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RFP No. 18-043 Al - Environmental Site Assessment Work Plan • Ninyo & Moore will prepare a detailed work plan for the Phase II ESA. The work plan will be prepared in accordance with the regulatory requirements and will include a health and safety plan. The HASP will be prepared in accordance with CCR Title 8, Section 5192 and 29 CFR 1910.120. The work plan will be submitted to the City for review and approval prior to submittal to the RWQCB. The chemicals of potential concern (COPCs) will likely be TPH and VOCs. Focused sampling consisting of advancing 12 soil borings proposed in areas around the site where known and suspected release of contaminants has taken place. The borings are proposed to collect soil vapor, soil, and potentially grab groundwater samples. Proposed locations of the soil borings and the wells will be based on the results of the Phase I ESA. The soil borings will be proposed to be advanced until groundwater is encountered. Pre -Field • After approval of the work plan, Ninyo & Moore will obtain all necessary permits required to implement the Phase 11 ESA activities and coordinate access with the City and on-site personnel. • During the pre -field activities we will locate and mark all proposed boring locations with white paint, then notify Underground Service Alert three business days in advance of the sampling. • Prior to conducting subsurface activities, we will perform a geophysical survey to evaluate for the presence of subsurface equipment, utilities, structures, and conveyances. The survey will be conducted concurrent with the site investigation. A combination of electromagnetic induction, magnetometry, ground -penetrating radar and a utility locator with line tracing capabilities may be used during the survey. Proposed boring locations may be adjusted based on suspected utility conflicts identified. Soil and Groundwater Investigation • The subsurface investigation will include advancement of 12 direct -push soil borings by a licensed drilling subcontractor. as shown on the attached Figure 1 (Appendix C) to first encountered groundwater, which is estimated to be at approximately 10 feet bgs. The presence of petroleum hydrocarbons (and associated thickness) will be recorded on the boring logs. The investigation will be conducted under the direct supervision of a California -registered professional geologist. • Soil samples from exploratory borings will be collected at approximately 5, and 10 feet bgs for analytical testing. A portion of each soil sample collected will be placed in a clean glass jar or zip -tight bag, placed in a warm area for approximately 15 minutes, and measured for VOCs using a calibrated photo -ionization detector. The readings will be recorded on the boring logs. • The soil samples will be delivered to a State of California certified environmental analytical laboratory under standard chain -of -custody and with the samples properly preserved. The COPCs and their associated analytical methods are listed below: o TPH by EPA methods 8015B/5035. o VOCs by EPA methods 826013/5035. • Select grab groundwater samples may be collected from each boring using a Hydropunch® module to evaluate the extent of the dissolved plume at the site and sampled for the same constituents as for soil samples noted above. The depth to groundwater will be recorded and the groundwater will be inspected for the presence of free product using an interface probe. Soil Vapor Survey • A soil vapor survey will be conducted at the site to determine whether significant VOCs are emanating from the subsurface and off -gassing from the groundwater table and migrating into indoor air of future site building structures. Following completion of the 12 borings into dual -nested soil vapor probes, the probes consisting of temporary implants will be sampled at approximately 5 and 9 feet bgs (above the water table) in general accordance with the DTSC/RWQCB (2015) Advisory for Active Soil Gas Investigations soil gas sampling protocol. Soil vapor samples will be analyzed for the full suite of VOCs by EPA Method 82608 by a California certified on-site mobile laboratory. Ninyo & Moore I City of Santa Ana - (A1) Environmental Site Assessment 1 05-00713 1 June 5. 2018