ARCHIVED REPORTS_DRYWELL CLOSURE AND INVESTIGATION

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NOA Drywell Closure and Investigation Page 9 of 26 ' May 30, 2014 sample was collected from drywell 1 at sixty (60) feet bgs and split between two (2) identical sampling containers for Replicate Samples Quality Assurance/Quality Control purposes. For drywell 2, groundwater was first encountered at 58.5 feet bgs. Soil samples were collected at fifty-five (55) and sixty (60) feet bgs. The total number of soil samples collected from the drywells is thirteen (13). The drywell and sampling locations are shown on Plate 6 and Plate 7, Appendix A. 4.3 Sampling Equipment and Collection Methods Field exploration was performed under the supervision of a California Professional Geologist and/or Engineer. A geologist experienced with investigation and remediation of chemical releases at commercial properties was present during sampling and drilling to perform sample collection, maintain logs of the boring, and make observations of site conditions. Groundwater and soil samples were collected by NOA under the supervision and oversight of EHD. 4.3.1 Groundwater A 36-inch long disposable bailer was used to sample groundwater from the drywells. No separate floating phase was observed while sampling. A clean disposable bailer was lowered into the wells to collect groundwater and then emptied into the appropriate sampling bottles as detailed below. The groundwater sampling equipment and collection methods described below for each drywell are listed in sequential sampling order. Two (2) pre-chilled, pre-labeled 40-ml VOA vials with a Teflon septum lid were filled for volatile organics testing. Two (2) vials are required for one VOA sample. The samples were preserved with hydrochloric acid. The VOA vials were filled completely at a rate of less than 100 milliliters per minute to prevent the presence of headspace. The lid with the Teflon septum was tightened j onto the vial. The vial was turned upside down and tapped to check for the presence of air bubbles. The sample was recorded, labeled and stored at a temperature of approximately 4°C in an ice chest for transportation to the analytical laboratory. One (1) pre-labeled, one-liter amber glass bottle with a Teflon septum was filled for semi- volatile organics testing. Collection methods specified for volatile organics were followed. The sample was recorded, labeled and stored at a temperature of approximately 4°C in an ice chest for transportation to the analytical laboratory. One (1) pre-labeled, polyethylene, certified metal-free bottles were filled for metals testing for each well. In addition, two (2) pre-labeled, polyethylene, certified metal-free bottles were filled from groundwater from DW-2 for Replicate Samples Quality Assurance/Quality Control purposes ' (See Section 4.5). No preservatives were added since the samples will be analyzed for Mercury. Samples were analyzed within the holding time. The samples were recorded, labeled and stored at a temperature of approximately 4°C in an ice chest for transportation to the analytical laboratory. Two (2) pre-chilled, pre-labeled 40-ml VOA vials with Teflon septa were filled for Total Petroleum Hydrocarbons (TPH) as Gasoline testing. The sample was preserved with hydrochloric acid. Collection methods specified for volatile organics were followed. The sample 902 Industrial Way• Lodi, CA 95240• 209.367.3701 • Fax 209.333.8303 02014 Neil 0. Anderson&Associates, Inc.