Naturally Occurring Radioactive Material (NORM) in seawater of the northern Arabian Gulf - Baseline measurements

This study focuses on creating baseline for 238U, 235U, 234U, 210Pb, 210Po and 40K concentrations in the northern Arabian Gulf. The respective concentration ranges were 0.047-0.050, 0.00186-0.00198, 0.054-0.057, 0.00085-0.00092, 0.00051-0.00062 and 18.6-19.1 Bq l− 1. These results suggest that the levels are generally comparable to other marine waters in the northern hemisphere. There were no hot spots observed from oil and gas industry. These data will serve as a baseline to gauge possible future inputs of TENORMs in the northern Gulf. A positive and linear correlation was observed between 238,234U, 40K isotopes and seawater salinity. The results also suggest significant fractionation between 210Po and 210Pb, attributed to rapid removal of 210Po by biota compared to 210Pb. The mean residence time for 210Po in the study area was 371 days. The 234U/238U and 238U/235U activity ratios in seawater samples vary between 1.14-1.15, and 0.038-0.040. The 234U/238U and 235U/238U ratio is similar to the expected composition of seawater (1.148 ± 0.002) and 0.0462.