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Mr. Himanshu H. Mehta, P.E. 2 June 2023 Page 6 Geosptec(" consultants During the June 2023 mobilization for the semi-annual groundwater monitoring event, Geosyntec personnel will collect groundwater samples from monitoring wells GR-MW20B, MW26B, MW30B, MW37B, MW02D, MWIOD, and MW30CC. Groundwater samples will be collected using conventional low flow purging methods to evaluate concentrations of dechlorination indicators including dissolved gases, total organic carbon, and dehalococcoides (Dhc) and VC- and TCE- reductase analyses (FGA [vcrA/bvcA/tceA]). Proposed groundwater sample analyses are provided in Table 10 of the 2022 Annual Groundwater Monitoring Report. Groundwater sampling activities are estimated to take 2 field days with 1 person to complete. Investigation -Derived Waste (IDW) Management Soil removed from the top 5 feet of the subsurface during utility clearing at each location will be returned to the borehole. IDW consisting of purge water and decontamination water from the drilling equipment will be drummed and staged for off-site disposal. Soil cuttings from two DPT soil borings will also be drummed and stored for off-site disposal. IDW characterization samples will be collected and submitted to a fixed -base laboratory for analysis of VOCs by EPA Method 8260B (for liquid IDW) and TCLP VOCs (EPA Method 8260B) and TCLP RCRA 8 metals (EPA Method 6010D and 7470A for mercury) (for solid IDW), as required by the waste disposal facility. The analytical results will be used to profile the IDW prior to transport and disposal. It is assumed that IDW will be characterized as non -hazardous. The estimated hours and associated breakdown of hours in Phase 6 are as follows: Staff professional — a total of 20 hours, including: • 4 hours to prepare the THA; • 8 hours to prepare for the field event; and • 8 hours oversight of IDW pickup for off-site disposal. Senior Staff professional — a total of 100 hours, including: • 4 hours to prepare for the field event; • 12 hours to mark locations and oversee the brush clearing and utility locate prior to the field event; • 60 hours DPT groundwater and soil sampling (five 12 -hour days); • 20 hours monitoring well sampling; and • 4 hours to return equipment, complete documentation, etc. after the field event; Senior professional — a total of 20 hours, including: • 2 hours to review the THA; • 2 hours for a Senior Geologist to develop the scope of work; • 4 hours for a Senior Engineer to review the scope of work; • 10 hours to provide field support and data analysis (2 hours per drilling day); and • 2 hours of project management/communication with the client. FR0766\XR23010.docx engineers I scientists I innovators