Environmental and mineralogical studies on the stream sediments of Baltim-El Burullus coastal plain, North Delta, Egypt.

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.

Separation, reserve estimation and radioactivity responsibility of the economic heavy minerals of East El- Arish black sand, North Sinai, Egypt.

Multi-heavy mineral separation techniques like density, magnetic, and electromagnetic techniques are followed by picking, grain counting, and mineralogical examinations conducted with an environmental scanning electron microscope (ESEM). These techniques have been applied to several drill hole (well) composite samples representing beach sand and dunes of East El-Arish area, North Sinai, Egypt. The results explain the remarkable enrichment in total heavy minerals (THM) of beach sand (4.4%) compared to sand dunes (2.6%): this is due to the natural concentration of the currents of the Mediterranean Sea. After characterizing the heavy minerals in terms of the abundance of each mineral species, the mean values of content relative to total economic heavy minerals (TEHM) were determined as 70.03% ilmenite, 3.81% leucoxene, 3.03% magnetite, 8.7% garnet, 10.6% zircon, 3.13% rutile, 0.37% monazite, and 0.31% titanite in the sand dune samples. The total economic heavy minerals in the beach samples were 64.08% ilmenite, 1.6% leucoxene, 2.84% magnetite, 18.16% garnet, 10.4% zircon, 2.18% rutile, 0.61% monazite, and 0.13% titanite. Monazite, thorite, zircon, and apatite are the main radioactive minerals in the study area. The combination of two specific characteristics of the studied monazite (relatively high Th-U content and high frequency) makes monazite the main contributor to radioactivity of the study area.

Design and Gamma-Ray Attenuation Features of New Concrete Materials for Low- and Moderate-Photons Energy Protection Applications.

We aimed, in this investigation, to prepare novel concretes which can be used in gamma-ray shielding applications. The experimental approach was performed using a NaI (Tl) detector to measure the concrete's shielding features for different energies, ranging from 0.081 MeV to 1.408 MeV. The density of the fabricated concretes decreased with increasing W/C ratio, where the density decreased by 2.680 g/cm3, 2.614 g/cm3, and 2.564 g/cm3 for concretes A, B, and C, respectively, with increases in the W/C ratio of 0.4, 0.6, and 0.8, respectively. When the energy was elevated between 0.08 MeV and 1.408 MeV, the highest values were attained for concrete A, with values ranging between 0.451 cm-1 and 0.179 cm-1. The lowest half-value layer (Δ0.5) values were achieved for concrete C, where the Δ0.5 values varied between 1.53 cm and 3.86 cm between 0.08 MeV and 1.408 MeV. The highest Δ0.5 values were achieved for concrete A, where the Δ0.5 varied between 1.77 cm and 4.67 cm between 0.08 MeV and 1.408 MeV. According to this investigation, concrete A has the highest promise in radiation shielding purposes because it has the most desirable properties of the concretes studied.

Radioactive risk assessment of beach sand along the coastline of Mediterranean Sea at El-Arish area, North Sinai, Egypt.

Beach sand includes various levels of natural radioactivity, which can cause health effects. The natural radioactivity was measured in the beach sand along the coastline of the Mediterranean Sea at the east of the El-Arish area, Egypt. Using the HPGe spectrometer, the contribution of radionuclides 226Ra, 232Th and 40K in the gamma emitted radiation illustrated that the 226Ra, 232Th and 40K activity concentrations are 8.8 ± 3.9, 30.8 ± 12.2 and 106.9 ± 46.8 Bq kg-1, respectively, which is lower than the reported worldwide limit 33, 45 and 412 Bq kg-1. The radioactive hazards associated with the beach sand along the coastline of the Mediterranean Sea at the east of the El-Arish area were investigated. The obtained results among the radiological hazard parameters, the radium equivalent content (Raeq), the absorbed dose rate (Dair), annual effective dose (AED), external (Hex) and internal (Hin) hazard indices were estimated. Moreover, the excess lifetime cancer risk (ELCR) and the annual gonadal dose equivalent (AGDE) were also computed and illustrated their values less than the recommended levels. Multivariate statistical approaches like Pearson correlation, the principal component analysis (PCA) and the hierarchical cluster analysis (HCA) were applied to investigate the correlation between the radionuclides and the corresponding radiological hazard variables. Based on the statistical analysis, the 226Ra and 232Th mainly contribute to the radioactive risk of beach sand. Finally, no significant risk of the public associated with utilizing beach sand in building materials.