Natural radioactivity measurements in groundwater from Al-Jawa, Saudi Arabia

Natural radioactivity level in Yemen: A systematic review of radiological studies

This paper aimed to conduct a systematic review of 26 published articles from 13 different regions in the Republic of Yemen related to the study of natural radioactivity (NORM) and enhanced artificial radioactivity (TENORM). The study relied on the analysis of various sample types, including air, groundwater, surface water, hot spring water, soil, sand, rocks, building materials, and oil field samples. It also analyzed the study areas, the types of detectors employed, and the study's timeframe. The analytical results raised significant concerns regarding the high levels of radioactivity observed in many of the studied regions. Moreover, some regions indicated the absence of any prior radiological study, despite apparent effects on the population and the environment, which suggest the presence of potential radionuclide concentration. Based on this study, it is strongly recommended that researchers conduct further radiological studies in regions previously studied over extended periods and in areas where no prior radiological studies have been conducted to assess potential radionuclide concentration.

Environmental evaluation of radioactivity levels and associated radiation hazards in groundwater around the WIPP site

Groundwater may contain radioactive substances which can be dangerous to human health. Concentrations of natural radionuclides polonium (Po), thorium (Th), uranium (U), and radium (Ra) isotopes were measured in groundwater samples collected from different locations in the vicinity of the Waste Isolation Pilot Plant (WIPP) site in Carlsbad, New Mexico. The average values of gross activity concentrations of ²¹⁰Po, ²²⁸Th, ²³⁸U, ²³⁴U, ²²⁶Ra and ²²⁸ Ra isotopes were determined to be 1.62 Bq L^-1 in shallow groundwater and 5.88 Bq L^-1 in deep groundwater, respectively. The total radioactivity in deep groundwater was higher than that in shallow groundwater, and most of the radioactivity in the water is from ²²⁶Ra. Furthermore, the effective doses for ingestion of natural radionuclides were about 0.333 mSv y^-1 for shallow groundwater and about 1.338 mSv y^-1 for deep groundwater samples, which are higher than the World Health Organization (WHO, 2017) guideline level (0.1 mSv y^-1) for drinking water. Ra dominated the total ingestion dose, contributing 93.06 % and 75.40 % of the total effective doses to the deep and shallow groundwater, respectively. The ingrowth and decay of natural radionuclides suggested that ²²⁸Ra/²²⁶Ra ratio can be a useful indicator of the source of radioactive contamination. The radioactivity data obtained from the investigated groundwater samples can be used to establish a baseline for radioactivity levels in groundwater around the WIPP site.

Evaluation of Radiological Health Risks in Popularly Consumed Brands of Sachet Water in Nigeria

Radiological investigation of 35 brands of most popularly used sachet drinking water in Ondo state, Nigeria has been carried out using a spectrometric method for evaluating the concomitant health risks to the members of the public. Activity concentrations of the investigated radionuclides ⁴⁰K, ²²⁶R, and ²²⁸Ra were in the range from 16.35 ± 4.10 to 199.94 ± 38.40 Bq L⁻¹ with an arithmetic mean (AM) of 66.22 ± 54.99 Bq L⁻¹, from 1.35± 0.79 to 17.06 ± 5.13 Bq L⁻¹ with an AM of 6.88 ± 3.66 Bq L⁻¹, and from 1.95 ± 0.08 to 17.22 ± 3.87 Bq L⁻¹ with an AM of 9.49 ± 4.98 Bq L⁻¹, respectively. The determined annual effective doses and the corresponding excess lifetime cancer risks due to ²²⁶Ra and ²²⁸Ra were found to exceed the acceptable limits of 0.1 mSv y⁻¹ and 10⁻³ respectively, as suggested by the World Health Organization (WHO). This implies a non-negligible carcinogenic health hazard due to the intake of the surveyed drinking water, especially for the lactating babies (0–1) y and teenagers (12–17) y. The data from this research may form an invaluable component of radiometric values of the database in Nigeria, as well as the world for setting up guidelines and control policies for the use of sachet water.

Factors controlling groundwater radioactivity in arid environments: An automated machine learning approach

Groundwater resources in the Kingdom of Saudi Arabia (KSA) have high levels of natural radioactivity. Within the northwestern KSA, gross alpha (α) and gross beta (β) levels exceed national and international drinking-water limits. In this study, we developed and used an automated machine learning (AML) approach to quantify relationships between gross α and gross β activities and different geological, hydrogeological, and geochemical conditions. Two AML model groups (group I for gross α; group II for gross β) were constructed, using water samples collected from 360 irrigation and water supply wells, to define a robust model that explains the spatial variability in gross α and gross β activities, as well as variables that control the gross activities. Each group contained four model families: deep neural network (DNN), gradient boosting machine (GBM), generalized linear model (GLM), and distributed random forest (DRF). Model inputs include chemical compositions as well as geological and hydrogeological conditions. Three performance metrics were used to evaluate the models during training and testing: normalized root mean square error (NRMSE), Pearson's correlation coefficient (r), and Nash-Sutcliff efficiency (NSE) coefficient. Results indicate that (1) the GBM model outperformed (training: NRMSE: 0.37 ± 0.10; r: 0.92 ± 0.05; NSE: 0.85 ± 0.09; testing: NRMSE: 0.71 ± 0.08; r: 0.72 ± 0.08; NSE: 0.49 ± 0.12) the DNN, DRF, and GLM models when modelling gross α activities; (2) gross α activities are controlled by pH, stream density, nitrate, manganese, and vegetation index; (3) the DRF model outperformed (training: NRMSE: 0.41 ± 0.05; r: 0.92 ± 0.02; NSE: 0.83 ± 0.04; testing: NRMSE: 0.67 ± 0.09; r: 0.77 ± 0.07; NSE: 0.54 ± 0.12) the GBM, DNN, and GLM models when modelling gross β activities; (4) input variables that affect the gross β actives are pH, temperature, stream density, lithology, and nitrate; and (5) no single model could be used to model both gross α and gross β activities-instead, a combination of AML models should be used. Our computationally efficient approach provides a framework and insights for using AML techniques in water quality investigations and promotes more and improved use of different geological, hydrogeological, and geochemical datasets by the scientific community and decision makers to develop guidelines for mitigation.

Groundwater Quality Studies in the Kingdom of Saudi Arabia: Prevalent Research and Management Dimensions

Groundwater is a valuable resource because it is widely used for drinking, and for domestic, agricultural, and industrial purposes. Globally, Saudi Arabia is known to be one of the driest regions with scarce water resources. The shallow groundwater near the major cities in the Kingdom of Saudi Arabia is becoming polluted because of industrial effluent discharge, use of fertilizers in agriculture and domestic sewerage in the region. This review tries to focus on groundwater quality problems due to anthropogenic or geogenic sources in the region of Saudi Arabia. In this paper, we focus on different water-quality variables, for groundwater quality evaluation and aquifer vulnerability assessment due to pollutants/contaminants present in groundwater. The current study gives a holistic understanding of different groundwater quality problems and therefore identifies the gaps of the previous studies and identifies the viewpoints of the future research dimensions. We describe the different groundwater quality problems related to toxicities of the fluoride, nitrate, and heavy metals and radionuclides in Saudi Arabia. A majority of the groundwater pollutants are of natural origin, but there is significant wastewater effluent discharge in the region that is also responsible for contamination of aquifers with heavy metals.

The assessment of the annual effective dose due to ingestion of radionuclides from drinking water consumption: calculation methods

In the present paper the different ways of assessing the annual effective dose due to ingestion of radionuclides by drinking water consumption were examined and exemplified. On a set of 10 samples the gross alpha activity, the gross beta activity, the concentration of 210Po, 210Pb, 238U, 232Th and, 226Ra were measured. The highest annual effective dose values assessed by relying on the investigated sample set were found by using the rationale according to which all the gross alpha and beta activity is due to the alpha and beta radionuclide, with the highest effective dose coefficient, namely 210Po and 210Pb/228Ra, respectively.

226Ra AND 228Ra CONCENTRATIONS IN SOILS WITH INTENSE GROUNDWATER IRRIGATION IN AN ARID ENVIRONMENT

The enhancing effect due to long-time irrigation with radium-containing groundwater on soil was investigated in this work. Samples from the Al-Qassim and Hail areas in Saudi Arabia were studied for their 226Ra and 228Ra inventories. Groundwater and soil samples were collected from 32 farms where agricultural activities are intensively irrigated with radium-containing groundwater. A noticeably good correlation was observed between radium isotopes inventories in the groundwater used for irrigation with those in the associated soils. It was concluded that there are enhanced levels of radium isotopes in the soils due to the existence of radium isotopes in irrigated groundwater. The additional annual effective dose values ranged between 0.00 and 0.412 with an average of 0.09 mSv y-1.

Assessment Framework for Natural Groundwater Contamination in Arid Regions: Development of Indices and Wells Ranking System Using Fuzzy VIKOR Method

Limited groundwater resources in arid regions have been found polluted for drinking purpose due to the presence of natural minerals and radioactive substances, in the sub-soils, higher than the drinking water quality standards. Municipalities in these regions are spending extensive resources to transport (from well fields) and treat this raw water to provide safe water to the community. Regular monitoring of various physical, chemical, and radioactive water quality parameters (WQPs) in raw water generates large datasets, which makes it difficult to come up with convenient findings for both the decision-makers and general public. A hierarchical water quality assessment framework develops three sub-indices, an overall water quality index, and a system for ranking of groundwater wells. Fuzzy analytical hierarchy process (fuzzy-AHP) establishes the importance weights of different WQPs and the sub-indices based on their impacts on human health, treatment processes, distribution system infrastructure, and irrigation applications. Fuzzy VIekriterijumsko KOmpromisno Rangiranje (fuzzy-VIKOR) method aggregates the WQPs’ performance for each well and ranks all the wells in a well field based on their overall pollution levels, i.e., remoteness from the applicable standards. For evaluating the pragmatism of the framework, data of 11 WQPs were obtained for 39 wells operating in three different well fields located along the boundaries and the central part of Buraydah, Qassim, Saudi Arabia. Spatial water quality maps showing physical, chemical, radioactive, and overall water quality assessment results revealed that the oldest well field located in the middle of the city outperforms the other two more recently developed well fields with lesser anthropogenic activities in their catchments. These findings testify that the primary source of contamination in deep aquifers is the natural sub-soil condition. The water quality indices will be useful to demonstrate the current situation of groundwater quality in Qassim Region and will facilitate the decision-makers for defining the intended uses of raw water sources (i.e., drinking, unrestricted irrigation, and restricted irrigation) and rehabilitation and renewal planning of the groundwater wells. The framework is applicable in the Kingdom of Saudi Arabia (KSA), Gulf Region, and elsewhere for groundwater quality assessment with desired modifications.

Assessing the Committed Effective Dose From 226Ra in Thermal Spring Water From San Diego De Alcala, Chihuahua, Mexico

The oral administration of mineral-rich spring water is known as hydropinic treatment and is used to treat certain ailments. Health benefits are attributed to thermal spring water containing radioactive elements such as radium; this has popularized use of such radioactive water in various parts of the world, causing those who ingest it to increase their internal radiation dose. The goal of this study was to assess the activity concentrations of Ra present in the thermal spring waters of San Diego de Alcala, in the state of Chihuahua, Mexico, and to estimate the health risk posed to patients by the effective dose received from ingesting this water during hydropinic treatments. Water samples were taken from different areas of the San Diego de Alcala thermal springs, and pH, temperature, electrical conductivity, and total dissolved solids were measured. The Ra activity concentrations were measured with a liquid scintillation counter. The activity concentrations of Ra in sampled water varied from 125 to 452 mBq L with an average of 276 ± 40 mBq L. The committed effective dose from each of the Ra activity concentrations found in samples ranged from 9.80 × 10 to 4.0 × 10 mSv for hydropinic treatments being carried out in San Diego de Alcala thermal spring spas. Different treatments had different intake rates (200, 600, 1,000, and 1,500 mL d) and occurred over periods of 2 or 3 wk. According to the guidelines of the US Environmental Protection Agency, the maximum permissible amount of radium in drinking water is 185 mBq L; the Ra content in most of the collected samples exceeded this limit. The committed effective doses varied with Ra concentration and intake rate; none exceeded the World Health Organization's reference dose for drinking water of 0.1 mSv y, which is the maximum amount to which the population should be exposed.

Assessment of radiation dose from radon ingestion and inhalation in commercially bottled drinking water and its annual effective dose in Eastern Province, Saudi Arabia

The isotopes of radium, uranium, polonium, lead, and short-lived radon are the common radionuclides found in drinking water. The abnormal amount of radon in drinking water causes health risks. In this study, an attempt has been made to estimate the level of radon concentrations and its annual effective dose from bottled water brands and tap drinking water. A total of 77 samples of drinking water sources; 47 bottled water brands and 27 tap water samples including 3 samples from water storage tank supplier were collected and examined. The measurements were performed using active detection method technique called Durridge RAD7-H₂O with closed loop. The minimum and maximum level of average radon concentrations was 0.10 ± 0.02 BqL^-1 and 9.2 ± 0.02 BqL^-1. The results were below the limit recommended by the Environmental Protection Agency (11 BqL^-1). The annual effective dose for children and adults was in the range from almost 0.51 µSvy^-1 to 46.69 µSvy^-1. There are no indications of significant threat from radon concentrations in bottled water brands or tap drinking water, and it is safe as far as health hazard is concerned.

Radon concentrations in the community groundwater system of South Korea

Groundwater samples were collected from 3818 wells used for the community groundwater system (CGS) in the remote rural areas of South Korea and analyzed to determine radon concentrations. Radon concentrations varied with rock type, ranging from 0.1 to 2393.5 Bq/L with an average of 86.6 Bq/L and a median of 46.4 Bq/L. Among 10 geological units, the median CGS radon concentration was highest (59.6-103.0 Bq/L) in granite, and lower in sedimentary rocks (16.9-21.1 Bq/L) and porous volcanic rocks (17.6 Bq/L), respectively. Of the 3818 samples, 26.1% exceeded the World Health Organization (WHO) radon level limit of 100 Bq/L. The application of the natural radon reduction rate (26.5%) recently suggested by Yun et al. Applied Radiation and Isotopes, 126(1), 23-25 (2017) to the CGS water tank appeared to decrease exceedance of the WHO radon level limit to 20.2%. Because of the high radon concentrations in CGS groundwater in South Korea, the establishment of a radon level limit for drinking water is strongly recommended to ensure the health and safety of the people using CGS water.

Effect of grain size on radon emanation coefficient, surface and mass exhalation rates and the correlation coefficient between them in different masses of soil and phosphate fertilizer

It is important to study the behavior of recoiling radon atoms 222Rn after decay of parent 226Ra and the effect of parameters on their access to the surrounding medium. The present study was carried out using CR-39 detector to study the effect of grain size on the correlation between surface and mass exhalation rates and the correlation between emanation coefficient and exhalation rate at different masses of soil and phosphate fertilizer. In addition, the relationship between emanation coefficient and the sample mass was studied for different grain sizes (0.1, 0.3, 0.5 and 1 mm). The results showed that there is no effect of grain sizes on the correlation coefficient between surface and mass exhalation rates in soil and fertilizer. The correlation coefficient between emanation coefficient and exhalation rate in different masses of soil was slightly influenced by the grain sizes. While the correlation coefficient between emanation coefficient and exhalation rate in different masses of phosphate fertilizer samples was not affected by the grain sizes (0.1, 0.3 and 0.5 mm). However, it was found that the emanation coefficient decreases exponentially with the mass for soil and phosphate fertilizer. This relationship was not significantly affected by grain size in soil except grain size 1 mm. While this relationship was affected by grain size >0.3 mm in phosphate fertilizer.

Radon-222 and radium-226 occurrence in water: a review

A total of 2143 dissolved radon-222 and radium-226 activity concentrations measured together in water samples was compiled from the literature. To date, the use of such a large database is the first attempt to establish a relationship for the 226Ra–222Rn couple. Over the whole dataset, radon and radium concentrations range over more than nine and six orders of magnitude, respectively. Geometric means yield 9.82±0.73 Bq l−1 for radon and 54.6±2.7 mBq l−1 for radium. Only a few waters are in 226Ra–222Rn radioactive equilibrium, with most of them being far from equilibrium; the geometric mean of the radium concentration in water/radon concentration in water (CRa/CRn) ratio is estimated to be 0.0056±0.0004. Significant differences in radon and radium concentrations are observed between groundwaters and surface waters, on the one hand, and between hot springs and cold springs, on the other. Within water types, typical ranges of radon and radium concentrations can be associated with subgroups of waters. While the radium concentration characterizes the geochemistry of the groundwater–rock interaction, the radon concentration, in most cases, is a signal of non-mobile radium embedded in the encasing rocks. Thus, the 226Ra–222Rn couple can be a useful tool for the characterization of water and for the identification of water source rocks, shedding light on the various water–rock interaction processes taking place in the environment.

Dissolved radon and uranium in groundwater in a potential coal seam gas development region (Richmond River Catchment, Australia)

The extraction of unconventional gas resources such as shale and coal seam gas (CSG) is rapidly expanding globally and often prevents the opportunity for comprehensive baseline groundwater investigations prior to drilling. Unconventional gas extraction often targets geological layers with high naturally occurring radioactive materials (NORM) and extraction practices may possibly mobilise radionuclides into regional and local drinking water resources. Here, we establish baseline groundwater radon and uranium levels in shallow aquifers overlying a potential CSG target formation in the Richmond River Catchment, Australia. A total of 91 groundwater samples from six different geological units showed highly variable radon activities (0.14-20.33 Bq/L) and uranium levels (0.001-2.77 μg/L) which were well below the Australian Drinking Water Guideline values (radon; 100 Bq/L and uranium; 17 μg/L). Therefore, from a radon and uranium perspective, the regional groundwater does not pose health risks to consumers. Uranium could not explain the distribution of radon in groundwater. Relatively high radon activities (7.88 ± 0.83 Bq/L) in the fractured Lismore Basalt aquifer coincided with very low uranium concentrations (0.04 ± 0.02 μg/L). In the Quaternary Sediments aquifers, a positive correlation between U and HCO3(-) (r(2) = 0.49, p < 0.01) implied the uranium was present as uranyl-carbonate complexes. Since NORM are often enriched in target geological formations containing unconventional gas, establishing radon and uranium concentrations in overlying aquifers comprises an important component of baseline groundwater investigations.