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Aeolian concentration of iron-titanium oxides (black sand) is a common phenomenon on coasts around the world but associated aeolian detrital gold is relatively rare. In contrast, Holocene and active dunes at Waipapa beach on the coast of the southern South Island of New Zealand host aeolian black sand layers with locally abundant finely particulate (<200 µm) gold and platinum, some of which have been mined historically. Aeolian concentration of black sand, gold and platinum is driven by strong prevailing westerly winds (gusts >100 km/h) on annual or decadal time scales. Holocene fluvial recycling of aeolian sands has been important in upgrading the black sand, gold, and platinum contents. Surf concentration of black sand on the beach is minor and merely feeds the aeolian system, and this differs from other beach gold deposits around the world, which are surf-dominated. Most of the Waipapa beach gold (>90%) has flaky morphology with abundant superficial transport-related deformation reflective of fluvial transport, probably down the nearby Mataura River (∼200 km transport) between Miocene and Holocene. Minor distinctive wind-sculpted toroidal gold, and the platinum, arrived from the west (∼300 km transport) via the Waiau River and Foveaux Strait. [ABSTRACT FROM AUTHOR]

Black sand is beach deposits that come from the headwaters of the Nile, which are rich in heavy minerals. The major economic mineral is ilmenite. It represents around 60 – 70 % of economic minerals quantity. To increase the adding value of the national resources carried out a serial of experiments to study smelting process for producing high Titania slag and cast iron. The main factors which affected on the process are the amounts of carbon, time of experiments and amount of flux agent. The effect of many factors such as time which were (20, 25 & 30 min), carbon content which were (15 %, 20 % & 30 %) and using a flux agent which were (1 %, 2 % & 3 %) were studied, as well as the properties of some mechanical samples such as hardness and drop number. As a result of these studies, we obtained some important results on the importance of the effect of time on iron yield, and that the content of the preferred flux agent gives good results on iron yield. The obtained iron yield is 80.5 % and the assay of titanium dioxide in Titania slag is 77.6 %.

Abstract This study assessed the radioactivity levels and associated risks in the black sand-separated products obtained from the black sand separation plant in Delta, Egypt. A total of sixteen samples were taken from hot spots during and after the separation process. These include water samples and other samples that represent monazite, rutile, zircon, granite, ilmenite, and silica products. The hot spots included the area where the ore was stored. The activity concentrations of $$^{232}Th$$ 232 T h , $$^{226}Ra$$ 226 R a , and $$^{40}K$$ 40 K were determined in these samples using a p-type HPGe detector. Based on gamma spectrometric analysis, samples of rutile, zircon, and monazite had the highest amounts of radioactivity because they contained the highest NORM’s activity concentrations. In addition, it indicated that the radiological hazard indices of the collected samples were higher than the average world limits for sand texture. These findings suggest that the black sand separation process reveals potential risks to human health and the environment, and therefore, appropriate measures need to be taken to mitigate these risks, especially for the safety of the workers on-site. Reducing the risk associated with those sites should be controlled by implementing the recommendations declared for the series of International Basic Safety Standards of the International Atomic Energy Agency (GSR) Part 3, as affirmed in Document No. 103 of 2007 by the International Commission on Radiological Protection (ICRP) as will be presented in the paper body.

Black sand is beach deposits that come from the headwaters of the Nile, which are rich in heavy minerals. The major economic mineral is ilmenite. It represents around 60 – 70 % of economic minerals quantity. To increase the adding value of the national resources, a series of experiments to study the smelting process for producing high Titania slag and cast iron. The effect of many factors such as time (20, 25 & 30 min), carbon content (15 %, 20 % & 30 %) and using a flux (1 %, 2 % & 3 %) were studied. The results revealed that time of the experiment has the most significant affecting on the iron yield among other factors. The maximum obtained iron yield was about 80.5 % and the assay of titanium dioxide in Titania slag was about 77.6 % for 30% carbon at 30 minutes. [ABSTRACT FROM AUTHOR]

The objective of the present work is to demonstrate the ability of the laser-induced breakdown spectroscopy (LIBS) technique for quick detection and quantification of rare earth elements (REEs) and radioactive elements in the black sands at selected locations of the Konkan coast (Goa) and Malabar coast (Kerala) in India. Several REEs such as Ce, Nd, Sm, Dy, Ho, Tm, Gd, and Th have been detected in the LIBS spectra. Calibration-free LIBS method has been used to calculate the concentration of REEs and radioactive elements. The experimental result shows that the concentration of REEs such as Sm, Dy, Ho, and radioactive element Th is maximum in the sands collected from Thiruvananthapuram (Kerala) beach and minimum in the Baga (Goa) beach. The reliability of the results (qualitative and quantitative) obtained by the LIBS method has been examined by other spectroscopic techniques like XRF and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and found to be in close agreement. The multivariate approach (principal component analysis) has been applied to discern the samples based on their spectral data. Photoacoustic spectroscopy and XRD technique are used to detect compounds/minerals of REEs. The relative hardness, degree of crystallinity (DOC), and crystallite size have been calculated. [ABSTRACT FROM AUTHOR]

This study investigates the naturally occurring radionuclides in Egyptian black sands collected from the Mediterranean Sea Coast, an area rich in sediments from the White Nile, Blue Nile, and Atbara rivers. The black sands mainly comprise two groups of minerals: the gangue group, consisting of quartz, feldspar, amphiboles, pyroxenes, epidote, and micas, and the economic minerals group, which includes magnetite, garnet, zircon, monazite, and uncommon commercial minerals like thorite. A gamma spectrometry with a NaI (Tl) detector was employed to analyze black sand samples for the presence of radionuclides. Additionally, radium equivalent activities (Raeq), absorbed dose rate, annual effective dose, gamma radiation hazard index (Iγ), external hazard index, internal hazard index (Hin), and lifetime cancer risk (ELCR) were calculated based on the measured activity concentrations of 226Ra, 232Th, and 40K. This comprehensive analysis contributes valuable insights into the radiological properties and potential hazards associated with Egyptian black sands. Due to the significant radioactive risk associated with these black sand samples, specifically in the Mediterranean Sea Alexandria coastal area, must be considered while using them as building materials. Measured values include Ra-226 (56 Bq/kg), Th-232 (77 Bq/kg), and K-40 (55 Bq/kg). [ABSTRACT FROM AUTHOR]

This study assessed the radioactivity levels and associated risks in the black sand-separated products obtained from the black sand separation plant in Delta, Egypt. A total of sixteen samples were taken from hot spots during and after the separation process. These include water samples and other samples that represent monazite, rutile, zircon, granite, ilmenite, and silica products. The hot spots included the area where the ore was stored. The activity concentrations of 232 T h , 226 R a , and 40 K were determined in these samples using a p-type HPGe detector. Based on gamma spectrometric analysis, samples of rutile, zircon, and monazite had the highest amounts of radioactivity because they contained the highest NORM’s activity concentrations. In addition, it indicated that the radiological hazard indices of the collected samples were higher than the average world limits for sand texture. These findings suggest that the black sand separation process reveals potential risks to human health and the environment, and therefore, appropriate measures need to be taken to mitigate these risks, especially for the safety of the workers on-site. Reducing the risk associated with those sites should be controlled by implementing the recommendations declared for the series of International Basic Safety Standards of the International Atomic Energy Agency (GSR) Part 3, as affirmed in Document No. 103 of 2007 by the International Commission on Radiological Protection (ICRP) as will be presented in the paper body. [ABSTRACT FROM AUTHOR]

Abstract This work is mainly concerned with the effect of anthropogenic activities and natural radioactivity due to the presence of highly radioactive black sand spots, factory construction, and shipping, in addition to other activities like agriculture on human beings. Forty samples were collected along Baltim–El Burullus coastal plain to detect the effect of these problems and determine the suggested solutions. The black sand of the Baltim–El Burullus coastal plain exhibits a considerable amount of economically heavy minerals, their ratio relative to the bulk composition in the investigated samples ranges from 3.18 to 10.5% with an average of 5.45%. The most important of them are magnetite, ilmenite, rutile, leucoxene, garnet, zircon and monazite. The existence of some radioactive-bearing accessory mineral deposits like zircon and monazite led to measuring the naturally occurring radionuclides 226Ra, 232Th and 40K to evaluate the excess lifetime cancer risk (ELCR). The results showed that these concentrations are 19.1 ± 9.73, 14.7 ± 9.53 and 211 ± 71.34 Bq kg−1 were lower than the corresponding reported worldwide average of 35, 45, and 412 Bq kg−1 for each radionuclide (226Ra, 232Th, and 40 K). The gamma hazard indices such as absorbed dose rate (Dair), the annual effective dose (AED), and excess lifetime cancer risk (ELCR) factor were computed in the investigated sediments and all the results were found (Dair = 26.4 nGy h−1, AED = 0.03 mSv year−1, ELCR = 0.0001) to be lower than the values suggested by the United Nations Scientific Committee on the effect of Atomic Research (59 nGy h−1, 0.07 mSv year−1 and 0.0029 for Dair, AED and ELCR, respectively). The study suggests that the black sand is safe to use in various infrastructure applications at Baltim–El Burullus coastal plain. The levels of radioactivity are not high enough to pose a risk to human health.

This work is mainly concerned with the effect of anthropogenic activities and natural radioactivity due to the presence of highly radioactive black sand spots, factory construction, and shipping, in addition to other activities like agriculture on human beings. Forty samples were collected along Baltim–El Burullus coastal plain to detect the effect of these problems and determine the suggested solutions. The black sand of the Baltim–El Burullus coastal plain exhibits a considerable amount of economically heavy minerals, their ratio relative to the bulk composition in the investigated samples ranges from 3.18 to 10.5% with an average of 5.45%. The most important of them are magnetite, ilmenite, rutile, leucoxene, garnet, zircon and monazite. The existence of some radioactive-bearing accessory mineral deposits like zircon and monazite led to measuring the naturally occurring radionuclides 226Ra, 232Th and 40K to evaluate the excess lifetime cancer risk (ELCR). The results showed that these concentrations are 19.1 ± 9.73, 14.7 ± 9.53 and 211 ± 71.34 Bq kg−1 were lower than the corresponding reported worldwide average of 35, 45, and 412 Bq kg−1 for each radionuclide (226Ra, 232Th, and 40 K). The gamma hazard indices such as absorbed dose rate (Dair), the annual effective dose (AED), and excess lifetime cancer risk (ELCR) factor were computed in the investigated sediments and all the results were found (Dair = 26.4 nGy h−1, AED = 0.03 mSv year−1, ELCR = 0.0001) to be lower than the values suggested by the United Nations Scientific Committee on the effect of Atomic Research (59 nGy h−1, 0.07 mSv year−1 and 0.0029 for Dair, AED and ELCR, respectively). The study suggests that the black sand is safe to use in various infrastructure applications at Baltim–El Burullus coastal plain. The levels of radioactivity are not high enough to pose a risk to human health. [ABSTRACT FROM AUTHOR]

Abstract Methylene blue (MB) is commonly a persistent and perilous pollutant in industrial wastewater effluent. While MB has a massive negative effect on human and ecology safety. The neutralization of such harmful material would save a huge clean water amount. This work proposes the natural and abundant black sand as a catalyst for MB photodegradation. The sand sample was calcined at three temperatures of 300°, 400°, and 600 °C. The properties of samples were analyzed with different micro- as well as spectroscopic techniques. The experimental data revealed the sample's main composition of SiO2, Fe2O3, and Al2O3. XRD and XPS results proved the formation of mixed oxides composites due to calcination, especially at 400 °C. The UV–vis analysis conducted showed that samples can absorb light in the visible range. The photodegradation reached a maximum of 975.3%, 82.7%, and 75.7% for BS400, BS600, and BS300 respectively; by illumination for 2.5 h in the visible range. The observed distinguishable catalytic performance was discussed via the spectroscopic analysis and oxygen availability in the catalyst lattice. When AO, t-BuOH, and BQ are used as scavengers instead of just BQ during the photodegradation of MB dye over BS400 catalyst, the photodegradation rate drops significantly. The degradation % of MB dye diminished to 60%, and 70% by using AO, t-BuOH, and BQ scavengers; respectively. This proved that rather than hydroxyl radicals, superoxide radicals or positive hole production is the main determining step in MB photo-degradation over BS400 catalyst.

Several studies have investigated the process of alteration of ilmenite, especially in black sand. To predict the mechanisms of ilmenite alteration and the role of some minor element oxides in the alteration process, separated non-magnetic altered ilmenite grains were examined using a binocular microscope and a Cameca SX-100 microprobe instrument. Twenty intergrown phases of alteration products were concluded in three postulated scenarios for the following alteration processes, carried out after forming the most stable lowest Leached pseudorutile (LPSR) phase FeTi3O6(OH)3. Most of the alteration phases of pseudorutile (PSR) and LPSR have real Ti/(Ti+Fe) ratios between 0.6 and 0.75. Some misleading calculations of definite analyzed ilmenite alteration spots showed that all the analyzed TiO2 percentage is contained within the chemical formula of the analyzed LPSR phase. In these cases, the false Ti/(Ti+Fe) ratios attain up to 0.9, the false included total number of anions (O, OH) ranges between 7 and 8.5, and the associated molecular water ranged between half and two water molecules (0.5-2 H2O). In these cases, the structure of the remaining LPSR phase may be intergrown with a separated individual triple rutile phase, which appears to have the same X-Ray Diffraction (XRD) pattern as the single PSR phase, or intergrown with a cryptocrystalline TiO2 phase. Some molecular formulas of PSR or Hydroxylian PSR (HPSR) from previous studies were discussed and explained following the proposed approach. [ABSTRACT FROM AUTHOR]

Methylene blue (MB) is commonly a persistent and perilous pollutant in industrial wastewater effluent. While MB has a massive negative effect on human and ecology safety. The neutralization of such harmful material would save a huge clean water amount. This work proposes the natural and abundant black sand as a catalyst for MB photodegradation. The sand sample was calcined at three temperatures of 300°, 400°, and 600 °C. The properties of samples were analyzed with different micro- as well as spectroscopic techniques. The experimental data revealed the sample's main composition of SiO2, Fe2O3, and Al2O3. XRD and XPS results proved the formation of mixed oxides composites due to calcination, especially at 400 °C. The UV–vis analysis conducted showed that samples can absorb light in the visible range. The photodegradation reached a maximum of 975.3%, 82.7%, and 75.7% for BS400, BS600, and BS300 respectively; by illumination for 2.5 h in the visible range. The observed distinguishable catalytic performance was discussed via the spectroscopic analysis and oxygen availability in the catalyst lattice. When AO, t-BuOH, and BQ are used as scavengers instead of just BQ during the photodegradation of MB dye over BS400 catalyst, the photodegradation rate drops significantly. The degradation % of MB dye diminished to 60%, and 70% by using AO, t-BuOH, and BQ scavengers; respectively. This proved that rather than hydroxyl radicals, superoxide radicals or positive hole production is the main determining step in MB photo-degradation over BS400 catalyst. [ABSTRACT FROM AUTHOR]

Black sands represent a good source of economic minerals with various industrial applications. However, their radioactive properties may prevent their use in specific applications. In this study, zircon, ilmenite, magnetite, and rutile are four minerals represent more than 75% of the black sand content, were selected to evaluate their Intrinsic radiological properties. The chemical composition of these minerals was determined along with their density and particle size. Then, the activity concentrations of the naturally occurring radioactive nuclides were experimentally determined and the most important radiological hazard indices were calculated. The results indicated that the upgrading process concentrates the natural radioisotopes in some minerals like the zircon and rutile leaving the magnetite and ilmenite with lower content than permissible limits. Moreover, the risk analysis identified the dangerous conditions and situations and suggest possible solutions to reduce these hazardous situations to a minimum and to keep a safe environment for the workers. [ABSTRACT FROM AUTHOR]

Trace elements such as titanium, zirconium, thorium, and uranium, are found in black sand (BS) after weathering and corrosion. Precious metals are not the only valuable elements in black sand, rare earth elements are also found. The aquatic life in lakes and reservoirs is negatively affected by lithophilic elements such as lithium, uranium, and tin. Accordingly, intensive experiments were conducted on Nile tilapia (Oreochromis niloticus) after exposure to isolated black sand. Blood biomarkers, antioxidant balance, morpho-nuclear erythrocyte’s alterations, and histopathological signs have been investigated after fish exposure for 15 days to a 6.4 g BS/kg diet, 9.6 g BS/kg diet, and 2.4 g BS/kg diet. The blood profile, including platelets and white blood cells, was pronouncedly decreased as a result. Functions of the liver and kidneys were impaired. An increase in serum-antioxidant enzymes such as catalase activities and superoxide dismutase was recorded. Also, exposure to black sand induced cellular and nuclear abnormalities in the erythrocytes. In conclusion, the black sand isolated from the Red sea beach influenced Oreochromis niloticus’s hematology, biochemistry, and antioxidant parameters. Poikilocytosis and RBC nuclear abnormalities were also associated with exposure to black sand. The resulting erosion of rocks and rocks’ access to water forces us to consider the seriousness of climatic change on the aquatic ecosystem.

A novel type of silica namely black sand (BS) with silane coupling agent was chosen as reinforcing filler in butyl rubber (IIR). BS was obtained from the beach area of Rosetta in Egypt. The filler was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and transmission electron microscope (TEM). The XRD analysis showed that BS is composed mainly of Albite (Sodium Aluminium Silicate) up to 64% approximately. Novel nanocomposites were prepared via a two-roll mill by incorporating different concentrations of BS nanoparticles (5,10, 15, 20,30 and 40 phr) in IIR. The effects of filler loading on shape factor, curing characteristics, and mechanical and dynamic properties of IIR vulcanizates were investigated. The modulus of IIR vulcanizates was used to predict the shape factor of BS aggregation in the polymer. The data indicated that cure time decreased with the increase in filler loading, and the change in scorch time is less. It was found that the shape factor is independent of the concentration. With an increase in the filler loading, tensile and elongation of the composites were significantly increased, especially at 30 phr. The bound rubber content increased with increasing BS content up to 30 phr exhibiting the rubber-filler interaction. The reinforcing factor, R (related to the difference in tan δ peak height at the glass transition temperature (Tg) for the filled and unfilled rubbers), also demonstrated that the BS-IIR interaction was stronger than for unfilled rubber. Since 30 phr black sand loaded IIR composite showed superior physical-mechanical properties. In general, the results indicated that the black sand filler was an effective reinforcement material for the butyl rubber. [ABSTRACT FROM AUTHOR]

The Egyptian black sand contains several types of altered ilmenite grains which have various magnetic susceptibility values, ranging from the strongly paramagnetic, such as ilmenite, to the non-magnetic, such as rutile grains. The altered ilmenite grains of relatively higher mass magnetic susceptibility, separated at 0.1, 0.2, 0.25, and 0.35 A using the Frantz isodynamic magnetic separator, were investigated. Both brown and black altered grains were investigated using the binocular microscope and the Cameca SX-100 microprobe. Most analyzed spots of grains are composed mainly of pseudorutile (psr) and leached pseudorutile (lpsr), with the contents of TiO2 and Fe2O3 ranging between 56.76 and 78.09% and 37.98 and 12.16%, respectively. The Ti/(Ti+Fe) ratio ranges between 0.59 and 0.85. The chemical formula range of the investigated psr-lpsr is Fe2.07-0.54Ti3O9-4.68(OH)0-4.32. The lowest cationic iron content of the lpsr phase is 0.5 with a corresponding molecular formula of Fe0.5Ti3O4.5(OH)4.5. In the detected leached ilmenite spots, the cationic Fe2+ ranges between 0 and 2.46, while the cationic Fe3+ ranges between 0.17 and 1.94. The Ti/(Ti+Fe) ratio ranges between 0.51 and 0.6, and the Fe/Ti ratio ranges between 0.91 and 0.67. Considering the chemical formula of ilmenite is Fe3Ti3O9, the leached ilmenite formulas have the composition Fe2.72-2.02Ti3O9 with the minimum value of total iron being equal to 2.02. Some of the contained inclusions may be responsible for the acquired magnetic characteristics of some of the detected altered grains. The powdered X-ray diffraction patterns of the investigated different magnetic grains were detected before and after heating at 1100 oC for one hour. The hexagonal psr/lpsr structure is more unstable at 1100 oC than the tetragonal rutile structure. According to the calculations of the molecular formulas for the detected alteration phases, the lowest iron content of the altered lpsr is much lower than that previously reported. Also, during the alteration process, the alteration mechanism is changed in the region of 68-70 wt % of contained TiO2. Then, in the late alteration stages, the lpsr structure does not suddenly collapse but gradually produces other associated mineral phases. [ABSTRACT FROM AUTHOR]

Iron titaniferous sands, also called black sands, are a source of various magnetic minerals, such as iron and titanium (Fe–Ti) oxides, with countless scientific and industrial applications. Ecuador is deemed a geo-diverse country that contains deposits of black sands in the Andean and coastal regions; therefore, the industrialization of these magnetic sands might be of high interest. This study presents a preliminary industrial design for the magnetic separation process of Fe–Ti oxides from iron titaniferous Ecuadorian beach sands. Four stages are considered for the process, involving collecting, drying, screening, and magnetic separation. This proposal returns the large particles (>150 μm) and the non-magnetic fraction to the original place, generating a minimum environmental impact with the support of natural marine and coastal processes. The process design criteria are based on engineering guidelines, sampling, and characterization of eleven black sand samples. Using conventional techniques, the water content, granulometric distribution, particle size, and semi-quantitative Fe–Ti oxide concentration were determined for the different sand samples. It is estimated that Fe–Ti oxide production may reach 5.835 metric tons per day (5.835 mtpd) with a magnetic content of 97.50%, starting from 100 mtpd of black sands. Based on an economic analysis (Class V), a net profit of USD 835,875.63 is expected during the first year of production. Thus, the magnetic separation and enrichment of Fe–Ti oxides from iron titaniferous coastal sands exploitation should allow the commercial valorization of these resources in an eco-friendly way, i.e., with economic benefits and minimization of environmental impact in the source area. [ABSTRACT FROM AUTHOR]

In Egypt, the distribution of black sand in various coastal regions has been readily apparent by thorough research. Unfortunately, these investigations did not measure radioactivity in black sand, particularly in the vicinity of the Red Sea. Gamma-ray spectroscopy was used to detect the naturally occurring radioactivity from 238 U, 232 Th, 40 K, and 226 Ra in black sand samples from eight locations along the Red Sea coast: Ras Elbehar, Gemsa, Hurghada Elahiaa, Hurghada Titanic, Safaga, Qusier Elsharm Alqbly, Gabal Alrosass, and Marsa Alam. The resultant data were interpolated to represent the spatial distribution. Additionally, the potential rocks sources of radionuclides were geologically mapped to elucidate the relationship between rock components and radioactivity. The results showed that 226 Ra, 232 Th and 238 U were higher at samples collected from Ras Elbehar, Hurghada Elahiaa and Hurghada Titanic compared to the other sites. On the other hand, 40 K showed the lowest mean value (75.3 ± 3.8 Bq/kg) in Hurghada Titanic samples, while it peaked (563 ± 28 Bq/kg) in Qusier Elsharm Alqbly samples. The interpolated results show notable differences in radioactive amounts between the north and south, which are indicative of several environmental conditions and human activities. Alkaline syenite, syenogranite, older granites (tonalite and granodiorite), and minor acidic volcanic/metavolcanic rocks make up the upstream area of the basin area draining into, for example, the Ras Elbehar locality (highest activity concentrations for 238 U (1596 ± 80 Bq/kg) and 226 Ra (886 ± 44 Bq/kg)), while alkali-feldspar granite, schist, and shale rocks make up the mid-stream area. The findings provide a basis for scientific forecasting on the impact of synthetic or naturally occurring radioactive isotopes introduced into aquatic environments., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Extensive and systematic investigations have been carried in almost all parts of the world in order to obtain a clear understanding of basic dynamics of radionuclides in the environment. In this context, this review is an attempt to probe the environment of coastal Kerala by consolidating the major studies carried out on environmental radioactivity mostly employing well-established nuclear techniques and radiochemical methods.The review indicated the need for more in depth and focused studies in this sector to confirm the sources of monazite bearing black sands and the geological factors influencing their formations. The consolidation will be scientific assessment for the future, the impact of assessment of major and minor industrial activities and other human interventions in the environment of coastal Kerala. [ABSTRACT FROM AUTHOR]

Iron titaniferous sands, also called black sands, are a source of various magnetic minerals, such as iron and titanium (Fe–Ti) oxides, with countless scientific and industrial applications. Ecuador is deemed a geo-diverse country that contains deposits of black sands in the Andean and coastal regions; therefore, the industrialization of these magnetic sands might be of high interest. This study presents a preliminary industrial design for the magnetic separation process of Fe–Ti oxides from iron titaniferous Ecuadorian beach sands. Four stages are considered for the process, involving collecting, drying, screening, and magnetic separation. This proposal returns the large particles (>150 μm) and the non-magnetic fraction to the original place, generating a minimum environmental impact with the support of natural marine and coastal processes. The process design criteria are based on engineering guidelines, sampling, and characterization of eleven black sand samples. Using conventional techniques, the water content, granulometric distribution, particle size, and semi-quantitative Fe–Ti oxide concentration were determined for the different sand samples. It is estimated that Fe–Ti oxide production may reach 5.835 metric tons per day (5.835 mtpd) with a magnetic content of 97.50%, starting from 100 mtpd of black sands. Based on an economic analysis (Class V), a net profit of USD 835,875.63 is expected during the first year of production. Thus, the magnetic separation and enrichment of Fe–Ti oxides from iron titaniferous coastal sands exploitation should allow the commercial valorization of these resources in an eco-friendly way, i.e., with economic benefits and minimization of environmental impact in the source area.

Ilmenite (FeTiO3) concentrates were modified by high energy ball milling (HEBM) at different times (1, 2, and 3 h) and in the presence of MgO or metallic Mg at different contents (0.5, 1.0, and 3.0 wt%), with the aim of obtaining a low-cost and highly available photocatalyst with enhanced performance towards H2 production. FeTiO3 concentrates were obtained from ilmenite-rich black sand by gravimetric concentration followed by wet electromagnetic and dry magnetic separation. HEBM was performed to insert Mg into FeTiO3 structure and to simultaneously reduce the particle size. The insertion of Mg intended to shift the conduction band of the materials to more negative potentials, in spite of the band-gap widening. XRD patterns of the milled samples showed a decrease in the intensity of ilmenite peaks without any displacement, indicating slight amorphization without significant changes in the crystalline structure. However, the increase in the intensity of hematite peaks suggests substitutional doping according to the proposed solid-state reactions. Although thermodynamic analyses showed that doping with metallic Mg should be more favorable, doping with MgO appears to be kinetically favored due to the physical characteristics of the precursor, as it was revealed by XRD, XPS, Raman spectroscopy, SEM–EDS, and UV–Vis DRS results. Deconvolution of high-resolution XPS spectra corresponding to Mg1s exhibited the presence of an additional component peak for the sample milled with metallic Mg, in comparison to that with MgO. This result evidenced the formation of a new phase, suggesting that part of the metallic Mg was not inserted into FeTiO3, as it was confirmed by Raman spectroscopy. UV–Vis DRS analyses showed an increase in the band-gap of the samples milled in the presence of Mg precursors (from 2.51 to 2.55–2.59 eV) which were attributed to slight modifications of the conduction band due to the insertion of Mg. The performance towards hydrogen production under UV irradiation was improved from 240.5 µmol g−1 h−1 (unmilled sample) to 255.3 µmol g−1 h−1 (2 h milled in the absence of Mg precursor), 296.0 µmol g−1 h−1 (2 h milled with 1.0 wt% MgO), and 265.2 µmol g−1 h−1 (2 h milled with 1.0 wt% metallic Mg). This improvement was attributed mainly to the insertion of Mg, and the consequent modification of the band structure, rather than the modification in the surface area. [ABSTRACT FROM AUTHOR]

Heterogeneous photocatalysis with natural minerals (geocatalysis) has been considered for a wide variety of redox processes, which require the participation of metals either as catalysts or promoters in the reactive system. Black mineral sand as raw material (RM), which is a natural composite frequently found in coastal deposits, was used for the preparation of a semiconductor potential. Due to iron content of mineral, it was applied several magnetic fields (0.0311 and 0.1645 Tesla) to obtain the fractions M1 and M2, respectively. The fraction that was not magnetically attracted was named NM. The chemical, structural and optical properties of each obtained composite were characterized by Zeta potential (ζ), X-ray fluorescence (XRF), energy-dispersive X-Ray analysis (EDX), scanning electron microscopy (SEM), BET area, thermal gravimetric analysis (TGA), X-ray diffraction (XRD) patterns, Fourier transform infrared (FT-IR) and UV–Vis spectroscopy techniques.

Lanthanum zirconates has been suggested as a thermal barrier coating for many high temperature applications. This work is focusing on the possibility of La2Zr2O7 from economic natural resources using Egyptian monazite and zircon. For this purpose, the prepared product of monazite REEs concentrate was subjected to Ce separation by its oxidation and precipitation as Ce (IV) at pH 3 with contact time 15 min and 30% excess amount of KMnO4. The REE-cake almost free from Ce (IV) was passing through Dowex50X8 cation exchange resin for the separation of pure product of La2O3. A homogeneous single phase compound of La2Zr2O7 has been formed at 3 h sintering time with sintering temperature 1100 °C and ZrO2/La2O3 ratio 50% this confirmed with XRD (X-ray diffraction), Raman and EDX analysis techniques.

Black sand from coastal deposits composed by a mixture containing oxides (Fe2O3, TiO2, SiO2, ZrO2, MnO, Al2O3, etc.) and metals (V, Cr, Ni, Sr, Ce, etc.). Both this mineral, as well as a fraction obtained from it, have been used as a photocatalyst for hydrogen production from EDTA (electron donor agent) solutions under UV/Vis irradiation. The physical, chemical and optical properties of materials were studied by X-ray fluorescence, scanning electron microscopy/energy-dispersive X-Ray analysis, BET area, thermal gravimetric analysis, X-ray diffraction patterns, Fourier transform infrared and UV–Vis spectroscopy techniques. The effect of several variables, such as chemical composition (Fe/Ti atomic ratio), catalyst dosage, initial pH of suspension, and sacrificial agent (EDTA) concentration on photocatalytic hydrogen production using these minerals were evaluated. The hydrogen production rate was favored by the high content of iron and low initial pH. Catalyst dosage and sacrificial agent concentration show a synergistic effect due to free radicals generated by the photocatalytic mechanism and the turbidity of the suspension (optical depth). In acidic conditions, M1 fraction produced 35,459.78 µmol g−1 (0.5 g l−1 catalyst and 10 mM EDTA), while lowest hydrogen production (350.294 µmol g−1) was obtained using the same sacrificial agent concentration but employing 0.1 g l−1 of M1 at natural pH suspension (pH 4.8). The results are promising since the hydrogen levels produced by this natural ore are close to yields obtained under similar conditions, using synthetized semiconductors. It's highlight, that in this study a natural catalyst (principle of the geocatalysis), that not was substantially modified. [ABSTRACT FROM AUTHOR]

The growing attention to naturally occurring radionuclides in building materials has a significant societal impact. This impact is apparent in recent research studies and the latest European Council directives, where reference levels for indoor radon concentrations and gamma radiation levels are reported. This paper studies black sand samples from the Estonian coast, mainly from Kihnu island. The results are discussed from various aspects to determine if utilization of these sands as a building material component is viable. For this reason, this paper focuses on the mineralogical and radiological characterization of these samples with special attention to radon emanation and exhalation. Furthermore, a detailed correlation study of mineralogical components against emanation and exhalation factors and the levels of 226Ra, 232Th and 40K was performed. It is found that the sand samples are composed of very high heavy mineral content as compared to the rest of Estonia; the black sands studied here include a heavy fraction dominated by garnets and a light fraction characterized by quartz and feldspars. The analysis also indicates that the higher 232Th and 226Ra content in the samples is correlated with an increase in zircon, ore minerals and garnets; on the other hand, the 40K content is connected to amphiboles. A strong correlation was also found between the 226Ra activity concentration and the measured massic exhalation rates. [ABSTRACT FROM AUTHOR]

Fly ash is the major wastes generated during the combustion of coal in thermal power plants. More than 110 million tons of fly ash produced in India annually. It leads to a significant disposal problem. An attempt has been made by numerous researchers to integrate the fly ash in the industry sector. The key applications include the manufacturing of bricks, production of cement, soil amelioration, mine backfilling, etc. Nevertheless, the refractory bricks for furnace lining are mainly formed from iron and steel, which are imported and are very expensive. Hence, to tackle this issue, the current study is focused on the synthesis of fly-ash-rich brick for high-temperature applications. In this investigation, fly ash material combined with minor additives such as granite powder, alite cement, and black sand were manufactured. The pellets of these materials with a varying additive percentage from 5 to 30% were prepared using hydraulic pressure. The heat-treated pellets were physically and mechanically characterized to ensure the brick properties suitable for furnace lining applications. Surface morphology of raw materials and particle–particle interaction after palletization were evaluated using scanning electron microscopy. Energy Dispersive x-Ray Analysis and x-ray diffraction technique were conducted to detect elemental analysis and phase evaluation of raw materials and fly-ash-rich brick after heat treatment. Microhardness of the samples was determined using a Vickers hardness tester. It is found that the formation of various complex compounds with respect to constituent composition, and pellet formation temperature has a great influence on the variation in hardness. [ABSTRACT FROM AUTHOR]

In the alluvial mining of Madre de Dios-Perú región, they use mercury in the gold extraction process, generating a solid waste called Arenas Negras. The objective of the work was the preliminary characterization of these sands that werecollected from different mining concessions, according to the soil sampling guideline of the Ministry of the Environment. The mercury metal was determined by atomic emission spectrophotometry, the physical parameters using the international methodology solid waste and phases with the conventional method using an X-ray Diffractometer. The Arenas Negras of high Madre de Dios revealed a total mercury value of more than 275 mg.Kg-1 of waste, while Inambari a value of 13,1 mg.Kg-1. An average difference of 137,79 mg.Kg-1. The pH was between 7 and 6,5 and conductivities up to 0,01092 S.m-1. The phases identified in the arenas negras were mainly quartz, ilmenite, hematite and goethite. [ABSTRACT FROM AUTHOR]

Frequently, black sand from coastal deposits is a magnetic ore with a complex structure that is composed principally by iron, titanium and silica oxides, and metals such as vanadium, chromium, nickel, strontium, etc. This material could be used in oxidation/reduction processes as a photocatalyst doped naturally. However, its surface area low and the mass transfer constraints caused by the cluster formation in bulk reaction due to its magnetic character, limits the photocatalytic performance. Microspheres of black sand have been prepared by a simple associating method with alginate-Na and calcined under oxidizing atmosphere at 1100 °C. These have been characterized by XRF spectroscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area analysis, XRD diffraction, N2 adsorption/desorption measurements, FT-IR spectroscopy, differential thermal thermogravimetric analysis, and UV-Vis spectrophotometry. The catalytic activity for photocatalytic hydrogen production from EDTA solutions under UV light irradiation, using the response surface methodology in order to determine the optimum conditions of the process, has been tested. At calcination temperature, rounded microspheres with rough surface, have had apparent density different from the raw material and although the specific surface of the microspheres decreased owing to surface sintering, the chemical composition has been similar compared with the starting material. Due to their buoyancy in the suspension, the hydrogen production due to the contact between photons that entered into suspension and the as-prepared microspheres, has been favored. [ABSTRACT FROM AUTHOR]

A nanostructured material from black sand, whose structure is composed by Fe2O3 and TiO2 oxides, was prepared via hydrothermal treatment (at 120 °C for 72 h), The starting mineral (as‐synthesized nanostructure) was characterized by XRF spectroscopy and thermogravimetric analysis (TGA/DTA) whereas the calcined nanostructures were analyzed by scanning electron microscopy/EDX, BET single point measurements, X‐ray diffraction, FTIR spectroscopy, and UV‐Vis spectrophotometry. The effect of thermal treatment on structural, morphological and redox properties of nanostructured samples (NS) have been thoroughly studied in the samples calcined at 400, 700 and 1000 °C, together with a non‐treated sample (M1). Their photocatalytic activity toward hydrogen production in the presence of EDTA as sacrificial agent has been tested. The as‐synthetized samples calcined at 1000 °C (NS‐1000) showed a higher photocatalytic activity for hydrogen production, possibly due to the transformation of magnetite into more active photocatalytical phases (hematite) driven by the changes in surface morphology (such as reduction of crystallite and pore size reduction) according to thermal equilibrium of its phases. The highest activity for photocatalytic hydrogen production was achieved by the materials calcined at 1000 °C (M1‐1000 and NS‐1000), while the sample calcined at lower values (<700 °C) were the least active. The catalyst activity was assigned to the appearance of a new active phase (α‐Fe2O3), which improves the electronic mobility during the photocatalytic mechanism. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the radioactivity levels and radiological impacts of representative black sand samples collected from different locations in the Rashid area, Egypt. These samples were prepared and then analyzed using the high-resolution gamma ray spectroscopy technique with a high-purity germanium detector. The activity concentration (Ac), minimum detectable activity, absorbed gamma dose rate, external hazard index (Hex), annual effective dose rate equivalent, radium equivalent, as well as external and internal hazard index (Hex and Hin, respectively) were estimated based on the measured radionuclide concentration of the 238U(226Ra) and 232Th decay chains and 40K. The activity concentrations of the 238U, 232Th decay series and 40K of these samples varied from 45.11 ± 3.1 Bq/kg to 252.38 ± 34.3 Bq/kg, from 64.65 ± 6.1 Bq/kg to 579.84 ± 53.1 Bq/kg, and from 403.36 ± 20.8 Bq/kg to 527.47 ± 23.1 Bq/kg, respectively. The activity concentration of 232Th in Sample 1 has the highest value compared to the other samples; this value is also higher than the worldwide mean range as reported by UNSCEAR 2000. The total absorbed gamma dose rate and the annual effective dose for these samples were found to vary from 81.19 nGy/h to 497.81 nGy/h and from 99.86 μSv/y to 612.31 μSv/y, which are higher than the world average values of 59 nGy/h and 70 μSv/y, respectively. The Hex values were also calculated to be 3.02, 0.47, 0.63, 0.87, 0.87, 0.51 and 0.91. It was found that the calculated value of Hex for Sample 1 is significantly higher than the international acceptable limit of

Experimental work was carried out to study new fine aggregate shielding construction materials, namely black sand (BS). The BS effect on the mechanical, durability, and shielding characteristics of heavyweight high-performance concrete (HWHPC) was evaluated. This study aimed at improving various HWHPC properties, concertedly. Fifteen mixtures of HWHPC were made, with various variables, including replacing 10% and 15% of the cement with fly ash (FA) and replacing normal sand by BS at various contents (15%, 30%, 45%, 60%, 75%, and 100%). The test specimens were subjected to various exposure conditions, including elevated temperatures, which ranged from 250 °C to 750 °C, for a duration of 3 h; magnesium sulfate (MS) exposure; and gamma-ray exposure. The effects of elevated temperature and sulfate resistance on concrete mass loss were examined. The results revealed that BS is a promising shielding construction material. The BS content is the most important factor influencing concrete compressive strength. Mixes containing 15% BS demonstrated significantly better strength compared to the control mixes. Exposure to 250 °C led to a notable increase in compressive strength. BS showed a significant effect on HWHPC fire resistance properties, especially at 750 °C and a significant linear attenuation coefficient. Using 10% FA with 15% BS was the most effective mixing proportion for improving all HWHPC properties concertedly, especially at greater ages.

The level of natural radioactivity in 20 black sand and 20 sediment samples collected from Temsah Lake beaches of Suez Canal district, Egypt was investigated. The gamma-ray spectrometry system with hyper-pure germanium (HPGe) detector has been used to determined radioactivity concentrations. Mathematical model is used to estimate the activity concentrations of 222Rn in the air with the activities of 226Ra. The activity concentrations of the sediment and black sand samples range from 4.29 ± 1.66 to 30.06 ± 8.80 and 4.29 ± 0.68 to 18.52 ± 5.22 Bq/kg) for 226Ra. The ranges of radioactivity concentration of 232Th vary from 6.69 ± 1.54 to 39.24 ± 9.80 and 4.56 ± 1.07 to 18.65 ± 5.27 Bq/kg. The effective annual dose rate in the samples under study varies from 0.01 to 0.05 mSv/y for sediment samples and from 0.01 to 0.05 mSv/y for black sand samples. The concentrations of radon gas in the air were determined as well as the activity concentrations of 226Ra. Radon 222Rn doses from gas inhalation for humans were estimated to be in the range of 0.13–13.09 μsv/y for all samples. The activity concentrations of all samples, which were measured in the present work, were compared with the values in other countries in the world, and it was found they were within the permissible limits, which indicates that the study area was radiologically safe for humans.

The natural radioactivity measurements and analysis of 232Th have been studied using γ-ray spectroscopy depending on its decay daughters in equilibrium; 208Tl of 583.19 keV, 228Ac of (911.2 and 968.97 keV) and 212Pb of 238.63 keV. When using these gamma transitions to calculate the 232Th specific activity, the 208Tl daughter of 583.19 keV gamma line with its 0.845 branching ratio gives activity of approximately 33.94% less than the other gamma transitions. This article is trying to explain and validate this difference and discrepancy that may encounter analysts during calculation of 232Th activity based on 208Tl (583.19 keV) gamma line. Very efficient HpGe detector was used to carry out this work. The MDA and figure of merit as functions of HpGe and energy sensitivity were calculated and tabulated. This issue was verified and validated using Black sand and natural environmental samples. A correction factor was proposed and applied on the 583 keV line of these samples that contain 232Th in equilibrium with its daughters to minimize and eliminate the abovementioned difference in the calculated 232Th specific activity. [ABSTRACT FROM AUTHOR]

Gamma and alpha spectrometry techniques were applied to determine the activity concentrations of 238U and 232Th (Bq kg–1) as well as the 234U/238U and 230Th/234U isotopic ratios for commercial grade monazite (purity ≈50%) supplied from the Egypt nuclear materials authority. A method for total dissolution of monazite followed by the sequential radiochemical separation using anion-exchange chromatography is presented. The average activity concentrations of 238U and 232Th, measured by α-ray spectrometry, are 2.49 g kg–1 (0.24 wt %) and 30.09 g kg–1 (3.1 wt %), respectively. The calculated 234U/238U and 230Th/234U isotopic ratios are close to unity, suggesting closed system equilibrium. The possibility of using leaching of monazite with water at different pH values for gaining information about the masses of uranium and thorium that pass into the solution and remain fixed in the crystal lattice was examined. [ABSTRACT FROM AUTHOR]

Black sand is sand that is black in color, there are a number of different dark sand grains that can form black sand, it concentrates often contain additional valuables, other than precious metals: rare earth elements, thorium, titanium, tungsten, zirconium and others are often fractionated during igneous processes into a common mineral-suite that becomes black sands after weathering and erosion, several gemstones such as garnet, topaz, ruby, sapphire, and diamond are found in placers and in the course of placer mining, and sands of these gems are found in black sands and concentrates. black sand is found in Egypt with economical quantities, it is located in the Mediterranean sea coast from Al Arish in north Sinai to Rashid in Al Buhayrah, the main concentration of black sand is in Kafrelshiekh. Black sand is considered as source of many ores used in building and construction such as Iron and steel industry, that is beside wide application in concrete and painting industries. In this work, Chemical, physical and mechanical characteristics of black sands compounds in Egypt are mentioned, the composition and locations of black sand will be discussed, the main common applications of black sands in building and construction industries will be mentioned, the application of black sands in insulation materials industries will be discussed the disadvantages and precautions of using black sands in some applications in buildings will be evaluated. The work end with group of results and recommendations to improve the economic of black sand applications in new fields related to construction and building material industries such as Titanium industries and composite materials. [ABSTRACT FROM AUTHOR]

This article presents a case study of a dispute over magnetite mining in the Municipality of Gonzaga in the Philippines that culminated in the assassination of the town's mayor by the New People's Army (NPA) insurgency. Drawing on the analysis of qualitative data compiled from key informant interviews, survey responses, and document review, it examines the deployment of scalar politics by local politicians, antimining activists, and the NPA during the conflict. Results suggest that failures of resource governance, in conjunction with grievances related to the environmental and socioeconomic impacts of mining, created opportunities for the NPA to forge alliances with local civilian networks and propagate its revolutionary narrative. The findings offer generalizable insights regarding the role of natural resources in shaping vulnerability to, risk of, and opportunity for armed conflict, as well as the mechanisms by which local conflicts can become entangled with broader patterns of civil violence. In particular, it is argued that the multiple overlapping scalar configurations that define extractive industry create unique opportunities for political actors to engage in "scale jumping" to challenge established power structures. Key Words: natural resources and civil conflict, political ecology, scale, scale jumping. 本文呈现在菲律宾刚萨加市的磁铁矿採矿冲突之案例研究，该冲突随着该城镇的市长被新人民军（NPA）叛变暗杀后达到高峰。本文对主要的受访者、调查回覆和档案回顾集结而成的质性数据进行分析，以检视地方政治人物、反採矿倡导人士、以及NPA在冲突中运用的尺度政治。研究结果显示，资源治理的失败，加上对採矿的环境及社会经济冲击的不满，为NPA创造了与地方公民网络建立联盟并传播其革命叙事的机会。研究发现提供了有关自然资源在形塑对武装冲突的脆弱性、武装冲突的风险，以及武装冲突的机会的可普遍化之洞见，以及地方冲突能与更广阔的公民暴力模式相互纠结的机制。本文特别主张，定义榨取产业的多重相互交叠的尺度结构，为政治行动者创造了涉入"尺度跳跃"以挑战建置的权力结构之独特契机。关键词：自然资源和公民冲突，政治生态学，尺度，尺度跳跃。 Este artículo presenta un estudio de caso relacionado con una disputa sobre la minería de magnetita en la Municipalidad de Gonzaga, en las Filipinas, que culminó en el asesinato del alcalde del pueblo por la insurgencia del Ejército del Nuevo Pueblo (NPA). Co base en el análisis de datos cualitativos compilados de entrevistas con informantes claves, respuestas a estudios y revisión de documentos, el artículo examina el despliegue de políticas escalares durante el conflicto por los políticos locales, los activistas contra la minería y el NPA. Los resultados sugieren que los tropiezos de la gobernanza de los recursos, en conjunción con las quejas relacionadas con los impactos ambientales y socioeconómicos de la minería, crearon oportunidades para el NPA de lograr alianzas con las redes civiles locales y propagar su narrativa revolucionaria. Los hallazgos ofrecen perspicacias generalizables en relación con el papel de los recursos naturales en configurar la vulnerabilidad al conflicto armado, y el riesgo y oportunidad para el mismo, lo mismo que los mecanismos por medio de los cuales los conflictos locales pueden enredarse con los patrones más amplios de la violencia civil. En particular, se arguye que el múltiple solapamiento de las relaciones escalares que definen la industria extractiva crean oportunidades únicas entre los actores políticos de comprometerse en un "salto de escala" para desafiar las estructuras de poder establecidas. Palabras clave: ecología política, escala, recursos naturales y conflicto civil, salto de escala. [ABSTRACT FROM AUTHOR]

The 238U, 226Ra and 232Th contents of six samples from the Mandena black sand placer deposit were determined by gamma-ray spectrometry and varied from 2280 to 4600 Bq/kg, 1530 to 2900 Bq/kg and 11,600 to 25,400 Bq/kg, respectively. The activity concentration of 232Th is significantly higher than 238U and there is no equilibrium between 238U and 226Ra. Due to the gamma interferences at the line 1461 keV and very high 228Ac activity, the 40K was calculated through potassium analyzed using ICP-AES and varied from 1 to 19 Bq/kg. The calculated gamma absorbed dose rate ranged from 7700 to 16,700 nGy/h. [ABSTRACT FROM AUTHOR]

A study was carried out on the concentrations of elements presented in beach black sand samples collected from North of Nile Delta along Mediterranean Coast using instrumental neutron activation analysis (INAA) as an effective analysis technique, especially for monitoring elements. The Egyptian Research Reactor-2 (ETRR-2) as a facility was used for the samples irradiation in the thermal mode of a neutron flux 3 × 1011 n/cm2 s. Natural radioactive elements, rare element and heavy elements as U, Th, La, Lu, Sm, Ce, Nd, Eu, Gd, Sc, Tb, Yb, As, Br, Na, Sb, Ba, Co, Cr, Fe, Hg, Hf, Sr, Ta, Zn and Zr were determined with concentrations average values 16.3, 78.8, 195.4, 3.3, 31.3, 445.1, 223, 7.2, 8.5, 97.1, 3.6, 31.1, 6.1, 24.5, 27,236.8, 1.42, 1327.7, 81.1, 1814.3, 263,735, 0.1, 237.3, 878.7, 20.8, 671.1 and 6225.9 (mg/kg), respectively. The experimental data results were analyzed to evidence any correlations of these elements as well as to know the geological formation in the study area. The elements concentrations in the black sand samples were found higher than the world average crustal soil values except for As and Sb. Results were compared with similar beach black sand in previous studies. The enrichment factor (EF) and geoaccumulation index (Igeo) for heavy elements were presented to evaluate the contamination rate. We can summarize that exposure for natural radionuclides (U and Th) in this area were still within the acceptable limits due to little time of exposure. Therefore, the black sands from North of Nile Delta are not recommended for use in building constructions due to high radioactive doses. [ABSTRACT FROM AUTHOR]

The recently completed Avenue of Saints (AOS) highway project in the Mississippi Valley of northeastern Missouri resulted in the documentation of Woodland period sites ranging from approximately 200 cal BC to AD 1200. This article updates the existing Woodland chronology for this locality based on new information collected during the project. Data pertaining to Early, Middle, and Late Woodland sites are presented. The approximately 1,400-year occupation span provided researchers an opportunity to view diachronic trends in tool manufacture, subsistence economy, and landscape use. Based on regional comparisons of ceramic and lithic technologies and vessel decoration, the Woodland sequence in northeastern Missouri was influenced by population movements originating from east of the Mississippi River and from southern sources in the Salt River valley. [ABSTRACT FROM AUTHOR]

Black sand samples collected from Baltim beaches (Kafr El-Sheikh governorate) in Egypt on the Mediterranean Sea shore were analyzed radiometrically and evaluated using a nondestructive gamma ray spectroscopic techniques. The natural radionuclides of 226 Ra, 232 Th and 40 K in the black sand samples were identified and quantified. It is found that the activity concentrations for 226 Ra, 232 Th and 40 K in different eleven sites (S1 S11) were found within the ranges of 28–322, 91–308 and 81–339 Bq/kg, respectively. Moreover, different radiological hazardous parameters (absorbed dose rate, annual effective dose equivalent, radium activity, annual gonadal dose equivalent and excess lifetime cancer risk) were calculated. The results show that these values are greater than the permissible values due to increasing the activity concentrations of the primordial radionuclides 226 Ra, 232 Th and 40 K. The dose rate for radiation emitted at 1 m from the surface of land was measured directly and the results shown that all sites emit radiation doses more than the international permissible value (57 nGy/h) especially at three sites which around 340 nGy/h. These values are important to establish baseline levels of this environmental radioactivity to detect any upcoming change for the local population and resorts people. The relatively high dose rate will be considered as a spa for the physical therapy such as treatment of some skin diseases and rheumatoid. [ABSTRACT FROM AUTHOR]

Study is made of the radioactivity in the beach sands of Langkawi island, a well-known tourist destination. Investigation is made of the relative presence of the naturally occurring radionuclide 40 K and the natural-series indicator radionuclides 226 Ra and 232 Th, the gamma radiation exposure also being estimated. Sample quantities of black and white sand were collected for gamma ray spectrometry, yielding activity concentration in black sands of 226 Ra, 232 Th and 40 K from 451 ± 9 to 2411 ± 65 Bq kg − 1 (mean of 1478 Bq kg − 1 ); 232 ± 4 to 1272 ± 35 Bq kg − 1 (mean of 718 Bq kg − 1 ) and 61 ± 6 to 136 ± 7 Bq kg − 1 (mean of 103 Bq kg − 1 ) respectively. Conversely, in white sands the respective values for 226 Ra and 232 Th were appreciably lower, at 8.3 ± 0.5 to 13.7 ± 1.4 Bq kg − 1 (mean of 9.8 Bq kg − 1 ) and 4.5 ± 0.7 to 9.4 ± 1.0 Bq kg − 1 (mean of 5.9 Bq kg − 1 ); 40 K activities differed insubstantially from that in black sands, at 85 ± 4 to 133 ± 7 Bq kg − 1 with a mean of 102 Bq kg − 1 . The mean activity concentrations of 226 Ra and 232 Th in black sands are comparable with that of high background areas elsewhere in the world. The heavy minerals content gives rise to elevated 226 Ra and 232 Th activity concentrations in all of black sand samples. Evaluation of the various radiological risk parameters points to values which in some cases could be in excess of recommendations providing for safe living and working. Statistical analysis examines correlations between the origins of the radionuclides, also identifying and classifying the radiological parameters. Present results may help to form an interest in rare-earth resources for the electronics industry, power generation and the viability of nuclear fuels cycle resources. [ABSTRACT FROM AUTHOR]