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KEI-P88-1013 .QR5 August 9 , 1993 Page 2 Water samples were collected by KEI from all of the Unocal wells (except MW6) on June 28, 1993 . Prior to sampling, the wells were each purged of between 6 . 5 and 8 gallons of water by the use of a surface pump. During purging operations, the field parameters pH, temperature, and electrical conductivity were recorded and are presented in Table 3 . Once the field parameters were observed to stabilize and a minimum of approximately three casing volumes had been removed from each well, samples were then collected by the use of a clean Teflon bailer. The samples were decanted into clean VOA vials that were then sealed with Teflon-lined screw caps and stored in a cooler, on ice, until delivery to a state-certified labora- tory. On June 28 , 1993 , a joint monitoring and sampling event was also conducted with the nearby Montgomery Ward site (the site of a former service station) . Monitoring data from the Montgomery Ward site are summarized in Table 2 . HYDROLOGY The measured depth to ground water at the former Unocal site on June 28, 1993 , ranged between 56. 66 and 57 . 73 feet below grade. The water levels in all of the wells have shown net decreases ranging from 3 . 16 to 4 . 50 feet since March 25 , 1993 . Based on the water level data gathered during the joint monitoring event conducted on June 28, 1993 , the ground water flow direction over the majority of the site vicinity was to the south, varying from the south-southeast to the south-southwest, as shown on the attached Potentzometric Surface Map, Figure 1. Based on the water level data gathered during the May 27 , 1993 , and April 26, 1993 , monitoring events, the ground water flow direction at the Unocal site appeared to be to the southeast, as shown on the attached Potentiometric Surface Maps, Figures 2 and 3 , respectively. The ground water flow direction at the Unocal site has varied from the southwest to the east-northeast since July of 1992 . The average hydraulic gradient over the ma3ority of the site vicinity on June 28, 1993 , was approximately 0. 008 . ANALYTICAL RESULTS The ground water samples collected from all of the existing Unocal monitoring wells this quarter were analyzed at Sequoia Analytical Laboratory and were accompanied by properly executed Chain of Custody documentation. The samples were analyzed for total petroleum hydrocarbons (TPH) as gasoline by EPA method 5030/modi- fied 8015 , benzene, toluene, ethylbenzene, and xylenes by EPA method 8020 , and for EPA method 8010 constituents.