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Mr. Himanshu H. Mehta, P.E. 28 December 2016 Page 2 monitoring reports provided to the FDEP. As outlined in the RAPM Addendum No. 2, it was anticipated at the time that additional bioremediation injection activities would likely be warranted in 3 to 5 years as the injected electron donor was depleted. Trichloroethene (TCE) concentrations in the former source area (GR-MW30B) have fluctuated following the injection activities associated with RAPM Addendum No. 2, with semi-annually reported concentrations above the Groundwater Cleanup Target Level (GCTL) ranging from 124 to 3,150 micrograms per liter (gg/L) since June 2014, indicating that while groundwater concentrations at the Site have significantly improved (with concentrations lower by several orders of magnitude over pre -source removal concentrations), there may be recalcitrant CVOC mass in the vicinity of the former source area that continues to contribute CVOCs to groundwater. A RAPM3, requested by FDEP in correspondence dated 21 September 2015, was approved by FDEP on 15 July 2016 and proposed a follow up injection of electron donor and dechlorinating microbial culture in the former source area. Former source area pre-injection investigation activities, including collection of discrete groundwater samples via direct push technology (DPT) and collection of groundwater samples from site monitoring well injection wells, were conducted in July 2016 and resulted in a refined target treatment area within the former source area. PROPOSED SCOPE OF WORK The proposed scope of work includes the activities required to implement the FDEP-approved RAPM Addendum No. 3, including .the procurement of injection amendment and drilling subcontractor and performance of the injection activities. The remainder of this letter provides details regarding the proposed scope of work and a budget estimate to accomplish the work described herein. For the purpose of budgeting, the scope of work has been divided into the following four phases: • Phase 1 — Project Management; • Phase 2 — Meetings/Regulatory Interaction; • Phase 3 — Injection Activities; and • Phase 4 — UIC and Performance Monitoring and Reporting. The remainder of this section presents a general description of the activities to be performed in each phase. Phase 1— Proiect Manaeement Under this task, Geosyntec will perform project planning and management responsibilities, such as correspondence with IRC SWDD and FDEP, invoice review, project coordination. XR16044 - Gifford RAPM3 Imp engineers I scientists I innovators P175