Development of a Standardized Leaching Procedure for the Evaluation of Uranium Mobility in Groundwater in Nova Scotia

Abstract

Approximately 4% of drinking water wells in Nova Scotia contain elevated concentrations of naturally-occurring uranium. There is demand for a simple and effective procedure to evaluate soil and rock formations for uranium mobility prior to the development of potable water supplies in vulnerable regions. Empirical evidence shows that uranium mobilization in groundwater can be enhanced in the presence of key ions. A series of extractions were performed on uranium-bearing Nova Scotian rocks, noting the impact of calcium, sodium, chloride, and bicarbonate concentrations in the extraction fluid on uranium mobilization. A uranium leaching procedure (ULP) was developed and compared to the general synthetic precipitation leaching procedure (SPLP). The ULP was capable of mobilizing an order of magnitude or more uranium than the SPLP from six Nova Scotian rock samples and shows promise as a tool for choosing groundwater resources to minimize the risk of groundwater contamination through uranium mobilization.