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i Kearney-KPF HAR Quarterly Report -2- 6 July 1990 PSI-9, PS2-14, and PS2-19. These areas should be resampled and analyzed for soluble concentrations of cadmium to determine whether they exceed the SOL. (The surface soil sample from PS1-9 was previously analyzed for the soluble cadmium concentration (Table 36) and may be eliminated because the soluble cadmium concentration was less than the detection limit. ) Additionally, all surface soils to be resampled must be analyzed for electrical conductivity (EC) , and total dissolved solids (TDS) , using the DI Waste Extraction Test (WET) . These analyses must be performed on soil samples that may contain designated levels of waste because salinity may also impact the beneficial uses of ground water. The 3 November 1988 letter from the Regional Board to owners and operators of Class III landfills regarding wastes acceptable for discharge to Class III landfills discusses this procedure. Closure/Subchapter 15 The SAR proposes to either excavate or stabilize soils that need remediation after the analytical results from resampling are received. If all designated levels of contaminated soil are excavated, and the necessary confirmation sampling is performed, then the area could be regraded for drainage and revegetated as the closure alternative. If the designated contaminated soils are to be stabilized, then bench tests for the selected treatment technology must be performed on the stabilized soil to demonstrate that the extract is below the SOL. Whether Portland Cement or another additive such as lime is used, these bench tests must be performed using the DI WET to assure that all of the constituents of concern are not leachable under the stabilized conditions. If the designated wastes are not excavated (refer to the attached flow chart) , but wastes are left in-place, then the surface impoundments must be closed as a Class II landfill . The regulations for closure of Class II landfills can be found in §§2510, 2540, 2541 , 2580, and 2581 of Subchapter 15, Title 23 of the California Code of Regulations (CCR) . Closure of a surface impoundment as a Class II landfill must comply with the prescriptive standards of Subchapter 15, which require construction of a liner, leachate collection system, and a cover. However, if compliance with the prescriptive standard is not feasible then an engineered alternative can be approved. The discharger must show the engineered alternative affords equivalent protection against water quality impairment and must perform an economic analysis of the proposed engineered alternative which demonstrates that compliance with the prescriptive standard is burdensome. The SAR has proposed an engineered alternative and has estimated closure costs. The engineered alternative would be the installation of a two to three foot thick compacted clay cover and the facility has demonstrated through data reportedin the SAR that there would be equivalent protection against water quality impairment. The estimated cost of closure is $124,300. However, an economic analysis demonstrating that compliance with the prescriptive standard is burdensome has not been performed. Prior to acceptance of the final closure plan and issuance of the revised closure waste discharge requirements (WDRs) , the analytical results of the resampling and the engineering and design documents for closure must be submitted. These technical reports must also contain the economic analysis to meet the requirements of Subchapter 15. If the surface impoundments are closed as a Class II landfill , a Facilities Permit will probably be needed from the Local Enforcement Agency (LEA). The