238U Activity Research Articles

Effects of <sup>238</sup>U variability and physical transport on water column <sup>234</sup>Th downward fluxes in the coastal upwelling system off Peru

Abstract. The eastern boundary region of the southeastern Pacific Ocean hosts one of the world's most dynamic and productive upwelling systems with an associated oxygen minimum zone (OMZ). The variability in downward export fluxes in this region, with strongly varying surface productivity, upwelling intensities and water column oxygen content, is however poorly understood. Thorium-234 (234Th) is a powerful tracer to study the dynamics of export fluxes of carbon and other elements, yet intense advection and diffusion in nearshore environments impact the assessment of depth-integrated 234Th fluxes when not properly evaluated. Here we use vessel-mounted acoustic Doppler current profiler (VmADCP) current velocities, satellite wind speed and in situ microstructure measurements to determine the magnitude of advective and diffusive fluxes over the entire 234Th flux budget at 25 stations from 11 to 16∘ S in the Peruvian OMZ. Contrary to findings along the GEOTRACES P16 eastern section, our results showed that weak surface wind speed during our cruises induced low upwelling rates and minimal upwelled 234Th fluxes, whereas vertical diffusive 234Th fluxes were important only at a few shallow shelf stations. Horizontal advective and diffusive 234Th fluxes were negligible because of small alongshore 234Th gradients. Our data indicated a poor correlation between seawater 238U activity and salinity. Assuming a linear relationship between the two would lead to significant underestimations of the total 234Th flux by up to 40 % in our study. Proper evaluation of both physical transport and variability in 238U activity is thus crucial in coastal 234Th flux studies. Finally, we showed large temporal variations on 234Th residence times across the Peruvian upwelling zone and cautioned future carbon export studies to take these temporal variabilities into consideration while evaluating carbon export efficiency.

Characterization of radionuclide activity concentrations and lifetime cancer risk due to particulate matter in the Singrauli Coalfield, India.

In this study, the activities of 40K, 210Pb, 232Th, 234U, 235U, and 238U in size-segregated particulate matter (PM) were measured in the Singrauli Coalfield, India. Different isotopic compositions were found relative to natural uranium ratios. The radioactivity concentration ratios in different PM sizes [PM2.5, PM10, and suspended particulate matter (SPM)] suggested that anthropogenic sources affected the uranium isotopic compositions in the area. A different isotopic composition from the natural uranium composition was found. The correlation coefficients between the measured isotopes (40K, 210Pb, 232Th, 234U, 235U, and 238U) and meteorological factors were calculated. PM emissions were affected by the meteorological conditions, which in turn, influenced the U and Th concentrations in PM. The 232Th/238U activity ratio in particulate matter was between 0.20 and 1.54 with an average value of 0.9 ± 0.5, 0.2 to 1.1 (0.8 ± 0.7), and 0.2 to 1.2 with an average value of 0.8 ± 0.8 in PM2.5, PM10, and SPM, respectively. These range were quite different from the average crustal ratio of 3.5, indicating that the 238U concentrations were elevated in this region relative to Th. However, compared with Th, the dose contribution of U to the public was negligible. The average effective dose in public owing to inhalation of natural radioactive 40K, 210Pb, 232Th, and 234U, 235U, and 238U in the atmosphere was between 0.03 and 327 nSv year-1. These doses associated with the inhalation of particulate matter were lower than world airborne reference value as reported by UNSCEAR(2000a). Graphical abstract.

Radiological Impact Assessment of Farm Soils and Ofada rice (Oryza sativa japonica) from Three Areas in Nigeria

Oryza sativa japonica (ofada rice) is largely grown in Aramoko, Abakaliki and Ofada are communities and consumed by both the poor and rich in Nigeria. A total of twenty ofada rice farmlands were identified in each study area and rice samples were randomly collected, thoroughly mixed to make a representative sample from each farmland. Soil samples were collected in each farm to a depth of 5-15cm from at least eight different points and thoroughly mixed together to form a representative sample. The samples were thereafter taken to the laboratory for preparation and spectroscopic analysis. A well-calibrated NaI(Tl) gamma-ray detector was used in spectrometric analysis of the samples and descriptive statistics was used to analyze the results.
 The respective mean 40K, 238U and 232Th activity concentrations in the rice were 261.8±52.5Bq/kg, 9.6±1.2Bq/kg and 8.7±1.0Bq/kg (Ofada); 257.3±39.0Bq/kg, 9.3±1.1Bq/kg and 7.8±1.8Bq/kg (Abakaliki); and 248.2±54.8Bq/kg, 9.3±0.9Bq/kg and 7.6±1.5Bq/kg (Aramoko). The respective mean 40K, 238U and 232Th activity concentrations in the soils were 333.9±62.8Bq/kg, 11.1±1.1Bq/kg and 11.0±1.4Bq/kg (Ofada); 306.8±36.0Bq/kg, 10.7±0.8Bq/kg and 9.4±1.8 Bq/kg (Abakaliki) and 321.8±42.4Bq/kg, 10.9±0.5Bq/kg and 9.5±0.6Bq/kg (Aramoko). The highest mean ingestion dose of 106.0±8.0µSv/y and outdoor effective dose of 32.4±3.40µSv/y were recorded in Ofada community. The highest mean ingestion cancer risk of (0.33±0.004) x10-3was recorded in Aramoko. The results indicated significantly lower radionuclide ingestion dose than the world limit value of 290µSv/y and lower cancer risks than the UNSCEAR recommended limit of 0.29x10-3, therefore consumption of ofada rice from the areas may not pose any serious health impact.

Measurement of radiological baseline data of the hazard radiation in bottled drinking water samples in Basrah/Iraq

An investigation was carried out on several radiological hazard indices in twenty three bottled drinking water samples that were collected from various locations in Basrah/Iraq. The specific activity of 238U, 232Th, 40K and 137Cs isotopes was measured using the surveillance and measurement (SAM) device, model 940-2G. The specific activity values of U-238, Th-232, K-40 and Cs-137 ranged as (0.029±0.001-3.017±0.003) Bq/l, (0.025±0.002-2.326±0.001) Bq/l, (4.706±0.002-161.560±0.001) Bq/l and (0.040±0.003-0.953±0.001) Bq/l, respectively. The calculation of many risk indices have been carried out for all drinking water samples. All results have agreed with those reported in published studies and all these obtained findings have been recognized to be below the worldwide limit values. Therefore, there is no significant radiological risk in drinking bottled water brands in Basrah governorate, Iraq.

Characterization of Naturally Occurring Radioactive Material (NORM) Generated from the Lower Cretaceous Carbonate Formations in the Arabian Peninsula and Gulf

For most of the petroleum reservoirs in the world, the impact of the mother nuclides such as uranium-238 on the deposition of radioactive materials a.k.a. NORM from the formation and particularly as mineral scales adherent to tubulars and other equipment is considered insignificant. Uranium is regarded as insoluble in the reservoir formation and the prevailing understanding is that dissolved radium is not generated necessarily by U and Th in solution. Consequently, “uranium scale”, as a technical term, seems to be non-existent in the oil and gas industry. However, gamma spectroscopy and chemical analysis of NORM scale samples of carbonate origin, performed in the course of this research, has proven that they actually can contain uranium. A fundamental relationship between uranium and vanadium in scales is presumed. The highest specific activity of 238U in scale analyzed with gamma spectroscopy was at 11.4 [Bq/g] and supplementary chemical analysis has shown concentrations of up to 740 ppm total uranium and up to 260 ppm vanadium.

Vertical distribution of radionuclides in Lake Qinghai, Qinghai-Tibet Plateau, and its environmental implications

Radionuclides are widely used to perform geochronologic investigations of the trace sediment deposition process in aquatic environments on different temporal scales. This study presents the activities of radionuclides to select a reasonable geochronologic dating method and study the sediment depositional environment in Lake Qinghai on the Qinghai-Tibet Plateau. The range of activities (Bq.kg−1) of 137Cs, 226Ra, 238U, 228Ra, 228Th, and 40K were 2–103, 24–49, 33–156, 20–49, 30–50, and 403–664, respectively. The sedimentation flux was calculated as 1.66 × 106 ton.a−1 based on the summary sedimentation rate in Lake Qinghai, and the sediment contributions from rivers, authigenic carbonates, lacustrine organisms, and atmospheric deposition were 45.18%, 22.44%, 3.02%, and 29.36%, respectively. The decreased 226Ra/238U radioactivity ratios from the catchment to the lake centre indicated that the removal of uranium relative to its daughter products occurs during erosion processes. The positive 228Thex (excess 228Th) values in the upper 1 cm of the sediment suggested that the sediment in the top 1 cm have been resuspended, mixed and/or transported. The distribution of 137Cs in the sediments indicated that the maximum activity of 137Cs in the sediments corresponds to the 1963 peak in the global fallout from atmospheric nuclear weapons testing; moreover, the 1986 Chernobyl accident signal was difficult to identify. The use of 137Cs as a chronologic tool must be performed carefully due to its migration process in sediments.

Application of Natural Radionuclide in the Subsurface Hydrogeology of Selected Two Local Governments in South Western Nigeria

This research investigated the use of radioactive isotopes to study the underground water characteristics of Ife South and Ife North Local governments area of Osun state in Southwestern Nigeria. The study aimed to determine the origin of water, the flow paths, residence time, and prediction of the geological formation of the study area. Twelve water samples were collected from the two local governments using standard methods for isotope study. Uranium 234U and 238U were analyzed for water samples using a gamma-ray spectrometer with Caesium Iodide (CsI) scintillation detector and physical analyses such as pH, electrical conductivity, total dissolved solids, and temperature were also determined. The specific activity of 238U ranged between 27.44±0.55 to 36.89±1.70 Bq/kg; activity ratio of water samples from the two LGA ranged from 0.83 to 1.07 with average activity ratio of 0.901. All the sample locations have an activity ratio of less than 1.00 except two locations in Ife South LGA (Ooni 1 and 2); a 234U value of 30.386747 Bq/kg was taken as constant. Ife North and Ife South have an average EC, turbidity, TDS, residence time of 493.3 (µs/cm), and 686.6 (µs/cm); 1.2 NTU and 3.33 NTU; 108.67 mg/l and 523.33 mg/l; 2.889 ma and 2.784 ma respectively. In conclusion, the groundwater of the two LGA originate from the same source and are in the oxidation state; aquifers within Ife North and Ife South are separated with a barrier; hence its groundwater does not flow through one another. The residence time of groundwater in the two LGA is over 2.8 ma; Ooni 1 and 2 area is underlain by rocks rich in Uranium (granite), rocks underlying Ife South is younger to Ife North, Ife North is underlying by old weathered rocks (sedimentary rocks).

Assessment of Levels of Natural Radioactivity in Sand Samples Collected from Ekalakala in Machakos County, Kenya.

Construction sand is naturally polluted with radionuclides of terrestrial origin. In this study, specific activities of 238U, 232Th, and 40K in 30 sand samples collected along the Ekalakala River, Machakos County, Kenya, were measured using a high-purity germanium γ-ray spectrometer. The specific activities ranged between 9.7 Bqkg−1 and 24.0 Bqkg−1, 11.5 Bqkg−1 and 26.2 Bqkg−1, and 820 Bqkg−1 and 1850 Bqkg−1 for 238U, 232Th, and 40K, respectively. While the mean specific activities for 238U and 232Th were less than half of the world average values of 33 Bqkg−1 and 45 Bqkg−1, respectively, the average specific activity of 40K was significant since it was three times the global mean value of 420 Bqkg−1. A calculated absorbed radiation dose rate for the sand varied between 46.8 nGyh−1 and 94.2 nGyh−1 with a mean of 68.5 ± 13.3 nGyh−1. This is not significantly different from the world average dose rate of 60 nGyh−1 for geological samples. The AEDR and Hex had maximum values of 0.29 mSvy−1 and 0.52, respectively, both within the recommended limits of radiation exposure for members of the general public. Based on these results, the sand from Ekalakala River does not pose significant health implication to the sand harvesters as well as the inhabitants of the houses constructed using this sand.

Uranium and plutonium isotopes and their environmental implications in surface sediments from the Yangtze River catchment and estuary

The U-series and Pu isotope signatures in the environment have emerged as important tools for promoting geochemical studies. To enhance the understanding of U and Pu sources and behaviours in river systems, this study examined 234U, 235U, 236U, 238U and 239Pu, 240Pu isotopes in surface sediments collected from the Yangtze River catchment and estuary in China, for the first time. The 234U, 235U, 238U and 236U concentrations were measured in the range of 8.29–20.6 Bq/kg, 0.352–0.789 Bq/kg, 7.39–16.4 Bq/kg and (3.05–21.1) × 107 atoms/g. Additionally, the 236U/238U, 234U/238U and 235U/238U atom ratios were in the range of (1.43–6.85) × 10−8, (6.08–7.01) × 10−5 and (7.49–8.08) × 10−3 respectively. For all samples, the 239+240Pu activity concentrations ranged from 0.01 to 3.40 Bq/kg. In the Yangtze River catchment, 240Pu/239Pu atom ratios presented typical global fallout values (0.168–0.201); while in the Yangtze River estuary, higher values of 0.216–0.264 located between global fallout and PPG (Pacific Proving Grounds) close-in fallout values. From west to east, the 234U, 235U, 236U and 238U activities generally exhibited decreasing trend from the upstream parts of the river to the estuary. The values of 236U concentrations and 236U/238U, 240Pu/239Pu, 236U/239Pu atom ratios located in the range of global fallout level in environmental samples from other regions, therefore, it may be concluded that 236U in surface sediments of the Yangtze River catchment and estuary are mainly derived from global fallout.

Physico-chemical conditions controlling the radionuclides mobilisation in various granitic environments

ABSTRACT Nine samples were chemically characterized and radiometrically analyzed for determination of 234U, 238U, 235U, 230Th, 232Th, 226Ra and 40K by γ-ray spectrometer Hyper Purity Germanium (HPGe detector). 238U activity concentrations reach up to 79.78 Bq Kg-1in the altered granites, 1714.11 and 2223.48 Bq Kg-1in the episyenite and pegmatite. Average 234U activity concentrations in the altered granite is 59.26 Bq Kg-1, between 175.88-543.47 Bq Kg-1and 48.19-1102.88 Bq Kg-1in the episyenite and pegmatite, respectively. 232Th activity concentrations vary between 14.16-1024.8 Bq Kg-1in the episyenite, 11.46-240.27 in the pegmatite and reach up to 201.45 Bq Kg-1in the altered granites. 40K activity concentrations range between 4.42-9.15, 2.76-7.34 and 2.68-9.94 Bq Kg-1in the altered granite, episyenite and pegmatite, respectively. 235U activity concentration ranges between 3.74–2.56, 12.45-78.86 and 0.58-102.34 Bq Kg-1 in the altered granite, episyenite and pegmatite, respectively. The studied altered granite, episyenite and pegmatite samples have relatively higher values than recorded in the international standards with the exception of potassium which has lesser amounts. It is demonstrated that pH changes, oxidation-reduction conditions, mineralogical constituents, in addition to alteration processes in these variable granitic environments were the main factors controlling uranium mobilization according to valid processes. The difference in alteration processes and La/Y ratio clarified the presence of more than one event of uranium accumulation and/or leaching in these rocks as confirmed by the presence of uranium accumulation and uranium vacant occurrences. Also, the isotopic ratios of uranium as 238U/235U,234U/235U, 234U/ 238U, 226Ra/ 238U,226Ra/ 230Th, 210Pb/ 226Ra, 230Th/ 238U, 230Th/ 234U with major, trace and rare earth elements were also affected by physico-chemical conditions changes. The present study shows that the samples of episyenite and pegmatite have been affected by leaching-accumulation events in the period from (1 × 105 to ˃2 × 105years).

Estimation the cancer risk due to ingestion the food spices commonly used in Iraqi kitchen

Spices are natural substances taken from special plants and have a different taste when added to food and some of them have great benefits for health and body. These plants vary from country to country depending on the type of soil and how they are grown and this affects their quality. In this study, the specific activity of 40K, 238U and 232Th series and 137Cs in some selected natural food spices commonly used in Iraq kitchen were determined using gamma spectrometry and the ingested doses via food consumption were also assessed. The average specific activity of 40K, 238U, 232Th and 137Cs in the samples are 72.00 Bqkg−1, 106.576Bqkg−1, 148.74 and 191.88 Bq.kg−1 respectively. The highest activity concentration of 40K, 238U, 232Th and 137Cs was recorded in cumin (401.7) for 40K, laurel paper (260.67) for 238U, briana spices (733.7) for 232Th and Chamomile (833.4) for 137Cs. The maximum value of total annual effective dose received from 40K, 238U, 232Th and 137Cs due to consumption of natural spices by the inhabitants was 169.83 μSvy−1. This value is low compared to the average radiation dose of 290 μSvy−1 received per caput worldwide due to ingestion the food spices. The excess lifetime cancer risk due to ingestion of radionuclide in food spices was estimated and the values obtained were compared with standards. Based on these results it can be concluded that the foods spices studied in this work do not present any serious radiological effect. Spices are natural substances taken from special plants and have a different taste when added

Assessment of Uranium Concentrations in Drinking Water Supply Sources Based on the Results of Laboratory Analysis of 238U and 234U Specific Activities and Laboratory Determination of Uranium According to GOST R 54499–2011

Introduction. The cause of toxicity and damaging effects of uranium and its compounds on the body lies in radioactivity of uranium isotopes and their decay products as well as their high chemical activity. In view of the above, we conducted parallel studies of specific activities and concentrations of uranium in household and drinking water supply sources. Materials and methods. We studied specific activities of uranium-234 and uranium-238 in the centralized drinking water supply sources of the Republic of Khakassia exceeding control levels in terms of specific total alpha activity (Aα) and converted them to mass concentrations of uranium. Parallel analyses of uranium concentrations in water using the luminescent method according to GOST R 54499–2011 were performed. Results. Our assessment of the radionuclide composition of centralized drinking water supply sources showed that Aα levels exceeding control levels were largely due to natural radionuclides uranium-238 (contribution up to 25%) and uranium-234 (contribution up to 69%). Based on the specific activities of uranium-234 and uranium-238, we estimated masses (concentrations) of uranium in water ranging from 0.007 to 0.06 mg/L depending on the water source. In the parallel tests of water samples according to GOST R 54499–2011, uranium concentrations ranged from 0.007 to 0.061 mg/L. Conclusions. The uranium concentrations in the republican centralized drinking water supply sources estimated on the basis of uranium-234 and uranium-238 specific activities differed from the concentrations of uranium measured by the luminescent method according to GOST R 54499–2011 within the error of the test method. In some settlements uranium concentrations in water exceeded the hygienic standard of 0.015 mg/L (GN 2.1.5.2280–07).

EVALUATION OF RADIOACTIVITY IN THE PHOSPHOGYPSUM STOCKPILE OF “HIV” VELES, THE REPUBLIC OF NORTH MACEDONIA

The production of phosphoric acid from natural phosphate ore generates an industrial waste product named phosphogypsum. Phosphogypsum contains considerable amounts of natural radionuclides from the 238U chain, originating from the ore but enriched during the technological process. In order to perform radiological characterization of the “HIV” (Chemical Industry Veles) phosphogypsum stockpile, five phosphogypsum samples were collected and analyzed. The mean values of gross alpha and beta specific activities ± standard deviation values were: (950±104) Bq/kg and (1694±220) Bq/kg, respectively. Further analysis showed increased gross activities of radionuclides of the 238U chain, while the radionuclides of the 232Th chain and 40K were below the detection limit. The mean values of the specific activities of 238U and 226Ra were (360±55) Bq/kg and (280±84) Bq/kg, respectively. The estimated annual outdoor effective dose, at 1m received by adults was 0.25 mSv/y, which is below a dose limit of 1 mSv/y for members of general public. The results obtained in this study show that radionuclides, although present in relatively high concentrations in the phosphogypsum pile, do not imply an increased external radiation risk for members of the population. The possible use of phosphogypsum in civil construction and agriculture may not be excluded if conditions of prior good planning taking into account the radionuclides activities exist.

Natural radioactivity and external dose rates in tailing samples from Rosterman gold mine, Kakamega county, Kenya

In this article, documented results of natural radionuclide concentrations in tailings at Rosterman gold mine, Kakamega county, Kenya were evaluated. Thirty tailing samples from Rosterman gold mine were collected as per standard sampling procedures and were analyzed for 238U, 232Th and 40K by NaI (TI) gamma-ray spectroscopy. The activities of 238U, 232Th and 40K was found to vary from 39 ± 1.63 Bq/Kg to 118 ± 4.43 Bq/Kg, 72 ± 2.24 Bq/Kg to 223 ± 8.36 Bq/Kg and 85 ± 3.6 Bq/Kg to 362 ± 10.65 Bq/Kg respectively. Radium equivalent activities were found below 370 Bq/Kg in all the collected samples. External gamma dose rates estimated from the levels of radionuclides in sediments had a range of 32 ± 3.4 nGy/h to 68 ± 5.83 nGy/h. Hence, mining of gold at Rosterman has minimal significant health implications to the general population and the miners.

Investigation and Analysis of Soil Radioactivity Level in Parks in a City

Using a portable microcomputer multi-channel gamma spectrometer to directly measure the radioactive content in the soil, the on-site gamma energy spectrum measurement was carried out on the soil of 7 parks in a certain city. The survey results show that the specific activity of 40k in the urban park soil ranges from 470.88 bq/kg to 640.2 bq/kg. The specific activity of 238u ranges from 26.77 bq/kg to 33.31 bq/kg. The specific activity of 232th ranges from 42.14 bq/kg to 54.72 bq/kg. The content of the three radionuclides in the soil in the park is lower than the national average, and far lower than the radioactivity of ordinary building materials.

Study of the Mobilization of Uranium Isotopes in a Sandstone Aquifer in Combination with Groundwater Data

This work is part of a research project that aims to develop a method for combined radiocarbon and uranium-isotope dating of groundwater. The specific objective of this study was to investigate the mobility of uranium isotopes in the various mineral phases of rocks of an aquifer of sandy-clay deposits of the Vendian in the northwest of Russia, for which a partial extraction procedure was used. Representative aliquots of each core sample were treated with various reagents: distilled water, low mineralized fresh natural groundwater, minopolycarboxylic acid chelating agent (0.05 M EDTA), 0.5M HCl, 15 M HNO3, as well as total digestion, and the U isotope data for each procedure are reported in this study. The following mineral phases of core samples were characterized: sorbed material, carbonate minerals, amorphous iron oxides, partially soluble aluminosilicates and crystalline iron oxides, totally digestible aluminosilicates and a clay/quartz resistate. Red-colored siltstones and sandstones were depleted in uranium in relatively readily soluble mineral phases. The concentration of sorbed uranium was established in the range 15.8 ± 2.1–30.5 ± 3.9 μg/kg and carbonate minerals contained even less uranium. For iron hydroxides and the most readily soluble aluminosilicates, uranium concentrations were in the range 168 ± 24–212 ± 28 μg/kg. The most insoluble fraction contained uranium in the range 1.65 ± 0.21–4.32 ± 0.45 mg/kg. In green-colored siltstones, the concentration of sorbed uranium was much higher in the range 106 ± 14–364 ± 43 μg/kg. Carbonate minerals and amorphous iron oxides contained uranium in the range 1.91 ± 0.21–2.34 ± 0.26 mg/kg. In aluminosilicates and a clay/quartz resistate, uranium concentrations were in the range 5.6 ± 0.5–16.8 ± 1.4 mg/kg. Elevated values of 234U:238U activity ratio prevailed in the sorbed material and iron hydroxides. In aluminosilicates and clay/quartz resistate, the values decreased. This indicates the replacement of primary sedimentogenic uranium by secondary hydrogenic uranium sorbed on the surface of minerals and coprecipitation with iron hydroxides. The results obtained made it possible to carry out preliminary quantitative estimates of the retardation factor and recoil loss factor of uranium in the groundwater of siltstones and sandstones of the studied Vendian aquifer.

238U and 232Th isotopes in groundwater of Jordan: Geological influence, water chemistry, and health impact

An extensive pioneer study was conducted to determine the activity concentration of 238U and 232Th in 94 groundwater samples to examine the influence of geological formations on the activity concentrations of 238U and 232Th and to investigate a relationship with the major chemical elements in groundwater. The study also aims to estimate the annual effective dose and health impact due to the intake of these radionuclides in the groundwater of Jordan. The mean activity concentrations of 238U and 232Th in groundwater were found to be 33 ± 5 mBq L−1 and 0.017 ± 0.002 mBq L−1, respectively. The highest mean of 238U and 232Th activity concentrations were found for lower Cretaceous geological formation, while Tertiary and Quaternary geological formations have the lowest mean 238U and 232Th activity concentration, respectively. The output of (ANOVA) and post hoc tests revealed the existence of significant influence of geological formations on 238U activity concentrations, while insignificant influence on 232Th activity concentrations was found in the groundwater of Jordan. The groundwater of Jordan was dominated by HCO3−1, Cl−1, Ca+2, and Na+1. The mean annual effective dose due to the ingestion of radionuclides 238U and 232Th in groundwater were found 1.143 μSv lower than recommended by WHO. The ingestion dose deduced is dominated by 238U of 99% where the average contribution from 232Th amounted to 1%. The results of the study will serve as a baseline data of 238U and 232Th activity concentrations in groundwater based on geological formations of Jordan.

Radioactivity and Geochemistry of Wadi El Reddah Stream Sediments, North Eastern Desert, Egypt

Wadi El Reddah is considered as semi closed basin where the only open tributary is very narrow and has higher ground relative to the ground adjacent to the surrounding peaks. The 238U activity concentrations range between 101.24 and 347.96 with an average 214.63 Bq Kg-1, 234U activity concentrations range between 89.67 and 308.19 Bq Kg-1 with average 190.10 Bq Kg-1. 232Th activity concentrations vary between 96.42 and 463.71 Bq Kg-1 with 240.46 Bq Kg-1 as an average. 40K ranges between 1092.71 and 1227.25 Bq Kg-1 with an average 1153.82 Bq Kg-1. 235U activity concentration ranges between 4.66 and 17.38 Bq Kg-1 with average 10.19 Bq Kg-1. Most of stream sediment samples exhibit increase in SiO2, Fe2O3t, Na2O, P2O5 and K2O and L.O.I. However, trace elements in the studied samples show enrichment in Ni, Cu, Pb, Zn, Cd, Ta, Nb, Zr, Y, Rb, Cs, Ga, Hf, Sn, Th, Tl, U, W, Mo, Bi, As, Be, Li, Sb and Au whereas they are depleted in Co, Sr, V, Ag, Cr and Sc. Zr, Hf and Y are relatively immobile and essentially concentrated in the accessory minerals (zircon and its alteration product branirite, xenotime, thorite and uranothorite). Their REE patterns are well characterized by the M- and W-type tetrad effects. The M- type tetrad effect could be inherited from the surrounding granitic rocks whereas the positive Y anomalies intimately associating with the W-type tetrad effect of REE mainly occur in natural aquatic solutions including seawaters and in some hydrogenous deposits.

Transfer of 238U and 232Th from soils to tea leave sin LuongMy farm, HoaBinh province, Viet Nam

The soil-to-plant transfer factors of natural uranium isotopes (238U and 232Th) were studied in Luong My tea farm, Tan Thanh district, Luong Son commune, HoaBinh province. The activity concentrations in leaves, trunk and root were determined for the tea tree at no harvest period (winter break). The measurements were carried out using gamma spectroscopy with high puritygermanium detector HPGe. Research results show that the activity of 238U and 232Th is higher in leaves than in trunk and roots.Soil-leaves transfer factor (TF) for238U and 232Th were as follows:TFU238 = 0,52 – 0,87; TFTh-232 = 0,25 – 0,43.

Radioactivity Levels in Soil And Drinking Water Samples Collected from Andon Region (Rize Province, Turkey)

In the present study, radionuclide and radon concentrations were measured in drinking water samples collected in Andon springs and Rize Andon Drinking Water Treatment Facility located at Rize province in Eastern Black Sea Region in Turkey and radionuclide concentrations were measured in soil samples collected in the same regions. Radionuclide activity concentrations in soil and drinking water samples were measured with gamma ray spectrometry, and 238U, 232Th, 40K and 137C activity concentrations were determined. Annual effective dose equivalents were calculated based on the measured results. Radon concentration measurements for the drinking water samples collected in the region were conducted with a radon gas analyzer (Alpha Guard PQ 2000PRQ). All measured radon gas levels and radionuclide values were found to be among the limit values recommended by international organizations.