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Map ID MAP FINDINGS Direction Distance EDR ID Number Elevation Site Database(s) EPA ID Number DEFENSE DISTRIBUTION DEPOT SAN JOAQUIN SHARPE SITE (Continued) 1000368504 Quality Control Board-Central Valley Region (RWQCB). This ROD amendment was developed in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 1170 as amended. This ROD amendment is also in compliance with the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), Section 300.435(c)(2)(ii), and Chapter 6.8 of the California Health and Safety Code, Section 25300, at seq. Furthermore, this action is being taken in accordance with the California Water Code (Section 13300, at seq.). VOC (primarily TCE) contamination was caused by previous use and disposal of VOCs at the Sharpe Site. The disposal of VOCs occurred in designated disposal areas within the South Balloon and the North Balloon. Disposal also occurred at undesignated, isolated locations in other parts of the installation, such as the Central Area. TCE-contaminated sites are designated with a "P" (e.g., Site P-1A). This designation was introduced for these sites in the Operable Unit 2 Remedial Design Work Plan (Radian Corporation, 1996). The "P"-designated names were necessary in the work plan to isolate smaller areas for remediation and characterization, from the larger areas that were Identified in the OU 2 ROD on the basis of groundwater plumes (e.g. , Plume 1 , Plume 2, etc.) Based on the results of the 1994 remedial Investigation/feasibility study (RI/FS), the OU 2 ROD identified seven sites that had been sufficiently characterized and found to be degrading groundwater. Using the "P" designations, these sites were: -P-1A; P-18; P-1C; P-1 D; P-5A; P-6A; P-8A Seven other sites were Identified in the OU 2 ROD as requiring further characterization to determine whether they were causing groundwater degradation. These sites would be subject to remedlalion based on the results of the characterization. Using the "P" designations, these sites were: -P-1 E; PAF; P-1 G; P-2A; P-3A; P-4A; P-413 During preparation of the Operable Unit 2 Remedial Design Work Plan, Sites P-213 and P-4C were added to the characterization effort because a review of RI data indicated that these two sites may also be degrading groundwater. With these two additional sites, the total number of "TCE-contaminated" sites increased to 16. Post-ROD (pre-design) Investigations at the 16 TCE sites were completed in 1996, 1997, and 1999 to further define the extent of TCE contamination in the vadose zone and determine whether each site was causing groundwater degradation, hence requiring remediation. The results of the 1996 and 1997 investigations are presented in the Operable Unit 2 Pre-Design Technical Summary and Addendum to the Operable Unit 2 Pre-Design Technical Summary. The results of the 1999 Investigation are presented in the Operable Unit 2, No Further Action, Remedial Action Report. Following completion of the post-ROD investigations, five TCE sites (P-1A, PAB, PAC, P-1 E, and P-6A) were determined to require a remedial action to protect groundwater quality (Radian International, 1997a), and 11 TCE sites (PAID, PAF, P-1G, P-2A, P-213, P-3A, P-4A, P-413, P-4C, P-5A, and P-8A) were determined to require no further action. However, the results of recent investigations indicated that a residual TCE source area exists at Site P-5A; therefore, as of April 2010, Site P-5A is being remediated using SVE in accordance with OU 2 ROD requirements. A ROD Amendment addressing Operable Unit 2 of the Sharpe Army Depot Site was completed in September 2011 . CERCLIS Assessment History: Action Code: 001 Action: DISCOVERY Date Started: Date Completed: 11/01 /80 Priority Level: Not reported Operable Unit: SITEWIDE Primary Responsibility: Federal Facilities Planning Status: Not reported Urgency Indicator: Not reported TC4755450.2s Page 22