PW-2, and PW-3 are not being used as pumping wells, they were sampled as monitoring wells. Samples were collected in accordance with Groundwater Technology SOPS 9, 1o, 11, and 12 (Appendix B) . Groundwater sampling was conducted by first purging water from each well using a clean polyvinyl chloride (PVC) bailer. Each well was purged of a minimum of four well volumes of rwater by GROUNDWATER TECHNOLOGY.INC.