SITE INFORMATION AND CORRESPONDENCE

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Mr. Fred Proby -2- 4. Individual Site Investigations. We have received a copy of ARCO's 12 October 1990 report and Volume 2 of the 1 November 1991 report. We have requested Arco to send us a copy of Volume 1 of the latter report so we can proceed with our review of these reports. 5. Site Assessment. The September 1989 Site Summary and Proposed Site Assessment Plan is deficient. Following are our comments: a. Page 3-1 of the report indicates that no comprehensive soil sampling program was developed or implemented to define the horizontal and vertical extent of contamination. In spite of this major omission, a soil sampling program is not proposed in the work plan. Furthermore, the soil testing results that were available were merely discussed qualitatively and tabulated without any interpretation or recommendation for additional work to define the extent of contamination or identify the contaminant source. b. Drawing No. 7 shows nine exploratory borings/test holes at Support Terminal Services (ST) . These test holes were not discussed in the report. In fact, ST was not even included in the discussion of site soil chemistry and site ground water chemistry. Additional work is needed at the ST site. c. Drawing No. 7 also shows 50 cone penetration test (CPT) locations of which only 33 are proposed. We understand these locations are preliminary, and the investigation is exploratory. However, a rationale for the proposed locations needs be provided with consideration of existing data, particularly at ARCO. d. A program for contamination sources identification is not specified in the work plan. The program must include a description of all drainages, utilities, septic tanks, leachfields, or any other features natural or man-made that affect the fate or movement of the contamination. It also must include identifying past and present aboveground tanks, underground tanks, and associated piping, and for each tank, the capacity, content, construction type (e.g. welded steel ), history regarding leaks, ruptures, spills, etc. , and any corrective actions taken if any. It is imperative to identify the contaminant sources so that they can be removed and recurrence of discharges would be prevented. e. With the exception of the three deep HydroPunch samples shown on Drawing No. 7, the locations of the wells and piezometers to be sampled during preliminary ground water sampling were not identified. The rationale for the selection of piezometer and well locations must be provided in the work plan. Samples shall be analyzed for total petroleum hydrocarbons in the diesel and gasoline range, volatile organic chemicals using EPA Methods 601 and 602, and organic lead.