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4. Allow the Beacon samplers to be exposed to subsurface gas for 14 days unless the timeframe <br /> was adjusted. <br /> 5. Record the location, sampler identification, date, and time on field data sheets. <br /> 6. Return 14 days later to remove the Beacon samplers. Carefully remove each of the samplers, <br /> repackage and seal each sampler according to manufactures directions,complete the chain of <br /> custody and send the samplers back to the laboratory. <br /> 7. Cold patch holes drilled through asphalt/concrete. <br /> Samples will be analyzed by U.S. Environmental Protection Agency (EPA) Modified TO-17 by BEACON <br /> Environmental Laboratory. The following Beacon laboratory reporting limits will be provided and are <br /> sufficiently low to be compared to the applicable sub slab/soil gas Environmental Screening Level (ESL): <br /> ESL 1 Day 3 Days 7 Days 14 Days <br /> ESL Commercial/ <br /> Residential Industrial <br /> Screening Screening <br /> Level Levels RL RL RL RL <br /> VOC Compounds (pg/m3) (lag/m3) (pg/m3) (pg/m3) (pg/m3) (pg/m3) <br /> Vinyl Chloride 0.32 5.2 2.25 0.75 0.32 0.16 <br /> 1,1-Dichloroethene 2,400 10,000 5.26 1.75 0.75 0.38 <br /> trans-1,2-Dichloroethene 2,800 12,000 3.95 1.32 0.56 0.28 <br /> cis-1,2-Dichloroethene 280 1,200 3.22 1.07 0.46 0.23 <br /> Trichloroethene 16 100 5.11 1.70 0.73 0.36 <br /> Tetrachloroethene 15 67 4.23 1.41 0.60 0.30 <br /> Notes: <br /> ESL San Francisco Bay Regional Water Quality Control Board Environmental Screening Levels January 2019(Rev. 1) <br /> ljg/m3 microgram per cubic meter <br /> RL reporting limit <br /> VOC volatile organic compound <br /> The passive soil gas results will be reviewed to determine if conditional sub-slab, indoor air, and outdoor <br /> air sampling is required. On receipt of the soil gas results, APTIM will provide the RWQC13 with maps <br /> posting the soil gas results and a table with sampling details, if required. <br /> 4.3 Limited Groundwater Investigation <br /> The purpose of the Limited Groundwater Investigation task is to assess whether PCE has impacted shallow <br /> groundwater at the Site. This task will include use of Direct Push Technology (DPT) to advance three <br /> temporary soil borings to collect grab groundwater samples. <br /> Historical gauging data for nearby Nestle monitoring wells M-1013 and M-13B indicate that depth-to- <br /> groundwater in this area has ranged from approximately 21 to 35 feet bgs. One groundwater sample will <br /> FINAL RIPON PCE INVESTIGATION WORK PLAN.DOCX 4-3 PROJECT NO.631021512 <br />