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r <br /> Second paragraph- <br /> Revise to include the following additional requirements for <br /> samples collected around the perimeter of the north yard. <br /> Excluding N-8, locations N-5 through N-9 shall be sampled at <br /> 5 feet below land surface and every 5 feet thereafter until <br /> groundwater is encountered. These samples along with all <br /> north yard samples scheduled for analysis (Table 4-1) , shall <br /> be submitted for determination of total chromium, hexavalent <br /> chromium, copper, and arsenic concentrations. Sample <br /> moisture content must also be determined at time of analysis <br /> with the value recorded as part of the analytical report. <br /> Note- <br /> Pursuant to paragraph 5.3.4 (E) (2) of the Department' s <br /> March 1, 1988 Remedial Action Order (RAO) , characterization <br /> of the vadose zone is required. As part of this <br /> characterization all soil samples collected in accordance <br /> with the modified workplan shall be classified using the <br /> Unified Soil Classification Scheme (USCS) . See page 26 of <br /> the RAO for additional characterization requirements. <br /> MCTC Response: <br /> Zinc will be added to the list of constituents as requested. <br /> From locations N-5, N-6, N-7 and N-9, soils will be sampled at 5 <br /> feet below land surface and every 5 feet thereafter until <br /> groundwater is encountered. Table 4-1 will be revised to <br /> identify which samples will be analyzed upon collection and which <br /> samples will be archived for analysis at a later time if <br /> warranted by initial results. The purpose of this additional <br /> characterization is to confirm that vadose zone contamination <br /> does not extend offsite. <br /> MCTC will obtain additional information pertaining to soil <br /> physical characteristics as part of the soil sampling efforts. <br /> Using samples of soil from clayey-silt, sandy and sandy-silt <br /> soils encountered in borings, the following tests will be run for <br /> each soil type: <br /> o Hydraulic conductivity <br /> o Relative permeability <br /> o Bulk density <br /> o Porosity <br /> o Soil sorptive capacity <br /> o Soil organic content <br /> o Mineral content <br /> o Soil moisture tention <br /> 11654 2 <br />