Measurement of 224Ra and 225Ra activities in natural waters using a radon-in-air monitor.
We report a simple new technique for measuring low-level radium isotopes (224Ra and 226Ra) in natural waters. The radium present in natural waters is first preconcentrated onto MnO2-coated acrylic fiber (Mn fiber) in a column mode. The radon produced from the adsorbed radium is then circulated through a closed air-loop connected to a commercial radon-in-air monitor. The monitor counts alpha decays of radon daughters (polonium isotopes) which are electrostatically collected onto a silicon semiconductor detector. Count data are collected in energy-specific windows, which eliminate interference and maintain very low backgrounds. Radium-224 is measured immediately after sampling via 220Rn (216Po), and 226Ra is measured via 222Rn 218Po) after a few days of ingrowth of 222Rn. This technique is rapid, simple, and accurate for measurements of low-level 224Ra and 226Ra activities without requiring any wet chemistry. Rapid measurements of short-lived 222Rn and 224Ra, along with long-lived 226Ra, may thus be made in natural waters using a single portable system for environmental monitoring of radioactivity as well as tracing of various geochemical and geophysical processes. The technique could be especially useful for the on-site rapid determination of 224Ra which has recently been found to occur at elevated activities in some groundwater wells.
Kim
G
G
School of Earth and Environmental Sciences, Seoul National University, Korea.
Burnett
W C
WC
Dulaiova
H
H
Swarzenski
P W
PW
Moore
W S
WS
D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D011883:Radium / Q000032:analysis*; D012680:Sensitivity and Specificity; D013910:Thorium; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D014881:Water Supply
D014875:Water Pollutants, Radioactive; C026062:thorium X; D013910:Thorium; D011883:Radium