Evaluation of natural radioactivity content in high-volume surface water samples along the northern coast of Oman Sea using portable high-resolution gamma-ray spectrometry

A review of radioactivity in the Gulf region

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.

Determination of natural radioactivity levels and gamma radiation attenuation coefficients in propolis samples and the study of its antioxidant properties

Thanks to its rich content, propolis has been used to protect the hive from all kinds of external influences and for disinfection by bees. Furthermore, it is an important marker for monitoring environmental pollution because the main sources of propolis are plant and secretions. So, the present study aimed to research radiation attenuation capability and the natural radioactivity level of propolis samples. For this reason, both natural radioactivity concentrations (226Ra, 232Th and 40K) and attenuation coefficients (Linear and Mass) in the propolis samples collected from 10 different points in Turkey were measured using high purity germanium detector (HPGe). The average natural radioactivity concentrations in samples were found to be 0.56 ± 0.19, 2.65 ± 0.31 and 70.08 ± 2.42 Bq/kg for 226Ra, 232Th and 40K, respectively. These values were much lower than the average world values (35 Bq/kg for 226Ra, 30 Bq/kg for 232Th and 400 Bq/kg for 40K) reported by United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR) in foodstuff. The average linear attenuation coefficient, mass attenuation coefficients and half value layer values for gamma rays with 59.54 keV energy were determined as 0.1970 cm−1, 0.1831 cm2 g−1 and 3.56 cm, respectively. In addition, antioxidant properties of the samples were measured using total phenolic content and ferric reducing antioxidant power. Their correlations with radioactivity were investigated.

Radiation hazards and lifetime risk assessment of tap water using liquid scintillation counting and high-resolution gamma spectrometry

In this work, two complementary techniques, viz. liquid scintillation counting and high-resolution gamma spectrometry are utilized to analyze radionuclides concentrations in tap water of Irbid governorate, Jordan, and study their correlation. Gross alpha and gross beta concentrations, in the tap water samples collected from the nine districts of Irbid governorate, ranged from <82 to 484 mBq/L with a mean of 295 mBq/L and from <216 to 984 mBq/L with a mean of 611 mBq/L, respectively. Furthermore, gamma spectrometry analysis, for the tap water samples, shows that the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K ranged between <19 and 302 mBq/L, 24 to 119 mBq/L, and <101 to 342 mBq/L, respectively. There was a weak or even no correlation among the identified natural radionuclides with no trace of artificial radioactivity. In addition, the results of both techniques show that storing tap water in drilled wells leads to higher levels of radioactivity concentrations beyond the international permissible limits. Furthermore, the average lifetime risk and annual effective dose received by age-grouped inhabitants due to direct and indirect tap water consumption are evaluated, where most of the received dose is attributed to ²²⁶Ra.

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 18.6-19.1Bql^-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 371days. 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.

Assessment of 226Ra, 238U, 232Th, 137Cs and 40K activities from the northern coastline of Oman Sea (water and sediments)

Water and sediment samples were collected from northern coast of Oman Sea covering from Goatr to Hormoz canyon seaport. Water and sediment quality assessment for naturally or anthropogenic radionuclides at Oman Sea as a main strategic golf for trade and transit, is an important issue. Correspondence analysis (CA) by R-mode analysis represents that sigma(T)-temperature-conductivity-O₂ parameters are well-correlated with ²²⁶Ra, ²³²Th and ⁴⁰K. Accordingly Q-mode analysis revealed an indicator samples of ST13W for different radionuclides, ST03W for O₂, and simultaneously ST34W-ST21W-ST08W-ST04W for sigma(T) parameters. The CA results overlapped with factor and cluster analysis results that explained 85.8% of total variance of water samples. Descriptive analysis of sediments indicates more significant variation than water samples. The ²³²Th and ²²⁶Ra generally showing that ST13D to ST25D sediments that restricted to Pi Bashk coastline are concentrated from ¹³⁷Cs and ⁴⁰K. By comparison with reference-values from Iran and other parts of the world, they are acceptable with respect to environmental and radioisotope hazards.

Assessment of natural radioactivity and (137)Cs in some coastal areas of the Saudi Arabian gulf

The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO2. Shore sediment samples were analyzed for (226)Ra, (228)Ra ((232)Th), (4)°K and (137)Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02 mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected.