A Method To Measure Arsenic Readily Released To Pore Waters From Uranium Mill Tailings

A method to quantify the amount of readily released arsenic in uranium mill tailings was developed using a technique known as Equilibrium Partitioning In Closed Systems (EPICS). The method employs a gentle leaching solution that, except for its arsenic (As) concentration, is identical to the neutralized raffinate that contacts the tailings. Prior to implementation, the experimental design and mathematical approach were verified in geochemical models using PHREEQC. Laboratory experiments using tailings from the Athabasca Basin of Northern Saskatchewan demonstrated that As that could be readily released to pore waters is about 0.2 % of the total As in the tailings.