SITE INFORMATION AND CORRESPONDENCE_1988-1991

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David Wang, P.E. , Chief Page 6 March 6, 1991 Recommendation: The rate and times of pumpage for off- site wells be determined. This information should be used to help further define the movements of Plumes 4 and 5. o The potential for ground water contamination from non-VOC sources was presented, primarily lead and heavy petroleum fractions. Recommendation: That ground water evaluation programs be developed for these constituents. o With the discovery of the AB zones and the CD zones, their affect on the aquifers and contamination plumes need to be addressed. Questions that need to be answered are: - How broad is the aerial and vertical extent of these zones? - How much interconnection and influence do they provide between the known water bearing units? 3 . Delineation of Soil Contaminants: The following three questions remain with regards to the soil investigation. The Department's primary concern is how these questions will affect the follow-up on documents (the FS and Risk Assessment) . o Earlier (1987) soil and soil gas investigations prematurely targeted TCE only. Subsequent soil investigations failed to discern any significant VOC contamination. The Department is concerned with the possibility of using TCE targeted data which may skew interpretations for soil risk or fate and transport calculations. Recommendation: This possibility be addressed when these calculations are done. o Soil samples for VOCs were screened using Photo Ionization Detectors (PID) . The PID readings were not substantiated by the subsequent soil boring data. Are the PID readings going to be discarded or used in some manner? o As stated in the previous comment, lead and fuel oils may represent a source of contamination. All data was not available at the time the RI was developed.