The effect of water treatment on the presence of particle-bound210Po and210Pb in groundwater

Abstract

SummaryThe distribution of210Po and210Pb in various particle-size fractions in Finnish groundwater was studied at five private homes. Each site had water treatment equipment comprising either an ion exchange unit or a granular activated carbon filter. Samples of both raw and treated water were filtered using pore sizes ranging from 450 nm to 100 kDa and the activity concentration of210Po and210Pb in the filtrate was determined. In untreated groundwater 86% of210Pb, on average, was found in the large particle fraction (>450 nm). However, in Fe- and Mn-rich water with a high Fe/Mn ratio and in organic-rich water, the majority of210Pb was found in either the intermediate particle (100 kDa–450 nm) or small particle (<100 kDa) fractions. Compared to210Pb,210Po was bound more to the intermediate and small particle fraction. After water treatment,210Pb was found most frequently in the large particle fraction. The size distribution of particle-bound210Po was not as clear as that for210Pb, and in treated water,210Po was more evenly distributed among fractions. The ion exchange unit removed210Pb and210Po bound to the intermediate or small particle fraction, whereas the efficiency of the activated carbon filters in removing210Pb and210Po was independent of the particle size.