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Page6of16 <br /> NOA Drywell Closure and Investigation Work Plan <br /> March 18, 2014 <br /> Collecting soil samples from the drywells is not anticipated to be feasible. Therefore, soil <br /> samples will be collected from the three (3) boreholes detailed above. The borehole and <br /> sampling locations are shown on Plates 4 and S. <br /> Three (3) borings will be drilled to collect soil samples starting at depths equivalent to the <br /> bottom of the drywells: forty (40) feet bgs. From forty (40) feet bgs to fifty (50) feet bgs, the <br /> area of suspected contamination, a five-foot interval will be observed. Two (2) soil samples will <br /> be collected at forty (40) feet bgs, one (1) soil sample will be collected at forty-five (45) feet <br /> bgs, and one (1) soil sample will be collected at fifty (50) feet bgs in each boring. A 10-foot <br /> interval will then be observed from fifty (50) feet bgs to the groundwater table at approximately <br /> seventy (70) feet bgs. One (1) soil sample will be collected at sixty (60) feet bgs and one (1) <br /> soil sample will be collected just above the water table at approximately seventy (70) feet bgs. <br /> One (1) additional soil sample will be collected from one (1) of the boreholes for Replicate <br /> Samples Quality Assurance/Quality Control purposes. The total number of soil samples collected <br /> from the boreholes is estimated to be nineteen (19). <br /> 3.3 Sampling Equipment and Collection Methods <br /> Field exploration will be performed under the supervision of a California Professional Geologist <br /> and/or Engineer. A geologist experienced with investigation and remediation of chemical <br /> ' releases at commercial properties would be present during sampling and drilling to perform <br /> sample collection, maintain logs of the boring, and make observations of site conditions. Sample <br /> analysis will begin within five (5) days of collection; no preservatives are required for the <br /> desired analyses. <br /> Groundwater and soil samples will be collected by NOA under the supervision and oversight of <br /> 1 EHD. If sampling by NOA is not permitted, a third party will perform groundwater and soil <br /> sampling under the oversight of NOA and EHD. <br /> 3.3.1 Groundwater <br /> The diameter of the boreholes will be six (6) inches and therefore constitutes a small sampler; a <br /> disposable bailer will be used to sample groundwater from the boreholes. If a separate floating <br /> phase is observed while sampling, a sampling device will be utilized that can collect fluid <br /> beneath the floating phase. A clean disposable bailer will be lowered into the wells to collect <br /> groundwater and will then be emptied into the appropriate sampling bottles as detailed below. <br /> The groundwater sampling equipment and collection methods described below for each <br /> borehole are listed in sequential sampling order. <br /> Two (2) pre-chilled, pre-labeled 40-ml VOA vials with a Teflon septum lid will be filled for <br /> volatile organics testing. The VOA vials will be filled completely at a rate of less than 100 <br /> milliliters per minute to prevent the presence of headspace. The lid with the Teflon septum will <br /> then be tightened onto the vial. The vial will then be turned upside down and tapped to check <br /> for the presence of air bubbles. If air is present, the sample will be retaken. The sample will be <br /> recorded, labeled and stored at a temperature of approximately 4°C in an ice chest for <br /> transportation to the analytical laboratory. <br /> "04 <br /> 902 Industrial Way•Lodi,CA 95240•209.367.3701 -Fax 209.369.4228 02014 Neil O.Anderson&Associates,Inc <br />