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ATTACHMENT <br /> A. General Comments for Establishing Soil and Ground Water Cleanup Levels <br /> 1 . There are three objectives for the investigation of soil and ground <br /> water contamination. <br /> a. Establish base-wide background concentrations. Background soil <br /> and groundwater concentrations must be established in a manner <br /> that satisfies Article 5 of Chapter 15, Title 23 of the California <br /> Code of Regulations (CCR) . Background concentrations for metals, <br /> general minerals and parameters must be established in soils, <br /> surface waters and groundwater. <br /> b. Determine all contaminants at each site that could create impacts <br /> to ground or surface waters. Health based risk assessment numbers <br /> may not be sufficient for defining aquifer/soil cleanup levels for <br /> contaminants. All pollutants, not just contaminants of concern, <br /> above background values will have to be remediated or demonstrated <br /> as having no potential for impacting ground or surface waters. <br /> c. Develop and/or collect sufficient information to support a <br /> disposal alternative evaluation as part of the remedial action. <br /> This includes any constituents or contaminants that may be present <br /> in soils and groundwater above base-wide background. <br /> 2. The recently adopted State Water Resources Control Board Resolution <br /> 92-49, Policies and Procedures for Investigation and Cleanup and <br /> Abatement of Discharges under Water Code Section 13304, is an <br /> applicable or relevant and appropriate requirement (ARAR) that must be <br /> satisfied. Specifically, Section III items F & G of Resolution 92-49 <br /> must be satisfied. <br /> 3. The site closure requirements of Chapter 15, Title 23 may be <br /> applicable at any soils site that has contaminants at concentrations <br /> above base-wide background concentrations and/or are not naturally <br /> occurring. If it cannot be demonstrated that the contaminants will <br /> not impact groundwater if left in-place then the site must satisfy <br /> these requirements. <br /> B. Methodology for Developing Soil Cleanup Levels <br /> 1 . A comparison of base-wide background concentrations with actual site <br /> concentrations will have to be made before any of the following <br /> determinations can be made with respect to the site: <br /> a. No Action alternative is appropriate. <br /> b. Closure or continued monitoring under Title 23, Chapter 15 is <br /> required. <br /> c. What cleanup levels must be achieved before clean closure can be <br /> considered. <br />