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NOA DrywelI Closure and Investigation Work Plan Page 5 of 16 <br /> March 18, 2014 <br /> 3.0 SAMPLING AND ANALYSIS PLAN <br /> ! 3.1 Sampling Objectives <br /> The objective of the groundwater and soil sampling around the drywells at the subject property <br /> is to confirm the presence or absence of contamination as a result of the industrial use of the <br /> drywells. NOA will collect the groundwater and soil samples under the supervision of NOA's <br /> California Registered Professional Geologist and the San Joaquin County Environmental Health <br /> Department. Sampling activities will occur prior to well destruction. <br /> ! NOA proposes to collect all soil and groundwater samples under the direct supervision and <br /> oversight of EHD. Samples will be picked up by the analytical laboratory directly; all laboratory <br /> correspondence and results will be sent exclusively to EHD. If this is not permitted by EHD, <br /> ! sampling can alternatively be performed by a third party. <br /> 3.2 Sampling Locations and Depths <br /> ! Three (3) boreholes will be drilled to the water table, estimated to be seventy (70) feet bgs, for <br /> sampling purposes. The boreholes will be located as near as reasonably possible to the two (2) <br /> drywells. The drywells are approximately one (1) foot apart; it is not feasible to drill a borehole <br /> ! between the drywells. However, a central borehole is important. A borehole will therefore be <br /> located one (1) foot north of the center of the two (2) drywells. In addition, one (1) borehole <br /> will be located five (5) feet north of the center of the drywells and one (1) borehole will be <br /> ! located five (5) feet south of the center of the drywells. These boreholes are offset as such to <br /> delineate the impacted area. The soil boring locations will be recorded in the field by use of a <br /> handheld GPS unit. GPS equipment will provide a minimum of submeter accuracy. The <br /> ! borehole and sampling locations are shown on Plates 4 and S. <br /> 3.2.1 Groundwater <br /> ! Release to the drywell was terminated on March 6, 2014. Groundwater in the drywells has <br /> consistently dropped since this event. It is anticipated that on-site groundwater levels will drop <br /> ! to approximately seventy (70) feet bgs by the sampling event; sampling of groundwater in the <br /> drywells that extend to forty (40) feet bgs will not be feasible. <br /> Six (6) groundwater samples will be collected from each of the three (3) boreholes detailed <br /> above. One (1) additional sample will be collected from one (1) of the boreholes for Replicate <br /> Samples Quality Assurance/Quality Control purposes. A total of nineteen (19) groundwater <br /> samples will be collected. The borehole and sampling locations are shown on Plates 4 and S. <br /> 3.2.2 Soil <br /> If present, one (1) sediment/sludge sample will be collected from the Concrete Cure Room floor <br /> drain at the approximate vertical extent, one and one-half(1.5) feet bgs. The pipe drainage line <br /> is a contained system and there is no reason to suspect leakage. Therefore, no soil samples will <br /> be collected beneath the vertical extent of the drain. <br /> I902 Industrial Way•Lodi,CA 95240-209.367.3701 •Fax 209.369.4228 C20I4 Neil O.Anderson&Associates,Inc <br />