White Oak Creek Embayment site characterization and contaminant screening analysis

Analyses of sediment samples collected near the mouth of White Oak Creek during the summer of 1990 revealed [sup 137]Cs concentrations [> 10[sup 6] Bq/kg dry wt (> 10[sup 4] pCi/g dry wt)] near the sediment surface. Available evidence indicates that these relatively high concentrations of [sup 137]Cs now at the sediment surface were released from White Oak Dam in the mid-1950s and had accumulated at depositionalsites in the embayment. These accumulated sediments are being eroded and transported downstream primarily during winter low-water levels by flood events and by a combination of normal downstream flow and the water turbulence created by the release of water from Melton Hill Dam during hydropower generation cycles. This report provides a more thorough characterization of the extent of contamination in WOCE than was previously available. Environmental samples collected from WOCE were analyzed for organic, inorganic, and radiological contaminants in fish, water, and sediment. These results were used to conduct a human health effects screening analysis. Walkover radiation surveys conducted inside the fenced area surrounding the WOCE at summer-pool (741 ft MSL) and at winter-pool (733 ft MSL) level, indicated a maximum exposure rate of 3 mR h[sup 1] 1 m above the soil surface.