210Bi - from interference to advantage in 210Pb determination with liquid scintillation counter

A novel method for determination of 210Pb activity concentration using a liquid scintillation counter (LSC) in environmental samples is presented. After radiochemical separation of 210Pb on Eichrom Sr Resin column, the decay product 210Bi starts to in-grow and interfere with the 210Pb during measurement with LSC. Instead of eliminating this interference, a novel method utilises 210Bi in-growth to improve the detection efficiency and subsequently to lower the minimum detectable activity (MDA). This allows for substantial reduction of the MDA compared to conventional methods.