A review of radioactivity in the Gulf region

Abstract

The region around the Gulf is moving toward a nuclear energy option with the first nuclear power plant now operational in Bushehr, Iran. Others are soon to be commissioned in Abu Dhabi and in Saudi Arabia. For this reason, radiological safety is becoming a prime concern in the region. This review compiles published data on radionuclide concentrations in seawater, sediment, and biota that have been analyzed in the Gulf countries, along with spatial distribution patterns to enable a synoptic view of the available datasets. The seawater concentrations of ³H, ²¹⁰Po, ²¹⁰Pb, ¹³⁷Cs, and ⁹⁰Sr varied between 130 and 146, 0.48-0.68, 0.75-0.89, 1.25-1.38, 0.57-0.78 mBq L^-1, respectively. The ²²⁶Ra concentration in seawater varied between 0.26 and 3.82 Bq L^-1. Extremely high ⁴⁰K concentrations between 132 and 149 Bq L^-1 have been reported from the Iranian coast compared to 8.9-9.3 Bq L^-1 from the western side of the Gulf. Concentrations of ⁴⁰K, total ²¹⁰Pb, ¹³⁷Cs, ⁹⁰Sr, ²²⁶Ra, ²²⁸Ra, ²³⁸U, ²³⁵U, ²³⁴U, ^239+240Pu, and ²³⁸Pu were determined in sediment and ranged between 353 and 445, 23.6-44.3, 1.0-3.1, 4.8-5.29, 17.3-20.5, 15-16.4, 28.7-31.4, 1.26-1.30, 29.7-30.0, 0.045-0.21 and 0.028-0.03 Bq kg^-1 dry weight, respectively. Significantly higher ¹³⁷Cs values have been reported from the Iranian coast compared to the western coast of the Gulf. Whole fish concentrations of ⁴⁰K, ²²⁶Ra, ²²⁴Ra, ²²⁸Ra, ¹³⁷Cs, ²¹⁰Po and ⁹⁰Sr ranged between 230 and 447, 0.7-7.3, <0.5-6.6, <0.5-15.80, <0.17, 0.88-4.26 and 1.86-5.34 Bq kg^-1 dry weight, respectively. ²¹⁰Po was found to be highly concentrated in several marine organisms with the highest ²¹⁰Po concentration found in the clam Marcia marmorata (193.5-215.6 Bq kg^-1 dry weight). The review highlights the overall paucity of data and inconsistencies in the measurement of radionuclides throughout the Gulf region. Further, since the region is moving toward nuclear energy to meet its increasing energy demand, and coupled with the environmental effects from offshore oil exploration and the heavy impact of climate change, there is a pressing need to undertake a comprehensive marine radioactivity monitoring and assessment effort by conducting a joint cruise in the Gulf with participation of all the adjoining countries. Several recommendations on sampling marine matrixes in the Gulf are given with the aim of improving comparability of radionuclide data from the various studies undertaken in the Gulf region.

Keywords: 137-Cs; Biota; Marine area; Seawater; Sediment; Spatial distribution.