Sample activity report for cobalt sampling at the 300-FF-1 South Process Pond

摘要

This report has been prepared to summarize the sampling conducted under the Cobalt Sampling Plan for the South Process Pond (SPP). The sampling plan was prepared to support near-term decisions being made with respect to cleanup criteria for cobalt-60 in the SPP within the 300-FF-1 Operable Unit. Statistically based sampling was designed to provide sufficient data to state confidence and error in estimating the mean of cobalt-60 concentrations in the SPP surface soils. Process knowledge and sample data taken in 1987 and 1991 indicate that the major SPP contaminants are cobalt-60 and uranium with some metals at low concentrations. Specifically, the cobalt-60 data indicate the current average concentration of cobalt-60 in the surface soils of the pond as near 8 pCi/g based on eight surface samples. The sampling event was designed to verify the average cobalt-60 concentration by taking enough randomly located samples to make statistical statements regarding the data. Sampling procedures conformed to the requirements established by the Environmental Restoration Contractor Team Environmental Investigations Procedures. The sampling plan called for only four biased samples. During the sampling, additional biased samples were taken to investigate several hot spots in the SPP.