SITE INFORMATION AND CORRESPONDENCE

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Duncan Austin, Site File 0 - 5 - 11/3/2005 Former Morton Paint Manufacturing Site Stockton, San Joaquin County designated." Please indicate the role this person shall have in coordinating the work with GSE,the Redevelopment Agency and the Regional Board. 16. The Investigation Work Plan states, "Trenching will be performed with a backhoe, using a one-foot wide bucket. The excavation alignment will be in the east-west direction, to a depth of no greater than 6 feet bgs." The Investigation Work Plan must provide a rationale for selecting 6 feet below ground surface (bgs) as a maximum depth. A preliminary review of the information reveals that 6 feet bgs is not adequate. The Investigation Work Plan indicated that the site may have as much as two feet of fill and typically underground storage tanks are buried at six to eight feet bgs, which would result in a minimum investigation depth of ten feet bgs. 17. The Investigation Work Plan, " If during trenching the USTs and associated piping are not present in support of soil closure, soil samples will be collected from the trench and stockpiled"VOC' soil." The Redevelopment Agency proposes to analyze the samples for total petroleum hydrocarbon in the gasoline, diesel and motor oil range with EPA Method 8015M and for volatile organic compounds with EPA Method 8260B. The Redevelopment Agency needs to provide a rationale as to why these methods are proposed and why metal analyses are not included. 18. The Investigation Work Plan states, "If USTs and associated piping are present, soil samples will only be collected beneath piping runs and from any stockpiled soil. Additional soil samples will be collected during UST removal." The Investigation Work Plan must discuss how the pipes and tanks would be removed and include a plan for their final disposition. 19. The Investigation Work Plan states, "Soil management will include soil segregation, engineering controls, soil characterization,on-site soil management, coordination of off-site disposal, and possible on-site treatment." The Investigation Work Plan must describe any of these soil management strategies in detail and include the screening criteria that will be used to determine which of these strategies are implemented. 20. The Investigation Work Plan states, "A trenching summary letter report will be prepared that summarizes field activities, findings, information and data interpretation, and conclusions. If recommendations or further actions are anticipated, they will be outlined in the report. A scheduled of activities will also be included." The work proposed is not sufficient to determine if soil and/or groundwater remediation will be necessary at the site. As described earlier, a detailed and comprehensive sampling and analyses plan is necessary for the Morton Operable Unit. 21, The Investigation Work Plan contains no provision for investigating groundwater and proposes no groundwater sampling at locations where an underground storage tank or piping is found. This is not adequate. The Redevelopment Agency must include provisions to collect grab groundwater samples. Soil Field Screening Letter 22. The Soil Field Screening Letter proposes to use a photo-ionization detector (PID)reading of 500 parts per million(ppm) in replacement of the 50 ppm used at the L&M Operable Unit cleanup