Disequilibrium of uranium isotopes in some Syrian groundwater

Uranium concentration in groundwater samples from three areas of Syria was determined using α-spectrometry and INAA. It was in the range of 0–6.13 μg/l in the phosphate areas, and lower than 1 ppb in the volcanic areas. The activity ratio of 234U/238U was investigated, and disequilibrium of uranium isotopes was found to occur (234U/238U=[0.52−2.02]. The excess of 234U was calculated. This excess can be interpreted by higher mobility of 234U, which more readily forms the soluble (UO2)2+ ion in comparison with 238U, most of which remains in the insoluble 4+ state. This excess increases with increase in uranium concentration. Thorium concentration was measured using INAA, it was found to be in the rang 0–1.15 μg/l.