Source of Gross-Alpha Radioactivity Anomalies in Recharge Wells, Central Florida Phosphate District

摘要

The central Florida phosphate industry utilizes recharge wells to mitigate withdrawals of water from the Florida aquifer and to dewater the surficial aquifer prior to mining. From a water management point of view, these wells are efficient and serve a vital function. Recent monitoring of the radiation environment in these wells, however, casts doubts on the safety of the wells. While most of the wells conform to state and federal standards for radium, gross-alpha radiation frequently exceeds standards. The purpose of the study was to determine the radionuclide(s) responsible for the high gross-alpha radiation and to identify a method for sampling of the recharge wells that would standardize data across the phosphate district. It was found that excess gross alphais primarily due to polonium-210. Since gross alpha and polonium-210 measurements are quite sensitive to methods of sample collections, preservation and analyses, standard procedures for sample processing are presented in the report.