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e z <br /> Union Ice - 2 - 30 July 1991 <br /> TABLE I and TABLE III 1:8X11 , 119S" <br /> TABLE II "MW-8" and "Monitoring Well 8", <br /> "EX-1" and "Extraction Well 1" <br /> Boring logs "EX-1" , 11MW811 <br /> The nomenclature is confusing. The consultant must settle on one name for the <br /> extraction well and one name for the monitoring well . I prefer that the names <br /> match the boring logs; Extraction Well 1 or EX-1 and Monitoring Well 8 or <br /> MW-8- <br /> The site status is more difficult to summarize than the missing reports and <br /> well nomenclature problem. I have the following problems with the <br /> investigation: <br /> 1. Wells MW-4S and MW-4D may be constructed improperly and it may not be <br /> possible to collect representative samples from them. The log for well <br /> MW-4S indicated that concrete from adjacent well MW-4D (ten feet away) <br /> is migrating into the boring for MW-4S. Concrete was observed on auger <br /> flights. I found no further explanation of this phenomenon in the file. <br /> What caused this? Was MW-4D pressure-grouted? Did the sand layer have <br /> anything to do with the movement of the concrete? Was an inordinate <br /> amount of concrete used during the construction of MW-4D? Was MW-4D <br /> properly grouted if concrete was found ten feet away? Did the concrete <br /> interfere with the proper construction of MW-4S? Was MW-4S developed <br /> properly? Were measurements of pH, EC, and temperature used to <br /> determine when ground water had stabilized in MW-4S? (A high pH might <br /> indicate the presence of fresh concrete. ) <br /> 2. Plates 4 and 7 in the 28 May 1991 Report show a water supply line that <br /> appears to run parallel and very close to MW-4S and MW-4D but it is not <br /> clear if the line ends before reaching the two wells. If the water line <br /> does pass near the wells, is it possible that the concrete in MW-45 was <br /> from the water line? <br /> 3. With soil saturated with gasoline at about 16 feet and ground water <br /> occurring at the same depth, why does MW-4S not show ground water <br /> contamination? <br /> 4. Why has MW-4D had contamination several times? If it was constructed <br /> properly, it should not be acting as a conduit for contamination from <br /> the upper aquifer to the lower aquifer. Are we, therefore, to assume <br /> that contamination in sand at 16 feet has migrated through a clay layer <br /> to the lower aquifer in a sand layer encountered at 50 feet? <br /> 5. Plate 7 of the 28 May 1991 report shows a diagram of the excavoakfton, <br /> indicating the locations and depths of soil samples. The plate <br /> indicates that the northern extension of the excavation was excavated to <br />