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Correlations between radium and radon occurrence and hydrogeochemical features for various geothermal aquifers in Northwestern Romania
Abstract
Geothermal waters originating from three aquifers in northwestern Romania have been analyzed for
several physico-chemical parameters namely, pH, temperature, electrical conductivity, total dissolved
solids, hardness, redox potential, and chemical oxygen demand. In addition, major dissolved ions and
organic matter content and radium and radon occurrence have been analyzed. The three aquifers
are the fissured Middle Triassic limestone/dolomite aquifer from Oradea, the Lower Cretaceous limestone
aquifer from 1Mai–Felix Spa, and the Lower Pontian (Late Miocene) granular (sand) aquifer from
S˘acuieni. The first two aquifers belong to the Inner Dacides and the last to the Pannonian Basin. We
have examined the relationships between the occurrence of radium and radon in the thermal waters
and the hydrochemical and geothermal features of the aquifers, which may impart a secondary control
on the activity of these radionuclides. According to their chemistry, the thermal waters were classified
as sulfate–bicarbonate–calcium–magnesium (Oradea), bicarbonate–sulfate–calcium–magnesium
(Felix–1Mai Spa), and bicarbonate–sodium–chloride (S˘acuieni). The activities of radon and radium were
higher in S˘acuieni (up to 22.88 and 1.40 Bq/L) and Oradea (up to 34.82 and 1.82 Bq/L) than in Felix–1Mai
Spa (up to 16.76 and 0.19 Bq/L). The data shows that the thermal processes may control the migration
and distribution of radionuclides, and that the mobility of radionuclides may be influenced by several
physico-chemical parameters, such as pH, total dissolved solids, and redox potential, or by some chemical
processes, such as adsorption on humic acids or partitions into the organic (hydrocarbons) phase. The
data illustrate no significant differences between the parameters analyzed from February to July 2009,
proving that the production regime of the aquifers has a minor impact on their chemical and physical
parameters.
... faktor meteorologi seperti hujan, yang dapat mempengaruhi nilai konsentrasi radon terukur. Konsentrasi radon tinggi juga dapat memberikan informasi keberadaan patahan atau rekahan yang berhubungan dengan zona permeabel (Cox, 1980; Whitehead, 1984; Roba et al., 2012; Balcazar et al., 2014; Jolie et al., 2015). Pengukuran gas thoron biasa dilakukan bersamaan dengan pengukuran gas radon. ...
... Keberadaan struktur geologi tersebut dapat diidentifikasi dengan memetakan sebaran gas radon. Nilai radon yang lebih tinggi dimungkinkan berasosiasi dengan struktur geologi yang ada (Cox, 1959; Whitehead, 1984; Roba et al; 2012; Balcazar et al., 2014; dan Jolie et al., 2015). Sedangkan untuk mengidentifikasi kemenerusan struktur geologi ke bawah permukaan dilakukan dengan menghitung rasio thoron/radon (Giammanco et al., 2007; Haerudin et al., 2013). ...
... Keberadaan struktur geologi tersebut dapat diidentifikasi dengan memetakan sebaran gas radon. Nilai radon yang lebih tinggi dimungkinkan berasosiasi dengan struktur geologi yang ada (Cox, 1959; Whitehead, 1984; Roba et al; 2012; Balcazar et al., 2014; dan Jolie et al., 2015). Sedangkan untuk mengidentifikasi kemenerusan struktur geologi ke bawah permukaan dilakukan dengan menghitung rasio thoron/radon (Giammanco et al., 2007; Haerudin et al., 2013). ...
One of the methods used in geothermal exploration is to take advantage of the presence of radon in nature. In this study, we measured radon and thoron in Papandayan Volcano area, which was assumed to have a high geothermal potential. Measurements were carried out in around the crater of the volcano by using Rad7 on soil and water. The duration of measurement in each point is 15 minutes at a depth of 75 cm with a sniff mode. The result indicated that the concentration of radon gas is relatively high. The high concentration might be interpreted as the permeable zone , which associated with the zone of faults or fractures. The results also showed relatively high concentrations of radon gas around the east and the west of the crater. This concentration reflects the presence of permeable zones that may be associated with the southwest trending fault - northeast and also the presence of the caldera boundary. The continuity of permeable zone below the surface was interpreted based on the thoron- radon ratio ( 220 Rn / 222 Rn). A high ratio (indicating the source of radon shallow) found in the northern ridge of the Papandayan crater. Salah satu metode yang digunakan dalam kegiatan eksplorasi panasbumi adalah dengan memanfaatkan keberadaan gas radon alam. Dalam penelitian dilakukan pengukuran gas radon dan thoron di lokasi Gunung Papandayan karena daerah ini diduga memiliki potensi panas bumi yang tinggi. Kegiatan pengukuran dilakukan di sekitar kawah Gunung Papandayan dengan menggunakan alat Rad7 pada media tanah dan air. Lama pengukuran pertitik adalah 15 menit pada kedalaman 75 cm dengan mode sniff. Hasil pengukuran menunjukkan konsentrasi gas radon yang relatif tinggi, yang dapat diinterpretasikan sebagai keberadaan zona permeabel, berkaitan dengan adanya zona rekahan atau patahan. Hasil pengukuran menunjukkan konsentrasi gas radon yang relatif tinggi di sekitar tebing kawah timur dan barat. Konsentrasi tersebut mencerminkan keberadaan zona permeabel, yang mungkin berasosiasi dengan patahan berarah baratdaya – timurlaut, dan juga keberadaan batas kaldera. Kemenerusan zona permeabel sampai ke bawah permukaan dianalisa berdasarkan rasio thoron/radon ( 220 Rn/ 222 Rn). Rasio tinggi ditemukan (menunjukkan sumber radon dangkal) dipunggungan utara kawah Papandayan.
... Recently, spa waters have been frequently used by people for therapeutic and consumption purposes such as drinking since they are believed to contain health benefits. Hence, radioactivity measurements in spas in different parts of the world were conducted by many researchers [7][8][9][10][11][12][13][14][15][16][17][18][19]. Such investigations are important in evaluating radiological parameters. ...
... The levels of radon in the investigated spa water samples are compatible with those reported in the case of other spas in Venezuela [8], Italy [9], China [10], Iran [11], Serbia [16] and Poland [43]. However, the activity concentration of spa waters measured in this study is higher than those reported in Spain [7], India [12], Hungary [14], Romania [15] and Turkey [17,19]. [7] 0.2-130 Venezuela [8] 1-560 Italy [9] 8-506 China [10] 53-293 Iran [11] 145-2731 India [12] 3-47 Hungary [14] 2-98 Romania [15] 5-111 Serbia [16] 25-648 Turkey [17] 3-83 Turkey [19] 0.3-31 Poland [43] 4-1703 a Present study. ...
... However, the activity concentration of spa waters measured in this study is higher than those reported in Spain [7], India [12], Hungary [14], Romania [15] and Turkey [17,19]. [7] 0.2-130 Venezuela [8] 1-560 Italy [9] 8-506 China [10] 53-293 Iran [11] 145-2731 India [12] 3-47 Hungary [14] 2-98 Romania [15] 5-111 Serbia [16] 25-648 Turkey [17] 3-83 Turkey [19] 0.3-31 Poland [43] 4-1703 a Present study. Spa resorts are becoming more popular for therapy and relaxation and related activities such as showering and laundry; on the other hand, spa waters are unconsciously consumed by the public whether they are healthy or not. ...
The current study presents the results of the activity of radionuclides in spa waters, and evaluates their radiological influences on the population consuming these waters in the Central and Eastern Black Sea regions of Turkey. Since these waters are used for therapy and consumption purposes unconsciously, their radiological impact on the people was computed by taking into consideration the annual intake through ingestion of (226)Ra, (232)Th, (40)K, (137)Cs and (222)Rn. The mean activities were estimated to be 11.35 for gross alpha, 6.23 for gross beta, 2.96 for (226)Ra, 0.42 for (232)Th, 0.069 for (137)Cs, 0.19 for (40)K, and 267 Bq L(-1) for (222)Rn, respectively. The estimated effective doses from spa water were found to be 49.77 µSv a(-1) ((226)Ra), 5.95 µSv a(-1) ((232)Th), 0.07 µSv a(-1) ((137)Cs), 0.83 µSv a(-1) ((40)K) and 56.03 µSv a(-1) ((222)Rn). These values were evaluated and compared with related verified values from literature. Also, physico-chemical characterizations of spa water samples considered in the current study were investigated. This study would be useful for consumers and official authorities for the assessment of radiation exposure risk due to usage of the considered spa waters.
... a). Oppositely radon, radium is highly chemically reactive element and is influenced by several physico-chemical parameters (Roba et al. 2012). ...
... AgNO 3 (0.05 N) was solution titrated for Cland SO 4 -2 , precipitated with BaCl 2 and determined gravimetrically. HCO 3 determination was made by using phenolphthalein and methyl orange indicators titrated with 0.1 N HCl solutions (Bolca et al. 2007;Tabar et al. 2013 (Planinic et al. 1996), Denizli/Turkey (Erees et al. 2006), Hungary (Nagy et al. 2009), Bursa/ Turkey (Gurler et al. 2010), India (Chaudhuri et al. 2010), Northwestern Romania (Roba et al. 2012), Seferihisar/ Turkey (Tabar et al. 2013). Beitollahi et al. (2007) clarified that the higher radon levels (145-2731 Bq/l) in Iran hot springs are derived from travertine deposits (CaCO 3 ). ...
... It can be related that the geological and geophysical features of the area (Pasculli et al. 2014). Generally, the production regime is very high in winter season, and oppositely extraction flows in summer is relatively low (Roba et al. 2012). ...
The radioactivity levels (222Rn and 226Ra) and physico-chemical properties of geothermal waters from two spas of Bayındır are investigated. Radon and radium measurements were made with collector chamber method. The radon concentrations range from 3.0 to 13.3 Bq/l, whereas the radium varies from 0.35 to 1.71 Bq/l. It has been observed that radon levels increase in winter and decrease in summer. The 222Rn/226Ra ratio was found to range from 4.91 to 30.53. Physico-chemical properties of water samples were also analysed. Water samples have considerably stable total dissolved solids values, slight acidity, low electrical conductivity, and temperature (42–48 °C).
... Due to of its potential for significant negative health effects and just long enough half-life to play an important role in environmental processes [12], 210 Po (138 day of halflife) is one of the most toxic radionuclides [1,13]. The 210 Po activity concentration depends on the geological structure of the aquifer and distribution of the parent element in the rock matrix and the thermal water [14][15][16]. In addition, the solubility and mobility of 210 Po are also affected by the chemical and physical composition characteristics of the aquifer [16]. ...
... The 210 Po activity concentration depends on the geological structure of the aquifer and distribution of the parent element in the rock matrix and the thermal water [14][15][16]. In addition, the solubility and mobility of 210 Po are also affected by the chemical and physical composition characteristics of the aquifer [16]. ...
There are eight famous thermal water sources, with medium temperature, neutral pH, high ranges of TDS values located in different carbonate formations in Northern Vietnam. The chemical composition results showed the major elements present were Na, K, Mg, Ca, Sr, while trace amounts of rare earth elements (REE), Ag, As, Pb, Th, U were observed. The ²¹⁰ Po activity concentration and the annual committed effective doses for adults, children, and infants in all study areas were far less than 100 mBq L ⁻¹ and 0.1 mSv y ⁻¹ , respectively. Some significant correlations between ²¹⁰ Po and other chemical components have been observed.
... groundwater) (1) It is well-known that the specific activity of 222 Rn depends on the geological structure of the aquifer and distribution of its parent element in the rock matrix. (2,3) During its migration within the earth's crust, mineral waters may come in contact with the surfaces of radioactive eruptive rocks such as granites, quartz porphyry, basalt which contain radium. (3) The concentration of the radon in the water also depends on the solubility of the parent element and its own solubility in waters. ...
... (4) The solubility of radionuclides is affected by chemical and physical composition of the aquifer. (2) For example, the solubility of 222 Rn is varied with the physical conditions and it decreases with the increase of temperature. (5) Some geothermal waters have high concentrations of 222 Rn which may cause damage to the health of individuals. ...
This study presents the results of 222Rn in 24 sources of mineral water, 54 samples from different captured natural springs and drillings. 222Rn determination was performed by direct measurement using Alpha Guard with Aqua Kit. The results for the TDS, anions (F-, Cl-, SO42-), cations (Na+, Ca2+, Mg2+), pH and temperature of the investigated mineral waters were correlated with radon content by statistical software tool IBM SPSS. In the paper are shown the results of investigated correlations between the 222Rn content and gross alpha activity, gross beta activity and specific activity of 226Ra. The received results show that the 222Rn activities range from 0.40 to 476 Bq/l with a median value of 16 Bq/l. The Spearman's rho coefficients demonstrate a strong positive correlation between SO42- and F- anions and 222Rn (r, 0.731 and r, 0.784 respectively). Correlations between226Ra/222Rn, gross alpha activity/222Rn, gross beta activity/222Rn were investigated but not observed.
... The most stable isotope of radon is 222 Rn (with a half-life of 3.8235 days), which is a decay product of 226 Ra. There are 39 known isotopes of radon from 193 Rn to 231 Rn, all of which are radioactive (Roba et al., 2012). Radon-222 is one of the densest gas nuclides under normal condition. ...
... Certain chemical processes-common ion effect (Miller and Sutcliffe, 1985;Sturchio et al., 2001), cation exchange process (Appello and Postma, 1993;Vengosh et al., 2009), oversaturation with respect to barite (Glundl and Cape, 2006), adsorption on iron (Fe) and manganese (Mn) oxides and hydroxides or on organic matter like humic substances (Buckau et al., 2005) may influence the mobility of radionuclides in the environment. However, the mechanisms controlling radionuclides mobility are still not fully understood (Roba et al., 2012). Rn isotopes have been frequently used as tracers of groundwater discharge in several environments, including lakes (Kluge et al., 2007), streams (Burnett et al., 2010), coastal lagoons (Santos et al., 2008;Su et al., 2012) or wetlands (Charette et al., 2003;Cook et al., 2008;De Weys et al., 2011;Rodellas et al., 2012). ...
This study aims to assess the hydrogeochemistry of coastal groundwater, the occurrence of ²²²Rn and ²²⁶Ra, and their isotopic response to salinity and associated chemical compositions of groundwater in the coastal Urmia Aquifer (UA) at the western side of Urmia Lake (UL). The results of the PCA show that 87.3% of groundwater chemistry changes are controlled by six principal components. The interaction between groundwater and coastal igneous and metamorphic rocks in eastern areas (next to the UL) results in complex hydrogeochemical conditions than western areas. Based on correlation of U and salinity, some coastal samples display conservative and the others non-conservative behaviors. Differed from most previous studies, ²²⁶Ra and ²²²Rn concentrations in coastal groundwater samples of UA do not show a good correlation with salinity. Given 10% of groundwater ²²²Rn is originated from host rocks, the radon concentrations recorded in the coastal groundwater samples are relatively in range that can effectively be supplied by the local rocks (5-49 Bq/l). Results of different chemical and isotopic parameters in this area indicate that there is no direct connection between fresh groundwater and UL saltwater. This is because that the hard and thick salty layer in the lakebed acts as an impermeable barrier to prevent the underground hydraulic connection. Results show that removing the salty layer of UL as an option to progress in rehabilitation program of this lake may result in more hydraulic connection between the lake and groundwater resources in some areas.
... Therefore, the porosity of any system seems to be an important physical property that influences these processes related to radon flux 7 . Radon measurements in geothermal fields provide useful information for investigating possible correlations of radon with physical characteristics of geological formation (porosity, permeability and density), characteristics of aquifer (chemical and physical), to locate possible geothermal production area 8 and its potential 9 , the origin of fluids and aquifer structure in which the fluid ascends 10 . 222 Rn has most important applications in geothermal field, because of the high sensitivity to changes in tectonic and geothermal conditions. ...
... It is therefore important to characterize fire intensities for a region to assess the potential impact on the ecosystem and design appropriate fire management plans. Fire temperature is one such measure of fire intensity 8 influenced by factors such as fuel load, fuel type, fuel moisture and weather conditions [9][10][11][12][13] . While a definite relationship of increasing fire temperature with increasing fuel loads has been established in many cases 6,9,11,12,14 , the relationship between fire temperatures with fuel moisture is unclear. ...
Geological structures (faults, fractures and weak zones) and high heat flow in geothermal areas allow easy passage for release of radon gas to the atmosphere. Radon is constantly transported from the Earth's interior and vented out through exhalation points at permeable fault zones. 222 Rn concentrations were measured in a few hot springs and nearby groundwater using RAD7 at Tural and Rajwadi, Ratnagiri district, Maharashtra. The 222 Rn concentrations in the hot springs vary from 1087 132 to 1655 177 Bq/m 3 at Tural and from 152 67 to 350 82 Bq/m 3 at Ra-jwadi. Groundwaters from wells within a radius of 200 m around the geothermal fields have radon concentration between 1087 132 and 5445 337 Bq/m 3. We have assessed the radon activity in the vicinity of the hot springs to understand their hydrogeological control, origin of heat source and possible effect on the tourist and the human population residing nearby.
... The average pH values of the drinking water samples are varied between 6.96 and 7.28 with an average of 7.12. The variation in the pH value of the drinking water is due to the contact with the carbonate rocks such as limestone and dolomite [39]. The standard values of pH for drinking water by BIS (Bureau of Indian Standards) is in the range 6.5-8.5, while WHO its range is 7.0-8.5. ...
... In the analysed drinking waters, the average EC range from 473 to 3020 lS cm -1 with an average value of 1220 lS cm -1 . The EC is directly correlated with the amount of the salts dissolved in the water [39]. The measured TDS values of the drinking water samples varied from 345 to 1991 mg l -1 with an average of 790.62 mg l -1 . ...
Abstract The radon concentration has been determined in 27 drinking water samples of Hassan district and was estimated by using emanometry technique and physicochemical
parameters were estimated using standard techniques. The 222Rn concentrations in water are varying from 0.85 ± 0.2 to 60.74 ± 2.5 Bq l-1 with an average value of 26.5 ± 1.65 Bq l-1
. This study reveals that 66 % of the drinking water samples have radon concentration level in excess of the EPA recommended maximum contamination level of 11.1 Bq l-1. There is no significant correlation noted between radon concentration and physicochemical parameters. The mean annual effective ingestion doses received from all samples are lower than 0.1 mSv y-1
.
... The average pH values of the drinking water samples are varied between 6.96 and 7.28 with an average of 7.12. The variation in the pH value of the drinking water is due to the contact with the carbonate rocks such as limestone and dolomite [39]. The standard values of pH for drinking water by BIS (Bureau of Indian Standards) is in the range 6.5-8.5, while WHO its range is 7.0-8.5. ...
... In the analysed drinking waters, the average EC range from 473 to 3020 lS cm -1 with an average value of 1220 lS cm -1 . The EC is directly correlated with the amount of the salts dissolved in the water [39]. The measured TDS values of the drinking water samples varied from 345 to 1991 mg l -1 with an average of 790.62 mg l -1 . ...
The radon concentration has been determined in 27 drinking water samples of Hassan district and was estimated by using emanometry technique and physicochemical parameters were estimated using standard techniques. The 222Rn concentrations in water are varying from 0.85 ± 0.2 to 60.74 ± 2.5 Bq l-1 with an average value of 26.5 ± 1.65 Bq l-1. This study reveals that 66 % of the drinking water samples have radon concentration level in excess of the EPA recommended maximum contamination level of 11.1 Bq l-1. There is no significant correlation noted between radon concentration and physicochemical parameters. The mean annual effective ingestion doses received from all samples are lower than 0.1 mSv y-1.
... Measurement of the emission of radon from soil into the air has been used to assess the risk of radon exposure to the population. Further, the distribution of radon concentrations in soil has been successfully used in predicting Earth's kinetic phenomena such as earthquakes, karst caves, geological faults, and eruptions [10,11]. ...
The Bat Xat district in the Lao Cai province of Vietnam has enormous potential for resources of copper and rare earth minerals. In fact, exploration and exploitation activities for these minerals have brought about positive economic benefits to this area in recent years. However, this activity also brings about negative impacts on the environment and the surrounding population. The mineral deposits in this area contain a significant content of radioactive substances like uranium and thorium that radiate radon (222Rn) and thoron (220Rn). Therefore, the aim of this study is to investigate the distribution of radon as a function of depth of geological objects in the study areas. Results of this study showed that radon concentration has an exponential distribution with soil depth with R2 ranging from 0.87 to 0.97. It was found that radon concentration in sand was higher than that in clay and soils mixed with gravels. It was also shown that the density and moisture content of the soil is inversely proportional to the diffusion length of radon in the soil.
... Radon-rich waters are under extensive investigation due to their diversity in terms of chemistry, isotope systematics, age, and aquifer settings (Duenas et al., 1998;Horvath et al., 2000;Bohm, 2002;Bertolo and Bigliotto, 2004;Beitollahi et al., 2007;Gurler et al., 2010;Song et al., 2011;Roba et al., 2012;Nikolov et al., 2012;Atkins et al., 2016;Mittal et al., 2016;Seminsky et al., 2017;Abu-Khader et al., 2018;Telahigue et al., 2018;Poojitha et al., 2020 et al.). Radon ( 222 Rn) is a radioactive inert gas, a progeny of 238 U. ...
... 210 Po exists in water absorbed by suspended particles and enters fish and creatures (Çatal et al., 2012;Mishra et al., 2009; Van-Hao et al., 2020;Carvalho, F. P et al., 1994 and. In aquifers, 210 Po is derived from aquifers formations, sedimentary and parent isotopes (Balistrieri et al. 1995;Carvalho et al., 2017;Seiler et al., 2011;Zhong et al., 2020;Thakur et al., 2020;Chaudhuri et al., 2010;Szabo et al., 2012;Roba et al., 2012). 210 Po can enter the human body (IAEA et al., 2009;Martin et al., 2004;Momoshima et al., 2002;Al-Masri et al., 2004;Dubey et al., 2015;. ...
Determination of naturally radionuclides have been known well as an important topic in environmental study in recently. One of the most toxic radioisotope in nature, a daughter product of 238U decay chain is 210Po (polonium). The improvement and optimizations methods for determination of this attractive isotope are still presenting so far. In this paper, a new improved method was elaborated for 210Po determination in thermal water sample. In the proposed method, analytical optimization of spontaneous/auto deposition does not use Teflon cup, magnetic stirring or any preparing equipment/item only normal glass and a side of square silver. In addition, the optimization was neglected with absent of purification of polonium (Liquid-liquid extraction methods/Ion exchange chromatography/Extraction chromatographic separations). The outcome of optimal procedure were simplify, less time consuming, great reduction of costs with chemical recovery >80% and could apply for any liquid environmental samples.
... 210 Po exists in water absorbed by suspended particles and enters fish and creatures (Çatal et al., 2012;Mishra et al., 2009; Van-Hao et al., 2020;Carvalho, F. P et al., 1994 and. In aquifers, 210 Po is derived from aquifers formations, sedimentary and parent isotopes (Balistrieri et al. 1995;Carvalho et al., 2017;Seiler et al., 2011;Zhong et al., 2020;Thakur et al., 2020;Chaudhuri et al., 2010;Szabo et al., 2012;Roba et al., 2012). 210 Po can enter the human body (IAEA et al., 2009;Martin et al., 2004;Momoshima et al., 2002;Al-Masri et al., 2004;Dubey et al., 2015;. ...
Determination of naturally radionuclides have been known well as an important topic in environmental study in recently. One of the most toxic radioisotope in nature, a daughter product of 238U decay chain is 210Po (polonium). The improvement and optimizations methods for determination of this attractive isotope are still presenting so far. In this paper, a new improved method was elaborated for 210Po determination in thermal water sample. In the proposed method, analytical optimization of spontaneous/auto deposition does not use Teflon cup, magnetic stirring or any preparing equipment/item only normal glass and a side of square silver. In addition, the optimization was neglected with absent of purification of polonium (Liquid-liquid extraction methods/Ion exchange chromatography/Extraction chromatographic separations). The outcome of optimal procedure were simplify, less time consuming, great reduction of costs with chemical recovery >80% and could apply for any liquid environmental samples.
... Chiều dài khuếch tán radon từ đất vào không khí có thể sử dụng để đánh giá rủi ro cho nhà ở được xây dựng trên vùng đất này. Sự phân bố nồng độ radon trong đất có thể giúp dự đoán được các hiện tượng động học của đất như động đất, phun trào [6], v.v. Ngoài ra, khi cần chôn chất thải có chứa các đồng vị trước radon trong chuỗi phân rã uranium, việc khảo sát chiều dài khuếch tán của radon trong môi trường chứa hoặc bao phủ chất thải để thực hiện tốt công tác bảo đảm an toàn là điều cần thiết [4]. ...
Nồng độ phóng xạ radon theo độ sâu và chiều dài khuếch tán radon trong một số loại đất đã được khảo sát trong nghiên cứu của chúng tôi. Kết quả cho thấy, phân bố nồng độ radon theo độ sâu gần như tuân theo quy luật hàm mũ. Chiều dài khuếch tán radon trong đất cát và đất thịt cao hơn so với đất sét và đất chứa nhiều sỏi đá. Các yếu tố về độ ẩm và mật độ đất ảnh hưởng đến phân bố nồng độ radon cũng được xác định cụ thể.
... 226 Ra and 222 Rn are two of the most common naturally occurring radionuclides in groundwater. The concentration of dissolved radon is dependent not only on the radium content of rocks but also on local factors such as groundwater chemistry, the presence of shear zones, soil porosity or the residence time of water in a specific aquifer [3][4][5]. Moreover, the flow of groundwater through soil and rocks containing radon and radium can lead to a concentration of radon activity in addition to that due to the original aquifer [6]. ...
Seasonal variations of the radon and radium activity concentrations in karstic water sources originating in karstic formations were investigated as part of a premiere systematic survey conducted in Romania. A database including a total of 228 drinking water samples collected from 30 distinct water sources adjacent to rural communities was compiled. The radon and radium activity concentrations for all seasons, assessed based on solid scintillation, ranged from 2.1 to 19.7 Bq/L and from 0.6 to 3.0 Bq/L, respectively. Overall, the detected radon and radium contents did not exceed the radioprotection standards recommended by national and European legislation. However, in at least one season, the measured values for 31% of the samples exceeded the 11.1 Bq/L maximum contaminant level for radon in drinking water recommended by the Environmental Protection Agency of the United States. The associated radiological risk, reported in terms of annual effective dose, was calculated to be between 9.8 × 10−6 and 6.0 × 10−5 mSv/y for radon and between 5.9 × 10−5 and 2.7 × 10−4 mSv/y for radium, which are considerably below the WHO (World Health Organization) guidelines at a value of 0.1 mSv/y.
... Rather low content of SO − 4 and HCO − 3 , high content of Cl − due to mixing with seawater [8] are signs of shallow and not too hot origin of spring waters [40]. Thermal waters in the study area are slightly acidic most probably due to the contact with carbonates [37]. ...
Dikili-Izmir Region (Western Turkey) has been an active area of development for the utilization of geothermal resources. In this study, we aim to quantify the untapped resource-potential in this region for both direct and indirect utilization purposes. After collecting geological data from the literature, probabilistic heat-in-place calculations are carried out. Yuntdağ Volcanites and Kozak Pluton are considered, and the latter is proposed as an enhanced geothermal system. It is shown that, with 50% probability, 75 MW e and 17 MW e of net electrical power can be produced from Yuntdağ and Kozak reservoir systems, respectively. When the unit volumes of reservoirs are considered, Kozak can produce 3.2 and 2.5 times of what Yuntdağ can produce in terms of electrical and thermal power, respectively. A sensitivity analysis is performed to understand the impact of reservoir characteristics on the reserves. Within the uncertainty ranges defined, reservoir size, temperature and recovery factor are found to be critical parameters that affect the net power output. Sustainability attributes are evaluated from both economic and environmental perspectives and potential benefits are discussed.
... At least 80% of the radon emitted into the atmosphere comes from the top few meters of the ground surface (UNSCEAR, 2008). Radon in the soil and atmosphere is an important tracer in predicting earthquakes and other geological phenomena (Roba et al., 2012;Catalano et al., 2014). ...
The effects of moisture content, grain size, temperature, major elemental composition, and the pH of soils on the radon emanation and diffusion coefficients were evaluated in this study. The emanation and diffusion coefficients are strongly influenced by moisture content and grain size. The radon emanation coefficient increased and the diffusion coefficient decreased with decreasing particle size. However, for soils with large particle sizes, the radon emanation and diffusion coefficient remain almost unchanged with variation in grain size. Comparing five different sized soil particles, the emanation coefficient increased and the diffusion coefficient decreased with moisture content. The radon emanation coefficient reached a constant value with different moisture contents depending on the range of grain sizes. The saturation emanation coefficient for less than 0.1, 0.1-0.2, 0.2-0.3, 0.3-0.5, and more than 0.5 mm sized soil grain ranges are 0.47, 0.42, 0.35, 0.26 and 0.23, respectively, with saturation moisture contents of 16%, 14%, 10%, 6% and 4%, respectively. A drastic increase in radon emanation is found at smaller grain sizes with increasing moisture content. Based on the content of major elements and pH of the soils, the multiple regression indicates that the radon emanation coefficient appears to be significantly dependent on iron content and pH. Effective diffusion coefficient values calculated in our study agree with the results calculated by a previous model. Experimental values show that the temperature dependence of the radon diffusion coefficient follows Arrhenius behavior.
... During water-rock interaction processes, some toxic elements and natural radionuclides have been leached and their concentrations in water elevated. Therefore, the elemental concentrations in geothermal water depend first on the geological formation of the geothermal system (Roba et al. 2012;Chaudhuri et al. 2010) and second, on the solubility of the elements, which plays an important role in the concentration of these elements in geothermal waters (Szabo et al. 2012). ...
... During water-rock interaction processes, some toxic elements and natural radionuclides have been leached and their concentrations in water elevated. Therefore, the elemental concentrations in geothermal water depend first on the geological formation of the geothermal system (Roba et al. 2012;Chaudhuri et al. 2010) and second, on the solubility of the elements, which plays an important role in the concentration of these elements in geothermal waters (Szabo et al. 2012). ...
The present study was conducted to study the compositional trends of rare earth elements (REEs), Th, and U in marine sediment samples in terms of distribution patterns, anomalies, and indicator ratios. For this purpose, a total of 32 marine sediment samples were collected from 12 coastal areas of the Egyptian Red Sea and analyzed using instrumental neutron activation (INAA) and inductively coupled plasma mass spectrometry (ICP-MS) analytical techniques. The analyses investigated 14 REEs, Th, and U. The results revealed that the contents of REE, light REE (LREE), and heavy REE (HREE) are 47.6, 38.7, and 8.3 mg/kg, respectively, whereas the concentration of Th and U is determined as 2.15 and 2.23 mg/kg, respectively. Indicator ratios were calculated, and
inter-correlation elements with Th and U were constructed. Multivariate statistics were implemented on the data and GIS technology to construct the distribution patterns of REE, Th, and U along the Egyptian coast of the Red Sea. The obtained results were compared with the corresponding values published in literature to show a good matching. There is a significant enrichment of LREE relative to HREE, a reduced ratio of Th/U, a weak positive
anomaly of Eu/Eu*, and a slight positive Ce anomaly is noticed. Among the 12 studied areas, one area, Sharm ElBahari, located in the middle of the coast, shows peak values of REE, Th, and U relative to the other areas. However, it still shows a good agreement with the results published in the literature.
... The radon gas which is sparingly soluble in water finds its way/escapes into the air (indoor and outdoor) when the water becomes agitated during usages for various purpose [5][6][7][8]. The released radon accumulates and adds to the total indoor-airborne radon concentration already present due to migration of soil gas [9][10][11]. The prolonged exposure of inhabitants to high concentrations of radon and its progenies may lead to stochastic health effects such as lung cancer [12]. ...
In the present work, radon concentrations were measured in surface and underground water samples in Faridabad District of Southern Haryana, India using an active radon monitor based on alpha scintillation technique and results have been inter-compared. The average radon concentration in the underground water samples was observed to be 4 times higher than in the surface water samples. The estimated annual effective dose varied from 5.7 to 58.5 μSvy⁻¹ with an average of 24.2 μSvy⁻¹ for underground water samples and 1.1 to 12.5 μSvy⁻¹ with an average of 6.7 μSvy⁻¹ for surface water samples. The estimated annual effective dose for both type of samples was found to be less than 0.1 mSvy⁻¹, which is the safe limit as suggested by World Health Organisation and EU Council.
... During water-rock interaction processes, some toxic elements and natural radionuclides have been leached and their concentrations in water elevated. Therefore, the elemental concentrations in geothermal water depend first on the geological formation of the geothermal system (Roba et al. 2012;Chaudhuri et al. 2010) and second, on the solubility of the elements, which plays an important role in the concentration of these elements in geothermal waters (Szabo et al. 2012). ...
Due to the interaction of water with hot deep bedrock within the geothermal system, the geochemical, elemental and radiological aspects of water and nearby soil and sediment samples are essential to investigate the water quality and the potential ecological impacts on the nearby area. In this study, four geothermal water springs located within Al-Lith region, Saudi Arabia, (namely Al-Harra, Bani Hilal, Markoub and Daraka) have been investigated. In addition to 9 water samples, 15 soil and sediment samples were collected from the adjacent areas. Some physicochemical parameters of water samples such as major anions and cations, pH, EC, and temperature were measured. The concentration of some toxic and other elements such as As, Cd, Ni, Pb, Th, U, and Zn, as well as some natural radionuclides [e.g.²²⁶Ra (²³⁸U series), ²³²Th series, ⁴⁰K] and the artificial radionuclide (¹³⁷Cs) was measured using ICP-MS and gamma-ray spectrometer based on hyper-pure germanium detector. The ecological impacts of the discharged water were evaluated using pollution and risk indices such as enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), degree of contamination (Cd), pollution load index (PLI) and potential ecological risk index (RI). The water quality was evaluated by comparing the elemental concentration of water samples to the maximum contaminant level (MCL) of USEPA and WHO for drinking water. The elemental concentration of water samples was below the MCL except for Fe and As. Pollution and risk indices for soil and sediment samples revealed that there was a slight enrichment of Sr and Mo in three locations and considerable contamination with Hg in one location. However, the pollution load index was still below unity. The average activity concentration in Bq kg− 1of ²²⁸Ra (²³²Th series), ⁴⁰K and ¹³⁷Cs was within their world average values, while that of ²²⁶Ra (²³⁸U series) was slightly higher, which could be due to its accumulation from geothermal water to soil and sediment matrices.
... The values obtained for different samples collected at different locations of the study area are summarized in Table 3. pH is a measure of the hydrogen ion concentration in water and indicates whether the water is acidic or alkaline and its value of the collected water samples varied between 6.5 and 7.8 with an average of 7.1 which are well within the range 6.5-8.5 by Bureau of Indian Standards (BIS), while 7.0-8.5 range by WHO. The variation of pH value in the ground water samples is due to the contact with the carbonate rocks such as dolomite and limestone [23]. Total dissolved solids (TDS) indicate the nature of water quality for salinity and its value of the collected samples vary between 472 and 1785 mg l -1 with an average value of 972.8 mg l -1 . ...
Concentration of radon and physicochemical parameters present in ground water collected from 65 bore wells of 30 different locations around Kolar Gold Fields, Kolar District, India are estimated by emanometry technique and chemical analysis. Activity of radium present in rock samples of the study area using HPGe detector are
presented and discussed in the manuscript. The average radon concentration in the collected water samples are ranged from 3.3 ± 0.8 to 122.9 ± 2.1 Bq l-1 with an average value of 46.9 ± 1.7 Bq l-1
. Average value of activity concentration of radium is found to be
29.1 Bq kg-1 .
... For example, Dickson (1985) found that the average activity ratio ( 226 Ra/ 228 Ra) in saline water occurring in south-western Yilgan, Australia, amounted to 0.16, while the activity ratio ( 238 U/ 232 Th) in the rock aquifer amounted to 0.6. Some researchers observed the important role of chloride ions in radium desorption from the aquifer rocks into the groundwater, where the 226 Ra content in waters increases with salinity (Martin & Akber 1999, Labidi et al. 2010, Roba et al. 2012, Vinson et al. 2013. The radium concentrations in groundwater are also controlled by the presence of barium and sulfate ions (Sturchio et al. 1993, Grundl & Cape 2006, Szabo et al. 2012). ...
The influences of aquifer formations and water chemical composition on the occurrence and activity ratio of radium isotopes in groundwater are discussed. Based on the model of desorption/adsorption processes of natural radionuclides in the rock-water system, the concentrations of radium isotopes and their activity ratio in groundwater are evaluated by the numerical Monte Carlo method (MC). In cases where the groundwater is of a similar age, limited flow (up to several meters/year), the physical conditions and the uranium and thorium activity ratios in host water formations are similar, the activity concentrations of radium isotopes (Ra-226, Ra-228) and their activity ratio (Ra-226/Ra-228) are the highest in the water of high desorption coefficient for chloride sodium water (domination of Cl − , Na + ions), medium in water of moderate desorption (bicarbonate water – HCO 3 − , Ca 2+) and the lowest in waters with a low desorption coefficient (sulfate ions prevailing – SO 4 2− , Ca 2−). The statements are well confirmed in the case of the natural mineral waters from the Polish Outer Carpathians. The total dissolved solids (TDS) of the Polish Carpathians waters varies from several hundred milligrams per liter to several tens of thousands milligrams per liter. The minimum, maximum and average concentrations of Ra-226, Ra-228 and their activity ratio (Ra-226/Ra-228) are 82, 1340, 456 mBq/L, 19, 1240, 354 mBq/L and 0.89, 7.6 and 2.0 for chloride waters; 4, 140, 45.8 mBq/L, 12, 171, 62.7 mBq/L and 0.3, 1.7 and 0.70 for bicarbonate waters and 0.8, 9.3, 3.6 mBq/L, 5.3, 54, 20.1 mBq/L and 0.1, 1.0, 0.3 for sulfate ones, respectively. The desorption coefficients are the highest for the Cl-Na, moderate for the HCO 3-Ca and the lowest for the SO 4-Ca waters (in contrast to the adsorption properties of these waters).
... spring water the total annual effective dose varies from 0.0097 to 0.09 mSv/y with an average 0.022 mSv/y, and only one sample (sample no.12) is comparable with the values represented by world health organization (WHO) recommended level of 0.1 mSv/y for intake of radon in water In addition to radon concentration some physicochemical parameters such as pH and electrical conductivity for all samples are measured in order to find the effect of these parameters on the radon concentrations and summarized in Table (2 While the pH values for lake with streams varies from 7.8 -9.1 in spring, 7.5 -9.1 in summer, 7.7 to 9.1 in autumn and 8.1 to 9 in winter time, and the average values vary from 8.63, 8.6, 8.33, and 8.51 respectively. The variation of pH water for drinking water is due to contact with the carbonate S1 S6 S8 S9 S11 S12 S15 0.00 0.02 0.04 0.06 0.08 0.10 total annual effective dose mSv/y position spring summer autumn winter S2 S3 S4 S5 S7 S10 S13 S14 S16 S17 S18 S19 S20 S21 S22 S23 S24 S25 S26 S27 S28 S29 S30 S31 S32 S33 S34 S35 S36 S37 S38 S39 S40 S41 rocks such as limestone and dolomite [22]. The standard pH values of the drinking water by WHO is in the range 6.5-8.5. . ...
A total of 164 water samples were collected from Darbandikhan Lake with their different resources (spring, stream, and lake) during the four seasons, and the measurements were carried out using the electronic RAD 7 detector. For spring water the average radon concentration for spring, summer, autumn and summer were found to be 8.21 Bq/1, 8.94 Bq/1, 7.422 Bq/1, and 8.06 Bq/1, respectively, while for lake and streams the average values were found to be 0.43 Bq/1, 0.877 Bq/1, 0.727 Bq/1, 0.575 Bq/1 respectively. The radon concentration level was higher in summer and lower in spring, and only two samples from spring water have radon concentrations more than 11.1 Bq/1 recommended by the EPA. Total annual effective dose due to ingestion and inhalation has been estimated, the mean annual effective dose during the whole year for spring water was 0.022 mSv/y while for lake with streams was 0.00157 mSv/y. The determined mean annual effective dose in water was lower than the 0.1 mSv/y recommended by WHO. Some physicochemical parameters were measured and no correlation was found between them and radon concentration except for the conductivity of the spring drinking water which reveals a strong correlation for the four seasons.
... spring water the total annual effective dose varies from 0.0097 to 0.09 mSv/y with an average 0.022 mSv/y, and only one sample (sample no.12) is comparable with the values represented by world health organization (WHO) recommended level of 0.1 mSv/y for intake of radon in water In addition to radon concentration some physicochemical parameters such as pH and electrical conductivity for all samples are measured in order to find the effect of these parameters on the radon concentrations and summarized in Table (2 While the pH values for lake with streams varies from 7.8 -9.1 in spring, 7.5 -9.1 in summer, 7.7 to 9.1 in autumn and 8.1 to 9 in winter time, and the average values vary from 8.63, 8.6, 8.33, and 8.51 respectively. The variation of pH water for drinking water is due to contact with the carbonate S1 S6 S8 S9 S11 S12 S15 0.00 0.02 0.04 0.06 0.08 0.10 total annual effective dose mSv/y position spring summer autumn winter S2 S3 S4 S5 S7 S10 S13 S14 S16 S17 S18 S19 S20 S21 S22 S23 S24 S25 S26 S27 S28 S29 S30 S31 S32 S33 S34 S35 S36 S37 S38 S39 S40 S41 rocks such as limestone and dolomite [22]. The standard pH values of the drinking water by WHO is in the range 6.5-8.5. . ...
... In the case of water measurements, the samples were taken from wells in bottles of 0.5 l and totally filled. 222 Rn concentration was measured using the LUK- VR system consisting of a LUK-3A device and a VR-scrubber [17, 18]. The radon concentration dissolved in the water sample (0.3 l) is mixed with the air that is on the top of the water level within the scrubber volume. ...
Terrestrial gamma dose rates have been measured using thermoluminescence method in Alba county. More than 150 dosimeters were placed in 52 locations. The obtained values ranged from 41±2 to 91±4 nGy/h, being in agreement with UNSCEAR Report. Radon concentrations for indoor air were performed in 12 locations from Alba county using CR39 detectors accompanied by radon groundwater measurements, being in accordance with WHO and EURATOM Treaty. Annual effective doses due to radon exposure were also calculated. Alongside with previous results, this work represents an important stage in the development of the high resolution environmental radioactivity map for Transylvania region.
... Uranium and radium found naturally in soil and rocks, provide a continuous source of radon. Because of its gaseous nature, radon is able to escape from the rock depending on the density and porosity thereof, being one of the most common radioactive elements in groundwater (Roba et al., 2012). ...
Radon ((222)Rn) levels in air and water have been analyzed continuously for almost a year in Las Caldas de Besaya thermal spa, north Spain. Radon is a naturally occurring noble gas from the decay of radium ((226)Ra) both constituents of radioactive uranium 238 series. It has been recognized as a lung carcinogen by the World Health Organization (WHO) and International Agency for Research on Cancer (IARC). Furthermore the Royal Decree R.D 1439/2010 of November, 2010 establishes the obligation to study occupational activities where workers and, where appropriate, members of the public are exposed to inhalation of radon in workplaces such as spas. Together with radon measures several physico-chemical parameters were obtained such as pH, redox potential, electrical conductivity and air and water temperature. The devices used for the study of the temporal evolution of radon concentration have been the RTM 2100, the Radon Scout and gamma spectrometry was complementarily used to determine the transfer factor of the silicone tubes in the experimental device. Radon concentrations obtained in water and air of the spa are high, with an average of 660Bq/l and 2900Bq/m(3) respectively, where water is the main source of radon in the air. Radiation dose for workers and public was estimated from these levels of radon. The data showed that the thermal processes can control the behavior of radon which can be also influenced by various physical and chemical parameters such as pH and redox potential.
... 77 Fredj et al. (19) Tunisia 0.0008-0. 525 Chau et al. ( conditions decrease the adsorption of radium onto aquifer surfaces by reducing the stability ield of sulphate minerals (41) . As a result, the solubility of 226 Ra in water increases with reducing redox potential. ...
Background: There is a rapid increase worldwide in the consumpon of
mineral waters which may contain different level of radioacve elements,
especially 226Ra, in addion to varying amounts of beneficial salts. Therefore,
a comprehensive study was planned and carried out in order to determine
concentraon of 226Ra natural radionuclide in boled mineral waters that
commercially available in Marmara Region of Turkey. Materials and
Methods: The method used for 226Ra concentraon analysis bases on the
measurement of Radon (222Rn) coming from 226Ra dissolved in the water. The
measurements were performed using RAD 7, a solid state α detector, with
RAD H2O accessory manufactured by DURRIDGE COMPANY Inc. Results: The
226Ra concentraon in mineral waters was found to vary from <0.074 to 0.625
Bql‐1 with an average value of 0.267 Bql−1.The commied effecve doses due
to ingeson of 226Ra from the one year consumpon of these waters were
esmated to range from 10.8 to 90 μSvy‐1, from 9 to 75 μSvy‐1 and from 3.15
to 26.25 μSvy‐1, for infants, children and adults, respecvely. Conclusion: The
results obtained in this study indicate that the commied effecve doses are
below the WHO (World Health Organizaon) recommended reference level of
100 μSvy‐1.
The current study investigates the presence 222 Rn in tap water, natural spring water, and well water from various locations in Er-Rachidia, Morocco, to assess the potential radiological risks posed to the local community. Radon, a radioactive gas produced by the decay of uranium and thorium in rocks and soil, poses significant radiation hazards. Using a Nuclear Track Detector (LR-115), researchers investigated the presence of radon in water from wells, dams, and rivers. The highest radon concentrations are found in well water, with an average of 1.92 Bq/L. The concentration of river water is the lowest, coming in at 0.53 Bq/L, while the average concentration of dam water is 0.84 Bq/L. On average, the annual effective dosage for well water is 4.57 ms per year. The water dosages from dams range from 1.74 to 2.44 μSv/y, with 1.98 being the average. River water ranges from 0.51 to 1.69 mSv/y, averaging 1.24 µSv/y. The excess lifetime cancer risk varies significantly across water sources: 1.27 × 10−3 to 1.84 × 10−3 (average 1.60 × 10−3) for well water, 0.61 × 10−3 to 0.85 × 10−3 (average 0.69 × 10−3) for dam water, and 0.18 × 10−3 to 0.59 × 10−3 (average 0.43 × 10−3) for river water. The results dispel fears of significant radioactive dangers to the locals by suggesting that the measured radon concentrations are within the limits set by international organizations.
Radon, a known carcinogen, is the second largest cause of lung carcinoma as per the World Health Organisation. The primary purpose of the present research is to examine and compare the concentrations of radon gas (222Rn) in different sources of water in the Lar and Ganderbal tehsils of the district of Ganderbal, Jammu and Kashmir. Higher groundwater 222Rn concentrations indicate higher indoor radon concentrations and long-term radon exposure is extremely harmful to human health as it increases the risk of developing lung cancer.
A scintillation-based radon monitor called the smart RnDuo was used to quantify the amount of radon activity present in water samples collected from different locations of Lar and Ganderbal regions of district Ganderbal.
Average radon (222Rn) concentration of 1.84 BqL−1 was found in tap waters, 3.73 BqL−1 in surface waters, 16.56 BqL−1 in borewells, and 20.82 BqL−1 in springs. The higher radon concentration in groundwater is because of the direct and prolonged interaction of uranium-rich rocks and soil with the water. Hence, monitoring and regulating radon levels in these water sources is crucial to ensure public health and safety.
In this research, radon activity concentrations in the available types of bottled drinking water samples available in Iraqi Kurdistan region markets were measured by using passive (CR-39 SSNTDs) and active (Durridge RAD-7-H2O with a closed loop) methods. Radon concentration in bottled water ranged from (0.050 to 0.585) Bq/l for CR-39 with a mean value (0.143) Bq/l and ranged from (0.030 to 0.213) Bq/l for RAD7 with a mean value (0.074) Bq/l. The values of activity concentration were below the Maximum contamination level (MCL) suggested by USA-EPA which is (11.1) Bq/l. The rate of total annual effective dose for humans drinking this water is also determined. The results indicate that the total annual effective doses were lower than the MCL of 0.1mSv/y proposed by (WHO, 2004) for the intake of radionuclides in drinking water. The Cancer risk and lifetime heredity levels were also calculated and the mean value was very low compared to the acceptable limit of 1.0x10-3.
Study on the Nuanquanzi geothermal field in the Yanshan uplift is of great significance for understanding the origin of geothermal fluid in the intracontinental orogenic belt of the fault depression basin margin in North China. The geochemical characteristics and formation mechanism of the Nuanquanzi geothermal system were elucidated by classical hydrogeochemical analysis, multi-isotopes approach (δD, δ18O, δ13C, δ87Sr/86Sr), 14CAMS dating, and integrated geophysical prospecting of surface-soil radon gas measurement and CSAMT inversion. The results show that the Nuanquanzi geothermal field is a medium-low temperature convection-fault semi-enclosed geothermal system. The hydrochemical type of thermal water is primarily HCO3-Na, and rich in soluble SiO2, F− and Cl−. The geothermal water primarily originated from the recharging meteoric water with a maximum circulation depth of 2 400–3 200 m, but affected by the mixing of endogenous sedimentary water. The reservoir temperature calculated by Na-K and quartz geothermometer of the Nuanquanzi geothermal system was determined to be 73.39–92.87 °C. The conduction-cooling and shallow cold-water mixing processes occurred during the parent geothermal fluid ascent to surface, and the proportion of cold-water mixing during circulation was approximately 88.3% to 92.2%. The high-anomaly radon zones matched well to the low apparent-resistance areas and hiding faults, indicating that the Nuanquanzi geothermal field was dominated by a graben basin restricted by multiple faults.
Radon (²²²Rn) is a ubiquitous radioactive gas and could threaten human life due to its potential for cancer and non-cancer risks. This study examined the measurement of ²²²Rn concentration and associated health risks in the hot springs of Hunza-Nagar valley. For this purpose, the hot springs water of Hunza and Nagar districts and the background sites were analyzed for ²²²Rn concentration using the RAD7 detector (Durridge Company, USA). The average concentrations of ²²²Rn were 46.1 ± 0.94, 65.3 ± 0.45, and 5.47 ± 0.25 Bq/L in the Hunza district, Nagar district, and background sites, respectively. Results showed that ²²²Rn concentrations of hot springs water were multifold higher than the background sites. ²²²Rn concentrations for hot springs water in Hunza-Nagar valley had surpassed the maximum contamination level set by the US environmental protection agency (USEPA). Humans’ annual mean exposure dose rates of various age groups were calculated for the estimated lifetime cancer risk (ELCR) and non-cancer risks. The total annual mean exposure doses from ²²²Rn in water (EwTotal) values were (187 ± 3.80, 265 ± 1.84, and 22.2 ± 1.02 μSv/a) for infants (143 ± 2.92, 203 ± 1.40, and 17.0 ± 0.78 μSv/a) children, and (138 ± 2.80, 196 ± 1.35, and 16.4 ± 0.76 μSv/a) adults in the Hunza district, Nagar district, and background, respectively. Among the age groups of humans, infants showed a higher risk than others. Results showed that hot springs water consumption surpassed the world health organization threshold of 100 μSv/y for chronic or non-cancer and USEPA 0.1 × 10–3 for ELCR risks. The concentration of ²²²Rn showed a positive correlation (> 0.68) with hot springs' water temperature and pH suggesting a common origin.
Актуальность исследования заключается в получении актуальных изотопно-геохимических данных о природных водах и вмещающих горных породах проявления радоновых вод Седова Заимка. Цель: изучить особенности химического состава природных вод и водовмещающих пород и получить первые сведения по активности 222Rn и изотопному составу δD, δ18O, δ13С, 234U, 238U, 226Ra и 228Ra. Методы. Лабораторное изучение химического состава методами титриметрии, ионной хроматографии, масс-спектрометрии с индуктивно связанной плазмой проводилось в ПНИЛ гидрогеохимии ИШПР ТПУ. Определение комплекса величин δD, δ18O, δ13СDIC вод и растворенного неорганического углерода (Dissolved Inorganic Carbon (DIC)) проводилось в центре коллективного пользования ИГМ СО РАН с помощью прибора Isotope Ratio Mass Spectrometer FinniganTM MAT 253, снабженного приставками пробоподготовки H/Device (для определений δD) и GasBench II (для определений δ18O и δ13СDIC). Измерение содержаний 222Rn в водах проводилось на комплексе «Альфарад плюс» в лаборатории гидрогеологии осадочных бассейнов Сибири ИНГГ СО РАН. Данные по общей β-активности вод, а также активностях 234U, 238U, 226Ra и 228Ra получены после предварительной радиохимической пробоподготовки на альфа-спектрометре ALPHA-ENSEMBLE-8 (Ametek, ORTEC, США); гамма-спектрометрической системе, скомпонованной на базе колодезного коаксиального HPGe ППД с низкофоновым криостатом EGPC 192-P21/SHF 00-30A-CLF-FA фирмы EURISYS MEASURES (Франция) и альфа-бета радиометре для измерения малых активностей УМФ-2000 с кремниевым детектором (НПО «Доза», Россия). Разделение данных на однородные геохимические совокупности выполнено с помощью коэффициентов Са/Na, Са/Mg, Ca/Si, Mg/Si, Na/Si. Для выявления степени концентрирования химических элементов в природных водах были рассчитаны коэффициенты концентрации и водной миграции (по А.И. Перельману) . Результаты. Открыто проявление радоновых вод Седова Заимка, и впервые выполнены комплексные изотопно-геохимические исследования. Радоновые воды (активность 222Rn до 428 Бк/дм3) в основном характеризуются HCO3 Mg-Na-Ca составом с величиной общей минерализации от 158 до 581 мг/дм3 и содержанием кремния от 4,34 до 30,84 мг/дм3. Геохимические параметры среды варьируют от восстановительной до окислительной обстановки с величинами Eh от –40,2 до +28,4 мВ; pH от 7,5 до 7,6 и O2раств. от 2,99 до 5,24 мг/дм3. Значения геохимических коэффициентов составляют: Ca/Na 77,17; Ca/Mg 6,63; Ca/Si 11,42; Mg/Si 1,48; Na/Si 0,92; Si/Na 15,34; rNa/rCl 2,12; SO4/Cl 4,02, что закономерно указывает на процессы формирования химического состава радоновых вод во вмещающих породах преимущественно алюмосиликатного состава. Среди микрокомпонентов наиболее высокими средними содержаниями выделяются (мг/дм3): Si=17,77; Fe=1,18; Mn=0,16; Zn=0,020 и W=0,0036. Значимых коэффициентов концентрации микрокомпонентов не выявлено. Сильной миграционной способностью в растворе обладает Sr, средней – Si, Mn, Ba, Cs и U. Суммарная β-активность вод составляет 32 мБк/дм3. Содержания природных радионуклидов варьируют (мг/дм3): 238U от 3,91∙10–4 до 6,39∙10–4; 232Th от 6,02∙10–6 до 2,37∙10–5 и 226Ra от 6,66∙10–11 до 1,09∙10–10. 232Th/238U отношение в водах изменяется от 1,02∙10–2 до 3,71∙10–2, что является следствием окислительной геохимической обстановки, в которой торий не мигрирует. Уранизотопное отношение (γ) 234U/238U составляет 5,75 при активности изотопов урана (мБк/дм3): 234U (115±7), 238U (20±2), что указывает на неглубокую циркуляцию изученных вод. Активность изотопов радия в водах равна у 226Ra 70±7, а у 228Ra 51,8±3,9 мБк/дм3. Отношение 226Ra/228Ra в HCO3 Mg-Na-Ca радоновых водах составляет 1,35. Изотопный состав радоновых вод (от –126,3 до –121,1 ‰ для δD и от –16,8 до –16,3 ‰ для δ18O) указывает на их метеорно-инфильтрационное происхождение. Изотопный состав углерода δ13CDIC указывает на биогенное происхождение углекислоты и ее участие в процессе карбонат-силикатного выветривания пород.
Kütahya is one of the provinces with many well-known spas in Turkey. Radionuclide levels in the thermal waters of these spas have not been measured before. Therefore, the radon and radium concentrations in thermal waters collected from Kütahya spas were measured using the collector chamber method. In addition, the indoor radon concentrations of spas were determined using LR-115 type II solid-state nuclear track detectors. The annual effective doses from the inhalation and ingestion of radon and radium concentrations have been calculated. The sampling points' physical and chemical properties were also measured during the survey.
BRAZILIAN FOUNTAINS, BIOLOGICALLY ACTIVE COMPOUNDS.
The natural surrounds and resources wrapping hot or mineral springs belong to
sustainable matter involving governance and strategic planning of public health,
environment, welfare, tourism and mining sectors. Noted it, through the current
Brazilian policy demand: social thermalism/hydrotherapy/crenotherapy selected like
complementary alternative medicine (CAM) by health ministry law MS 971/2006
(PNPIC), hydro-thermal therapy qualifying DNPM (MME Ordinance 127/2011 and
MME 337/2002), health and wellness tourism formally oriented by tourism ministry
and environmental management groundwater resources (Resolution MME /
CONAMA 396/2008 and MME / CNRH 107/2010). Whereas as fresh potable
reserves or potential mineral aquatic strategic deposits, the main biologically active
components (BAC) were identified, with their minimum levels needed to related
health benefits. Similar to conventional mining prospection, these “cut off grade”
detection, at natural occurrences from Brazil, was the major goal in this work. The
bibliographic systematic review allowed identify the main bioactive substances (BAC)
related to springs sources of elements enougth or proven as health beneficial and at
which indications. Wards after, it was performed a georeferenced database with
these same variables (BAC) from Brazilian springs. Overlays all through thematic
maps assisted in geographical and geological evaluations, whereas, at the end,
statistical comparisons filtered target selection at all. The total 60 possible natural
BAC and its minimum values for efficacy globally reviewed and established were
detected at least one BAC occurrence from 703 mineral springs at 525 Brazilian
cities. The arguments utilized were important in demonstrating the abundant and
diverse existence of this endowment, where its potential health applications are
virtually unknown today.
In this study, the activity concentrations of radon gas C(222Rn) in the water of Jale and Mersaid springs were measured by using an HPGe spectrometer. The average C(222Rn) in the main Mersaid spring (T≈ 33 °C) and Jale warm outlet (T≈ 36 °C) was 24.10 ± 0.50 and 30.11 ± 0.67 Bq L−1, respectively. In the left cold outlet (T≈ 25 °C) and right cold outlet (T≈ 24 °C) of Jale spring, the average C(222Rn) was about 21.04 ± 0.52 and 19.04 ± 0.55 Bq L−1, respectively. The C(222Rn)/C(226Ra) ratio was 100. Results showed that a substantial amount of 222Rn might have been lost as water flowed to the surface.
Актуальность исследования состоит в получении новых сведений о гидрогеологии и гидрогеохимии слабоизученных месторождений радоновых вод города Новосибирска на юге Западной Сибири. Новосибирск относится к числу тех немногих городов России, которые были заложены на гранитах – источнике эманации радона (222Rn). В геологическом отношении изучаемая территория приурочена к внутренней области крупного Новосибирского гранитоидного массива. Научных обобщений имеющегося фактического материала не проводилось. Цель: выявление особенностей гидрогеологического строения и гидрогеохимии месторождения радоновых вод «Каменское», изучение форм миграции химических элементов в водах и оценка степени их насыщения относительно ряда карбонатных, сульфатных и силикатных минералов. Методы. Отбор проб выполнялся в соответствии с общепринятыми методиками. Обобщение и анализ гидрогеохимических данных проводилось с применением программных средств Microsoft Excel, STATISTICA, SURFER, Grid Master. В среде программных комплексов Visual Minteq и WATEQ4f выполнены физико-химические расчеты форм миграции химических элементов в радоновых водах и степени их насыщения к ряду породообразующих минералов. Результаты: В гидрогеологическом разрезе месторождения радоновых вод «Каменское» геологоразведочными работами установлено два водоносных комплекса (сверху вниз): поровых вод четвертичных отложений и трещинно-жильных вод верхнепалеозойских гранитов. В условиях Центрального района города Новосибирска, где почти вся площадь поверхности покрыта асфальтом и занята под сооружения и инфильтрация атмосферных осадков осложнена, естественный режим питания подземных вод нарушен. Порово-пластовые воды четвертичных отложений, воды зоны региональной трещиноватости и трещинно-жильные воды верхнепалеозойских гранитов находятся в единой области смешения, на которую оказывают влияние процессы подтопления и антропогенного загрязнения. В этой связи в водоносном комплексе верхнепалеозойских гранитов выделяется две гидрогеохимической зоны: верхняя – воды зоны региональной трещиноватости в зоне подтопления в условиях антропогенного воздействия, и нижняя – трещинно-жильные минеральные радоновые воды. Минеральные радоновые трещинно-жильные воды гранитов, не подверженные антропогенному влиянию установлены в скв. 4п (интервал 73–74 м) и в скв. 16 на глубинах от 73 до 128 м. Они холодные собственно пресные HCO3 Na-Ca и HCO3 Na-Mg-Ca состава с величиной общей минерализации от 613,4 до 689,9 мг/дм3 с содержанием кремния 10,3–13,6 мг/дм3. Они характеризуются рН от нейтральных до слабощелочных (6,9–7,8), кислородно-азотным составом водорастворенных газов. Установленная активность 222Rn варьирует в диапазоне 1101–1570 Бк/дм3 (сильно радоновые воды по классификации Н.И. Толстихина); содержания: 238U от 5,6∙10–3 до 6,5∙10–3 мг/дм3 и 226Ra от 2,7∙10–9 до 1,8∙10–8 мг/дм3. С ростом общей минерализации радоновых вод доля простых катионных форм Mg2+, Ca2+, Na+, Sr2+, Ba2+ в растворе уменьшается, это связано с образованием труднорастворимых карбонатных и сульфатных соединений. В радоновых водах формы Fe(II) представлены в виде Fe2+, FeHCO3+, FeCO30. Fe(III) мигрирует в форме положительно заряженных гидроксокомплексов Fe(OH)2+ и нейтральных Fe(OH)30. Среди форм миграции марганца доминирует простой катион Mn2+ (43,71–99,99 %), остальные формы представлены MnHCO3+ (9,89–28,27 %), MnCO30 (0,01–37,39), еще в меньшей степени MnSO40 (0,20–2,25 %), MnCl+ (0,04–1,12 %) и MnOH+ (0,01–0,05 %). Химические формы миграции тяжелых металлов (никеля и меди) представлены в виде свободных катионов (Ni2+, Cu2+), гидрокарбонатных (NiHCO3–, CuHCO3–) и карбонатных (NiCO30, CuCO30) комплексов. Медь также мигрирует в нейтральной форме Cu(OH)20. Бериллий (1 класс опасности) мигрирует в форме гидроксокомплекса Be(OH)2. Установленные особенности геохимических типов вод, долевого распределения форм и коэффициентов водной миграции химических элементов выявили усложнение состава равновесных минералов от сидерита, ферригидрита и гриналита в поверхностных водах до их насыщения кальцитом, доломитом, магнезитом, родохрозитом и тальком в трещинно-жильных водах верхнепалеозойских гранитов. Формы миграции химических элементов обуславливают механизмы растворения/осаждения минеральных соединений.
In this study, the spring water quality of a high natural background radiation region in North Iran was evaluated by measuring hydrochemical characteristics and concentration of potentially toxic elements (PTEs) and activity concentration of radioactive elements. The carcinogenicity potential from exposure to PTEs and radioactive elements was also investigated using probabilistic approach. The hydrochemical properties of water samples revealed that there were two different water types in the study area: (1) non-thermal Ca-HCO3 type and (2) thermal Na-Cl type. The concentrations of Al, Cd, Cr, Cu, Pb, Mo, Ni, Sb, Zn, and 40K were within the recommended water quality standard set by the World Health Organization (WHO). Elevated concentrations of As, Mn, Hg, 226Ra, and 232Th occur in Na-Cl water type while elevated concentrations of Fe occur in Ca-HCO3 water type. Also, health complications of dermal contact (via balneology or bathing) are within the safe limits. The major concern regarding the contaminated springs is the possibility of soil and groundwater contamination through uncontrolled runoff and spa effluents. Preventing the spread of toxic constituents in the study area via high-risk spring water requires periodic monitoring, and applying control measures where necessary.
There is currently some controversy in the scientific community regarding the efficiency of the water–rock interaction process in the contamination of radon in groundwater. In this study, some difficulties were found in the sampling phase. Many of the water collection points are used for human consumption. As such, some municipalities did not want to collaborate. When this natural contaminant is undetectable to the human sense and may cause pulmonary neoplasms in the long term, it is difficult to obtain collaboration from the municipalities concerned. To overcome this controversy, it is important to understand that geogenic, climatic, hydrological, and topographic features may contribute to the effective transfer of radon from rocks to groundwater. In brief, this new approach combines the radon transfer from the geological substrate to the groundwater circulation through hierarchic agglomerative clustering (HAC) and partial least squares-path modeling (PLS-PM) methods. The results show that some lithologies with higher radon production may not always contribute to noticeable groundwater contamination. In this group, the high-fracturing density confirms the recharge efficiency, and the physical-chemical properties of the hydraulic environment (electric conductivity) plays the main role of radon unavailability in the water intended for human consumption. Besides, the hydraulic turnover time of the springs can be considered an excellent radiological indicator in groundwater. In the absence of an anomalous radioactive source near the surface, it means that the high-turnover time of the springs leads to a low-radon concentration in the water. Besides linking high-risk areas with a short period required to free local flow discharges, this study exposes the virtues of a new perspective of a groundwater contamination risk modeling.
Geochemical and geophysical investigations were carried out to obtain more evidence of the potential of geothermal resources in Chunxiao Town (China). Hydrochemical data indicate the possible existence of mixing process between deep geothermal water and shallow groundwater. Analysis with SiO2 geothermometer shows that the geothermal reservoir temperature was estimated around 40–60 °C. In addition, combination investigations with CSAMT, radioactive radon, and soil thermal-released mercury detection reveal the specific location of the conduction fractures for thermal water circulation. Furthermore, the drilling work shows the deep thermal water temperature of >55 °C and the thermal water yield of 300 m3/d. All these results could provide important guidance for the scientific exploration and effective utilization of geothermal resources in coastal area.
Major elements concentrations (Na, K, Ca, Mg) and the activity concentrations of 226,228Ra, 234,238U, 210Po, 210Pb, 40K and 137Cs in northern and eastern Croatian thermal and mineral waters, collected directly from springs (or wells), are presented herein with total effective doses assessed for those waters that are considered as drinking 'cures' and are available for consumption. The methods used for radionuclide determination included alpha-particle spectrometry, gas-proportional counting and gamma-ray spectrometry, while the major element composition was determined by ICP-MS. The activity concentrations of all of the radionuclides were found to be below the guidance levels set by the WHO and EC Directive, with the exception of one water sample that measured 0.26 Bq L-1 of 228Ra. The effective ingestion dose assessment for the consumption of the so-called water 'cures' during 1, 2 or 4 weeks' time period throughout 1 year was well below the recommended 0.1 mSv for drinking water.
In this work, we collected 101 geothermal water samples to investigate comprehensively the radioactivity of geothermal water in Beijing. The concentrations of gross beta, 226Ra and 222Rn were measured and the obtained values were in the range of 0.032–7.060, 0.023–0.363 and 0.470–29.700 Bq/L, respectively. The samples with higher concentration of 222Rn were found to be located near large faults. The effective dose of 222Rn in the air for three cases were calculated to be greater than radiation dose limit of 1 mSv/a.
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 l21 for radon and 54.6+2.7 mBq l21 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.
Gano thermal spring is a karst spring located in the Zagros zone in southern Iran. Samples were collected in different seasons from this spring water. In addition to physicochemical factors, major and minor ions and dissolved radon concentration were measured at the sampling site using a RAD7 detector. The annual average temperature and electrical conductivity (EC) of Gano water spring is 41.2ºC and 17,417.5 μs/cm. The pH is in the neutral range and average TDS is 10,442.5 mg/l. The water type is Na-Cl. High Concentrations of Na, Cl, and SO4 ions probably result from the Hormoz Series salt domes and the dissolution of halite, gypsum, and anhydrite. The Ca/Mg ratio in spring water indicates that the reservoir rocks are dolomitic limestone. Concentrations of elements such as Ag, Hg, Cd, Sn, Pb, Cr, Co, and Bi in Gano water varies from less than 0.5 to 1 μg/l. The mean concentration of ²²²Rn in Gano water is 29.2 kBq/m³, so Gano is not a radon mineral spring. Mean annual effective²²²Rn doses for inhalation from the waters of Gano spring was computed to be 0.002 μSvy⁻¹, which is less than the reference level recommended by WHO.
Background: There is a rapid increase worldwide in the consumption of mineral waters which may contain different level of radioactive elements, especially 226Ra, in addition to varying amounts of beneficial salts. Therefore, a comprehensive study was planned and carried out in order to determine concentration of 226Ra natural radionuclide in bottled mineral waters that commercially available in Marmara Region of Turkey. Materials and Methods: The method used for 226Ra concentration analysis bases on the measurement of Radon (222Rn) coming from 226Ra dissolved in the water. The measurements were performed using RAD 7, a solid state α detector, with RAD H2O accessory manufactured by DURRIDGE COMPANY Inc. Results: The 226Ra concentration in mineral waters was found to vary from <0.074 to 0.625 Bql-1 with an average value of 0.267 Bql-1.The commitied effective doses due to ingestion of 226Ra from the one year consumption of these waters were estimated to range from 10.8 to 90 μSvy-1, from 9 to 75 μSvy-1 and from 3.15 to 26.25 μSvy-1, for infants, children and adults, respectively. Conclusion: The results obtained in this study indicate that the committed effective doses are below the WHO (World Health Organization) recommended reference level of 100 μSvy-1.
Physicochemical factors, major and some minor ions and 222Rn concentration was measured in Todruyeh, Fotuyeh and Sanguyeh thermal balneutherapy springs in Bastak, south of Iran. Water type of these springs is Na–Cl and water-mixing phenomena seem possible in them. The average of U concentration in Fatuyeh’s, Sanguyeh’s and Todruyeh’s water are 2.2, 1.1, 0.306 ppb, respectively, and the concentration of heavy metals such as Ag, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, Zn varies from 1 to 10 ppb. The concentration of 222Rn in the water of Fotuyeh, Sanguyeh and Todruyeh Springs includes 125–253, 53–104, and 7.4–134.7 kBq/m3, respectively. Values of mean annual effective doses for inhalation from these waters are below the reference level recommended by WHO.
Radon is a radioactive noble gas of natural origin that may be found anywhere in soil, air and in different types of water: surface, wells and springs. It is worth carrying out surveys for radon in natural water and indoor air for radiation protection as well for geological considerations. The results presented in this paper are from a survey carried out in Transylvania region, in North West of Romania for radon concentrations in water and indoor air. The measurements were made using a LUK-VR system based on radon gas measurements with Lucas cell for water and with track detectors based on CR-39 for indoor air. The results show that the radon concentrations are within the range of 0.9 to 68.9 BqL-1 with an average value of 11.4 BqL-1 for all types of water covered within this survey. The indoor radon concentrations range from 26 Bqm-3 to 415 Bqm-3 with an average of 138.1 Bqm-3.
The aquifer from Felix – 1 Mai spas with thermal springs and lots of wells is located
in a fissures network of cretaceous limestones, fragmentated and isolated in a few tectonic
blocks. Complex interpretation of geological, hydrogeological, hydrochemical-isotopical and
historical data concluded that the thermal aquifer represents the natural manifestation of the
convectional hydrothermal system located in triassic limestones and dolomites, exploited
by wells in Oradea city. Special measurements executed in both aquifers revealed their
hydraulic unity . The connection between the two aquifers, situated near the surface and
at 2000 – 2500 m depth, is realised through the major tectonic marginal lines of the Pannonian
Basin. The subaquatic thermal springs of Pețea River natural reserve are situated
at most elevated levels of the Felix – 1 Mai aquifer, and, like natural piezometers, reacts
immediately to any overexploitation. Since the recharge of aquifer is constant, , after the
disparition of thermal springs the sustained overexploitation will lead to the collapse of the
whole system. Given the demonstrated hydraulic unity of aquifers , extraction and reinjection
of the triassic aquifer must be executed carefully with regard to this interconnection.
Water that contains radium-226 radioactivity in excess of the 5.0-picocurie-per-liter limit set in the National Interim Primary Drinking Water Regulations was found in the majority of wells sampled throughout Sarasota County. Highest levels were found areally near the coast or near rivers and vertically in the Tamiami-upper Hawthorn aquifer where semiconsolidated phosphate pebbles occur. Analysis of data suggests that part of the radium-226 in ground water of Sarasota County is dissolved by alpha particle recoil. In slightly mineralized water, radium-226 concentrations are decreased by ion exchange or sorption. In more mineralized water, other ions compete with radium-226 for ion exchange or sorption sites. Dissolution of minerals containing radium-226 by mineralized water probably contributes a significant fraction of the dissolved radium-226. Two types of mineralized water were present in Sarasota County. One type is a marine-like water, presumably associated with saltwater encroachment in coastal areas; the other is a calcium magnesium strontium surfate bicarbonate type. In general, water that contains high radium-226 radioactivities also contains too much water hardness or dissolved solids to be used for public supply without treatment that would also reduce radium-226 radioactivities.
This study examines the influence of humic acids (HA) on adsorption of radium (Ra) ions onto coir pith (CP) in aqueous solution. The adsorption behaviours of Ra ions onto CP under the influence of HA in aqueous solution were investigated in the series of batch mode adsorption experiments. The effects of various experimental conditions such as pH, contact time, adsorbent dosage and initial concentration of Ra ions have been studied. The results revealed that the presence of HA in aqueous solution enhanced the adsorption of Ra ions onto CP. The adsorption results showed that the percentage of Ra adsorbed was increased with an increase in the pH or alkalinity of aqueous solutions. Time dependence of the batch studies showed that a contact time of one day was sufficient to reach equilibrium. The result also showed that there was no significant difference on the effect of adsorbent dose on adsorption of radium onto CP. It was shown that the equilibrium data could befitted by Freundlich equation.
In the present study, a simple procedure for the isolation by solid-phase extraction (SPE) and quantification by UV-Vis spectrometry
(400 nm) of the humic acids (HAs) in the natural waters was developed. Seven different sorbents: Porapak P (polystyrene-divinylbenzene
copolymer), Florisil (chemical composition: 84.0% SiO2, 15.5% MgO and 0.5% Na2SO4), Silica gel C18 (octadecyl silane), Strata X (surface modified polystyrene-divinylbenzene), Strata NH2 (silica-based trifunctional amino ligand), Strata SAX (silica-based trifunctional quaternary amine) and Strata C18-E (silica-based
trifunctional C18 with hydrophobic end-capping of silanols) were tested. The HAs, adsorbed on SPE cartridges, were eluted
using: NaOH (0.1 M), sodium dodecyl sulphate (SDS) (20 g L−1), and a 1:1 v/v mixture of SDS (20 g L−1) and NaOH (0.1 M). The extraction efficiency was evaluated by comparing the HAs recovery levels. The repeatability of results
was estimated by the relative standard deviation (RSD). The data confirmed that Porapak P, Silica gel C18, Florisil, Strata
NH2 and Strata X could be good alternatives for the traditional isolation of the aquatic HAs with XAD resin. The proposed method
was applied for the determination of HAs in some waters sampled from the Western Romanian Plain. The content of HAs was correlated
with the arsenic concentration and total organic carbon (TOC) level.
Acrylic fibers impregnated with manganese oxide-dioxide extract radium
and other trace elements from natural waters. This extraction technique
may be used to quantitatively extract radium from 20-liter water samples
for precise 226Ra analysis and to concentrate radium from
several-thousand-liter samples for 228Ra/226Ra
activity ratio determinations.
222Rn concentrations were measured in the bubble gases, spring waters, soil gases and in ambient air around the thermal springs at Bakreswar in West Bengal, India. This group of springs lies within a geothermal zone having exceptionally high heat flow about 230 mW/m2, resembling young oceanic ridges. The spring gas has a high radon activity (w885 kBq/m3) and is rich in helium (w1.4 vol. %) with appreciably large flow rate. The measured radon exhalation rates in the soils of the spring area show extensive variations from 831 to 4550/mBqm2 h while 222Rn concentrations in the different spring waters vary from 3.18 to 46.9 kBq/m3. Surface air at a radius of 40 m around the springs, within which is situated the Bakreswar temple complex and a group of dwellings, has radon concentration between 450 and 500 Bq/m3. In the present paper we assess the radon activity background in and around the spring area due to the different contributing sources and its possible effect on visiting pilgrims and the people who reside close to the springs.
Spring waters used as spas may contain significant amounts of natural radionuclides, so, in some circunstances, a radiation
protection issue can arise for the population and/or the spas workers. EU has identified some groups of employees to be exposed
to natural radiation in the 1996 Euratom Directive. Among these are workers of thermal spas who may be exposed to high radiation
doses due to high radon concentrations in indoor air. In order to evaluate the potencial risk of the spring waters used as
spas, gross-α and gross-β activity, 226Ra and 222Rn concentration levels were measured in 82 spas all over the country. Gross-alpha and gross-beta concentrations ranged from
LLD to 17 Bq·l−1 and from LLD to 60 Bq·l−1, respectively. 226Ra concentrations ranged from −1. 222Rn concentrations ranged from −1. Correlations between 226Ra concentrations and gross-α activity were obtained.
Groundwater found near the head of the Buena Lagoon in the State of Rio de Janeiro, Brazil, has high salinity and low pH values. There is a strong correlation between concentrations of radium and light rare earth elements (LREEs) that suggests the leaching of monazite as a common source. Radium is present predominantly as 228Ra. The factors responsible for high radium mobility in groundwater seem to be high levels of salinity resulting in the competition for adsorption sites, and low pH values resulting in the limited adsorption of Ra2+ on the positively-charged surface of adsorbents. The behavior of uranium and thorium is also influenced by their speciation and low pH conditions. Uranium is present as a positively charged uranyl ion UO22+ in low pH samples and is very mobile. Similarly, the presence of positively charged Th4+ and thorium complexes with sulfate result in relatively high thorium concentrations at a low pH range. On the other hand, the mobility of phosphate released by dissolving monazite is probably reduced due to its adsorption and precipitation close to its source.
Radium isotope activities (226Ra, 228Ra, and 224Ra), chemical compositions, and sulfur isotope ratios in sulfate were determined for water samples from thermal areas in Yellowstone National Park, Wyoming. Activities of 226Ra in these waters range from <0.2 to 37.9 dpm/kg. Activity ratios of range from 0.26 to 14.2, and those of range from 0.73 to 3.1. Radium concentrations are inversely correlated with aquifer equilibration temperatures (estimated from dissolved silica concentrations), while[]aq and activity ratios depend upon and ratios in aquifer rocks. Major controls on Ra concentration in Yellowstone thermal waters are inferred to be 1.(1) barite saturation (at Morris Geyser Basin, Mammoth Hot Springs, and other northern areas) and2.(2) zeolitewater ion exchange (at Upper Geyser Basin). The data are consistent with a model in which3.(1) radium and barium are supplied to water by bulk dissolution of aquifer rock, and4.(2) chemical equilibration of water with rock is rapid relative to the 1602 year half-life of 226Ra. The activity ratios of the waters may in some cases reflect surface enrichments of 232Th and/or may indicate that α-recoil input of 228Ra is rapid relative to water-rock chemical equilibration. Activity ratios of indicate a nearly ubiquitous 224Ra excess that generally increases with decreasing pH. Near-surface (≤100 m) thermal water flow velocities at Mammoth Hot Springs are estimated from variation to be ≥ 1 m h−1.
Naturally occurring U and Th series radionuclides have been analyzed in high temperature brines (~300°C, 25 wt% dissolved solids) and associated rocks from two deep geothermal wells located on the northeastern margin of the Salton Sea Geothermal Field (SSGF). These data are part of a study of the SSGF as a natural analog of possible radionuclide behavior near a nuclear waste repository constructed in salt beds, and permit evaluation of some characteristics of water-rock interaction in the SSGF.Rock/Brine concentration ratios (Rc = (dpm/g)rock/(dpm/g)brine) were found to vary from near unity for isotopes of Ra, Pb and Rn to about 5 × 105 for 232Th. The high sorptivity of 232Th is closely followed by that of 238U and 234U (Rc ~ 5 × 104), suggesting that U is retained in the +4 oxidation state by the reducing conditions in the brines. The relatively high solubility of 210Pb and 212Pb is attributed to formation of chloride complexes, while the high Ra solubility is attributed to chloride complexing, a lack of suitable adsorption sites due to the high brine salinity and temperature, and the reducing conditions that prevent MnO2 and RaSO4 from forming.The ratios in the brines are approximately equal to those of their parents () in associated rocks, indicating that Ra equilibration in the brine-rock system is achieved within the mean life of 228Ra (8.3 years). The ratios in these brines are about 0.7, indicating that either (1) brine composition is not homogeneous and 224Ra decays in fracture zones deficient in Ra and Th as the brine travels to the wellhead or (2) Ra equilibration in the brine-host rock system is not complete within the mean life of 224Ra (5.2 days) because the desorption of 224Ra from the solid phase is impeded. The activity ratio in the SSGF brines studied is <0.1, and from this ratio the residence time of 228Ac in the brine before sorption onto solid surfaces is estimated to be <70 minutes, indicating the potential for rapid removal of reactive isotopes fom brines.The brine is greatly enriched in 226Ra (2–3 dpm/g, about 104–105 times that of its parent 230Th), while reservoir rocks are about 10% deficient in 226Ra relative to 230Th. Material balance calculations for 2226Ra and 18O suggest that brines reside in the reservoir for 102–103 years, that the SSGF formed 10,000–40,000 years B.P., and that porosity cannot be more than 20%.
High levels of naturally occurring and carcinogenic radium isotopes have been measured in low-saline and oxic groundwater from the Rum Group of the Disi sandstone aquifer in Jordan. The combined 228Ra and 226Ra activities are up to 2000% higher than international drinking water standards. Analyses of the host sandstone aquifer rocks show 228Ra and 226Ra activities and ratios that are consistent with previous reports of sandstone rocks from different parts of the world. A compilation of previous data in groundwater from worldwide sandstone aquifers shows large variations in Ra activities regardless of the groundwater salinity. On the basis of the distribution of the four Ra isotopes and the ratios of the short- to long-lived Ra isotopes, we postulate that Ra activity in groundwater is controlled by the balance of radioactive decay of parent Th isotopes on aquifer solids, decay of the dissolved radium isotopes, and adsorption of dissolved Ra on solid surfaces. The availability of surface adsorption sites, which depends on the clay content in the aquifer rocks, is therefore an important constraint for Ra activity in sandstone aquifers. These findings raise concerns about the safety of this and similar nonrenewable groundwater reservoirs, exacerbating the already severe water crisis in the Middle East.
Radon bath is a well-established modality of balneotherapy for the management of degenerative musculoskeletal disorders. The present study was conducted to ascertain whether baths of relatively low (80 Bq/l) radon concentration have any influence on the functioning of the endocrine system. In the study, a non-randomized pilot study, 27 patients with degenerative musculoskeletal disorders received 30-min radon baths (of 31-32 degrees C temperature and 80 Bq/l average radon concentration) daily, for 15 days. Twenty-five patients with matching pathologies were subjected to balneotherapy according to the same protocol, using thermal water with negligible radon content (6 Bq/l). Serum thyroid stimulating hormone, prolactin, cortisol, adrenocorticotropic hormone, and dehydroepiandrosterone levels were measured before and after a balneotherapy course of 15 sessions. Comparison of the accumulated data using the Wilcoxon test did not reveal any significant difference between pre- and post-treatment values or between the two patient groups. It is noted that while the beneficial effects of balneotherapy with radon-containing water on degenerative disorders is widely known, only few data have been published in the literature on its effect on endocrine functions. The present study failed to demonstrate any substantial effect of thermal water with relatively low radon content on the functioning of the endocrine system.
The occurrence in the literature of numerous, inconsistent and limited definitions of a detection limit has led to a re-examination of the questions of signal detection and signal extraction in analytical chemistry and nuclear chemistry. Three limiting levels have been defined: LC-the net signal level (instrument response) above which an observed signal may be reliably recognized as "detected"; LD-the "true" net signal level which may be a priori expected to lead to detection; and LQ-the level at which the measurement precision will be satisfactory for quantitative determination. Exact defining equations as well as series of working formulae are presented both for the general analytical case and for radioactivity. The latter, assumed to be governed by the Poisson distribution, is treated in such a manner that accurate limits may be derived for both short- and long-lived radionuclides either in the presence or absence of interference. The principles are illustrated by simple examples of spectrophotometry and radioactivity, and by a more complicated example of activation analysis in which a choice must be made between alternative nuclear reactions.
The purpose of this study was to elucidate the processes controlling the distribution and behavior of the longer-lived radium (Ra) isotopes in continuous Paleozoic carbonate aquifers of parts of Missouri, Kansas, and Oklahoma. Activities of (²²â¸Ra) and (²²â¶Ra) were analyzed in fresh and saline ground waters, brines, and rocks. The fluids have a wide salinity range (200-250,000 mg lâ»Â¹ total dissolved solids). The (²²â¶Ra) activity ranges from 0.66-7660 dpm kgâ»Â¹ and correlates with salinity and other alkaline earth element (Ca, Sr, and Ba) concentrations. The range of (²²â¸Ra:²²â¶Ra) ratios in the fluids (0.06-1.48) is similar to that in the aquifer rocks (0.21-1.53). The relatively low mean fluid (²²â¸Ra:²²â¶Ra) ratio (0.30) reflects the low Th:U ratio of the predominant carbonate aquifer rock. Radium occurs mostly ({>=}77%) as Ra{sup 2+} species in the fluids. Salinity-dependent sorption-desorption processes (with log K values from 10°-10â´ and negatively correlated with salinity), involving Th-enriched surface coatings on aquifer flow channels, can explain the rapid solid-fluid transfer of Ra isotopes in the system and the correlation of Ra with salinity.
A wide range of isotopes in the ²³⁸U, ²³⁵U, and ²³²Th decay chains was measured in geothermal brines collected from two production zones at 1898 and 3220 m in the Salton Sea Scientific Drilling Project well. High concentrations of radium, radon, and lead isotopes are generated and maintained by the input of these isotopes from solid phases into brine by both recoil and leaching processes, by the high chloride content of the brine which complexes radium and lead, and by the apparent absence of suitable unoccupied adsorption sites. In contrast, uranium, thorium, actinium, bismuth, and polonium isotopes all have low concentrations due to their efficient sorption from brine to rock. The mean residence times of lead and radium in solution are about 30 years, and the residence time of radium in associated solid phases is about 2000 years. The estimated uncertainty in these residence times is about a factor of 2. -from Authors
This paper presents an up-to-date reservoir model of the Sacuieni geothermal area and direct use applications of its energy resources. It is featured as a typical example of the low enthalpy, porous/permeable, multi-layered reservoirs in the Western Plain of Rumania. The paper summarizes current industrial uses of geothermal in the Sacuieni area for drying and greenhouse uses. It also analyses the prospects for future industrial geothermal development encompassing crop drying, wood drying, pasteurization of milk and a novel method of increasing the temperature level of the geothermal water to make it suitable for pasteurization purposes. Cascaded uses are also featured.
Thermal waters in Romania have been used for therapeutic purposes for over 100 years. Methodical investigation of thermal aquifers began in 1960. This paper describes the geological structure of the country and the distribution of thermal waters. They are associated with three very different types of structure: deep sedimentary basins, fracture systems and areas of recent igneous activity. The depths at which thermal waters have been located, the lithology of the aquifers, ranges of temperature and well yields are given. In all areas except one, the water temperature at well head is less than 90°C.
The sensitivity of a 226Ra determination method of water samples by SSNTD was measured as a function of storage temperature during exposure. The method is based on an etched track type radon monitor, which is closed into a gas permeable foil and is immersed in the water sample. The sample is sealed in a glass vessel and stored for an exposure time of 10–30 days. The sensitivity increased more than a factor of two when the storage temperature was raised from 2 °C to 30 °C. Temperature dependence of the partition coefficient of radon between water and air provides explanation for this dependence. For practical radio-analytical application the temperature dependence of the calibration factor is given by fitting the sensitivity data obtained by measuring 226Ra standard solutions (in the activity concentration range of 0.1–48.5 kBq m−3) at different storage temperatures.
Gas compositions of mud volcanoes reveal multiple sources for gas exhalation in SW Taiwan. For comparison, two sites, Yan-chao (YC) and Chung-lun (CL), were chosen for measurements of soil Rn concentrations using a portable radon detector. The 222 Rn concentrations at the YC site were ca. 5200 Bq=m 3 . However, the average 222 Rn concentrations at the CL site exhibited higher value of ca. 16; 800 Bq=m 3 . With the reference of the gas ux and compositions from the nearby mud pool, the soil 222 Rn concentrations are largely controlled by the ux of carrier gases exhaled from deep reservoirs.
In Ge gamma-ray spectrometry for the annual radiation dose determination in the luminescence dating of sediments, the picture
of 226Ra enrichment or depletion (in the 238U decay series) obtained via measurement of its 214Pb and 214Bi daughters may be disturbed by the 222Rn-content of the sample being decreased due to manipulations such as drying and pulverizing. Therefore, it is common practice
to start the measurement only about 1 month after encapsulating the material, after which the 226Ra(1600 a)- 222Rn(3.82 d) mother-daughter equilibrium is re-established. Evidently, this only holds on condition that no significant escape
of Rn occurs out of the sediment after making it up for counting. In order to experimentally investigate this effect, in the
present work measurements were carried out with various types of dried and pulverized sediments that were either encapsulated
in screw-cap polystyrene vials or in sealed glass containers, or that were mixed with molten wax followed by solidification
in a cylindrical geometry. From the results obtained, it could be concluded that preparation and counting of the sediment-wax
mixture is the method of choice.
The radon concentration in the air and water of the Bizovac spa was measured by the Radhome silicon detector and the average values were obtained as 70 Bq/m3 in the indoor pool, 40 Bq/m3 in the hotel room, 135 Bq/m3 in the closed therapeutic bathroom, but the geothermal water had a Rn concentration of 25.3 kBq/m3 and the potable one 2.7 kBq/m3. The Rn transfer factor (f) from water to air in the indoor pool and therapeutic bathroom was 10 and 40 times higher than for normal dwellings (f
n=10–4), respectively. The effective equivalent dose of inhaled radon for permanent personnel under the worst conditions in the spa was 5.4 mSv/y, but visitors spending two weeks in the spa could receive the dose of 77 Sv.
The temperature increases downwards in the crust and there is therefore a transport of heat upwards, referred to as the heat
flow. Most of the flow is by conduction (thermal diffusion). Flow of porewater will also transport heat in the subsurface
but the flow rates in sedimentary basins are normally so small that we can ignore the contribution from fluid flow (advection).
Around igneous intrusions there is usually thermal convection with high flow rates and heat transport. In shallow areas with
high flow rates of meteoric water, advective heat transport is also significant.
Speciation and extractability of humic acids (HAs) and humate complexes of microelements are studied using the colloidal chemical
extraction method in combination with ICP MS with an example of natural mineral water with high HA concentration (800–1200
mg l−1) collected from the Salekhard region. Joint extraction behavior of ionic and colloid forms of anionic and cationic species
of a large number of microelements, including U(VI) and Th(IV), and HAs is examined at their natural abundance in mineral
water, as influenced by pH and HA concentration. Humic acids proved to behave in natural water as a pool of ion-colloidal
species, whose protonation results in precipitation at pH 2.0–3.5. In this case, some chemical elements are sorbed on the
resulting solid and may be separated along with HAs by colloidal chemical extraction into isobutanol. In natural humate solutions,
a considerable fraction (10–99 mol %) of chemical elements is associated with HAs in the form of colloid species extractable
with isobutanol.
Geothermal waters have been used on a large scale for bathing, drinking and medical purposes, while the consumption of bottled mineral waters is increasing. In this work, radon and radium activity concentrations of thermal and bottled mineral waters, originating from different regions of Hungary, were studied by different radioanalytical methods. It was found that the thermal springs, which supply the world famous baths of Budapest along the right riverside of the Danube, have high and activity concentration: up to about 100 and , respectively. The radium content of some investigated geothermal waters found in the NE region of the Great Hungarian Plain is even higher: up to several . The content of bottled mineral waters, commercially available in Hungary, was determined by gamma-spectrometric method, applying radiochemical separation. The highest value exceeded in the case of the Apenta mineral water, which is a popular brand in Hungary, as well as in Europe and North America.
Radium has been measured in deep saline formation waters produced from a variety of U.S. Gulf Coast subsurface environments, including oil reservoirs, gas reservoirs and water-producing geopressured aquifers. A strong positive correlation has been found between formation-water salinity and Ra activity, resulting from the interaction of formation water with aquifer matrix. Ra isotopes enter the fluid phase after being produced by the decay of parent elements U and Th, which are located at sites on and within the solid matrix.Processes that are belived to be primarily responsible for transferring Ra from matrix to formation water are chemical leaching and alpha-particle recoil. Factors controlling the observed salinity—Ra relationship may be one or a combination of the following factors: (a) ion exchange; (b) increased solubility of matrix silica surrounding Ra atoms, coupled with a salinity-controlled rate of reequilibration of silica between solution and quartz grains; and (c) the equilibration of Ra in solution with detrial barite within the aquifer.No difference was found in the brine-Ra relation in water produced from oil or gas wells and water produced from wells penetrating only water-bearing aquifers, although the relation was more highly correlated for water-bearing aquifers than hydrocarbon-containing reservoirs.
Naturally-occurring radionuclides (uranium, radium, and radon), major dissolved constituents, and trace elements were investigated in fresh groundwater in 117 wells in fractured crystalline rocks from the Piedmont region (North Carolina, USA). Chemical variations show a general transition between two water types: (1) slightly acidic (pH 5.0–6.0), oxic, low-total dissolved solids (TDS) waters, and (2) near neutral, oxic to anoxic, higher-TDS waters. The uranium, radium, and radon levels in groundwater associated with granite (Rolesville Granite) are systematically higher than other rock types (gneiss, metasedimentary, and metavolcanic rocks). Water chemistry plays a secondary role on radium and radon distributions as the 222Rn/226Ra activity ratio is correlated with redox-sensitive solutes such as dissolved oxygen and Mn concentrations, as well as overall dissolved solids content including major divalent cations and Ba. Since 224Ra/228Ra activity ratios in groundwater are close to 1, we suggest that mobilization of Ra and Rn is controlled by alpha recoil processes from parent nuclides on fracture surfaces, ruling out Ra sources from mineral dissolution or significant long-distance Ra transport. Alpha recoil is balanced by Ra adsorption that is influenced by redox conditions and/or ion concentrations, resulting in an approximately one order of magnitude decrease (~ 20,000 to ~ 2000) in the apparent Ra distribution coefficient between oxygen-saturated and anoxic conditions and also across the range of dissolved ion concentrations (up to ~ 7 mM). Thus, the U and Th content of rocks is the primary control on observed Ra and Rn activities in groundwater in fractured crystalline rocks, and in addition, linked dissolved solids concentrations and redox conditions impart a secondary control.
The migration mechanisms of endogenous gases in the geosphere are defined in relation to the fluid-rock conditions and analyzed by basic transport equations. Upon examining the geological factors that influence the physical parameters in the equations in porous and fracture media, and considering the widespread high-permeability of deep subsurface rocks, in terms of fracture aperture, (orders of 10−2 to 101 mm at depths of thousands meters, as suggested by recent crustal surveys) advection of carrier gases, in its several forms (gas-phase flow, water displacement by gas, gas slugs and bubbles) seems to represent a major migration process. Accordingly, in contrast with early views, the role of gas diffusion and water advection in the transport of endogenous gas to the Earth surface should be strongly minimized in many contexts. In a wide range of geological settings, carrier gases (CO2, CH4) may assume a dominant role in controlling transport and redistribution toward the Earth’s surface of trace gases (Rn, He). Bubble movement in fissured rocks seems to be an effective way of rapid (gas velocities in the order of 100 to 103 m per day) and long-distance gas migration. The evolution from bubble regimes to continuous phase flow and vice versa, as gas pressure and fracture width change, is the most suitable mechanism towards determining the surface geochemical processes of seismo-tectonic, environmental and geo-exploration relevance. The transport effectiveness of trace gases by a carrier gas has yet to be studied in quantitative terms. It is already clear, however, that further studies on the distribution and behavior of trace gases approaching the Earth’s surface may not be meaningful unless accompanied by carrier gas dynamics analyses.
Early measurements in the Herculane Spa region showed high helium content (6 mL/L) and high radon concentrations (up to 7.4 MBq m−3) for the emanated gases which accompany geothermal waters originating in the hydrogeothermal deposit existing in this area. This paper presents new data on the radon exhalation rate from soil, and indoor radon in some buildings in this resort. The greater values obtained in two places for radon flux are probably caused by transversal faults in this area. In the winter, the indoor radon mean value is two times greater than the summer value. The Ra, U, Th, and K content for six soils sampled in the vicinity of the site of radon flux measurement were also determined. The values obtained are somewhat higher than the values expected as a consequence of surface granitic rocks in this region. Large 137Cs deposits were found (up to 950 Bq kg−1).
Radon has been shown to have potential as a tracer in the study of geothermal reservoirs. The combination of its physical and nuclear properties and its emanation and transport in geothermal fluids makes several types of time and concentration measurements useful for studies of fracture permeability and porosity and flow characteristics in different types of geothermal resources. Radon concentrations in several vapor-dominated and liquid-dominated producing reservoirs have been measured by short-period sampling of wellhead geofluid followed by radon separation on a charcoal trap and counting in a sensitive low background ZnS detector. The results show significant variations not only among different fields, but also between neighbouring wells in a single field. Evidences for transport differences between the two major types of hydrothermal systems are noted.
Radon is a radioactive noble gas of a natural origin that may be found anywhere in soil, air and in different types of water: surface, well and spring. It is worth to carry out surveys for the radon in natural waters for radiation protection as well as for geological considerations. The results present here are from a survey carried out in the Transylvania region in Romania for radon concentrations in natural waters. The measurements were made using the LUK-VR system that is based on radon gas measurement with Lucas cell. Due to the large number of water samples (1511 samples) collected for analysis, a short counting time had to be used, so that the measurements were made during the non-equilibrium state between radon and its progeny. The results show that the radon concentrations are within the range of with an average value of for all types of water covered within this survey.
Radioactivity in underground waters from Mt. Etna was investigated on the basis of 13 samples. The samples were collected from springs, wells and galleries around the volcano. Water from nine out of thirteen intakes is used for consumption. Activity concentration of uranium isotopes 234,238U, radium isotopes 226,228Ra and radon 222Rn were determined with the use different nuclear spectrometry techniques. The measurements of radium and radon activity concentration were performed with the use of a liquid scintillation counter. The determination of uranium isotopes was carried out with the use of alpha spectrometry. All samples show uranium concentration above Minimum Detectable Activity (MDA), with the highest total uranium (234U + 238U) activity concentration equal to 130 mBq/l. For radium isotopes, all samples except one showed the activity concentration below MDA. Radon activity concentration was within the range from 1 to 13 Bq/l, hence these waters can be classified as low-radon waters.
The geochemistry of Ca, Sr, Ba and Ra sulfates in some deep brines from the Palo Duro Basin of north Texas, was studied to define geochemical controls on radionuclides such as 90Sr and 226Ra. Published solubility data for gypsum, anhydrite, celestite, barite and RaSO4 were first reevaluated, in most cases using the ion interaction approach of Pitzer, to determine solubility products of the sulfates as a function of temperature and pressure. Ionic strengths of the brines were from 2.9 to 4.8 m, their temperatures and pressures up to 40°C and 130 bars. Saturation indices of the sulfates were computed with the ion-interaction approach in one brine from the arkosic granite wash fades and four from the carbonate Wolfcamp Formation. All five brines are saturated with respect to gypsum, anhydrite and celestite, and three of the five with respect to barite. All are undersaturated by from 5 to 6 orders of magnitude with respect to pure RaSO4. 226Ra concentrations in the brines, which ranged from 10−11.3 to 10−12.7 m, are not controlled by RaSO4 solubility or adsorption, but possibly by the solubility of trace Ra solid solutions in sulfates including celestite and barite.
Radon-222 has been measured in natural gas produced from experimental geopressured-geothermal test wells. Comparison with published data suggests that while radon activity of this unconventional natural gas resource is higher than conventional gas produced in the gulf coast, it is within the range found for conventional gas produced throughout the US. A method of predicting the likely radon activity of this unconventional gas is described on the basis of the data presented, methane solubility, and known or assumed reservoir conditions of temperature, fluid pressure, and formation water salinity.
Multitracers were used to study water mixing in the Paraíba do Sul River estuary region in August 2007 (dry season) and March 2008 (rainy season) and to evaluate the reach of the river plume in the direction of the open ocean. Two sampling campaigns were carried out, each in a different season. Based on these results, it was possible to conclude that the multitracers used in this study (salinity, Si, Ba and U, as well as the radium isotopes 223Ra, 224Ra, 226Ra and 228Ra) presented satisfactory results toward defining the plume reach and determining the residence time and water-mixing processes in the estuary. A strong correlation was observed between tracers and the distance to the coast. During the low river water discharge period, the riverine water took about 10 days to reach open ocean waters (salinity approximately 35). During the rainy period this value decreased to 6 days. Based on the radium results, it was possible to calculate diffusion coefficients (K(h)) of 23 km(2) d(-1) and 38 km(2) d(-1) for 224Ra and 223Ra, respectively, during the dry season (winter). Values of 65 km(2) d(-1) and 68 km(2) d(-1) for 223Ra and 224Ra, respectively, were found for the rainy period (summer).
Water (226)Ra concentration in springs was measured in regions with high indoor radon: Ural, North Caucasus (Russia), Niska Banja (Serbia), Piestany (Slovakia), and Issyk-Kul (Kyrgyzstan). This paper presents the results for (226)Ra concentration above 0.03 Bq l(-1). Radium in water could indicate indoor radon problem in the region and water investigation is useful at the initial stage of radon survey. Even low (226)Ra concentration in water (0.1-0.6 Bq l(-1)) caused high (226)Ra activity in travertine (up to 1500 Bq kg(-1)), which resulted in indoor radon concentration above 2000 Bq m(-3) (Niska Banja).
Most studies on diffusion of metal ions in various water-rock systems have dealt with free ions (hydrated ions). However, it is often the case that metal ions are dissolved as complexed species such as with humic substances (HS) in natural waters. Hence, we need to study the diffusion behavior of these complexes in order to understand fully the diffusion phenomenon in natural. In this study, the diffusion coefficients of free metal ions (M(z+)) and their complexes with HS (M-HS) were compared to understand the effect of complexation with HS on the diffusion of metal ions such as Co(2+), Cd(2+), and rare earth elements (REE(3+)). Although the diffusion coefficients of free metal ions depend on ionic potential, such dependence was not observed in the presence of HS. Comparing the diffusion coefficients of metal complexes with ethylenediaminetetraacetate (EDTA), fulvic acid, and humic acid showed that the molecular weight (MW), or the size of the ligand, is of primary importance for the diffusion of M-HS. As a consequence, the diffusion coefficients of all REE(3+) were similar in the presence of HS, while they were different in the absence of HS due to the different size of each REE(3+). The similarity among the diffusion coefficients of REE-HS was caused by the much larger size of HS compared with each ion. However, the distribution coefficients of M-HS were not similar among REE(3+), Cd(2+), and Co(2+). REE(3+) and Cd(2+) which have higher affinities for larger MW fraction in HS diffused slower than Co(2+) which favors smaller MW fraction. The results show that the affinity for different MW fractions among HS controls the diffusion of M-HS, which must be important to predict precisely the diffusion behavior of metal ions bound to HS in natural systems.