Fluvial Placement of Radioactive Contaminants a Weldon Spring Case Study

The operation of the Weldon Spring Uranium Feed Materials Plant in St. Charles, MO between 1958 and 1966 resulted in the migration and emplacement of radioactive contaminants into surface water drainage systems. Multiple drainage systems, receiving from a variety of waste discharge points, combined to create unique and unexpected depositional environment. Discovery and investigation of the depositional environments was a significant technical challenge due to the complex nature of sediment movement and emplacement. The objective of this investigation was to show that application of the knowledge of geomorphic processes is an essential element of a complete stream characterization, pursuant to risk analysis and remediation. This paper sets out to describe many of the expected and unexpected findings of the investigations by the Weldon Spring Site Remedial Action Project (WSSRAP) into the placement and rework of contaminated sediments in stream systems. Information from this paper will be useful to other agencies and contractor personnel faced with the challenge of locating and quantifying contaminated sediments in seemingly haphazard fluvial depositional conditions