Radioactivity and elemental oxidation composition in soil from Yangjiang, a high background natural radiation area, China.

Soil is an important source and medium of radionuclides, and the content of radioactivity in soil is crucial for radiological impact evaluation. In this study, twenty soil samples in the high background natural radiation area of Yangjiang, China were collected and analyzed for 226Ra, 232Th, 40K and 137Cs concentrations in order to evaluate the radiological health risk in the area. Results showed that the average activity concentrations of 226Ra, 232Th and 40K are 66 Bq/kg, 109 Bq/kg and 211 Bq/kg, respectively. The calculated radiological parameters of radium equivalent activity (Raeq), absorbed dose rate (D), annual effective dose equivalent (AEDE), internal and external hazard indices (Hin and Hex) show a large variation at different sampling sites. Additionally, the elemental oxidation composition and 40K/K mass ratio in the soil were analyzed to further augment the background information of the high background radiation area in Yangjiang.

Radioactivity from oil and gas produced water accumulated in freshwater mussels.

Legacy disposal of oil and gas produced water (OGPW) to surface water has led to radium contamination in streambed sediment creating a long-term radium source. Increased radium activities pose a potential health hazard to benthic organisms, such as freshwater mussels, as radium is capable of bioaccumulation. This project quantifies the impact of OGPW disposal on adult freshwater mussels, Eurynia dilatata, which were examined along the Allegheny River adjacent to a centralized waste treatment facility (CWT) that historically treated and then discharged OGPW. Radium isotopes (226Ra and 228Ra) were measured in streambed sediment, mussel soft tissue, and mussel hard shell collected upstream, at the outfall, 0.5 km downstream, and 5 km downstream of the CWT. Total radium activity was significantly higher (p < 0.05) in mussel tissue (mean = 3.44 ± 0.95 pCi/g), sediment (mean = 1.45 ± 0.19 pCi/g), and hard shell (mean = 0.34 ± 0.11 pCi/g) samples 0.5 km downstream than background samples collected upstream (mean = 1.27 ± 0.24; 0.91 ± 0.09; 0.10 ± 0.02 pCi/g respectively). Mussel shells displayed increased 226Ra activities up to 5 km downstream of the original discharge. Downstream soft tissue and hard shell 87Sr/86Sr ratios, as well as hard shell metal/calcium (e.g., Na/Ca; K/Ca; Mg/Ca) and 228Ra/226Ra ratios demonstrated trends towards values characteristic of Marcellus OGPW. Combined, this study demonstrates multiple lines of evidence for radium retention and bioaccumulation in freshwater mussels resulting from exposure to Marcellus OGPW.

Health risk assessment for soil radioactivity around Shidaowan nuclear power plant in Shandong, China.

Monitoring radioactivity levels in the environment around nuclear power plants is of great significance to assessing environmental safety and impact. Shidaowan nuclear power plant is currently undergoing commissioning; however, the baseline soil radioactivity is unknown. The naturally occurring radionuclides 238U, 232Th, 226Ra and 40K, and artificial radionuclide (AR) 137Cs in soil samples around the Shidaowan nuclear power plant were measured to establish the baseline levels. Human health hazard indices such as external hazard indices (Hex), Radium equivalent (Raeq), outdoor absorbed dose rate (Dout), annual effective dose (AED) and excess lifetime cancer risk (ELCR) were estimated. The average concentration of 232Th, 40K, 137Cs, 238U and 226Ra were 42.6 ± 15, 581 ± 131, 0.68 ± 0.38, 40.13 ± 9.07 and 40.8 ± 12.8 Bq per kg, respectively. The average Hex, Raeq, Dout, AED and ELCR were 0.40, 146 Bq per kg, 68.8 nGy per h, 0.09 mSv per y and 3.29E-04, respectively. These data showed an acceptable level of risk to residents near the nuclear power plant and that the current radioactivity in the soil may not pose immediate harm to residents living close to the nuclear power plant. The observed lower AED and 40 K and 137Cs concentrations were comparable to other studies, whilst ELCR was higher than the world average of 2.9E-04. The commissioning of the Shidaowan nuclear power plant is potentially safe for the surrounding residents; further continuous monitoring is recommended.

Microbially formed Mn(IV) oxide as a novel adsorbent for removal of Radium.

Radioactivity of Ra isotopes in natural waters is of serious concern. Control of 226Ra concentrations in tailings ponds, which store waste from U ore extraction processes, is an important issue in mill tailings management. In this study, we tested microbially formed Mn(IV) oxide as an adsorbent for removal of Ra in water treatment. Biogenic Mn(IV) oxide (BMO) was prepared using a Mn(II)-oxidizing fungus, Coprinopsis urticicola strain Mn-2. First, adsorption experiments of Sr and Ba, as surrogates for Ra, onto BMO were conducted in aqueous NaCl solution at pH 7. Distribution coefficients for Ba and Sr were estimated to be ∼106.5 and ∼104.3 mL/g, respectively. EXAFS analysis indicated that both Sr and Ba adsorbed in inner-sphere complexes on BMO, suggesting that Ra would adsorb in a similar way. From these findings, we expected that BMO would work effectively in removal of Ra from water. Then, BMO was applied to remove Ra from mine water collected from a U mill tailings pond. Just 7.6 mg of BMO removed >98% of the 226Ra from 3 L of mine water, corresponding to a distribution coefficient of 107.4 mL/g for Ra at pH ∼7. The obtained value was convincingly high for practical application of BMO in water treatment. At the same time, the high distribution coefficient indicates that Mn(IV) oxide can be an important carrier and host phase of Ra in the environment.

Assessment of radiological hazards from radioactivity natural of cement used in Dwellings in Rio de Janeiro, Brazil.

Brazil is the fourth largest cement consumer in the world and the largest producer in Latin America, around 1.3% of global production. The main inputs in the manufacture of cement are limestone and clay. Few studies have been carried out in the country on the risk of these materials used in civil construction. Therefore, the objective of this present work is to evaluate the radiological danger that they can present to society. Gamma spectrometry analysis on 16 samples of different brands of cement used as construction material in Rio de Janeiro (Brazil) was performed in this study, using an HPGe detector and the Genie 2000 data acquisition software. Samples were set to count for an accumulation time of 14,400 s (4 h) and all measurements were corrected to eliminate background and backscattering. Activity concentrations are determined for 226Ra was from (41.2 ± 1.6 to 174.9 ± 3.9) Bq kg-1, 232Th was from (15.7 ± 0.5 to 43.1 ± 0.7) Bq kg-1 and 40K was from (82.6 ± 7.2 to 254 ± 17) Bq kg-1. To assess radiological health risks: mean values of Radium Activity Equivalent 150.0 ± 3.4 Bq kg-1, Annual Gonadal Dose Equivalent 468 ± 11 µSv year-1 and Lifetime Excess Cancer Risk (ELCR) 2.42 ± 0.06 were calculated. Total Absorbed Dose Rates ranged from 72.2 ± 1.7 to 225.1 ± 5.2 nGy h-1. The damage to collective health was also estimated from the annual effective dose rates with an estimated total cost of damage to health of US$ 130 million. Values are generally within global limits reported by UNSCEAR.

Assessment of NORMs (238U, 232Th, 40K) and radiation hazard indices in Beldih apatite mine region of Purulia district, West Bengal, India.

The radiation arising from naturally occurring radioactive materials (NORMs) is the foremost contributor to the collective dose received by the global population. The present study aims to measure the natural background radiation level and the associated gamma radiation dose in air in the Beldih apatite mine region of Purulia district, India. This study is primarily focused on the determination of 238U, 232Th and 40K activities in the sub-surface soil of the study area. The measurements were carried out using a High Purity Germanium (HPGe) detector-based gamma-ray spectrometer with a relative efficiency of 80%. To achieve uniformity in exposure estimations, radium equivalent activity has been calculated. Additionally, the internal hazard index, external hazard index, radioactivity level index and gamma dose rates have been evaluated to estimate the radiation hazard levels in the study area. The comparison of obtained concentrations and hazard indices with global data (UNSCEAR. (2008). Sources, effects and risks of ionizing radiation. United nations scientific committee on the effects of atomic radiation (report to the general assembly, with Annexes).) suggests that this region lies in a relatively high background radiation zone.

Analysis of internal gamma-ray dose to the public from brick as building material in Tamil Nadu, India.

Natural radioactivity due to 238U, 232Th and 40K in brick samples from Tamil Nadu was determined using gamma-ray spectrometry. The mean activity concentrations of 238U, 232Th and 40K, 69 ± 6, 62 ± 6 and 462 ± 23 Bq kg-1, are slightly greater than the world recommended limits of 35, 45 and 420 Bq kg-1, respectively, and they are compared with a similar work carried out across the world. The radiological parameters such as radium equivalent activity, Raeq (193 ± 17 Bq kg-1), internal hazard index, Hin (0.71 ± 0.06), and activity utilisation index, AUI (1.43 ± 0.13), was lower, whilst absorbed dose rate, DRin (89 ± 8 nGy h-1), annual effective dose equivalent, AEDEin (0.43 ± 0.04 mSv y-1), and excess lifetime cancer risk, ELCRin (1.52 ± 0.13 mSv y-1), are slightly greater than the world's recommended limit. Bi-variate statistical analysis was performed to corroborate the relationship between radionuclides and radiological hazards.

Characterization relationship between multinuclide nonequilibrium gamma radiation dose rate and 226Ra activity concentration in contaminated soil around uranium mines.

According to the characteristics of contaminated soil around uranium mines, combined with the pollution path of soil, the response relationship between the gamma radiation dose rate and radium activity concentration in contaminated soil was proposed by using a numerical model and subequilibrium theory. The results showed that the topsoil (depth 20 cm) made the mainly contribution of gamma dose rate (above 88%), and the main nuclide of concern was radium. Additionally, the uranium-radium equilibrium coefficient between 0 and 0.3 had a great influence on the gamma dose rate. The method proposed in this study could quickly identify the radium activity concentration in topsoil by using on-site gamma dose rate monitoring data. Compared with the actual monitoring results within ±10% error control, which had strong operability. This method could quickly identify the location and scope of contaminated soil and guide the on-site monitoring points around uranium mines.

Radiation risk assessment of quarry pit soil as construction material in Abeokuta, Nigeria: implications for environmental and public health.

ABSTRACTEnvironmental and health risks posed by radionuclides in quarry pit soils are of great concern in environmental health monitoring. The current investigation was aimed at determining the natural radionuclide activity concentration (in Bq kg-1) of the understudied quarry pit granules used as construction materials. The collection and preparation of pit soil samples from Abeokuta quarry sites were done using standard methods, analysis of radiological parameters was carried out using hyperpure germanium (HPGe) spectrometer. Specific activity concentrations of 226Ra, 232Th, and 40K were measured. The values obtained were greater than the world weighted average of 35, 30, and 400 Bq kg-1 for 226Ra, 232Th, and 40K, respectively. The absorbed dose, the annual effective dose, and the radium equivalent were calculated and demonstrated significant values. The radionuclide content of the samples is relatively high and the use of pit soils as a building material, therefore, raises radiological concerns for dwellers in this area and requires periodic monitoring and undergoing a radiation protection program.

Measurement of radium and radon gas in bottled mineral waters.

In this study, the radon gas and radium concentration in the bottled mineral water samples was measured. A total of sixty samples were collected from bottled mineral water sold in the markets in Kahramanmaras. DURRIDGE Rad7 electronic radon detector was used for measurements. Radon and radium activity amounts range from 33.50 ± 1.30 mBq/L to 51.70 ± 2.20 mBq/L, and 2.92 ± 0.15 mBq/L to 4.51 ± 0.26 mBq/L, respectively. Average radon and radium active amounts are 41.67 ± 1.54 mBq/L and 3.63 ± 0.18 mBq/L, respectively. Total annual effective dose values were calculated for these mineral waters according to three different scenarios. In the first of these, it was assumed that natural mineral water was consumed annually instead of 730 L of drinking water (S1). In the second case, 150 L which was the annual average amount of natural mineral water consumed in European Union member countries was used for the annual average amount of natural mineral water consumed by adults (S2). Finally, the annual average amount of natural mineral water consumed in Turkey, 14 L, was used for adults (S3). For scenarios (S1, S2, S3), the total (ingestion + inhalation) annual average dose values ranged from 6.83E-04 mSv/y to 1.05E-03 mSv/y, 1.40E-04 mSv/y to 2.17E-04, and 1.32E-05 mSv/y to 2.03E-05 mSv/y, their average values were 8.49E-04 mSv/y, 1.75E-04 mSv/y, and 1.64E-05 mSv/y, respectively. The total effective dose values calculated within the scope of the current study were below the limit value announced by WHO.

Natural radioactivity in mineral phosphate fertilizers and its impacts on human health: an overview.

Humans are constantly exposed to radioactivity present in rocks, soils, and water, mainly from materials in the Earth's crust that contain chemical elements belonging to the radioactive series of uranium and thorium. An important anthropogenic source of these natural radioisotopes to the environment is fertilizers, widely used to increase agricultural productivity. Exposure to ionizing radiation can become a public health problem worldwide, since it is related to the development of different cancers in humans. The present study aimed to survey research on the radioactive content in different types of mineral phosphate fertilizers used around the world through a comprehensive review of the Scopus and Web of Science databases. About 80 scientific articles fit the purpose of this review. The concentration activity values found varied widely from one country to another, and there is no specific legislation that determines the maximum allowed limits of radioisotopes in these agricultural inputs. In addition, there are still uncertainties regarding the impact of natural radioactivity from fertilizers on human health, highlighting the need for further investigations on the subject.

Environmental radiological baseline in unconventional oil and gas areas of Mexico.

Environmental radioactivity study was performed in unconventional hydrocarbons areas for the first time in Mexico, where four unconventional hydrocarbon exploratory wells (UHEW) are planned. This study assesses natural radiological conditions in areas around UHEW. Equivalent dose rate distribution displayed in Geographic Information System (GIS) had a maximum of 1.83 mSv a-1 and minimum of 0.04 mSv a-1, GIS was also used for introducing land usage, water resources and population occupancy. Measurements of gross alpha and gross beta in water were below the national permissible limits for drinking water 0.5 and 1.0 Bq L-1 respectively, even though samples do not correspond to drinking water. Evaluation of 238U and 226Ra in groundwater were below minimum detectable concentration 1.3 and 1.0 Bq L-1, respectively. This study provides a radiological baseline for the impact of future industrial activities, especially if exploitation of unconventional hydrocarbons produces naturally occurring radioactive material.

Distribution of naturally occurring radionuclides and gamma dose rate assessment in the soils of high background natural radiation area Odisha, India.

A study on the activity concentration of primordial radionuclides 226Ra, 232Th and 40K was carried out on the surface soil samples collected from the coastal villages between Chhatrapur and Gopalpur regions of high background natural radiation area Odisha, India, using high purity germanium gamma spectroscopy. The mean activity concentrations of 226Ra, 232Th and 40K were found to be 231, 1692 and 250 Bq/kg, respectively. The total mean absorbed dose owing to the presence of 226Ra, 232Th and 40K was 1139 nGy/h. The mean annual effective dose was found to be 1397 µSv/y and higher than the UNSCEAR average value 70 µSv/y.

Evaluation of natural radioactivity in soils of Konya (Turkey) and estimation of radiological health hazards.

Surface soil samples were collected from Konya, Turkey and natural activity concentrations were determined using the ɤ-ray spectroscopy system with HPGe detector. The activity concentrations of 226Ra, 232Th and 40K were found to vary from 14.07 ± 0.71 Bq kg-1 dw to 67.27 ± 1.62 Bq kg-1 dw, 10.19 ± 2.60 Bq kg-1 dw to 46.09 ± 0.76 Bq kg-1 dw and 107.87 ± 13.32 Bq kg-1 dw to 605.95 ± 11.34 Bq kg-1 dry weight (dw), respectively. The radiological hazard parameters such as Raeq, D, AEDE, ELCR, AGDE, Hex, Hin, and Iɤ evaluated the radiological risk for the public and environment. The mean values of D, AEDE and ELCR are lower than the world average value of 57 nGy h-1, 70 µSv y-1, 0.29 × 10-3 respectively. The activity concentration distribution maps of 226Ra, 232Th and 40K and the radiological maps of the radiological hazard parameters were plotted using the Surfer programme. Cluster analysis was carried out to indicate the similarity between the variables.

Evaluation of soil radioactivity in the areas of underground nuclear explosions at the Pomuk gas field site in Uzbekistan.

This study investigates soil radioactivity at the Pomuk gas field in Uzbekistan, a region with history of underground nuclear activity. Using a NaI (Tl) scintillation gamma spectrometer, soil samples were analyzed for concentrations of 232Th, 226Ra, 40K, and 137Cs. Concentrations were found to be in the range of 19.0-31.0 Bq/kg for 232Th, 12.0-32.0 Bq/kg for 226Ra, 450.0-634.0 Bq/kg for 40K, and 2.4-11.0 Bq/kg for 137Cs. Surface radon flux density was measured using a coal sorbent-based passive method, with values ranging from 26.1 to 79.0 mBq/m2s. Mean activity values for radium equivalent (Raeq) and gamma representative level index (Iγ) were calculated to be 75.2-96.5 Bq/kg and 0.3-0.4 Bq/kg, respectively. The absorbed airborne gamma dose rates (GDR) varied between 41.0 and 52.0 nGy/h, while annual effective dose rates (AEDR) were 0.3-0.4 µSv/year. The radiological risk assessment indicates the area is within safe limits for the population and environment, providing a foundation for future radiological monitoring programs.

Ingestion exposure of public to natural radionuclides and committed effective dose and cancer risk through tuber crops cultivated in Ebonyi State, Nigeria.

Internal exposure of public to radiation arising from ingestion of natural radionuclides in tuber crops of Ebonyi State origin was investigated in this study. Committed effective doses and lifetime cancer risk of 40K, 226Ra, and 232Th in cassava, cocoyam, water yam, and white yam were calculated. The average activity concentrations of 40K, 226Ra, and 232Th determined by gamma spectrometric Na (TI) detector were, respectively, 199.15 ± 23.51, 77.57 ± 7.98, and 118.20 ± 10.72 Bq/kg in cassava; 146.62 ± 40.69, 43.42 ± 7.63, and 75.61 ± 2.89 Bq/kg in cocoyam; 162.81 ± 20.43, 63.17 ± 11.36, and 81.50 ± 10.27 Bq/kg in water yam; and 184.50 ± 20.22, 80.23 ± 10.93, and 116.29 ± 5.93 Bq/kg in white yam. The total committed effective dose via ingestion aligned in this order of cassava (7.05 mSv/year) > white yam (4.38 mSv/year) > water yam (0.42 mSv/year) > cocoyam (0.21 mSv/year) with overall average dose of 3.12 mSv/year. The values of dose were higher than world average of 0.29 mSv/year given by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The lifetime cancer risk values were above tolerance level of >10-4 prescribed by United States Environmental Protection Agency (USEPA), suggesting probable evolvement of radiogenic cancer morbidity. The data presented in this study contributes to baseline information on radiological characteristics of tuber crops in Ebonyi, which would be valuable to WHO/FAO food safety policy in Nigeria and rest of the world.

Assessment of natural radioactivity, radon gas and soil characteristics along the Volta Lake in the Kpando municipality of Volta region, Ghana.

Assessment of radionuclides, indoor radon (222RnI), radon exhalation (222Rnex), and soil characteristics in the coastal part of Kpando has been studied using HPGe, CR-39 and sieving techniques. Statistical analysis between radionuclides, radon levels and soil characteristics was done using Pearson's correlation. The mean radionuclide concentration, radon levels and soil characteristics were obtained as 226Ra (23.1 ± 1.4 Bq per kg), 232Th (34.6 ± 2.9 Bq per kg), 40K (187.1 ± 13.7 Bq per kg), 222RnI (64.70 ± 2.7 Bq per m3), 222Rnex (7.9 ± 0.5 µBq per m2h), sandy (45.9 ± 3.9%), silt (40.7 ± 3.1%), clay (13.5 ± 0.8%), porosity (0.6 ± 0.1) and moisture (7.6 ± 0.8%). Radiological effects estimated were within recommended limits. The maximum positive and negative coefficients exist between 222Ra/222Rnex (1.0) and 222Rnex/MC (-0.9), respectively. Radon exhalation correlates better with soil characteristics. The statistical analysis indicated that soil characteristics have significant effects on radionuclides and radon levels in soils and dwellings.

Geological control of terrestrial background radiation in Garhwal Himalaya, India.

Activity concentrations of 226Ra, 232Th, and 40K were measured in soil samples from several areas of Garhwal Himalaya, Northern India, by gamma-ray spectrometry. In this region, which extends around the Himalayan Main Central Thrust, a tectonic line that separates several geological provinces, background levels of natural terrestrial radiation were assessed. The maximum levels of radium, 285 Bq/kg and 136 Bq/kg, respectively, were found in the Budhakedar and Uttarkashi regions, exceeding the world average value of 35 Bq/kg. The mean radiation levels were found to be different between the areas, which reflects the geological diversity in the region. The overall absorbed dose rate owing to radionuclide presence in the Uttarkashi area ranged from 79 to 188 nGyh-1, with an average of 118 nGyh-1. That is more than UNSCEAR's world-populated weighted average value of 59 nGyh-1. The present investigation indicated that the absorbed dose rates are greater in Uttarkashi and Budhakedar than in other places. The multiple comparison analysis between geology and absorbed dose rate shows that the geology of Uttarkashi and Budhakedar are statistically similar. According to several hazard indices, terrestrial background radiation is not of radiological concern in the investigated region.

Dolphin-shaped island: Exploring the natural resources and radiological hazards of Wadi El Gemal Island.

The objective of this study is to assess the natural resources and radiological risks of Wadi El Gemal Island by examining its topography, mineralogy, geochemistry, and radioactive distributions. This island, which is situated at the outlet of Wadi El Gemal in Egypt's southeastern Desert, has a unique shape resembling a dolphin based on Landsat imagery. It's a part of the Wadi El Gemal-Hamata Protectorate and is notable for its diverse environmental, geological, economic, and archeological features, including recent reefs, sandy deposits, Quaternary carbonate sediments, and mangroves. The main natural resources on the island are fauna, mangrove forests, and flora. Samples collected from the island were analyzed using a NaI detector to measure the concentrations of radionuclides such as 238U, 232Th, 226Ra, and 40K, which were found to be within acceptable levels according to UNSCAR guidelines. The radionuclide 238U, 232Th, 226Ra, and 40K activity concentrations of the collected samples were 32.55 ± 9, 12.63 ± 4, 12.49 ± 4, and 325 ± 34 Bq/kg, respectively. Regarding radiological hazard indices, the values of absorbed gamma dose rate (36.06 ± 5.42 nGy/h), radium equivalent activity (73.88 ± 14.4 Bq/kg), annual effective dose indoor (0.18 ± 0.03 mSv/y) and outdoor (0.04 ± 0.01 mSv/y), internal (0.29 ± 0.05) and external (0.2 ± 0.03) indices, and excess lifetime cancer index (0.15 ± 0.05 × 10-3).This is suggest that there is no significant risk associated with these sediments.

Determination of the radiation dose from radon ingestion and inhalation in different types of drinking water samples collected from Bethlehem province -Palestine.

The objective of this study is to investigate the levels of radon gas and increase public awareness of its hazards to health in Bethlehem governorate- Palestine. The concentrations of radon-222 and radium- 226 in 79 different types of water samples were measured. The average values of radon and radium concentrations in tap water, rainwater, groundwater, and mineral water samples were 0.93 Bq/ℓ and 45.5 Bq/kg, 1.01 Bq/ℓ and 49.3 Bq/kg, 1.21 Bq/ℓ and 59.3 Bq/kg, and 0.60 Bq/ℓ and 29.2 Bq/kg, respectively. All the measured radon concentrations in the collected samples were within the limit of 11 Bq/ℓ established by UNSCEAR in 1982. The annual effective doses for ingestion and inhalation due to radon in water were calculated for adults, children, and infants using parameters introduced by UNSCEAR in 2000. The results show that there is no significant risk to public health from radon inhalation or ingestion through drinking water in the study region.