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Antonia Vorster -7- 25 August 1989 <br /> C. The analytical database (as well as the water level , stratigraphic, <br /> and aquifer parameters databases) must be continually updated with new, <br /> qualified data as it is collected. Since the Agencies compiled, <br /> correlated, and reviewed all of the analytical data for their January <br /> 1989 plume estimates, Sharpe has collected three more complete sets of <br /> monitoring well data. There is no evidence that Hunter/ESE has reviewed <br /> and incorporated this data into the data base. For that matter, there <br /> is no evidence that Hunter/ESE has yet compiled and qualified the <br /> already existing data as the Agencies did (they have not requested our <br /> compilation). This same comment applies to water level data, which is <br /> being collected by Sharpe on almost a daily basis, and all other data <br /> collected at the Depot. <br /> 4. Capture zone analysis maps for the South Balloon extraction system, dated <br /> 31 May 1989, were submitted per requests. The maps cover the months of July <br /> through December 1988. No maps covering months in 1989 have been submitted. <br /> I generally agree with EPA's comments (21 August 1989) regarding the need <br /> for extraction well locations, pumping rates, water level plots, and <br /> concentration data. I disagree with EPA' s assessment that "the extraction <br /> system appears to have been effective between July and December 1988, in <br /> controlling plume migration" . The plume geometry indicated on the maps does <br /> not correspond to those prepared by either the Agencies or Hunter/ESE's <br /> latest versions. Thus it is difficult to show plume control effectiveness <br /> on maps that do not show the actual plume or plumes. <br /> More importantly, even if the plume geometries and water level contours on <br /> the submitted maps are accepted on face value, they do not show plume <br /> control . The maps do show control of most of the A-zone contamination with <br /> the exception of the northwest leading edge and indicate complete control <br /> of the B-zone for five months, but no control in December. The C-zone maps <br /> indicate control in only one month, October, with no control in the other <br /> five months. In fact, except for December, the maps indicate that C-zone <br /> contamination is probably being accelerated through the area. That <br /> Hunter/ESE contends that "the treatment system not only captures the 100-ug/l <br /> plume, but apparently has captured the entire plume in the South Balloon <br /> Area" (from August 1988 RI report) again makes me question the project <br /> personnel 's interpretation abilities. <br /> 5. The following secondary comments concern specific proposed procedures in <br /> the draft Work Plan (Sample Plan): <br /> a. After completion of the next drilling program, all monitoring wells <br /> important to plume definition need to be sampled. Hunter/ESE has <br /> proposed an apparently arbitrary limit of 50 samples; with 27 new well <br /> this would allow only 23 additional wells to be sampled for comparison <br /> and consistency. Such an approach has no scientific basis. It may be <br /> possible to utilize the on going quarterly sampling being conducted by <br /> the Depot in conjunction with the installation of new wells to minimize <br /> sampling costs. Additionally, it may be possible to reduce the number <br /> and/or frequency of wells being regularly sampled based on their <br />