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R603 UPDATE-13 2/15/93 BTEX The next quarterly sampling will occur in March, 1993 . 3 .0 RESULTS 3 . 1 PRODUCT AND RECOVERY During the initial site assessment and subsequent site visits, floating product was observed in monitor wells MW-1, MW-3 and MW10 Product thickness in MW-1 has ranged from 0 . 01' to 1 26' and from 0 . 17' to 1 66' in MW-3 Only a product sheen has been observed in MW10 during the March, June and September, 1991 and the March 10, 1992 sampling. Since November 11, 1992 no product sheen has been observed in any of the wells at this site The removal of the floating product can be attributed to the active vapor extraction at this site 3 .2 GROUND WATER SAMPLE RESULTS With the exception of MW10, ground water samples were obtained from all of the monitoring wells on December 9 , 1992 , MW10 did not recharge enough volume for a sample The latest sample results shows the continual decline in contaminant levels associated with the ground water at this site Of the wells that have some degree of ground water contamination (MW1, MW2, MW3 , MW8 and MW12) MW1, MW2 and MW3 showed reductions . MW8 continues to show fluctuations and increased from the September, 1992 sampling. These fluctuations seem to be associated with ground water elevation, as is shown on Table 1, gasoline range hydrocarbons in concentrations of 5 ppm or greater are associated with depth to ground water measurements between 53 . 5 feet to 55 22 feet, samples obtained outside these depths are 3 ppm or less The increase in contaminant concentrations found at MW12 is thought to be associated with similar conditions as found at MW8 Whereas, contaminant levels are associated with the ground water elevation and associated soils that have capillary contamination upgradient of MW12 , see Table 1 and Figures 5A, 5B and 6 . 3 . 3 VAPOR RECOVERY VAPOR RECOVERY SYSTEM AND MONITORING rr_ .7 4[-"e St-.-tus Report n5, me -Nnwells MWl MW2 AS s�aLCU Iii v�uca�.c .��-a�-u MW3 , MW10 and the excavation 6 inch (EX-4) have been individually manifolded to a vapor extraction system with individual valved orifices for flow control sampling and vacuum and flow measurements from the individual wells MW2 and MW3 are manifolded together with 2 inch tubing teed at the wells, but can be individually tested by placing a packer below the extraction tee of the well to seal that well from the vacuum system The individual wells are fitted with a PVC tee head with an air tight cap for well access The tee lateral (2 inch) is fitted with a PAGE 4