Atef El-Taher

Environmental and radio-ecological studies on shallow marine sediments from harbour areas along the Red Sea coast of Egypt for identification of anthropogenic impacts

Analysis of marine sediments of the studied localities provides investigators with data to characterise the composition of these sediments allowing for the identification of particular pollution sources. A study of texture, geochemistry, X-ray diffraction and natural radionuclide content of shallow marine sediments from Quseir harbour, Safaga harbour and El-Esh area in the Red Sea coast of Egypt was conducted for the purpose of assessing the possible influence of human activities on the composition of the sediments. The activity concentrations of the naturally occurring radionuclides 226Ra, 232Th and 40K were measured by using γ-ray spectrometry. The mean activity concentrations of 226Ra, 232Th and 40K in all areas studied were found to be 71±6, 66±5 and 92±7 Bq kg−1 for 226Ra, 83±5, 71±7 and 162±23 Bq kg−1 for 232Th and 513±10, 493±20 and 681±28 Bq kg−1 for 40K, respectively. The results of the study presented were compared with corresponding results obtained in other coastal and aquatic environments in the Red Sea.

Ecological impacts of Al-Jalamid phosphate mining, Saudi Arabia: Soil elemental characterization and spatial distribution with INAA.

Phosphate (P) industries will be one of the main industrial sectors in Saudi Arabia within the next few years. Al-Jalamid phosphate mine, which started operation a few years ago, is one of the biggest mining locations in the Middle East region. It is planned to mine 12 million tons run of mine ore per year (Mty) and produce about 4.5 Mty of phosphate concentrate for the next 20 years. Long term ecological impacts of phosphate mining activities on soil and groundwater should be investigated. The contaminated soil acts as a long term source of environmental contamination. The main aim of this work was to shed more light on the elemental characterization and spatial distributions in soil areas located in the vicinity of the phosphate mining activities. A total of sixty eight surface and subsurface soil samples from 34 locations around Al-Jalamid phosphate mine have been collected. The elemental characterization of soil samples was achieved using instrumental neutron activation analysis (INAA). Pollution indices, geoaccumulation (I(geo)) and pollution load (PLI) indices were calculated from some elements to evaluate the soil pollution. Until now, there is no existing pre-operational elemental characterization in soil to evaluate the foreseen ecological impacts of phosphate mining. Our results are the first to evaluate the present situation that will be the base for the future evaluations. The main aim of this work was to shed more light on the elemental characterization and spatial distributions in soil and their relation to phosphate mining activities, and to better understand the behavior of different elements in soil in an arid environment.

Elemental analysis of natural quartz from Um Higlig, Red Sea Aea, Egypt by instrumental neutron activation analysis.

A scheme for INAA of 25 elements: As, Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sc, Sm, Th, U, Yb, Zn and Zr in quartz collected from the eastern desert along the Egyptian Red Sea coast is proposed. The samples were prepared together with standard reference material and irradiated in a neutron flux of 7×10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The gamma spectra were collected by a HPGe detector and the analysis was done by a computerized multichannel analyzer.The accuracy of the procedure is evaluated by the analysis of two geo-standard reference materials (Dolerite WSE and Microgabro PMS). The choice of the nuclear reaction, irradiation and decay times and of the proper gamma radiation in counting are presented and discussed. The data presented here are our contribution to understanding the elemental composition of the quartz rock. Because there are no existing databases for the elemental analysis of quartz, our results are a start to establishing a database for the Egyptian quartz. It is hoped that the data presented here will be useful to those dealing with geochemistry, quartz chemistry and related fields.

Environmental implications and spatial distribution of natural radionuclides and heavy metals in sediments from four harbours in the Egyptian Red Sea coast

Measurements of natural radionuclides concentrations (226Ra, 232Th and 40K) in sediments collected from sea, rivers or ocean is significant to protect the sea water ecosystem and to human health from radiation. Thirty-three sample of sediment have been collected from four ports in the Red Sea coast, Egypt for investigation by gamma-ray spectrometer using NaI(Tl) detector. The average and range activity concentrations of 226Ra, 232Th and 40K were 26(5-58), 19(4-33) and 458(16-2665)Bqkg-1 in Quseir Harbour, 30(14-53), 20(14-34) and 430(378-511)Bqkg-1 in Abu-Tartour Harbour. However, the average and range activity concentrations were 23(14-35), 21(15-32), and 602(327-821)Bqkg-1 in Touristic Harbour and 14(5-26), 13(2-23) and 489(36-950)Bqkg-1 in Hurghada harbour. These results were compared with reported ranges in the literature from other location in the world. The radiation hazard parameters; radium equivalent activity annual dose, external hazard were also calculated and compared with the recommended levels by UNSCEAR reports. Eight heavy metals (Fe, Mn, Ni, Co, Zn, Cu, Pb and Cd) have been measured and analyzed by atomic absorption spectrometer. The concentration for the investigated heavy metals overtakes the allowable limits recommended by the Canadian Environmental Quality Guidelines. Because there are no existing databases for the natural radioactivity in the sediment samples from Egyptian Red Sea ports, our results are a start to establishing a database for Red Sea harbours environment.

Influence of γ-irradiation on optical parameters of electron beam evaporated ZnSe1−xTex nanocrystalline thin films

In the present paper, we reported the effect of γ-irradiation with different doses (100–300 kGy) on the optical parameters of nanocrystalline ZnSe1−xTex (x=0.0, 0.2, 0.5, 0.7, 1.0) thin films. In the wavelength range 400–2500 nm, the optical parameters of the as-deposited and γ-irradiated were extracted from transmission spectra using the Swanepoel method. It was found that the refractive index of the investigated films increases with increasing the doses of γ-radiation. Such post-irradiation increase in the refractive index was attributed to the increase of the density of the investigated films with irradiation doses due to structure transformation induced by thermal effects during irradiation. In addition, the refractive index dispersions of both as-deposited and γ-irradiated of nanocrystalline ZnSe0.8Te0.2 films are found to follow the single oscillator model. The calculated single oscillator parameters; oscillator strength Ed, static refractive index no, increased after irradiation while the oscillator energy Eo, reduced after irradiation. The absorption coefficient was found to increase with the increase of the doses of γ-radiation. Furthermore, the obtained optical energy gap of nanocrystalline ZnSe1−xTex films was found to decrease with increasing the doses of the γ-radiation which is attributed to the increase of the telluride (Te) atoms or defects after irradiation. This is confirmed by the decrease in the Urbach energy Ee after radiation. The γ-irradiation stimulated increase in the absorption coefficient and change in the optical parameters, which can be utilized for industrial dosimetric and detector purposes.

Uranium and rare earth elements in Hazm El-Jalamid phosphate, Saudi Arabia: concentrations and geochemical patterns comparison

This work was carried out to analyze and compare Hazm El-Jalamid phosphate ores—Saudi Arabia with other ores, for their uranium (U) and rare earth elements (REE) abundance and geochemical pattern. Fifteen representative phosphate ore samples were collected from three phosphate mines (Hazm El-Jalamid and Umm Wu’al) in Saudi Arabia and (El-Sibayia) Egypt and analyzed for some elements (Si, Al, Fe, Ca, Mg, Na, K, Cr, Ti, Mn, P, Sr and Ba), U and REEs using inductively coupled plasma mass spectrometry. Detailed studies of the Hazm El-Jalamid phosphorite samples were conducted using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The average U contents in the Hazm El-Jalamid samples were considerably lower than those of other phosphate ores from different origins and countries. The SEM–EDX analyses reveal the presence of uranium-bearing minerals (apatite) and uranyl vanadate minerals [carnotite, K2 (UO2)2(VO4)]. The highest REE concentration values were recorded for La in all samples, followed by Ce and Nd. The lowest REE concentrations were recorded for Tm in all samples. Hazm El-Jalamid phosphate samples are highly enriched in heavy REEs (HREEs) and depleted in light REEs (LREEs), except for La. The REEs exhibit the same behavior in the phosphate deposits of Hazm El-Jalamid, Umm Wu’al, El-Sibayia, Florida and Morocco and the opposite behavior in the phosphate deposits from Jordon and Kola, which are enriched in LREEs (except for La) and depleted in HREEs.

Environmental impacts of heavy metals, rare earth elements and natural radionuclides in marine sediment from Ras Tanura, Saudi Arabia along the Arabian Gulf

Ras Tanura city is one of the most important cities in Saudi Arabia because of the presence of the largest and oldest oil refinery in the Middle East which was began operations in September 1945. Also its contains gas plant and two ports. The concentration of natural radionuclides, heavy metals and rare earth elements were measured in marine sediment samples collected from Ras Tanura. The specific activities of 238U, 226Ra, 232Th, 40K and 137Cs (Bq/kg) were measured using A hyper-pure Germanium detector (HPGe), and ranged from (20.4 ± 4.0-55.1 ± 9.9), (6.71 ± 0.7-46.1 ± 4.5), (3.51 ± 0.5-18.2 ± 1.5), (105 ± 4.4-492 ± 13) and from (0.33 ± 0.04-2.10 ± 0.4) for 238U, 226Ra, 232Th, 40K and 137Cs respectively. Heavy metals and rare earth elements were measured using ICPE-9820 Plasma Atomic Emission Spectrometer. Also the frequency distributions for all radioactive variables in sediment samples were analyzed. Finally the radiological hazards due to natural radionuclides in marine sediment were calculated to the public and its diagramed by Surfer program in maps. Comparing with the international recommended values, its values found to be within the international level.

Occurrence of 222Rn in irrigation water from Wadi Al-Rummah Qassim province, Saudi Arabia

Naturally accruing radioactive materials in the environment have received attention since they may be present in high level and pose risk to human health. The present work deals with measuring of 222Rn in irrigation water samples from Wadi Al-Rummah, Qassim province, in central of Saudi Arabia. 222Rn concentrations were measured by RAD7. It was found that the concentration of 222Rn ranged from 2.1 ± 1.2 to 7.2 ± 1.5 BqL−1. These values are below 11.1 BqL−1 the maximum contamination level recommended from the U.S. Environmental Protection Agency. The calculated annual effective dose (AED) ranging from 7.5 to 26.1 µSv/y. It was evident that the total annual effective dose resulting from radon in irrigation groundwater in Wadi Al-Rummah in Qassim area were significantly lower than the recommended limit 1 mSv/y for the public.

Assessment of radiological parameters and metal contents in soil and stone samples from Harrat Al Madinah, Saudi Arabia

Graphical abstract

Assessment of anthropogenic and geogenic impacts on marine sediments along the coastal areas of Egyptian Red Sea

The present study was conducted to assess the possible impacts of human activities and naturally occurring on the marine sediments, to test for anomalous enrichments in metals. A total of 32 marine sediments samples collected from 12 coastal areas of the Egyptian Red Sea analyzed using different analytical techniques. The analysis explored 43 elements for the marine sediments. Principal component analysis and multivariate statistics were implemented on the data. The extent of pollution was quantified for selected 6 pollutants using the geoaccumulation indices (Igeo), enrichment factor (EF), metal pollution index (MPI), contamination factor (Cf), and degree of contamination factor (Cd). The associated risk using potential ecological risk factor (PER), and risk index (RI) was calculated. The data was interpolated using ArcGIS technology to construct the spatial distribution maps of the selected 6 pollutants along the coastal areas of the Egyptian Red Sea. The data was normalized and the peak values were observed for Ca (13.6%) >Na (1.9%) > Mg (1.6%) >Br (41.1 ppm). The obtained findings were compared with other local and regional data shows that the metal enrichment in studied areas is in line and anomalous enrichments in metals were not evidenced. Even though out of 12 studied areas 2 areas viz., Sharam El-Bahari in the middle of the coast and downwards to the southern Marsa Hemira area found to have peak values of metals, however still show a good agreement with results with other data. Moderate enriched sediments with Cr were noticed. It could be stated that comparison of the gained data from this study with others clearly indicates that nearly the metal concentrations were in the natural unpolluted sediments range.