Investigation of a novel method for polonium-210 determination in groundwater.

摘要

A novel method was investigated for the quantification of 210 Po in water as an alternative to the standard method of spontaneous plating onto Ag disks followed by quantification with an alpha spectrometer. The novel method concentrated a 0.5L sample by MnO2 co-precipitation followed by dissolution of the precipitate into a solution. Polonium-210 was separated from the solution and quantified in a column containing a 50:50 by volume mixture of Pb resin (Eichrom Technologies, Inc.) mixed with granulated CaF2:Eu scintillator. The column containing 210Po is quantified on a liquid scintillation counter without the introduction of liquid cocktail. The minimum detectable concentration (MDC) is 53 mBq/L for the novel method compared to 2 mBq/L for the standard method. This MDC of the novel method meets the WHO limit of 100 mBq/L, but is significantly higher than the standard method. Polonium-210 concentrations were determined for five groundwaters from locations in upstate region of South Carolina and Nevada. The 210Po concentration as determined for the novel method ranged from Po concentration as determined for the novel method ranged from MDC to 3703.0 mBq/L. Correlation between the concentrations found by the standard and novel methods was not good. In every case where the concentration was above the MDC, the concentration determined by the novel method trended higher, ranging from 37.2% to 90.3 %. In most cases, the higher concentration was attributed to uranium in the groundwater. Due to high variability in the background for the novel method columns, there is significant uncertainty in the concentrations determined by the novel method.