SITE INFORMATION AND CORRESPONDENCE

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Duncan Austin, Site File - 4 - • 11/3/2005 Former Morton Paint Manufacturing Site Stockton, San Joaquin County 8. A description of site soils is provided. However,the Investigation Work Plan should be augmented to provide supporting documentation, such as boring logs to support its assertions. 9. The Investigation Work Plan states, "During demolition, generally less than 0.5 foot,with up to less than two feet, of fill was imported to the Site to bring the Site to grade, exclusive of foundations, concrete,brick, etc. that would be buried more than two feet below ground surface(bgs)." The Investigation Work Plan should also detail the site artifacts and reference the source for this information. It is also not clear why the Redevelopment Agency would clear a property and leave building foundations. In addition, the composition and soil characteristics of the fill material needs to be included in the Investigation Work Plan, or the investigation should include provisions to collect this information if it is not currently available. 10. The Investigation Work Plan states, "Groundwater beneath the Morton-Alco OU has been defined in conjunction with groundwater investigations at the Morton-Alco OU and adjacent OUs." Regional Board staff believes that groundwater pollution at the site has not been completely defined. The Investigation Work Plan does not and should provide supporting documentation, such as tabulated data summaries, off-site investigation results, evaluations of vertical and horizontal preferential pathways, and vertical and horizontal groundwater gradients and their trends over time. The investigation plan for the Morton Operable Unit needs to be complete and more detailed. 11. The Investigation Work Plan states, "Site investigations have been performed at the Alco OU since 1989, including several soil sampling investigations and groundwater monitoring events." However, none of the investigations and data collected is summarized in the Investigation Work Plan and should be included. 12. Section 1.5 Contaminant Distribution contains a limited discussion of petroleum fuel associated pollution and does not detail any evaluation of any release from the paint manufacturing operation, including, but not limited to,paint-related volatile contaminants in groundwater and metals in soil. 13. The Investigation Work Plan states, "Monitoring well MW-6 is located in the northeast quadrant of the Morton-Alco OU, approximately 75 feet to the north of the referenced location of the USTs." The Investigation Work Plan contains no current maps nor figures for the referenced underground storage tanks and no figures detailing the planned investigation. 14. Section 2 Confirm Removal of Underground Storage Tanks contains a scope of work to confirm that the underground storage tanks were removed. This sections contains no actual proposed work but does contain language such as"A Health and Safety Plan will be prepared...The location of the USTs will be surveyed based on historic documentation,". The Investigation Work Plan is incomplete and needs to include specific actions to achieve its stated objectives. 15. The Investigation Work Plan states, "Prior to implementation of this Workplan, the Project Coordinator, having expertise in hazardous substance and hazardous waste cleanup, will be