SITE INFORMATION AND CORRESPONDENCE FILE 2

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Antonia Vorster 10 February 1988 Teichert needs to determine the levels of concern for soil and ground water contamiantion, define or reasonably estimate the respective contamination extents, and then design actions to remove ori! mitigate the defined volumes of contami- nation. Installed systems must meet design objectives in the field and all other regulating agency requirements. In addition to the above, I also have the following specific comments: 1. Details of accomplished and proposed work must be included in submitted reports. For the subject site this includes drilling, logging, construction, development, and..sampl.ingW:pr.ocedurpc for monitoring wells;- we11 construction. �;. . materials (screen slot sizes, gravel pack material , etc.); and soil sampling procedures. 1 2. The ground water velocity and pumping radius of influence calculations are incorrect and unclear. The Theim equation is used for estimation of the pumping rate, but it is impossible to tell what equation was used for . estimating the radius of influence. Inconsistent units (gal/day/ft2 resulting in ft/day and gal/min) and misuse of the equation (using well loss in place of saturated thickness) result in errors. More important, however, is the use of extremely limited data and methodology to design the extraction , system. I strongly recommend that -aquifer testing be used to derive design parameters. Regardless of the approach used, however, Teichert must even- tually install a system that extracts or controls the volume of ground water exceeding levels of' concern. - 3. Two proposed monitoring well No. 8, locations are shown on Plate 4. Existing monitoring well No. 6 and past monitoring well No. 2 are not shown. 4.- Monitoring well locations and elevations need .to be surveyed, preferably to + an accuracy of ± 1 and 0.01 feet respectively: 5. The column in the table on page 9 labeled "Detection Limit" should actually be labeled "State Action. Levels". 6. The first 20 feet of the monitoring well boreholes were not logged. Thisis a deficiency previously pointed out in our 17 .lune comments All future wells/boreholes- must be legged (preferably continuously) forL stratigraphic identification and correlation. r 7. Calibration, sensitivity and field operation information for the organic vapor analyzer should be supplied.. ' For future reference, a photoionization detector (PID) is a better selection for aromatic hydrocarbon detection. 8. What is the status of soil aeration? 'What volume of soil_ has been successfully aerated; how often. are representative samples collected; how are samples collected and "compos=ted"? Aerated soil samples analyzed by Crown Environ- mental and Eureka Laboratories (29 October and 25 November, respectively) . indicate contamination. What was done with the soil from which .these samples were collected? GAR:ej