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Mr. Marcus Pierce, Engineering Geologist February 2012 Central Valley Regional Water Quality Control Board Subject: Copper Sulfate Impacted Soil Removal Excavation of copper sulfate impacted soil was discontinued once the limits of the General Service Administration (GSA) contract for waste disposal were reached. A visible seam of suspected copper sulfate was observed in the west wall of the completed excavation. The CA ARNG did not expect to remove all copper sulfate impacted soil during this mobilization, and following discussions between Versar and the CA ARNG regarding the remaining copper sulfate in soil, additional excavation was not performed. Confirmation samples were collected from the floor of all three excavations, and the north, south, and east sidewalls of the main excavation prior to backfill using visually unimpacted excavated soil, mechanical compaction, and resurfacing with asphalt. Laboratory analysis of the confirmation samples identified 13 metals with concentrations above the method detection limits, including arsenic concentrations ranging from 5.04 to 7.63 milligrams per kilogram (mg/kg), exceeding the US EPA Region 9 Preliminary Remediation Goal (PRG) for Industrial Soil (1.6 mg/kg). The confirmation samples confirmed that the copper sulfate impacted soils were fully removed in all directions except to the west, as anticipated. GENERAL DESCRIPTION OF PROPOSED REMEDIAL ACTIVITIES Upon approval of this Work Plan, preparation for remedial activities will be implemented. The objective for the proposed work is to complete the copper sulfate impacted soil removal initiated by Versar in 2005. Activities associated with this effort will be performed in strict conformance with an Accident Prevention Plan/Site Safety and Health Plan developed under the oversight of, and approved by, OTIE's Corporate Health and Safety Manager, and will consist of subsurface utility locating, contaminated soil excavation (based exclusively on soil coloration), and backfilling with clean import soil. The proposed excavation area (Figure 3) will be properly marked prior to notifying Underground Service Alert about proposed subsurface excavation activities. A private underground subsurface utility locator will be contracted to determine if any underground utilities (water, sewer, telecommunications, cable television, electric and gas) or other obstructions are located within the proposed excavation footprint. Any subsurface utilities observed within the excavation footprint or in adjacent vehicle storage areas will be marked with spray paint on the ground surface. Soil excavation, transport, and disposal, backfilling and site restoration activities are anticipated to be completed during one working day. The copper sulfate impacted soil will be excavated using a backhoe and directly loaded onto an end dump truck, then transported and disposed under waste manifest in accordance with all applicable state and federal regulations. Soil excavation will proceed until the extent of visually identifiable copper sulfate impacted soil has been removed. The excavation is anticipated to be approximately 15 feet wide by 15 feet long and 10 feet deep upon completion (approximately 85 cubic yards). Immediately after soil excavation is completed and concurrent with offsite transport of the impacted soil, confirmation soil samples will be collected from the excavation bottom and from each of the sidewalls of the excavation. Soil samples will be transported under proper chain -of -custody documentation to a California -certified analytical laboratory, where they will be analyzed for California Title 22 Metals using USEPA Method 601013/7000. The purpose of these samples will be to confirm removal of copper sulfate impacted soil. A secondary objective will be to evaluate arsenic concentrations relative to the 1.6 mg/kg Region 9 PRG, although the previously detected arsenic concentrations indicated above appear to be consistent with typical background values, and are not the focus of the proposed removal action. Oneida Total Integrated Enterprises, LLC Page 2 of 4