Determination of natural radioactivity in Euphrates river

Levels of naturally occuring radionuclides (radium isotopes, U isotopes, ²¹⁰Po and ²¹⁰Pb) in water, sediments and biota samples collected from Euphrates river during the 1999–2000 period have been determined. Results have shown that the water contained relatively high levels of ²²⁶Ra; the largest value of 1150 mBq·l^–1 was observed. These relatively high levels of ²²⁶Ra, which is one of the main radioactive contaminants in the oil industry, may be due to past discharges of production water from the oil fields situated near the river banks. ²²⁶Ra/²³⁸U activity ratio was found to be more than unity in all water samples varying between 13 and 242. In addition, the results of sediment analyses have also shown lower values for ²²⁸Ra/²²⁶Ra activity ratio than unity in those samples collected nearby the oil fields. Moreover, concentrations of other naturally occurring radionuclides such as uranium isotopes, ²¹⁰Po and ²¹⁰Pb for most samples (water, sediments and biota) were found to be within the natural levels and in agreement with those values reported for other local and international studies. Only mussel species were found to contain high levels of ²¹⁰Po, about 1335 Bq·kg^–1 dry mass was observed in Anodonta sp species. However, the results of this study can be considered a baseline for monitoring of future changes. A regional research project (including Turkey, Syria and Iraq) to study this river (from the Anatolia Mountains to the Arabian Gulf) is necessary to determine the impact of all potential sources of contaminants.This revised version was published online in November 2005 with corrections to the Cover Date.