Stontium-90 contamination in vegetation from radioactive waste seepage areas at ORNL, and theoretical calculations of 90Sr accumulation by deer

This report describes data obtained during a preliminary characterization of 90Sr levels in browse vegetation from the vicinity of seeps adjacent to ORNL solid waste storage areas (SWSA) where deer (Odocoileus virginianus) were suspected to accumulate 90Sr through the food chain. The highest strontium concentrations in plant samples were found at seeps associated with SWSA-5. Strontium-90 concentrations in honeysuckle and/or blackberry shoots from two seeps in SWSA-5 averaged 39 and 19 nCi/g dry weight (DW), respectively. The maximum concentration observed was 90 nCi/g DW. Strontium-90 concentrations in honeysuckle and blackberry shoots averaged 7.4 nCi/g DW in a study area south of SWSA-4, and averaged 1.0 nCi/g DW in fescue grass from a seepage area located on SWSA-4. A simple model (based on metabolic data for mule deer) has been used to describe the theoretical accumulation of 90Sr in bone of whitetail deer following ingestion of contaminated vegetation. These model calculations suggest that if 30 pCi 90Sr/g deer bone is to be the accepted screening level for retaining deer killed on the reservation, then 5-pCi 90Sr/g DW vegetation should be considered as a possible action level in making decisions about the need for remedial measures, because unrestricted access and full utilization of vegetation contaminated with <5 pCi/g DW results in calculated steady-state (maximum) 90Sr bone concentrations of <30 pCi/g in a 45-kg buck