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y .. real I � F Nord£ng Lawson Assoela!®s �- The analyses of water samples from Well MW-1 indicate that concentra- tions of BTX are increasing. The sample obtained November 26, 1986 had nondetectable benzene and toluene and xylene concentrations f of 76 parts per billion ( -, PPb). The sample obtained March 12, 1987, however, had concentra-tions of 85 ppb benzene, 42 ppb toluene, and 240 Ppb xylenes. The concen- trations of BTX at Well MW-5 were ncodetectable on March 12, 1987. In our earlier report we indicated that the high TPN concentration in i" 'the soil at MN-1 could have resulted from site o rati Pe ons that washed leum products into the dry well. Our recent boring and petro- - g chemical test date indicate that the increased concentrations of BTX in the ground water at 3 W-1 can be explained by either of the following; 4 1. Larry amounts of hay well. .Because theldry welleum uis ploy advetheen washed into the ve migrated to the ground water. ' ptroleum products 2. The product that spilled into the tank backfill has continued t � migrate, increasing the concentrations of e gasoline products in the ground water downgrad{ent of the tank backfill. . Because the gasoline products apparently being transported by the ground water, we recommend that interim remedial Treasures should begin with � h9 the groundwater. 7-Eleven has suggested the installation of a well ne ar Or in " , the tank backfill that could be pumped by a vaccum truck. We believe that this alternative would be costly and not very effective in .removing free ,- product A large volume of water would be a generated by pumping, which would have to be treated. Because the dra+gdewr. in. the well woulLj d coeur s poradi- calf, this Pumping would have little impact ol� the migration of the flee AP product. 1 y