Radium Content Research Articles

Radon Assessment in Ceratophyllum demersum Plant Samples

The amount of radioactive isotopes in submerged Ceratophyllum demersum plants samples were estimated using passive track detector CR-39. The samples were collected from four selected sites along the Tigris River in Baghdad city, on a monthly basis for one complete year of 2019. Certain factors like radon concentration (Bq.m-3), radium content (Bq.kg-1) and uranium concentration (ppm) were evaluated. The average values of 222Rn level, 226Ra content and 238U concentration in Ceratophyllum demersum samples for site (1) were (593.1 Bq.m-3, 5.8 Bq.kg-1, 0.113 ppm), site (2) were (413.4 Bq.m-3, 3.8 Bq.kg-1, 0.074 ppm), Site (3) were (465.5 Bq.m-3, 4.3 Bq.kg-1, 0.083 ppm) and site (4) were (431.3 Bq.m-3, 3.9 Bq.kg-1, 0.077 ppm), respectively. The results obtained in this work indicated that the radium content and uranium concentration present in the Ceratophyllum demrsum is acceptable which does not pose any risk to the aquatic ecosystem.

An investigation of 222Rn exhalation rates from backfill mill tailings influenced by the different parameters in underground uranium mines

222Rn surface exhalation and mass exhalation rates measured from the backfill mill tailings using a new method comprising the smart-radon-monitor system and accumulation chamber in underground uranium mines are presented in this paper. The range values of 222Rn surface and mass exhalation rates were 0.6–4 Bq m−2 s−1 and 28–71 Bq kg−1 h−1, respectively. Further, Multivariate regression models involving radium content, porosity, moisture saturation and surface area to fit the 222Rn surface and mass exhalation of the backfill materials were developed in this paper. The curve fitting results showed that multivariate models could explain 86% of the variation of surface exhalation rate and 69% of the variation of mass exhalation rate from the backfill materials. This study also revealed that the 222Rn surface exhalation rate calculated based on the method of concentration gradient of 222Rn in soil, found to be about two times more than that of the measured surface exhalation rate. However, the theoretical 222Rn exhalation rate was prone to various uncertainties including a variation of moisture saturation, the occurrence of adsorption and advection in the backfill mill tailings. Therefore, the values of the 222Rn exhalation rate measured inside underground uranium mines are more realistic.

Time variation of radon in tap water in locations of a Greek area with geological background for elevated radon-in-water concentrations and correlation study between radon, gross alpha, uranium, and radium concentrations

Background: Radon (222Rn), a naturally occurring radioactive gas, dissolves in water, and it can be found in elevated concentrations in public water supplies when water originates from ground sources in areas rich in uranium. An area of great interest for measuring radon-in-water is the Migdonia basin in Northern Greece due to its geological background and because all of its villages are supplied with water from boreholes.
 Objectives: The main aim of this paper was to study the time variation of radon in tap water activity concentration in nine villages of the Migdonia basin supplied with water from boreholes and to determine factors that may affect it. Radon in water correlation between the source (borehole) and the consumption point (tap) was studied for some villages. Also, the correlation among radon, gross alpha, beta, uranium (238U), and radium (226Ra) activity concentration in water was studied.
 Design and methods: Water samples were collected and measured for their radon activity concentration from 66 villages in the Migdonia basin in order to find places with relatively high radon concentrations. The time variation of radon-in-water was studied for villages that showed relatively high radon concentrations for 3–4 years (2018–2022). All samples were measured for their 222Rn activity concentration using gamma-ray spectrometry. Water samples were also analyzed for their gross alpha, beta, and uranium isotopes activity concentration.
 Results and conclusions: Average radon in tap water activity concentrations measured in the area ranged from background concentrations to 185 Bq L-1. The corresponding annual effective doses from waterborne radon inhalation using both UNSCEAR and ICRP dose conversion factors ranged from 0.01 to 0.466 mSv y-1 and from 0.02 to 0.868 mSv y-1, respectively, while radon ingestion annual effective doses varied from 0.007 to 0.324 mSv y-1. Time variation of radon activity concentration in tap water for villages supplied from one borehole or a constant number of boreholes showed relatively low standard deviations (<24%) at a coverage factor of k = 1. Those deviations are probably caused by the time variation of boreholes’ radon concentration and water demand changes. A significant decline in radon concentration from the source (borehole) to the consumption point (tap water) was observed. Therefore, sampling should be performed at the consumption point. However, knowing the supplying borehole concentration is useful as it determines the potential for radon in drinking water. No apparent correlation was found among radon, gross alpha, beta, uranium, and radium concentrations in water. However, in some cases, remedial actions (withdrawal of boreholes) for uranium concentration also decreased radon concentration.

Impact of the geological and hydrogeological settings on the radon potential in Bulgaria

Natural radon (222Rn) is a radioactive noble gas that occurs in every rock or soil due to the content of radium (226Ra), part of the 238U family, in the lithosphere. One of the indicators for evaluating the impact of radon on a certain area/terrain, including on the biota, is the so-called geogenic radon potential. Different types of rocks and soils possess different 226Ra content and different permeability. Radon gas has high mobility and is driven by diffusion and convection with the soil gas throughout connected and water-unsaturated pores and/or cracks in permeable rocks and soils. Therefore the geogenic radon potential at the surface could be affected by the geological settings as a content of uranium and also by the hydrogeological settings as a degree of saturation near the surface. The present study mainly deals with the different by genesis shallow groundwater in Bulgaria based on the published since 1960’s sources. After analysis of the collected data several distinct regions have been determined regarding lithological and geomorphological conditions, and the 0–3 m depth of the groundwater table. In addition, a GIS-based map was elaborated relating the rocks with expected geogenic radon potential and shallow groundwater areas.

Evaluation of Radionuclide Levels in Drinking Water from Communities near Active and Abandoned Gold Mines and Tailings in the West Rand Region, Gauteng, South Africa

The history of gold mining in the Witwatersrand Basin has led to exponential growth in the economy, residential development, and the abundance of radionuclides in the environment, including the water system. This study aimed to evaluate the radionuclide levels in drinking water (municipal water and groundwater) and the health risks associated with the ingestion of the water in the communities of the West Rand region of Gauteng Province. The activity concentrations of uranium, radium, and thorium radioisotopes were established through alpha spectrometry and the activities were subsequently used to assess the health impacts. The results indicated that the groundwaters contain elevated activities of most radionuclides owing to prolonged periods of water–rock interactions. Similarly, the highest annual effective doses were recorded in groundwaters with a range of 0.0237–0.3106 mSv/yr, with most samples exceeding the WHO- and EU-prescribed limits of 0.1 mSv/yr. Cancer morbidity and mortality risks were higher in females than in males due to the higher life expectancy of females. Nonetheless, all morbidity and mortality risks were well below the USEPA radiological risk limit of 0.001. Based on the findings of this study, continuous monitoring is paramount to ensure that the activities remain below recommended regulatory limits.

MEASUREMENT OF THE CONCENTRATION OF 226RA, 232TH, 40K IN THE SOIL IN SETTLEMENTS ON THE COASTLINE OF LAKE VAN, TURKEY.

In this study, the natural radioactivity level and its effects on the environment of Lake Van, which is the largest lake in Turkey, were investigated extensively. Initially, 254 soil samples have been collected from the districts (Tusba, Edremit, Gevas, Tatvan, Ahlat, Adilcevaz, Ercis) located around the coastline of Lake Van in eastern Turkey. A Na(TI) detector was used to detect activity concentrations of radium (226Ra), thorium (232Th) and potassium (40K) in each collected soil sample. The obtained average results were compared with available data from Turkey and international data base. The average activity in soil samples was measured as 28.0 ± 3.7-43.6 ± 2.2 Bq/kg for 226Ra, 27.3 ± 4.1-55.4 ± 4.8 Bq/kg for 232Th and 377 ± 42- 706 ± 40 Bq/kg for 40K. It was observed that the average concentrations of 226Ra, 232Th, 40K (43.6 ± 2.2, 55.4 ± 4.8, 706 ± 40 Bq/kg, respectively) for Tatvan district and (37.0 ± 3.5, 51.4 ± 4.2, 479 ± 41 Bq/kg, respectively) for Ahlat district were higher than both national and international average value. In addition, radiological effect parameters originating from terrestrial natural radionuclides for the study area; gamma dose rate (Dout), annual effective dose equivalent (AEDE), and lifetime cancer development probability (LCR) were calculated. The Dout, AEDE, LCR (83.0 ± 3.9 nGy/h, 0.102 ± 0.005 mSv/y, 0.36 ± 0.02 x 10-3, respectively) parameters in Tatvan district were found to be above the international allowable value.

Radiation exposure of microorganisms living in radioactive mineral springs

The TIRAMISU collaboration gathers expertise from biologists, physicists, radiochemists and geologists within the Zone-Atelier Territoires Uranifères (ZATU) in France to study the response of microorganisms living in naturally radioactive mineral springs. Mineral springs are isolated ecosystems, extremely stable over geological time scales, which display different physicochemical and radiological parameters compared to their surroundings. Water and sediment samples collected in 27 mineral springs of the volcanic Auvergne region (Massif Central, France) have been analyzed for their microbial biodiversity and radionuclide content. Among the microorganisms present, diatoms (a microalgae species), widely used as environmental bioindicators of water quality, have shown to display an exceptional abundance of teratogenic forms in the most radioactive springs studied (radon activity up to 3700 Bq/L). The current work presents a first assessment of the dose received by the diatoms inhabiting naturally radioactive mineral springs. The radiological risk for microorganisms living in freshwater environments was estimated using the ERICA tool. Most of the sampled mineral springs were highly above the risk threshold of 10 mGy/h due to the large concentrations of radium in the sediments (up to 50 Bq/g). The complete radiological data on water and sediments are used as inputs to Monte Carlo simulations at micro- (GATE) and nano- (Geant4-DNA) scale in order to assess the direct and indirect damages on the diatom DNA.

Study of Radium Behavior in Contact With Calcium-Silicate-Hydrates

Abstract Radium-226 is an important radionuclide with respect to the long-term safety of repositories for low and intermediate-level radioactive wastes, as well as deep geological repositories for high-level radioactive waste and spent nuclear fuel. To evaluate its mobility in the engineered barrier system of a repository, the sorption of radium on calcium-silicate-hydrates (CSH), which form the major hydration phases in cementitious materials, was studied. Radium sorption to CSH was found to be very fast, leading to steady-state between solid and liquid phase after less than four days. The dependency of the equilibrium distribution ratios on radium concentration, the calcium to silicon ratio in CSH, liquid to solid ratio, and temperature was investigated, and estimates of apparent activation energy, reaction enthalpy, entropy, and Gibbs energy of the sorption process were derived. Radium sorption on CSH can be described by linear isotherms with Rd values mostly in the order of 104 L/kg. Radium sorption was found to be an exothermic and spontaneous reaction probably governed by chemical reaction rather than diffusion. As expected, the presence of ethylene diamine tetraacetic acid (EDTA) at low concentrations led only to a small decrease in radium sorption, due to the strong competition of dissolved calcium for EDTA complexation. A comparison of the sorption behavior of various alkaline earth elements used as chemical analogs for radium confirmed the significant difference in the Rd values with sorption on CSH decreasing in the order Ra > Ba > Sr.

Automation and Closed-Loop Systems Reduce HSE Risks

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31985, “Reducing HSE Risks Through Automation and Closed-Loop Systems,” by Simon Smith, Olof Nilsson, SPE, and Aksel Skåland, SPE, FourPhase. The paper has not been peer reviewed. Copyright 2022 Offshore Technology Conference. Reproduced by permission. Solids production in produced fluids is an industrywide challenge, incurring major costs to operators through lost production, asset integrity, and well-intervention campaigns. The complete paper highlights solids-management technologies that are currently available and still in use topside (and some of which are potentially outdated). It also identifies the amount of exposure to hazardous byproducts of produced oil and gas from these various technologies. The complete paper also presents a new-technology case study and compares this with legacy methods and practices in terms of health, safety, and environment (HSE) risk and cost. Naturally Occurring Radioactive Materials (NORM) NORM can be divided into sources that originate from the ground and those produced from the interaction of atmospheric gases with cosmic rays. The risks associated with NORM, and the solutions available to manage those risks, are not widely known in the industry. The complete paper focuses on 3 NORM, which originate from the ground. The paper further details the characteristics of benzene and hydrogen sulfide, two other hazardous materials often encountered in solids-handling within the industry. NORM Hazards. - The hazardous elements found in NORM are radionuclides such as radium 226 and 228, radon 222, and daughter products from these radionuclides. The concentration of radium and other daughter products builds up in the body over time. The elements can migrate to bone tissue and concentrate, causing bone cancers, lymphoma, leukemia, and other serious medical conditions. Employers should always prioritize minimization of exposure of their offshore personnel. NORM in the Oil and Gas Industry. - Scale may build up over time from naturally occurring radium and its daughter products in wellbores, pipes, and vessels. Isotopes build and radiate differently depending on the reservoir rock and salinity of the well. Because a correlation usually exists between the age of a well and salinity (which increases with age), old wells seem to carry higher NORM levels than younger wells.

Determining the radium concentration in vegetables and fruits in Al-Najaf, Iraq

Amount of pollution radiation in foodstuffs and feedstuffs are very necessary to measure because it is a direct contact with human and animal health. Therefore, the present investigation is useful for the health and environmental data base. The study included measurement of effective radium-226 content (CRa) in some chosen samples of vegetables and fruits (local and imported) in Najaf governorate. The CRa were measured in samples of vegetables and fruits using Solid State Nuclear Track Detectors (LR-115 Type II). Also, the annual effective dose (AED) associated with the exposure due to annual intake of 226Ra were calculated from ingestion of vegetables and fruits samples for adults. The results were revealed that the average value of CRa in vegetables and fruits samples in the present study was 3.98±1.08 Bq/kg and 1.73±0.11 Bq/kg, respectively. While, the average of AED (mSv/y) for vegetables and fruits samples was 0.067±0.018 and 0.082±0.005, respectively. Also, the results showed that the average value of AED from fruits consumption is larger than in vegetables, but the result is not significant. All results of the CRa and AED of the studied samples had been compared with the worldwide reported value (median). Accordingly, it was found that all findings were lower than that of the recommended limits of the UNSCEAR 2000. Finally, based on present investigations, no health risk expected when considering eating vegetables and fruits of Al-Najaf of Iraq. Keywords: Alpha emitters, Food contamination, Radium-226, Herbal samples, Al-Najaf.

Assessment of the Naturally Occurring Radioactive Materials (Norm) In Jos North, Nigeria. A Case Study of the Utan Artisanal Tin Mining Sites

Tin mining and milling can be an avenue for economic and technological development. Mining of this mineral contributes significantly to the distortion of the natural distribution of radioisotopes in the environment. This study assesses the concentration of natural radioactivity due to radioactive elements such as 40K, 238U and 232Th. Soil samples were taken from 20 distinct locations within the Utan mining sites, Jos North, Plateau State, Nigeria. Potassium, radium, and thorium in soil samples from mining sites were determined by measuring their concentration activities using the gamma-ray spectroscopy method. Activity concentrations of potassium, radium and thorium were determined. In soil samples, activity concentrations of 40K, 226Ra and 232Th were established. 40K 196.07±4.91 to 608.07±1.44 with an average of 386.48, 226Ra 0.71±0.02 to 5.11±0.07 with an average of 2.35 and 232Th 14.91±0.74 to 63.71±0.97 with average activity concentrations of 54.78. The average concentration activity of potassium and thorium was slightly above the world recommended average of 370.00 and 40.00 respectively, while radium was below the recommended average. The mines mean absorbed and annual effective dose rates were 14.27-nGy h−1and 18.62 μSvy-1, respectively. This average calculated absorbed dose rate in the air was found to be much less, than the global average of 57-nGy h−1. The absorbed dose is considered low compared to the external natural radiation of about 2000 μSv.y-1, to which no harmful effect is expected directly. However, the mean measured dose rate and calculated dose parameters for the mine were higher than the regulatory limit for public exposure.

Assessment of radon exhalation rates, effective radium content and radiological exposure dose, of coal and rocks in Tiru Valley Coal Field, India using track etched technique

In this study, the outcomes of assessments of radon exhalation rates for both mass and surface, radium content and annual effective dose from 45 numbers of geological samples in Tiru Valley Coal Field area are presented. The nuclear track detector LR-115 (II) of bulk etch rate, VB = 4 μm h−1 with a spark counter to archive alpha track density of radon was used to measure radon exhalation rate from the samples and to assess radiological exposure in the coalfield area, which has significant geological characteristics. In this work, the surface exhalation rates for coal, carbonaceous shale and sandstone samples have been estimated to be in the range of 217.4–659.9 mBq m−2 h−1, 234.0–381.1 mBq m−2 h−1 and 337.1–741.4 mBq m−2 h−1, respectively. The mass exhalation rates for coal, carbonaceous shale and sandstone samples varied in the range of 6.5–19.8 mBq kg–1 h−1, 7.0–11.4 mBq kg–1 h−1, and 10.1–22.2 mBq kg–1 h−1, respectively. The radium contents have been found to vary in the range of 6.7–20.3 Bq kg−1, 7.2–11.8 Bq kg−1 and 10.4–22.9 Bq kg−1 for coal, carbonaceous shale and sandstone respectively. The annual effective doses related to the inhalation of radon from the exposure to the samples have been estimated to be in the range of 15.8–47.9 μSv y−1, 17.0–27.7 μSv y−1 and 24.5–53.8 μSv y−1 for coal, carbonaceous shale and sandstone respectively. In this investigation, the lifetime fatality-risks have also been assessed. The values were generally higher in rock samples than in coal. However, the findings have shown that the obtained values are within the internationally accepted recommended values.

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.

Mathematical Modelling to estimate Radon exhalation rates: A study on soil samples from Pangi valley of Chamba district, Himachal Pradesh, India

Radon being radioactive gas is the main source of radiation exposure in the environment. When inhaled, it may cause carcinogenic diseases due to alpha emission during the radon decay, as alpha particles may damage respiratory and alveolar epithelial cells. Thus continuous investigation of the radon level in the environment is always required. In the same, correlation between concentration of radium with radon exhalation rates in the soil samples may be very helpful to know the variation of the radon level. In present study soil samples have been collected randomly from various locations of Pangi Valley of Chamba district, Himachal Pradesh, a northern hill state of India. Radon exhalation rates in collected samples have been measured using the closed can technique in correlation to different soil parameters. Radon mass exhalation rate in soil samples have found to vary from 0.018 to 0.179 Bq kg-1 h-1 with an average value of 0.082 Bq kg-1 h-1 and area exhalation rate from 0.56 to 5.42 Bq m-2 h-1 with an average of 2.47 Bq m-2 h-1. A Mathematical model has been developed using soil parameters viz. bulk density, porosity, emanation rates, diffusion coefficients etc. and use to estimate the radon exhalation rates in soil samples. A strong positive correlation has been obtained between the theoretically estimated and experimentally measured obtained values.

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

222Rn Activity Concentration Measurement and its Radiological Risks in the Environment of Barserin Village, Erbil-Iraq

Chemical composition, radioactive and stable isotopes in several selected thermal waters in North Vietnam

This work presents the chemical composition and concentration of radioactive and stable isotopes in water samples collected from nine well-known therapeutic centers located in north Vietnam. Excluding the Thanh Thuy – Phu Tho waters, which are hosted in Pleistocene sandstone with marble and gravel, the rest of studied waters are hosted in Paleozoic limestone formations. The thermal waters are extracted from 10 to 400 m below the surface, but the Keng Ga Ninh Binh intake is of an artesian nature. The temperature measured in the outlet waters ranges from 39 °C to 61 °C. The δ18O and δ2H (δD) vary from −9.13 to −5.09 ‰ and −63.9 to −34.1 ‰ respectively. All the thermal waters examined originate from infiltration water. This is also confirmed by the values of selected calculated hydrochemical indices. The hydrochemical types of the waters are HCO3-Ca-Mg, HCO3-Na, Cl-Na, SO4-HCO3-Ca-Mg, SO4-Ca-Mg and SO4-Ca. The mineralization of the concerned waters varies from 244 mgL−1 to more than 11,500 mgL−1. The concentrations of uranium and radium in the waters are in the broad interval from about 4 mBqL−1 to 680 mBqL−1 for 238U and from below 5 mBqL−1 (limit of detection - LOD) to above 3400 mBqL−1 for 226Ra. There is no 228Ra in most of the waters (below 10 mBqL−1- LOD), excluding two waters in the Thanh Thuy-Phu Tho district, where 228Ra is present with 18 and 27 mBqL−1.In all the waters studied, there is a very low concentration of polonium (210Po) which varies from 0.5 mBqL−1 to 8.2 mBqL−1. High mineralization and high radium concentration should be associated with a long residence time in the given geological formation. The linear relationship between the depth of the host water formations and the water temperature suggests that the study waters are mostly heated from the geogradient of heat energy. But the water from the My Lam district is probably heated by intrusive magmatic fluid.From a radiological point of view, the waters used for therapeutic and relaxation purposes are safe, however, there would be some problems if they were to be used for drinking purposes.

Intercomparison of Radon Flux Monitors at Low and at High Radium Content Areas under Field Conditions.

Interlaboratory exercises are a good tool to compare the response of different systems to the same quantity and to identify possible inconsistencies between them. One of the main goals of the EMPIR 19ENV01 traceRadon project is to harmonize radon flux measurements based on different systems and methodologies. In the framework of the traceRadon Project, two radon flux intercomparison campaigns were carried out in October 2021 at high and at low radon source areas. Four institutions participated in the field intercomparison exercises with their own systems. Every system was based on a specific radon monitor (diffusion or pump mode) and an accumulation chamber (with manual or automatic opening). Radon fluxes were calculated by each participant using both exponential and linear fittings of the radon activity concentration measured over time within the accumulation chambers. The results of this study show mainly: (i) the exponential approach is not advisable due to the variability of the radon flux and the leakage of the systems during long-time measurements; (ii) the linear approach should be applied to minimize the measurement period in agreement with the time response and sensitivity of the monitors; (iii) radon flux measured at high radon source areas (radium content of about 800 Bq kg−1) risks being underestimated because of the influence of advective effects; (iv) radon flux measured at low radon source areas (radium content of about 30 Bq kg−1) may present large uncertainties if sensitive radon monitors with pump mode are not used.

Risk survey for the population of Recife and neighboring cities due to the occurrence of radium in groundwater

The Metropolitan Region of Recife and its surroundings are heavily exploited to capture water for public supply through tubular wells. However, a survey of the levels of natural radionuclides from these sources had never been carried out, even though part of this region contains a phosphate deposit that has a high concentration of natural uranium. In this context, this research aimed to identify 228Ra and 226Ra levels in groundwater in the coastal region of Pernambuco, Brazil. About 110 points (wells) of drinking water for public supply were identified and studies were carried out to estimate the level of ingestion and subsequent risk due to the presence of this radionuclide. The average concentration of combined radium was 104 mBq.L−1. For 228Ra an effective dose of 0.46, 0.11, 0.12 and 0.0276 mSv.y−1 for infants, children aged 1 and 10 and adults, respectively, were obtained. Although doses above those recommended by WHO were found, the equivalent dose and the induction of bone sarcoma did not indicate a risk to the population. Groundwater with higher dose values is influenced by local geology.

Seasonal Variability of Nutrients and Radium Isotope Fluxes from Submarine Karstic Spring at the Southwest of Crimea, Black Sea

The groundwaters of the southwestern region of Crimea are formed on the karst plateaus of the Crimean Mountains, and a significant amount of them is discharged into the Black Sea. The Crimean Peninsula is a water-deficient region; therefore, the study of its hydrogeology is an urgent task, since groundwater is a valuable freshwater resource. Through submarine groundwater discharge (SGD), the transfer of chemical compounds to the sea in the event of anthropogenic interference may also occur. In this work the fluxes of submarine groundwaters in the area of Cape Peleketo in different seasons, and also the fluxes of nutrients within them, are evaluated for the first time, as well as the factors determining their variability. During the study, hydrological (temperature, salinity (S), current velocity) and hydrochemical (concentration of biogenic elements) parameters, as well as the concentration of long-lived isotopes of 226Ra and 228Ra, were measured. The SGD fluxes were estimated through the mixing formula. As the endmember, we used groundwater concentrations of nutrients or radiotracers, defined by extrapolation of nutrients or radium concentrations to zero salinity. Significant differences in the studied region’s SGD flux values (from 4100 to 13,900 m3/day) are shown; maximum values are in winter and summer, and minimum values are in autumn and spring. The relationship between the seasonal variability of the discharge intensity and the amount of precipitation in the groundwater formation area is shown. The data obtained show that this source makes a significant contribution to the local supply of nutrients. Substantial amounts of nitrates come from the karst cavity, which can lead to eutrophication and limit the primary production of phosphorus in the local coastal sea region.

Occurrence and behavior of uranium and thorium series radionuclides in the Permian shale hydraulic fracturing wastes.

Over the last decade, there has been a rapid growth in the use of hydraulic fracturing (fracking) to recover unconventional oil and gas in the Permian Basin of southeastern New Mexico (NM) and western Texas. Fracking generates enormous quantities of wastes that contain technologically enhanced naturally occurring radioactive materials (TENORM), which poses risks to human health and the environment because of the relatively high doses of radioactivity. However, very little is known about the chemical composition and radioactivity levels of Permian Basin fracking wastes. Here, we report chemical as well as radiochemical compositions of hydraulic fracking wastes from the Permian Basin. Radium, the major TENORM of interest in unconventional drilling wastes, varied from 19.1 ± 1.2 to 35.9 ± 3.2Bq/L for 226Ra, 10.3 ± 0.5 to 21.5 ± 1.2Bq/L for 228Ra, and 2.0 ± 0.05 to 3.7 ± 0.07Bq/L for 224Ra. In addition to elevated concentrations of radium, these wastewaters also contain elevated concentrations of dissolved salts and divalent cations such as Na+ (31,856-43,000mg/L), Ca2+ (668-4123mg/L), Mg2+ (202-2430mg/L), K+ (148-780mg/L), Sr2+ (101-260mg/L), Cl- (5160-66,700mg/L), SO42- (291-1980mg/L), Br- (315-596mg/L), SiO2 (20-32mg/L), and high total dissolved solid (TDS) of 5000-173,000mg/L compared to background waters. These elevated levels are of radiological significance and represent a major source of Ra in the environment. The recent discovery of large deposits of recoverable oil and gas in the Permian Basin will lead to more fracking, TENORM generation, and radium releases to the environment. This paper evaluates the potential radiation risks associated with TENORM wastes generated by the oil and gas recovery industry in the Permian Basin.