Improvement in the determination of 238U, 228-234Th, 226-228Ra, 210Pb, and 7Be by gamma spectrometry on evaporated fresh water samples.
For the U-Th series radionuclides investigation in natural freshwater, a simple, fast, and not laboratory intensive method which consists of evaporating the water samples to dryness in the presence of carriers is presented. The small volume of the residue (1-2 cm3) leads to a good efficiency for gamma counting and limits the self-absorption effect for the low energy gamma rays (less than 200 keV). The best efficiency is obtained with a well-type Ge detector. To determine the evaporation yields a river with a common uranium content, the Seine river (France), was selected. By using internal spikes and more conventional techniques of investigation, we demonstrate that the evaporation is quantitative for U, Th, Ra, Pb, and Be. The residue of a 3 L, standard superficial freshwater, evaporated sample was analyzed in a high efficiency, low background Ge detector, which leads to a sufficient precision for most environmental studies. The method has been applied to rain, river, and lake waters to study the impact of disused uranium mine water inputs on the 238U, 228-234Th, 226-228Ra, 210Pb, and 7Be river and lake contents in the U mining area of Limoges (France).
Cazala
C
C
Laboratoire des Sciences du Climat et de l'Environnement, domaine du CNRS, av de la Terrasse 91198 Gif sur Yvette, France. Charlotte.cazala@lsce.cnrs-gif.fr
Reyss
J L
JL
Decossas
J L
JL
Royer
A
A
D004784:Environmental Monitoring / Q000379:methods*; D011891:Rain; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013051:Spectrometry, Gamma / Q000379:methods; D014875:Water Pollutants, Radioactive / Q000032:analysis*; D014881:Water Supply
D014875:Water Pollutants, Radioactive