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Geosyntec l�' consultants 3. WORK PLAN OBJECTIVE AND RATIONALE The objective of this Work Plan is to present the scope of work necessary to meet the data objectives presented herein. In general the three data objectives are: 1) lateral and vertical evaluation of the groundwater impacts and to improve the understanding of the site's hydrogeology; 2) assess the performance of the existing groundwater extraction systems; and 3) to aid in the evaluation, selection and design of the final remedial action. 3.1 DATA QUALITY OBJECTIVES The objective of this Work Plan, as stated above, can only be achieved if the data obtained during the field investigation are sufficient for the purpose intended and are of demonstrably good quality. To ensure that these aims are achieved, Geosyntec has developed the scope of work detailed below in Section 4.0 and in the SAP included as Appendix A. In general accordance with the United States Environmental Protection Agency (USEPA) Guidance on Systematic Planning Using the Data Quality Objectives Process (USEPA, 2006), the seven-step data quality objective (DQO) process was used to identify and describe the data quality objective of the investigation outlined in this Work Plan. A DQO summary is provided as Table 1. The work to be completed falls under a single problem statement as follows: Chemicals of potential concern (COPCs) in groundwater may represent an unacceptable current or future risk to human receptors. To determine whether or not concentrations of COPCs in groundwater present an unacceptable risk to human receptors and whether or not complete exposure pathways need to be further evaluated, risk assessment benchmarks, including reference values, and quantitative risk assessment methods will be used. To complete the risk assessment and to determine the final remedial strategy, further evaluation of the downgradient area is necessary and is the focus of this Work Plan. Exposure, hydrostratigraphic, groundwater levels, and groundwater quality data inputs will be collected at locations as shown in Figures 3 through 5. Data will be collected in accordance with the scope of work presented in Section 4.0 and the SAP provided as Appendix A. To minimize the potential of outside interferences on the soil and groundwater samples and the analytical results, proper sampling, handling, and analytical procedures will be implemented. The data will be accepted based on the validation process identified in the QAPP (Section 4.0 of Appendix A). Pre-Design lnvestigation Work Plan 10 18.05.12