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6. Existing well groundwater sample collected (sampled 02/26/98). Depth to groundwater was approximately 29.89 feet bgs. A variable speed submersible pump was lowered approximately 190 feet bgs into the existing well. The well was purged at approximately 1 gallon per minute(gpm). The total purge volume was approximately 50 gallons. The groundwater sample was collected using the variable speed pump at a rate of less than approximately 0.25 gpm. A trip blank and equipment blank (collected prior to lowering the pump into the well)were also collected. The groundwater and quality control(QC)samples were analyzed for EPA Method 8260B. The laboratory report indicated that the QC samples were non-detect. The laboratory report for the groundwater sample indicated that 240 ,ug/L benzene was present in the sample. All other EPA Method 8260B detections were below respective California maximum contaminant levels (MCLS). 7. Downhole television video was conducted in the existing well on 03/30/98. Based on the video, the well is constructed of riveted steel casing from 0 feet to approximately 206 feet below ground surface (bgs). The well is open hole from approximately 206 feet bgs to the current bottom at approximately 218 feet bgs. The casing is apparently intact with no obvious breaks or offsets. Some scaling is apparent throughout the casing length. Discussion The depth of the existing well casing (as determined from the downhole television video) indicates that groundwater is most likely entering this well from below 206 feet bgs. Because no soil contamination was reported during the UST removal and the groundwater entering the existing well is apparently from considerable depth, we believe that the contaminants in the groundwater from this well may not be the results of Delta Pumps operations. Based on a brief review of your records for properties surrounding 646 California Street, it is apparent that several nearby sites have confirmed soil and groundwater contamination. The contaminant signature of the Delta Pumps groundwater samples may indicate that this well is located near the leading edge of a groundwater contaminant plume and that the plume source may originate from some other property. Delta Pumps understands that past practices at 646 California Street may have resulted in soil contamination. Delta Pumps is eager to define and mitigate contamination that is demonstrated to be a result of its past operations. The corporation is committed to its environmental and civic responsibilities as a longtime servant of the Stockton community. Again, we would like to meet with you at your earliest convenience to discuss the information contained herein. Should you have any questions, please call me at (209) 466-9625 or my niece's husband, Mr. Kent E. Parrish, CA CHG, at (916) 929-2346. Sincerely, Delta Pumps, jInc. William H. Crow, Jr. Proprietor Attachments cc: Blanche Crow Charles Patton Kent Parrish • CAPROJECTS\Delta Pumps\splrslts.tlr Page 3 of 9