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Mr. Marcus Pierce, Engineering Sogist February 2012 Central Valley Regional Water Quality Control Board Subject: Copper Sulfate Impacted Soil Removal "Hazcat" field tests indicated the substance contained elevated concentrations of copper, later tentatively identified as copper sulfate, a pesticide with reportedly no other hazardous properties, but which is toxic if ingested. The areal and vertical extent was not determined, and the powder was subsequently re -buried after sampling was completed. Versar recommended removal of an estimated 100 cubic yards of copper impacted soil for disposal at a Class I landfill. In October 2005, Versar returned to the site and removed copper impacted soil with concentrations exceeding 9,200 milligrams per kilogram (mg/kg) at the three pavement upwelling areas (Versar, 2006). The final excavations measured 25 feet by 15 feet by 10 feet deep (main excavation), and 2.5 feet by 6 feet by 3 feet deep for each of the two smaller excavations. Locations of the three excavations are depicted on Figure 3 (Attachment A). Approximately 100 cubic yards (130.85 tons) of impacted soil were removed from the site and delivered to Chemical Waste Management, Inc. landfill. During excavation activities, buried debris was encountered in the southwest portion of the main excavation, later identified as aircraft parts, and stockpiled for disposal. Excavation of copper sulfate impacted soil was discontinued once the limits of the General Service Administration 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. Confirmatory 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 confirmatory samples identified 13 metals with concentrations above the method detection limits (MDLs), including arsenic concentrations ranging from 5.04 to 7.63 mg/kg, exceeding the US EPA Region 9 Preliminary Remediation Goal (PRG) for Industrial Soil (1.6 mg/kg). The confirmatory samples indicated 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, pre -characterizing copper sulfate material (for disposal purposes) and collecting a groundwater grab sample beneath the excavation using direct push technique, excavating copper sulfate impacted soil (based exclusively on soil coloration), confirmatory soil sampling, backfilling with clean import soil, and restoring the rough asphalt surface. 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 Oneida Total Integrated Enterprises, LLC Page 2 of 6