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a <br /> The chemical MtBE was not tested for this quarter. It was tested <br /> for four quarters and no MtBE was found. <br /> iThe ferrous iron, nitrate and sulfate levels were not tested <br /> for this quarter. The anaerobic activity has been documented as <br /> taking place in the past and no further testing for it is <br /> planned. <br /> We tested for dissolved oxygen concentrations which indicates <br />' aerobic activity and how well the ORC compound is working. The <br /> oxygen readings in all of the wells where the ORC was placed have <br /> increased. They have also increased in wells 5 and a which do <br />' not have ORC. This indicates that the oxygen is being released <br /> and has spread beyond the ORC treated wells. Very high readings <br /> were found in wells BM-7 and 9 , however, the mass of contaminant <br /> has also increased over the last quarter. We believe that with <br />' time aerobic activity will remove some of the contaminant. <br /> Aerobic microorganisms take time to develop and the rise in <br /> contaminant could indicate that their population has not reached <br />' a level high enough to cause a noticeable effect on the <br /> contaminant. <br />' VAPOR EXTRACTION <br /> On June 18 , 1997 , we attempted to start the Vapor Extraction <br /> System (VES) . However, the laboratory results from the sample <br /> were too high. We then retuned the system and tested it again on <br /> July 14 , 1997 . This time the results from the output of the <br /> system were under limits required by the Air Pollution Control <br /> District's upper levels. We started the VES on July 16 , 1997 and <br /> it has been operating ever since. Table 5 lists readings taken <br /> from the VES operation. <br /> We have established the radius of influence of the VES vacuum <br /> system. This was done by measuring the vacuum at each well <br /> while the other wells were in operation. The vacuum applied to <br />' the wells was 4 inches of mercury. The readings at two of the <br /> wells VW-1 and VW-5 were 0 .9 and 0. 8 respectively. The nearest <br /> well to these wells was 26 and 28 feet respectively. By plotting <br />' this on regular graph paper we found the radius of influence to <br /> be approximately 45 feet. These radii are plotted in Figure 3 . <br /> Figure 3 also shows that there is no influence on VW-6 from the <br />' other wells. This is true since we did not record any vacuum in <br /> this well . We have also prepared two cross sections of the <br /> geology at the site. The wells are cased with slotted casing <br />' from about 10 feet below the surface (bgs) to 45 feet bgs. Wells <br /> VW-1 , 3 , 4 and 5 have a sand layer in all the wells at about 25 <br /> feet bgs. We believe this sand layer is controlling the vacuum <br /> in these wells. Well VW-6 does not have the sand layer and this <br /> is one of the reasons this well is not influenced by the other <br /> wells. As time goes by the sand and perhaps the silt layers will <br /> dry out and become more porous. If this occurs then the radius <br /> Page 2 <br />