A rapid and inexpensive method for 226Ra and 228Ra measurements of high TDS groundwaters

A series of laboratory-scale studies was conducted by preconcentrating 226Ra from spiked water test samples using Purolite ion-exchange resin to evaluate the adsorption efficiency of the resin under varying conditions. After removing the resin from the columns, it was sealed in gas-tight containers and measured via gamma spectrometry. The Purolite resin showed high radium uptake and retention from natural waters in the presence of high iron and total dissolved solids (TDS). This procedure allowed us to process a large number of high TDS samples at a typical rate of 15 samples/day using three germanium detectors. Quality assurance and method validation have been achieved by analyzing selected groundwater samples, with different 226Ra activities and high TDS values, and comparing the results to those using alpha spectrometry with a 133Ba yield tracer. There was very good agreement between the obtained 226Ra activities by both methods.

► Laboratory had to evaluate 226Ra and 228Ra in thousands of groundwater samples.
► Samples had to be done quickly and contained high iron and total dissolved solids (TDS).
► Paper details development of a simple method based on ion exchange and gamma spectrometry.
► Side-by-side comparison to an alpha spectrometry method showed excellent agreement.