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KEI-P89-1104 .R7 December 10, 1990 Page 5 Details of the existing water well at the site were researched at the California Department of Water Resources (DWR) in Sacramento. Mrs. Betty Swatsenbarg of the DWR reviewed the State records on March 14, 1990 and reported that no records were available for this well at the DWR. Based on Mars. Swatsenbarg's extensive experience at the DWR, the sub]ect water well was probably drilled and installed prior to 1951. At that time, steel casings were driven into the subsurface and the remainder of the wells were generally open below the casing. On April 23 , 1990, an attempt was made to destroy the existing six- inch diameter water well by West Hazmat of Rancho Cordova, California. The proposed plan involved drilling out the well casing, using 12-inch O.D. (6-1/4-inch I.D. ) hollow-stem augers, to the total depth of the casing; pulling out the old casing; redrilling the well to the full depth, and pressure grouting the well using a tremie pipe and a neat cement grout. During field activities on April 23, 1990, the old pump (5 feet long) and pump casing (60 feet long) were removed from the well. The total depth of the well was measured at 135 feet with the static water level measured at 55 feet. The length of the existing casing could not be determined with the equipment on-site. Approximately 135 gallons of water were bailed from the water well using a clean stainless steel bailer. A water sample was obtained for analyses, and it was noted that the water sample contained sediment and what appeared to be iron flakes. The water sample was analyzed at Sequoia Analytical Laboratory in Redwood City, Califor- nia, on April 24 , 1990 for TPH as gasoline and BTX&E. The analytical results indicated non-detectable levels of TPH as gasoline and BTX&E, except for 0.79 ppb of toluene. Mr. Harlin Knoll of the SJCPHS was informed on May 10, 1990, and indicated that the ground water should be treated as contaminated because of the detected toluene. West Hazmat only had 100 feet of the 12-inch O.D. augers available on-sate on April 23 , 1990, and therefore the well (135 feet deep) could not be fully drilled out and the casing removed from the ground. A phone call was placed from the field to Mrs. Diane Henson of the SJCPHS to determine if the work plan could be modified to allow the six-inch diameter well casing to remain in the ground and grout placed only on the inside of the casing for the full depth of the well. This modification to our work plan was verbally approved by Mrs. Diane Henson. However, further evaluation of the surface area adjacent to the six-inch diameter well casing identified a second casing, approxi- mately 10 inches in diameter, around the six-inch diameter casing. The depth of the second casing could not be determined, and it was