Measurement of radon levels in groundwater supplies of Riyadh with liquid scintillation counter and the associated radiation dose

Occurrence and hazard assessment of natural radioactivity in drinking water in South Lebanon

This study is intended to assess the natural radioactivity in the drinking water in the southern region of Lebanon and to determine its suitability for human consumption. In this context, activity concentrations for gross alpha, gross beta, ²³⁸U, ²³⁴U, and radon from selected drinking water sources, wells, and springs and the corresponding tap water, in the area under investigation, were determined during both the wet and the dry seasons. The maximum recorded activities of gross alpha, gross beta, and radon measured using liquid scintillation counter were found to be 374.6 ± 11.5 mBq L^-1 for gross alpha, 418 ± 12 mBq L^-1 for gross beta, and 42,900 ± 370 mBq L^-1 for radon. Whereas, alpha spectroscopy analysis for uranium content showed maximum activities of 53.7 ± 2.1 mBq L^-1 for ²³⁸U and 55.9 ± 2.3 mBq L^-1 for ²³⁴U. Significant seasonal activity variation between wet and dry season was noticed only in gross alpha concentrations. In addition, significant variation between sources and tap water was recorded only in radon concentrations. Whereas, no significant variation was noted in radioactivity concentrations in waters from springs and those from wells. In contrast to all sampled locations, the annual effective dose of only one sampled well (Aitaroun) exceeded the WHO individual dose criterion (IDC) level of 100 µSv year^-1 and recorded an annual effective dose of 170 µSv year^-1, 103 µSv year^-1, and 127 µSv year^-1 for infants, children, and adults, respectively.

The Potential Use of Zeolite, Montmorillonite, and Biochar for the Removal of Radium-226 from Aqueous Solutions and Contaminated Groundwater

The present work investigated the potential of using zeolite (clinoptilolite), montmorillonite (Swy2), and Conocarpus biochar as adsorbents to remove 226Ra from aqueous solution. The effect of the initial 226Ra concentrations on sorbents’ equilibrium activity concentrations and sorbents’ radium removal efficiency were investigated. The results showed that zeolite has a higher removal efficiency for 226Ra in comparison with the efficiencies of montmorillonite and biochar. In addition to the linear isotherm model, the Freundlich model, followed by Temkin’s model, provided a better description of the adsorption process than the Langmuir model. Kinetic studies indicated that a pseudo-second-order kinetic model could be the best fit for the adsorption of 226Ra onto the three investigated sorbents, which suggests that the mechanism of adsorption of 226Ra by sorbents was chemisorption. The intraparticle diffusion model indicated that adsorption of 226Ra onto the sorbents involves a multistep process: (i) boundary layer diffusion and (ii) intraparticle diffusion. Moreover, the remediation of groundwater samples polluted with 226Ra was assessed using the investigated sorbents; the results showed that zeolite also has the highest removal efficiency among other sorbents. Thus, the low cost, availability, and the high adsorption efficiency of zeolite can be a promising sorbent on 226Ra removal from aqueous solutions and groundwater remediation.

Heavy metals and radon content in spring water of Kosovo

Paper presents results of researches carried out on various locations and immediate vicinity of mining and industrial activities of the northern and south-eastern part of Kosovo. Concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn, Rn-222, as well as temperature and pH values of natural spring water were measured at 15 measuring sites (that belong to Zvečan, Leposavić and Novo Brdo municipalities), in April-May and September-October 2019. The quantification of heavy metals' content was performed by applying ICP-OES method. In analysed samples a high content of As, Pb, Fe and Ni was found. Carcinogenic and non-carcinogenic risks due to the content of heavy metals in water were evaluated. Concentration of radon in water was measured by the alpha spectrometric method, and measured values range in the interval from 0.34 ± 0.12 to 341 ± 35 Bq/L. The yearly doses of inhalation and ingestion were determined for the measured concentrations of radon. Mutual correlation by the Pearson correlation coefficient, principal component analysis, cluster analysis and spatial distribution analysis of the researched parameters of sampled water were done. The most expressed mutual dependence of some heavy metals leads to the conclusion that they have the same anthropogenic origin.

Assessment of radioactivity from groundwater samples from selected areas of Western Black Sea Region, Turkey

In this study, radon concentration measurements and chemical analyses of groundwater samples were performed in four sampling locations of Bartın Province of Western Black Sea Region, Turkey. 222Rn analysis was carried out in groundwater samples with liquid scintillation counting system in accordance with ASTM D5072 standard. The pH, total hardness, alkalinity and dissolved oxygen parameters of the groundwater samples were also determined. The radon concentrations for the water samples ranged between <3.00 Bq/L–12.03 Bq/L. Thirty eight percentage of the samples slightly exceeded the permissible limit of 11.1 Bq/L specified by USEPA for drinking waters. The annual effective doses of groundwater samples were calculated in the range of 7.41–30.74 μSv/y for ingestion of water (E w.Ig ), and in the range of 7.31–30.31 μSv/y for inhalation of radon released from water (Ew.Ih ). The total calculated annual effective doses due to ingestion and inhalation were found to be below the limit value of 100 μSv/y specified by the World Health Organization (WHO). The radioactivity measurement results significantly varied for three sampling points but not for one sampling point on two different measurement dates, which is attributed to the differences in geological structure. The chemical analysis results, except for total hardness in two sampling points, were within the permissible limits specified by international standards.

Radon in spring waters in the south of Catalonia

Spring waters in the south of Catalonia were analysed to determine the (222)Rn activity in order to be able to establish a correlation between the obtained values with the geology of the area of origin of these samples, and also estimate the potential health risks associated with (222)Rn. Most of the analysed samples (90%) show (222)Rn activities lower than 100Bq/L (exposure limit in water recommended by the World Health Organisation and EU directive 2013/51/EURATOM). However, in some cases, the activity values found for this isotope exceeded those levels and this can be attributed to the geology of the area where the spring waters are located, which is predominantly of granitic characteristics. To verify the origin of the radon present in the analysed samples, the obtained activity values were compared with the activities of its parents ((226)Ra, (238)U and (234)U). Finally, we have calculated the annual effective dose from all the radionuclides measured in spring water samples. The results showed that the higher contribution due to spring water ingestion come from (222)Rn and (226)Ra. The resulting contribution to the annual effective dose due to radon ingestion varies between 10.2 and 765.8 μSv/y, and the total annual effective dose due to his parents, (226)Ra, (234)U and (238)U varies between 0.8 and 21.2 μSv/y so the consumption of these waters does not involve any risks to population due to its natural radioactivity content.

Occurrence of radon in groundwater of Saudi Arabia

Samples were collected from 1025 wells supplying drinking water to the 13 regions of Saudi Arabia and analyzed for radon concentrations. The weighted radon median value for the entire country was found to be 4.62 Bq L(-1) with a range of 0.01-67.4 Bq L(-1). The percentage of samples with radon concentration equal to or greater than 11.1 Bq L(-1) (US EPA proposed MCL) was found to be 19.22%. The range of radon in shallow wells varied between 0.06 and 67.4 Bq L(-1) (median value 5.1 Bq L(-1)) and between 0.06 and 40.9 Bq L(-1) (median value 5.34 Bq L(-1)) for deep wells. However, 50% of the samples had radon concentrations equal to or greater than 4.0 and 2.87 Bq L(-1) for the shallow and deep wells, respectively. Correlation of well depth with radon levels revealed that wells drilled in Saq aquifer consisting of predominantly sandstone with significant shale layers in the upper parts, gave higher median radon levels than in Manjur aquifer which consists of predominantly limestone and sandstone.

Establishment of a method for ²²²Rn determination in water by low-level liquid scintillation counter

A procedure for the determination of (222)Rn in environmental water samples using liquid scintillation counting (LSC) was performed. The (226)Ra content in the water was determined by gamma-ray spectroscopy. An application of this procedure to drinking water collected from a public drinking fountain in Vojvodina (Serbia) is presented, including calculations of the annual effective dose for ingestion and inhalation for adults.