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Cleanup in Vulnerable Communities'Initiative Final Project Reference:Bobson Cleaners Discovery and Enforcement Discovery Project Number:60688620-5.1 Investigation Work Plan 1. Prior to sampling, each canister will have its vacuum checked with a dedicated gauge,with the expected vacuum ranging from-28 to-29 inches of mercury. If any canister differs from the others by 3 inches of mercury or more,the canister will not be used as the integrity of the canister may have been compromised. 2. Once the canisters are in place,the valve of the ambient air canister will be opened, and the start time and vacuum gauge reading will be recorded.This process is repeated for each other canister as quickly as possible. 3. Each ambient air canister will be equipped with an 8-hour flow controller.After 8 hours and when the pressure is at less than 8 inches of mercury,the final time and vacuum will be recorded, and the valves will be closed at approximately the same time. 3.2.5.6 Field Quality Control Samples The field QC samples planned for this Di are equipment rinsate blanks and duplicates.These two types of samples are discussed below. Field Equipment Rinsate Blanks (for groundwater sampling) Afield equipment rinsate blank is a sample that is prepared in the field by pouring de-ionized, distilled (for inorganics) or HPLC grade (for organics)water through and over cleaned sampling equipment. The water is then collected and analyzed as a sample.The field equipment rinsate blank gives an indication of contamination from field procedures (e.g., improperly cleaned sampling equipment or cross-contamination). Planned field equipment rinsate blanks are presented on Table 5. Field equipment rinsate blanks will be collected at a minimum frequency of one per set of sampling equipment per sample matrix per day that non-dedicated sampling equipment is used. The field equipment rinsate blanks will be submitted to the laboratory"blind" (i.e.,given a fictitious name so that the laboratory will not recognize them as blanks).The field equipment rinsate blanks will be analyzed by the same method, and for the same analytes as the samples collected with the sampling equipment. The analytical goal for field equipment rinsate blanks is to have no detectable analytes. Field Duplicates (for soil gas, sub-slab,and indoor air) Afield duplicate is a sample that is collected and analyzed in the same manner, and at the same time and location,as a primary sample. Field duplicate samples will be collected and analyzed to evaluate sampling and analytical precision (reproducibility).Agreement between primary and duplicate sample results will indicate good sampling and analytical precision.The precision goal for field duplicate results will be plus or minus 50 percent relative percent difference (RPD)as compared to the primary results. For soil gas samples,field duplicate samples will be collected by obtaining a second volume of gas immediately after the initial sample is collected. If more than one container is required,then the primary and duplicate bottles for each analysis will be filled before bottles for the next analysis are filled (the bottles for VOC analysis will be filled first). Specific locations for collection of field duplicates are indicated on Tables 1 through 3;these locations were selected at random, because there are no previous data available to estimate which locations may have moderate contaminant concentrations. Field duplicates will be collected at a minimum frequency of 10 percent of the primary samples collected, except that the soil gas survey will include at least one duplicate sample per 20 samples or per batch,whichever is more often, in accordance with the DTSC Advisory.The field duplicates will be submitted to the laboratory"blind"(i.e., given a fictitious name so that the laboratory will not recognize them as duplicates). 3.2.5.7 Field Equipment and Calibration All field equipment will be provided by AECOM and all field instruments will be calibrated per the manufacturer's instructions. List of Field Equipment AECOM will provide the following field equipment, materials, and supplies: 1. A RAE System by Honeywell such as a MiniRAE 3000+ PID (or equivalent); Prepared for: Department of Toxic Substances Control AECOM 16