Environmental characterization and radio-ecological impacts of non-nuclear industries on the Red Sea coast

A generalized machine learning model for long-term coral reef monitoring in the Red Sea

Coral reefs, despite covering less than 0.2 % of the ocean floor, harbor approximately 35 % of all known marine species, making their conservation critical. However, coral bleaching, exacerbated by climate change and phenomena such as El Niño, poses a significant threat to these ecosystems. This study focuses on the Red Sea, proposing a generalized machine learning approach to detect and monitor changes in coral reef cover over an 18-year period (2000-2018). Using Landsat 7 and 8 data, a Support Vector Machine (SVM) classifier was trained on depth-invariant indices (DII) derived from the Gulf of Aqaba and validated against ground truth data from Umluj. The classifier was then applied to Al Wajh, demonstrating its robustness across different sites and times. Results indicated a significant decline in coral cover: 11.4 % in the Gulf of Aqaba, 3.4 % in Umluj, and 13.6 % in Al Wajh. This study highlights the importance of continuous monitoring using generalized classifiers to mitigate the impacts of environmental changes on coral reefs.

Review and statistical analysis of activity values reported for coastal sands worldwide

The activity of natural radionuclides is unevenly distributed across the Earth's crust, with certain areas exhibiting significantly higher levels than others, known as High Background Radiation Areas (HBRAs). This study presents a statistical analysis of reported activity values for coastal sands globally. Through this statistical analysis, costal sands were classified into four categories based on their activity levels, providing a standardized framework to compare the natural radioactivity of these sands. This classification is a valuable tool for identifying populations exposed to different radiation levels, which is essential for the study of stochastic effects. The study proposes thresholds to define HBRAs as regions with activity values exceeding 203 Bq/kg for 238U, 517 Bq/kg for 232Th, or 960 Bq/kg for 40K. Regions with lower values are classified as NonHBRAs. Further subdivision of these categories resulted in four distinct regions: NonHBRA-, NonHBRA+, HBRA-, and HBRA+. The activity values for these subdivisions are 92 Bq/kg and 2,903 Bq/kg for 238U, 94 Bq/kg and 7,230 Bq/kg for 232Th, and 901 Bq/kg and 2,298 Bq/kg for 40K. By calculating the external dose rates from the reported activity data, a threshold of 357 nGy/h was identified as the dose boundary separating NonHBRAs from HBRAs. The values for the subdivisions resulted 101 nGy/h and 3,867 nGy/h. The study also explores the content of these natural radionuclides in relation to their bearing minerals and discusses correlations between the reported activity values and the characteristics of the sands. Additionally, the activity of the anthropogenic radionuclide 137Cs (reported values ranging from the detection limit to 63 Bq/kg) is examined.

A baseline monitoring of radiological sediment quality and associated risk assessment in coastal ecosystems of the Republic of Congo

This study presents the first data on levels of natural radioactive elements in sediments from coastal ecosystems of the Republic of Congo. Sediment samples from five coastal sites were collected and analyzed by high-resolution gamma spectrometry for determination of activities of long-lived gamma-emitting radionuclides (234Th, 238U, 226Ra, 210Pb, 228Th, 228Ra, and 40 K). The specific activities were of the same order of magnitude as those measured in sediments of most countries neighboring the Republic of Congo. However, variations in activities were observed from one site to another and also from one sampling point to another within the same site without exceeding the global average reference values. It can be assumed, therefore, that no significant anthropogenic impact is perceptible in the study area. The most commonly used radiological hazard parameters, based mainly on 238U, 232Th, and 40 K activities, were assessed and the ERICA tool was applied to quantify the radiation exposure burden to human and biota resulting from radionuclides in sediments. Besides being useful for future monitoring efforts, the data produced in this work could be important for the worldwide database on radioactivity in the oceans and seas (MARIS) since no data are available in the Congolese marine environment.

Influence of the industrial pollutant on water quality, radioactivity levels, and biological communities in Ismailia Canal, Nile River, Egypt

In the twenty-first century, numerous forms of pollution have adversely impacted freshwater and the entire aquatic ecosystem. The higher population density in urban areas also contributes to increased releases of substances and thermal contaminants, significantly stressing the ecosystem of industrial companies. This study aimed to assess the potential pressure of industrial and municipal activities on water quality, radioactivity levels, and biological diversity, focusing on the consequences of radionuclides on periphytic diatom communities. Furthermore, the environmental impact of pollutants will be evaluated to monitor the ecological condition of the Ismailia Canal. Chemical analyses employed various instruments and methods to identify and quantify matter, with radionuclide elements measured by gamma spectrometry and diatoms counted and identified by inverted microscopy. Our results revealed that the canal was classified as excellent for irrigation, aquatic life, and drinking water based on FAO, CCME, and EWQS water quality indices, with high nutrient levels at Abu Za'baal fertilizer company. The activity concentration of 226Ra-series, 232Th-series, and 40K in the water and sediment samples for two seasons was within the guideline values, except for a few stations in the zone [B] (the industrial zone). Fertilizer samples (raw material) showed a high value of the 226Ra-series activity. Diatom community structure significantly varied across the different canal locations regarding the presence or absence of industrial activities, with no discernible variations between the study seasons. A specific variety of algal species was found to be predominant at the highest radioactive sites. Redundancy analysis (RDA) showed a significant correlation between parameters (pH, Na, TDS, PO4, SO4, SiO2, K, and CO3), radionuclides, environmental conditions, and the composition of the diatom community, especially in the area affected by industrial discharges. Moreover, the radiological hazard index in water and sediment remained below the maximum for two seasons. This research provides valuable data and information for communities and decision-makers, suggesting the strategic use of phycoremediation as a water biotreatment process to protect the valuable economic resources of the Ismailia Canal.

Radiometric survey of sediments and health risk assessments from the southern coastal area of Delta State, Nigeria

Over the years, the release of potential radiological components around the oil exploration environment has increased with potential health implications.Yet; the mechanism and health associated assessment have remained fuzzy to most experimental scientists. The current study determines the activity concentration of radionuclides in sediments and the corresponding health risk assessments from the hydrocarbon exploration environment of the southern coastal area of Delta State, Nigeria. A Sodium-iodide NaI(Tl) detector, with a well-calibrated multichannel analyzer (MCA) to ensure efficiency and energy was utilized. A total of seventy-five sediment samples (Five sediment samples each per community) were collected from the southern coastal area of Delta State, Nigeria. The mean activity concentrations of 40K, 238U, and 232Th of the sediment samples were 3361.48 ± 194.26 Bqkg-1, 40.11 ± 16.17 Bqkg-1, and 45.73 ± 19.27 Bqkg-1 respectively. The obtained mean values exceeded the world standard limit of 400 Bqkg-1, 35 Bqkg-1, and 30 Bqkg-1 respectively. Also, the computed mean radiological health hazard risk of radium equivalent activity (Raeq), representative level index (Iyr), external hazard index (Hex), internal hazard index (Hin), absorbed gamma dose rate (D), annual effective dose equivalent outdoor and indoor (AEDE) and lifetime cancer risk (ELCR) values are 363.94 ± 32.37 Bkgl-1, 2.9657 Bkgl-1, 0.9839, 1.0919, 175.82 nGyh-1, 2.1556 mSvyr-1, 0.8625 mSvyr-1, and 7.5447 mSvyr-1 respectively. The values were found to be slightly higher than the world standard limit. Therefore, the residents that are using the sediments of the southern coastal area for the construction of buildings as well as dwelling in houses built with such sediments are exposed to these radiological materials. This may pose a radiological health risk concern. The obtained results will serve as radiation and radiological baseline data for sediments of the southern coastal area of Delta State, Nigeria.

Evaluation of radioactivity in soil and rock samples from an undiscovered sea beach in the southeastern coastline of Bangladesh and associated health risk

This study marks the first-ever assessment of radiological hazards linked to the sands and rocks of Patuartek Sea Beach, situated along one of the world's longest sea beaches in Cox' Bazar of Bangladesh. Through the utilization of an HPGe detector, a comprehensive analysis of the activity concentrations of 226Ra, 232Th, and 40 K was conducted, and their activity ranged from 7 to 23 Bq/kg, 9-58 Bq/kg, and 172-340 Bq/kg, respectively, in soils, and 19-24 Bq/kg, 27-39 Bq/kg, and 340-410 Bq/kg, respectively, in rocks. Some sand samples exhibited elevated levels of 232Th, while the rock samples displayed higher levels of 40 K compared to the global average. The radiological hazard parameters were assessed, and no values surpassed the recommended limits set by several international organizations. Hence, the sands and rocks of Patuartek sea beach pose no significant radiological risk to the residents or tourists. The findings of this study provide crucial insights for the development of a radiological baseline map in the country, which is important due to the commissioning of the country's first nuclear power plant Rooppur Nuclear Power Plant. The data may also stimulate interest in the rare-earth minerals present in the area, which is important for the electronics industry, thorium-based nuclear fuel cycles.

Natural radioactivity and its radiological implications from soils and rocks in Jaintiapur area, North-east Bangladesh

Natural radioactivity concentrations in recent alluvial soils from swampy areas and Tertiary rocks from Jaintiapur were measured using gamma-ray spectrometer equipped with HPGe detector. The average radioactivity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K were 47 ± 6, 64 ± 5 and 762 ± 40 Bqkg⁻¹ in soils, whereas, 25 ± 2, 37 ± 4 and 884 ± 41 Bqkg⁻¹ in rock samples, respectively. Average radioactivity concentrations of studied soil and rock samples exceeded the world average except ²²⁶Ra for rocks. Radio-elemental ratios suggest that an oxic depositional environment with low uranium and high thorium content. Regarding radiological hazard indices, radium equivalent activities (Ra_eq), external hazard index (H_ex) and internal hazard index (H_in) was found to be below the world permissible limits. Whereas, absorbed dose rate (D), and annual effective dose equivalent (AEDE) averages exceeded the world admissible values. Statistical studies show that radioactivity for ²²⁶Ra and ²³²Th linked to a source enriched in radioactive minerals and ⁴⁰K related to a different sources high in K enriched minerals.

Environmental risk assessment associated with acidic volcanics in Egypt

The present work aims to study gamma rays emitted by radionuclides such as ²³⁸U, ²³²Th and ⁴⁰K from acidic Monqul volcanics. The studied volcanics are represented by a thick stratified lava flows interbanded with their pyroclastics. They are composed of thick lava flows of andesite and, to a lesser extent of basalt, and acidic volcanics including rhyolite and dacite. The average values of ²³⁸U, ²³²Th and ⁴⁰K are (46 ± 24 Bq kg^-1), (62 ± 11 Bq kg^-1) and (1227 ± 318 Bq kg^-1) in the rhyolite-dacite samples are greater than the worldwide average. The variation of radioactive bearing minerals observed inside granite faults produced the great amounts of radioactivity perceived in the samples. Calculating radiological risks is used to assess the public's radioactive risk from radionuclides revealed in the studied Rhyolite-dacite samples. The acceptable limit for excess lifetime cancer (ELCR) evaluations has been exceeded. As a result, Rhyolite-dacite are inappropriate for apply in building materials.

Excess Lifetime Cancer Risk Associated with Granite Bearing Radioactive Minerals and Valuable Metals, Monqul Area, North Eastern Desert, Egypt

The present work is concerned with assessing the cancer risk contributed by the studied granite types including valuable metals, such as Cu, Au, and Ba mineralization, as well as radioactive-bearing mineralization, such as monazite and zircon, in south Monqul at Wadi Makhrag El Ebel, north Eastern Desert, Egypt. The mineralization analyses illustrated that copper mineralization containing chrysocolla and tenorite minerals were restricted to the alteration zone, especially (argillic, phyllic, and propylitic) in monzogranite. However, barite veinlets had an ENE–WSW trend, while gold mineralization was confined to quartz veins having NE–SW trends. Monazite and zircon are radioactive-bearing minerals recorded in monzogranite causing high radioactive zones in south Monqul. The radionuclide activity concentrations were detected in the studied monzogranites. The mean values of A_U (103 ± 91 Bq kg⁻¹), A_Th (78 ± 19 Bq kg⁻¹), and A_K (1484 ± 334 Bq kg⁻¹) in the monzogranite samples were higher than the recommended worldwide average. The change in radioactive-transporting minerals found inside granite faults caused the high amounts of radioactivity seen in the samples. Due to the monzogranites being applied in building materials, the radiological hazards were assessed by calculating risk indices such as annual effective dose (AED) and excess lifetime cancer risk (ELCR). The acceptable limit for the ELCR readings was surpassed. As a result, the investigated monzogranite samples are not suitable for use in infrastructure materials.

Natural Radionuclide Concentrations by γ-Ray Spectrometry in Granitic Rocks of the Sol Hamed Area, Southeastern Desert of Egypt, and Their Radiological Implications

The occurrence of heavy radioactive minerals in construction supplies such as granite has drawn attention to the extraction of heavy radioactive minerals. Granitic rocks were identified to serve an essential economic role in the study area’s surrounding locations. As a result, the current study attempted to detect the activity concentrations of 238U, 232Th, and 40K in the granitic rock samples tested and estimate the radiological dangers associated with these rocks. The obtained data on activity concentrations for 238U (610 ± 1730 Bq kg−1), 232Th (110 ± 69 Bq kg−1) and 40K (1157 ± 467 Bq kg−1) in the granitic samples (GR) were higher than the recommended worldwide average. The radioactive levels found in the samples were caused by radioactive materials being altered and trapped inside granite faults. The exposure to gamma radiation from the granitic rocks were assessed via various radiological parameters, such as radium equivalent content (856 Bq kg−1), absorbed dose rate (Dair) in the air (396 nGy/h), and annual effective dose for either outdoor (0.48 mSv y−1) or indoor (1.9 mSv y−1). Statistical analysis was performed to detect the correlations between radioactive concentrations and radiological parameters. The radioactive effects contributed by the uranium minerals were associated with the granitic rocks. Based on the analysis, the radioactive levels in the examined granitic surpassed the acceptable limits; therefore, they are not safe to use in building and infrastructure applications and may cause adverse health effects.

Radiological monitoring in some coastal regions of the Saudi Arabian Gulf close to the Iranian Bushehr nuclear plant

We studied the concentrations of terrestrial and anthropogenic radionuclides in seawater and shore sediment/sand of three selected regions; Khafji, Safaniyah and Menifah along the Saudi Arabian Gulf coast. The mean activity concentrations of the ²²⁸Ra, ²²⁶Ra, and ⁴⁰K in the analyzed sand samples are 5.9, 3.5 and 113.5 Bq/kg, and the respective values in seawater samples are 1.6, 0.8 and 10.4 Bq/L. All data show lower than the corresponding UNSCEAR (2000) reported world average values of 35, 30 and 400 Bq/kg for soil matrix. A few relevant radiological hazards were quantified by the estimation of the absorbed dose rate, and the results are compared with the prescribed limits set by international regulatory bodies. Measured data indicates that the studied coastal regions pose a negligible radiological hazards to the public, and show an insignificant radioactive loading to this coastal region by the Busher nuclear power plant.

An extended assessment of natural radioactivity in the sediments of the mid-region of the Egyptian Red Sea coast

In this study, nearly 84 marine sediment samples were collected from twelve points in four cities (Quseir, Safaga, Hurghada, and Ras Gharib) along the Egyptian Red Sea sectors. The collected samples were extensively examined to estimate the natural radioactivity level. The obtained results were compared to the reported ranges from other locations in different countries. Hazardous radiation parameters such as radium equivalent, annual dose, and external hazards were estimated and compared to United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended levels. The values were recorded in the first natural radioactivity database of coastal sediments from Egyptian Red Sea cities. The dose rate for certain organs was evaluated. The results showed that Red Sea beach sediments are safe in terms of natural radioactivity. It can be concluded that they do not pose a risk to tourists going to the beaches for recreation or to sailors and fishers involved in economic activities along the Egyptian Red Sea coast.

Statistical analysis and susceptibility properties of heavy/light metal pollution in surface seawater of Izmir Bay

The inner bay of Izmir is known as the part between Sasalı/Karşıyaka coastline and Güzelbahçe/Bayraklı. It is used extensively in transportation. There is constant ferry transportation and an international port operates in this region. There are also a few streams that flow into the inner bay. Therefore, the inner bay can be exposed to continuous chemical pollutants, and these wastes can intensively be observed in its natural structure. In this study, the magnetic susceptibility values and elemental analyses of the samples taken from the surface sea waters of the inner bay coastline were performed. Silicon, strontium, and manganese elements were mostly observed in the samples. The greatest susceptibility values were seen in the Bostanlı ferry port and Göztepe ferry. In addition, the standard deviation and correlation coefficient values of the samples were calculated and discussed. According to the correlation coefficient value, it can be said that there is a positive correlation between metal ion ratios and magnetic susceptibility.

Spatial distribution, radiological risk assessment and positive matrix factorization of gamma-emitting radionuclides in the sediment of the Boka Kotorska Bay

Surface sediment from the Boka Kotorska Bay (Adriatic Sea) was analyzed for the content of technogenic cesium (¹³⁷Cs) and naturally occurring (⁴⁰K, ²²⁶Ra, ²³²Th, ²³⁸U) radionuclides. The activity concentrations of the radionuclides have been correlated with the major elements (Si, Al, Ca, Fe, K, Mg, Ti, P, Mn) content of sediment samples. The spatial interpolation identified primordial radioactivity more pronounced in the inland of the bay. Correlation and hierarchical cluster analyses clearly distinguished ²²⁶Ra, ²³²Th, and ²³⁸U from ¹³⁷Cs. In addition, a strong association between primordial radionuclides and most major elements was found. Positive matrix factorization apportioned technogenic and natural radionuclides sources, while Si and Ca were separated from other elements. Radiological hazard parameters (Ra_eq, D, AEDE, H_in, H_ex, AGDE, AUI) that include the doses and indices, and the excess lifetime cancer risk indicate that the risk in the studied area due to gamma radiation is within the acceptable level.

Determination of uranium and thorium concentrations in sediment samples by using solid state nuclear track detectors

In this study, uranium and thorium concentrations in the sediment samples collected from the Gulf of Izmit in Marmara Sea were determined using neutron radiography method and alpha-autoradiography method. Mean uranium concentrations calculated for the sediment samples collected from the boreholes S2, S3, S5, S8 and KS-2 were found to be 5.99 μg/g (3.58-8.16 μg/g), 4,59 μg/g (2.54-8.22 μg/g), 4.03 μg/g (2.13-6.9 μg/g), 3.71 μg/g (2.36-4.48 μg/g) and 2.81 μg/g (2.16-4.06 μg/g), respectively. The highest uranium concentration in all borehole samples was obtained from borehole S3 with a value of 8.22 μg/g at a depth of 77.00 m, followed by borehole S2 with a value of 8.16 μg/g at 76.95 m depth. These results also confirms the possibility of thermal sources at boreholes S2 and S3. The mean thorium concentrations in boreholes S3 and S8 were found to be 15.26 μg/g (9.60-17.49 μg/g) and 15.76 μg/g (13.89-17.37 μg/g), respectively. The highest thorium concentration in obtained samples from all boreholes was obtained in borehole S3 with a value of 17.49 μg/g at a depth of 77.00 m.

Models for predicting the transport of radionuclides in the Red Sea

Two radionuclide transport models for the Red Sea are described: a Lagrangian model to deal with emergency situations and a Eulerian model better suited to longer term simulations, as for instance required in case of chronic radionuclide releases. Baroclinic circulation is obtained for both transport models from HYCOM ocean model. The Lagrangian model also includes tides, which are obtained from a standard tidal model customized to the Red Sea, and currents induced by local winds. Both models describe exchanges of radionuclides between water and sediments. A number of simulations were carried out to illustrate capabilities of the models. Additionally, flushing times over the Red Sea were evaluated with the Eulerian model, as another example of model use.

Transformation of the radionuclides composition of river sediments in the area of the exploited Lomonosov diamond deposit (NW Russia)

The article is devoted to the study of the activity of the natural radionuclides ⁴⁰K, ²³²Th, ²²⁶Ra and technogenic ¹³⁷Cs radionuclide in the river sediments of watercourses around the Lomonosov diamond deposit (northwestern Russia). This is the only large diamond mining and beneficiation complex in Europe. Samples of river sediments and surface waters were taken from the Zolotitsa River and its tributaries in the area of the diamond deposit. Samples of rocks were taken from quarries. Samples of kimberlites used for enrichment and rocks entering the dumps were selected. Measurements of the activity of radionuclides in bottom sediments and rocks were conducted using the low-background semiconductor gamma spectrometry method. For measurements, a detector from high-purity germanium was used. The study of uranium isotopes in bottom sediments and waters was conducted using the alpha spectrometry method. The average activity of ¹³⁷Cs, ²²⁶Ra, ²³²Th and ⁴⁰K were 5.4, 9.0, 11.2, 318.8 Bq·kg^-1 respectively. The impact of the development of the field on the change in the radioecological state of the bottom sediments was evaluated. Several patterns of radionuclide accumulation have been found depending on the physicochemical parameters of river sediments. These patterns are due to the technogenic influence of the mining and beneficiation complex. The performed studies present the first evaluation of the impact of diamond mining on natural radionuclides' distribution and accumulation in the river sediments within the adjacent territories.

Environmental assessment of radionuclides levels and some heavy metals pollution along Gulf of Suez, Egypt

This work aims to evaluate radioactivity levels of 238U (²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K and the associated radiological hazard indices, as well as to assess the current status and concentrations of heavy metals along the coastline of the Gulf of Suez, in order to identify potential sources of contamination and to construct radioactivity baseline for this area. Measurements of the activity concentrations of ²³⁸U(²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K in Bq kg^-1 of the collected samples were carried out using high-purity germanium (HPGe) detector. Heavy metals in seawater, shore sediment, and algae samples were determined using ICP-OES. The average activity concentrations of ²³⁸U(²²⁶Ra), ²³²Th(²²⁸Ra), and ⁴⁰K were found to be 13.79 ± 0.75, 14.57 ± 1.15, and 128.9 ± 4.15 Bq kg^-1, respectively. The radiological hazard indices of absorbed dose rate in nGy h^-1 (D), annual effective dose rate in mSv y^-1, AED, radium equivalent activity in Bq (Ra_eq), external and internal hazard indices (H_ex, H_in), and cancer risk factor were calculated and compared with the worldwide averages. The distribution patterns of annual effective dose (AED) at the Suez Gulf showed that the south east of the Gulf is characterized by higher AED. Water quality parameters (water temperature, salinity, pH, DO, and Eh) reveal that Suez Gulf was undoubtedly affected by the rate of the human activities. Heavy metal concentrations in shore sediments showed some variation within the study area and followed the following order: Fe > Mn > Zn > Al > B > Co > Ni > Pb > V > Cr > Mo > Cu > Cd. Furthermore, heavy metal concentrations indicated that northern part of the Gulf contains the highest levels of these metals compared to the southern one.

Allometric relationship in the bioaccumulation of radionuclides (134Cs &241Am) and delineation of contamination pathways (food and seawater) in bloody cockle Anadara senilis using radiotracer techniques

The uptake and depuration kinetics of ¹³⁴Cs and ²⁴¹Am were investigated in the bloody cockle Anadara senilis exposed via seawater and food in controlled conditions, using animals of different weight groups in order to assess how their bioaccumulation is affected by allometry and, hence, the individual's age. This study is one of the few experiments investigating bioaccumulation capacities of radionuclides in a West-African bivalve. Results showed that allometric relationships were mainly dependent on the exposure pathway considered. Significant relationships with body weight of bloody cockles were found during the uptake from dissolved phase for both radionuclides; they followed inverse power functions: smaller cockles concentrated both radionuclides more than larger ones. In contrast, radionuclide absorption and assimilation efficiencies from water and food, respectively, did not show any significant relationship with weight: only slight variation was observed between small and large organisms for the retention of ²⁴¹Am accumulated from food. A bioaccumulation model was used to assess the contribution of each pathway of exposure (food vs. water) in organisms grouped in small and large individuals. We found that, regardless of the size, ¹³⁴Cs was mainly bioaccumulated through the dietary pathway. In the case of ²⁴¹Am, the relative contribution of each pathway is weight-dependent: major contribution of dissolved pathway in smaller organisms and the major dietary contribution in larger organisms.

Assessment of gamma radiation and associated radiation hazards in coastal sediments of south east coast of Tamilnadu, India with statistical approach

Gamma spectroscopy was performed to determine the concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in sediment samples collected from Periyakalapet to Parangaipettai, East coast of Tamilnadu. The activity concentrations were determined by direct counting using a hyper pure germanium (HPGe) detector inter phased with a multi channel analyzer (MCA). The average activity concentrations of the corresponding nuclides were 30.81 Bq kg^-1 for ²²⁶Ra, 85.67 Bq kg^-1 for ²³²Th and 425.72 Bq kg^-1 for ⁴⁰K. The average activity concentration of ²³²Th and ⁴⁰K are slightly higher and ²²⁶Ra is lower than world average values. The radiation hazard indices namely Radium Equivalent Activity (Ra_eq) Absorbed Gamma Dose Rate (D_R), Annual Effective Dose Rate (H_R), Representative Level Index (RLI), Annual Gonadal Dose Equivalent (AGDE), Internal Hazard Index (H_in) and External Hazard index (H_ex) are calculated and compared with the previously reported data. The extracted values are comparable to the recommended values and they all fall within the safety limits. Hence harmful radiation effects are not posed to the public and tourists going to the beaches for recreation or to the fishermen involved in their activities in the area as a result of the natural radioactivity of sediments. Multivariate Statistical analyses were carried out between the parameters obtained from the radioactivity to know the existing relations and to study the spatial distribution of radionuclides.

Geochemical signature of NORM waste in Brazilian oil and gas industry

The Brazilian Nuclear Energy Agency (CNEN) is responsible for any radioactive waste storage and disposal in the country. The storage of radioactive waste is carried out in the facilities under CNEN regulation and its disposal is operated, managed and controlled by the CNEN. Oil NORM (Naturally Occurring Radioactive Materials) in this article refers to waste coming from oil exploitation. Oil NORM has called much attention during the last decades, mostly because it is not possible to determine its primary source due to the actual absence of a regulatory control mechanism. There is no efficient regulatory tool which allows determining the origin of such NORM wastes even among those facilities under regulatory control. This fact may encourage non-authorized radioactive material transportation, smuggling and terrorism. The aim of this project is to provide a geochemical signature for oil NORM waste using its naturally occurring isotopic composition to identify its origin. The here proposed method is the modeling of radioisotopes normally present in oil pipe contamination such as ²²⁸Ac, ²¹⁴Bi and ²¹⁴Pb analyzed by gamma spectrometry. The specific activities of elements from different decay series are plotted in a scatter diagram. This method was successfully tested with gamma spectrometry analyses of oil sludge NORM samples from four different sources obtained from Petrobras reports for the Campos Basin/Brazil.

Radioactivity levels and health risks due to radionuclides in the soil and sediment of mid-Black Sea: Kızılırmak Deltas-Turkey

Artificial and natural radionuclide pollutants of the marine environment have been recognized as a serious environmental concern. In this study, the activity concentrations of terrestrial and anthropogenic radionuclides in the soil and sediment samples collected from Bafra Kızılırmak Delta were measured by using gamma spectrometry with an NaI (Tl) detector. The average specific of activity concentrations for 238U, 232Th and 40K were found to be 28.59, 17.48 and 150.59 Bq kg−1, respectively. On the other hand, 137Cs was also measured in some samples. 137Cs (t1/2=30.17 years) is a man-made radionuclide released from nuclear fission and activation processes. It has a mean value of 5.32 Bq kg−1. From the activity concentrations, the radium equivalent activity (Raeq), the absorbed gamma dose rates (DR), the annual gonadal dose equivalent, annual effective dose equivalent, internal (Hin), external hazard index (Hex) and excess lifetime cancer risk were estimated. This study can be used as a base line for future investigations and the data obtained in this study may be useful for natural radioactivity mapping and also be used as a reference data for monitoring possible radioactivity pollutions in future.

Data on natural radioactivity and associated radiation hazards in coastal sediment of Chennai Coast, Tamilnadu, India using gamma ray spectrometry

This article contains data on the activity concentration of natural radionuclides in coastal sediment samples collected from Pulicat Lake to Vadanemmeli, East coast of Tamil Nadu using NaI(Tl) detector based γ-spectrometry. As marine sediments are found to be the repository of many radioactive pollutants, studied the objectives like (i) determine natural radionuclide activity concentrations in sediment samples in and around Chennai coast (ii) evaluate the radiological hazards due to natural radioactivity associated with coastal sediments and (iii) identify areas which may be radiological hazardous for the public along the study area. The average activity concentration of ²³⁸U, ²³²Th and ⁴⁰K in the present study is lower than world median value. The radiological hazard indices such as External hazard index (H_ex) and Gamma representative level index, (Iγ) were evaluated to assess radiation hazard associated with the sediments. The simulated results show sediments do not pose any significant radiation hazards due to concentration of natural radionuclides.

Impacts of warming on phytoplankton abundance and phenology in a typical tropical marine ecosystem

In the tropics, thermal stratification (during warm conditions) may contribute to a shallowing of the mixed layer above the nutricline and a reduction in the transfer of nutrients to the surface lit-layer, ultimately limiting phytoplankton growth. Using remotely sensed observations and modelled datasets, we study such linkages in the northern Red Sea (NRS) - a typical tropical marine ecosystem. We assess the interannual variability (1998-2015) of both phytoplankton biomass and phenological indices (timing of bloom initiation, duration and termination) in relation to regional warming. We demonstrate that warmer conditions in the NRS are associated with substantially weaker winter phytoplankton blooms, which initiate later, terminate earlier and are shorter in their overall duration (~ 4 weeks). These alterations are directly linked with the strength of atmospheric forcing (air-sea heat fluxes) and vertical stratification (mixed layer depth [MLD]). The interannual variability of sea surface temperature (SST) is found to be a good indicator of phytoplankton abundance, but appears to be less important for predicting bloom timing. These findings suggest that future climate warming scenarios may have a two-fold impact on phytoplankton growth in tropical marine ecosystems: 1) a reduction in phytoplankton abundance and 2) alterations in the timing of seasonal phytoplankton blooms.

Radioecological assessment and radiometric dating of sediment cores from dynamic sedimentary systems of Pra and Volta estuaries (Ghana) along the Equatorial Atlantic

The Volta and Pra estuaries (Ghana, West Africa) are dynamical sedimentary systems whose natural equilibrium is being affected by anthropogenic activities. This paper reports depth-distributions of ²¹⁰Pb, ²²⁶Ra, ²³⁴Th, ⁴⁰K, ²²⁸Ra and ¹³⁷Cs for two sediment cores from these estuaries. Bulk densities were not steady-state and well correlated with ⁴⁰K (p < 0.00005). Unsupported ²¹⁰Pb profiles were incomplete, non-monotonic and showed large fluctuations. The assumptions involved in the common ²¹⁰Pb-based dating models were not meet in these dynamical scenarios, and the use of ¹³⁷Cs as a time-marker is difficult in Equatorial and South-Hemisphere countries due to its low fallout rates. Chronologies have been solved with the new ²¹⁰Pb-based TERESA model, which operates with varying but statistically correlated fluxes and sediment accumulation rates (SAR). The core from the Volta reflects the conditions prevailing after the construction of the Akosombo Dam, with a mean SAR of 1.05 ± 0.03 g cm^-2·y^-1, while a higher value of 2.73 ± 0.06 g cm^-2·y^-1 was found in the Pra, affected by intense gold mining activities along its course. Radiological and radioecological assessments have been conducted by applying the UNSCEAR protocols and the ERICA model, respectively. The measured radionuclide concentrations do not pose any significant risk for the environment and human health.

Distribution and environmental impacts of heavy metals and radioactivity in sediment and seawater samples of the Marmara Sea

In this study, the natural and anthropogenic radioactivity levels in the sediment samples collected from the Marmara Sea in Turkey were determined. The average activity concentrations (range) of (226)Ra, (238)U, (232)Th, (40)K and (137)Cs were found to be 23.8 (13.8-34.2) Bq kg(-1), 18.8 (6.4-25.9) Bq kg(-1), 23.02 (6.3-31.1) Bq kg(-1), 558.6 (378.8-693.6) Bq kg(-1) and 9.14 (4.8-16.3) Bq kg(-1), respectively. Our results showed that the average activity concentrations of (226)Ra, (238)U and (232)Th in the sediment samples were within the acceptable limits; whereas the average activity concentration of (40)K in the sediment samples was higher than the worldwide average concentration. The average radium equivalent activity, the average absorbed dose rate and the average external hazard index were calculated as 100.01 Bq kg(-1), 48.32 nGy h(-1) and 0.27, respectively. The average gross alpha and beta activity in the seawater samples were found to be 0.042 Bq L(-1) and 13.402 Bq L(-1), respectively. The gross alpha and beta activity concentrations increased with water depth in the same stations. The average heavy metal concentrations (range) in the sediment samples were 114.6 (21.6-201.7) μg g(-1) for Cr, 568.2 (190.8-1625.1) μg g(-1) for Mn, 39.3 (4.9-83.4) μg g(-1) for Cu, 85.5 (11.0-171.8) μg g(-1) for Zn, 32.9 (9.1-73.1) μg g(-1) for Pb and 49.1 (6.8-103.0) μg g(-1) for Ni. S5 station was heavily polluted by Cr, Cu, Ni and Pb. The results showed that heavy metal enrichment in sediments of the Marmara Sea was widespread.

Assessment of natural radioactivity and (137)Cs in some coastal areas of the Saudi Arabian gulf

The levels of natural radioactivity have been investigated in some Saudi Arabian Gulf coastal areas. Sampling sites were chosen according to the presence of nearby non-nuclear industrial activities such as, the two main water desalination plants in Al Khobar and Al Jubail, and Maaden phosphate complex in Ras Al Khair, to ensure that effluents discharges into the Arabian Gulf didn't enhance radioactivity in seawater and shore sediments. Seawater samples were analyzed for radium isotopes (Ra-226 & Ra-228) and measured by gamma spectrometry using high purity germanium detector, after radiochemical separation of the isotopes by co-precipitation with MnO2. Shore sediment samples were analyzed for (226)Ra, (228)Ra ((232)Th), (4)°K and (137)Cs using gamma sepectrometry. A small variation was observed in the activity concentrations of the investigated radioisotopes, and the activity levels were comparable to those reported in literature. Quality assurance and methods validation were established through the efficiency calibration of the detectors, the estimation of uncertainties, the use of blanks, the analysis of standard reference materials and the intercomparison and proficiency tests. Radiological hazards were assessed, and the annual effective dose had an average value of 0.02 mSv. On the basis of the current results, we may conclude that any radiological hazards to the public visiting these shores are not expected.

Evaluation of radiological risks due to natural radioactivity around Lynas Advanced Material Plant environment, Kuantan, Pahang, Malaysia

Understanding the public awareness concerning the Lynas Advanced Material Plant (LAMP), an Australian rare earths processing plant located in Malaysia, a radiological study in soil and water samples collected at random surrounding the LAMP environment was undertaken using HPGe gamma-ray spectrometry. The mean soil activities for (226)Ra, (232)Th, and (40)K were found to be 6.56 ± 0.20, 10.62 ± 0.42, and 41.02 ± 0.67 Bq/kg, respectively, while for water samples were 0.33 ± 0.05, 0.18 ± 0.04, and 4.72 ± 0.29 Bq/l, respectively. The studied areas show typical local level of radioactivity from natural background radiation. The mean gamma absorbed dose rate in soils at 1 m above the ground was found to be 11.16 nGy/h. Assuming a 20 % outdoor occupancy factor, the corresponding annual effective dose showed a mean value of 0.014 mSv year(-1), significantly lower than the worldwide average value of 0.07 mSv year(-1) for the annual outdoor effective dose as reported by UNSCEAR (2000). Some other representative radiation indices such as activity utilization index (AUI), H ex, H in, excess lifetime cancer risk (ELCR), and annual gonadal dose equivalent (AGDE) were derived and also compared with the world average values. Statistical analysis performed on the obtained data showed a strong positive correlation between the radiological variables and (226)Ra and (232)Th.

Activity levels of some radionuclides in Mariout and Brullus lakes, Egypt

Mariout and Brullus are two of the highly fish-productive lakes in the northern coast of Egypt along the Mediterranean Sea. They are widely used to drain industrial wastes, sewage and agriculture drainage. The activities of (238)U, (232)Th, (40)K and (137)Cs were measured in the uppermost part of the surface sediments of the two lakes, using gamma-ray spectrophotometry. Brullus Lake recorded significantly higher (238)U and (232)Th and lower (40)K (17.22±2.49, 10.03±0.56 and 299.70±17.78 Bq kg(-1)) than Mariout Lake (12.65±1.53, 7.24±0.76 and 518.75±46.24 Bq kg(-1), respectively). Cesium-137 shows nearly equal activities in both lakes (3.33±0.46 and 3.68±0.70 Bq kg(-1), respectively). Activity distributions of (238)U and (232)Th in the sediments of Mariout Lake show a significant increase to the west, southwest and northeast, (40)K activity increased westwards, while the (137)Cs level was increased to the east and northeast, indicating agriculture drainage, industrial wastes and lands reclamation around the lake. At Brullus Lake, the activity trends of (238)U, (232)Th, (40)K and(137)Cs were increasing to the west and south towards the agriculture and industrial waste-water-feeding drains.

Some radioactive-elements in the coastal sediments of the Mediterranean Sea

The radioactivities of (234+235)U, (232)Th, (40)K and (137)Cs were measured in the coastal sediments of the western Mediterranean Sea between Alexandria and Salloum, Egypt. The recorded activities of the natural radionuclides were within the range of those measured worldwide. The highest activities of (234+235)U and (40)K (166.5 ± 7.7; 365.8 ± 2.3 Bq kg(-1) dry weight) were measured at Sidi Krir station while El-Max station recorded the highest (232)Th activity (22.7 ± 0.6 Bq kg(-1) dry weight) indicating that these radionuclides may accumulate in ionic and particulate forms from the drainage systems of the fertiliser, petrochemical and paper industries and from agricultural drains and also as the drifted particulates from longshore currents and accretion processes. The lowest (234+235)U activities were recorded at Salloum and the lowest (232)Th and (40)K activities were recorded at El-Hammam, indicating that the accretion process is more active in the eastern Mediterranean. Salloum recorded the highest activity levels for (137)Cs (7.9 ± 0.4 Bq kg(-1) dry weight) showing significant increases of the artificial (137)Cs westwards that may be indicative of to the anthropogenic sources from the northern Mediterranean.

Distribution of naturally occurring radioactivity and ¹³⁷Cs in the marine sediment of Farasan Island, southern Red Sea, Saudi Arabia

The present work is a part of a project dedicated to measure the marine radioactivity near the Saudi Arabian coasts of the Red Sea and Arabian Gulf for establishing a marine radioactivity database, which includes necessary information on the background levels of both naturally occurring and man-made radionuclides in the marine environment. Farasan Islands is a group of 84 islands (archipelago), under the administration of the Kingdom of Saudi Arabia, in the Red Sea with its main island of Farasan, which is 50 km off the coast of Jazan City. The levels of natural radioactivity of (238)U, (235)U, (226)Ra, (232)Th and (40)K and man-made radionuclides such as (137)Cs in the grab sediment and water samples around Farasan Island have been measured using gamma-ray spectroscopy. The average activity concentrations of (238)U, (235)U, (226)Ra, (232)Th, (40)K and (137)Cs in the sediment samples were found to be 35.46, 1.75, 3.31, 0.92, 34.34 and 0.14 Bq kg(-1), respectively.

Distribution of natural radionuclide concentrations in sediment samples in Didim and Izmir Bay (Aegean Sea-Turkey)

Natural and artificial radionuclide pollutants of the marine environment have been recognized as a serious environmental concern. The natural radioactivity activity concentrations of (226)Ra, (238)U, (232)Th and (40)K were measured by gamma spectrometry in sediment samples collected from two different areas in Aegean Sea Turkish Coast. There is no information about radioactivity level in the study areas sediments so far. The results showed that the concentrations of activity in the sediment samples are 9 ± 0.6 Bq kg(-1)-12 ± 0.7 Bq kg(-1), 7 ± 0.4 Bq kg(-1)-16 ± 1.0 Bq kg(-1), 6 ± 0.3 Bq kg(-1)-16 ± 1.0 Bq kg(-1) and 250 ± 13 Bq kg(-1)-665 ± 33 Bq kg(-1) for (226)Ra, (238)U, (232)Th and (40)K, respectively. In general, the distribution of activity concentrations along the coast of the Aegean Sea area were in the same order as international levels.