Assessment of Heavy and Trace Metals in Surface Soil Nearby an Oil Refinery, Saudi Arabia, Using Geoaccumulation and Pollution Indices.

The present study deals with the measurement of heavy and trace metals in the soils of Ras Tanura city nearby one of the oldest and largest oil refineries located on Arabian Gulf, eastern Saudi Arabia. Metals were analyzed in 34 surface soil samples using plasma atomic emission spectrometer (ICPE-9820). The result showed that the mean values of the metals concentrations were in the order: Cd > Mo > Tb > Ce > Hf > Eu > Yb > U > Sm > Rb > Cr > Ni > Pb > Sc > Cs > Zn > Lu > Co. The mean values of Cd (39.9 mg/kg), Mo (13.2 mg/kg), Eu (4.01 mg/kg), Hf (6.09 mg/kg), Tb (8.23 mg/kg), and Yb (3.88) in soil samples were higher than the background values in soil and the world average. The obtained results indicated to elevated levels of Cd and Mo in most samples, with mean concentrations exceeded the background levels by 113 times for Cd and 5 times for Mo. Pollution index (PI) and Geoaccumulation (Igeo) for each metal were calculated to assess the metal contamination level of surface soil in the study area. The assessment results of PI and Igeo revealed a significant pollution by Cd, Mo, Eu, Hf, Tb, and Yb in most of sampling sites nearby Ras Tanura refinery.

Ultra-flat wideband single-pump Raman-enhanced parametric amplification.

We experimentally optimize a single pump fiber optical parametric amplifier in terms of gain spectral bandwidth and gain variation (GV). We find that optimal performance is achieved with the pump tuned to the zero-dispersion wavelength of dispersion stable highly nonlinear fiber (HNLF). We demonstrate further improvement of parametric gain bandwidth and GV by decreasing the HNLF length. We discover that Raman and parametric gain spectra produced by the same pump may be merged together to enhance overall gain bandwidth, while keeping GV low. Consequently, we report an ultra-flat gain of 9.6 ± 0.5 dB over a range of 111 nm (12.8 THz) on one side of the pump. Additionally, we demonstrate amplification of a 60 Gbit/s QPSK signal tuned over a portion of the available bandwidth with OSNR penalty less than 1 dB for Q2 below 14 dB.

Noise and transmission performance improvement of broadband distributed Raman amplifier using bidirectional Raman pumping with dual order co-pumps.

We demonstrate a low noise bidirectional broadband distributed Raman pumping scheme combining dual order co-propagated pumps without increasing the signal RIN level. The noise performance improvement is compared experimentally and numerically with conventional counter-pumping only and bidirectional pumping with only a 2nd order co-pump for a 70nm bandwidth and 61.5km distributed Raman amplifier. The proposed broadband pumping scheme shows 1.2dB maximum noise figure improvement and extends the long-haul transmission reach up to 6150km with a Q-factor improvement of ~0.7dB compared with counter-pumping only scheme.

Assessment of natural radioactivity level and radiation hazards in soil samples of Wadi Al-Rummah Qassim province, Saudi Arabia.

The present work deals with estimation and distribution of natural radionuclides in 40 soil samples collected from Wadi Al-Rummah (Qassim part) Central Saudi Arabia. Estimations were carried out using NaI (Tl) gamma-ray spectrometer. Activity concentrations ranged from 5.3 to 45.0 Bq kg-1, from 4.3 to 33.8 Bq kg-1 and from 38 Bq kg-1 to 273.1 Bq kg-1 for 226Ra, 232Th and 40K, respectively. The average activity concentrations of 226Ra, 232Th and 40K in soil samples was 15.5 Bq kg-1, 14.1 Bq kg-1 and 143.1 Bq kg-1. The results of this study were compared with other studies around the world. Radiation hazard parameters such as radium equivalent activity, annual dose, external hazard were calculated and compared with the recommended levels quoted from International Commission on Radiological Protection (ICRP-60) and United Nations Scientific Committee on the Effects of Atomic Radiation UNSCEAR reports.

Radon activity measurements in irrigation water from Qassim Province by RAD7.

The present study deals with investigating radon level in groundwater, which is being used for irrigation in the environs of Qassim province, Saudi Arabia. Ninety nine samples of groundwater were collected from eight cities in Qassim province. Radon concentrations in the collected water samples were measured with RAD7 electronic radon detector connected to RAD- H2O accessory (Durridge Co., USA). The concentration of (222)Rn in 99 irrigation groundwater samples ranged from 1.20 to 15.43 Bq l-1Radon level in? 5 samples 2 from Al-Asyah, 2 from Al shamasia and one sample from Al Moznib exceeded the permissible level of radon 11 Bq l-1 in groundwater. The total annual effective dose varied with increase in radon concentration. The calculated effective dose per liter (EDL) and annual effective dose (AED) ranged from 6.1 to 77.15 nSvL-1 and 4.45 to 56.16 µSv y-1, respectively. It was evident that the total annual effective doses resulting from radon in 95% from groundwater in Qassim area were significantly lower than the permissible limit of 1 mSv y-1 for the public.

Effect of Rayleigh-scattering distributed feedback on multiwavelength Raman fiber laser generation.

We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ~22-km-long optical fiber. Twenty-two lasing lines with spacing of ~100 GHz (close to International Telecommunication Union grid) in the C band are generated at the watt level. In contrast to the normal cavity with competition between laser lines, the random distributed feedback cavity exhibits highly stable multiwavelength generation with a power-equalized uniform distribution, which is almost independent on power.

Dual-wavelength, ultralong Raman laser with Rayleigh-scattering feedback.

We present experimental demonstration of a 200-km-long, dual-wavelength Raman laser utilizing two slightly different-wavelength fiber Bragg gratings, one on each side of the fiber span. The obtained results clearly prove the generation of two independent Raman lasers with a distributed "random" Rayleigh scattering mirror forming a cavity together with each of the individual fiber Bragg grating reflectors.

Long-distance soliton transmission through ultralong fiber lasers.

We present the first experimental demonstration (to our knowledge) of long-distance unperturbed fundamental optical soliton transmission in conventional single-mode optical fiber. The virtual transparency in the fiber required for soliton transmission, over 15 complete periods, was achieved by using an ultralong Raman fiber laser amplification scheme. Optical soliton pulse duration, pulse bandwidth, and peak intensity are shown to remain constant along the transmission length. Frequency-resolved optical gating spectrograms and numerical simulations confirm the observed optical soliton dynamics.

Radiological assessment of Abu-Tartur phosphate, Western Desert Egypt.

The contents of natural radionuclides ((226)Ra, (232)Th and (40)K) were measured in sedimentary phosphate rock samples (Abu-Tartur phosphate, Western Desert Egypt) by using gamma spectrometry (NaI (Tl) 3"x 3"). Phosphate and environmental samples were collected from Abu-Tartur phosphate mine and the surrounding region. The results are discussed and compared with the levels in phosphate rocks from different countries. The activities of (226)Ra, (232)Th series and (40)K are between (14.9 +/- 0.8 and 302.4 +/- 15.2), (2.6 +/- 1.0 and 154.9 +/- 7.8) and (10.0 +/- 0.5 and 368.4 +/- 18.4) Bq kg(-1), respectively. The Abu-Tartur phosphate deposit was found to have lower activity than many others exploited phosphate sedimentary deposits, with its average total annual dose being only 114.6 microSv y(-1). This value is about 11.46% of the 1.0 mSv y(-1) recommended by the International Commission on Radiological Protection (ICRP-60, 1990) as the maximum annual dose to members of the public.

Radiological significance of beach sand used for climatotherapy from Safaga, Egypt.

As a part of national survey to evaluate natural radioactivity in the environment, concentration levels of radioactivity were analysed for sand samples from Safaga, Egypt, which is an ideal area for climatotherapy of psoriasis. Gamma dose rates of three beaches in Safaga were measured. The values ranged from 195.1 to 210.7 nGy h(-1). The activity concentrations (Bq kg(-1)) of radionuclides 238U series, 232Th series and 40K in three different sand profiles (0-5, 5-10, 10-15, 15-25 and 25 - 40 cm) were measured using gamma-ray spectrometry. The annual effective doses were 259 microSv y(-1) for Minveila, 255 microSv y(-1) for Ganet Safaga and 239 microSv y(-1) for Masab El-Ghazel beaches. The dose rates, radium equivalent activities and external hazard indices were evaluated and compared with the international data. These results may contribute to the determination of absorbed dose rate reference levels in Red Sea Coast at Safaga city.

Rare-earth elements in Egyptian granite by instrumental neutron activation analysis.

The mobilization of rare-earth elements (REEs) in the environment requires monitoring of these elements in environmental matrices, in which they are mainly present at trace levels. The similarity in REEs chemical behavior makes the separate determination of each element by chemical methods difficult; instrumental neutron activation analysis (INAA), based on nuclear properties of the elements to be determined, is a method of choice in trace analysis of REEs and related elements. Therefore, INAA was applied as a sensitive nondestructive analytical tool for the determination of REEs to find out what information could be obtained about the REEs of some Egyptian granite collected from four locations in Aswan area in south Egypt as follows wadi El-Allaqi, El-Shelal, Gabel Ibrahim Pasha and from Sehyel Island and to estimate the accuracy, reproducibility and detection limit of NAA method in case of the given samples. The samples were properly prepared together with standards and simultaneously irradiated in a neutron flux of 7 x 10(11)n/cm(2)s in the TRIGA Mainz research reactor facilities. The following elements have been determined: La, Ce, Nd, Sm, Eu, Yb and Lu. The gamma spectra was collected by HPGe detector and the analysis was done by means of computerized multichannel analyzer. The X-ray fluorescence (XRF) was also used.

Natural radioactivity levels and radiation hazard indices in granite from Aswan to Wadi El-Allaqi southeastern desert, Egypt.

Studies on radiation level and radionuclide distribution in granite from Aswan to Wadi El-Allaqi area that is located in southeastern desert of Egypt were undertaken. The samples collected from five locations: Gabal El Mesala, Umm Hibal, Abu Herigle, Abu Marw and Deneibit El Quleib. The purpose of this study is to provide a baseline map of radioactivity background levels in the investigated area environment, and this study will be used as reference information to assess any changes in the radioactive background level due to geological processes. The highest average values of 226Ra and 232Th concentrations (24.00 and 31.28 Bq kg(-1), respectively) were observed at Abu Herigle region, whereas the highest average value of 40K concentration, 589.95 Bq kg(-1), was detected in Umm Hibal. The absorbed dose rate in air was found to be in the range between 5.40 and 45.11 nGy h(-1), and radium equivalent activity concentration was found in the range between 29.57 and 71.85 Bq kg(-1). Also the representative external hazard index values for the corresponding samples were also estimated and given.

The sexual and reproductive health in men with generalized epilepsy: a multidisciplinary evaluation.

This study was specifically aimed to evaluate the sexual and reproductive health in a group of men with generalized epilepsy. In total, 44 men with generalized epilepsy were included in this study, their ages between 18 and 48 years (29.2+/-9.9) and duration of illness between 2 and 35 years (11.2+/-7.4); 34 patients were treated with conventional antiepileptic drugs (AEDs). Sexological and psychological interviews together with serum total testosterone, E(2), FSH, LH and prolactin were determined. Hyposexuality was diagnosed in 61.4%. Erectile dysfunction (ED) and premature ejaculation represented 70.4 and 66.7%, respectively. Variables such as hyposexuality, seizure duration and its poor control on AEDs were significantly associated with depressive symptoms. Compared to the normal control group, all patients reported elevated E(2) levels (P<0.001), 10 had FSH (n=4) and LH (n=6) levels exceeding that of the normal range for controls and two had hyperprolactinemia. Although the patients' mean value of total testosterone remained within the normal range, but it was significantly lower in hyposexual men compared to nonhyposexual (P<0.002), only two epileptic patients had markedly reduced level of total testosterone beyond normal control levels. This study strongly supports that: (1) The risk of hyposexuality and reproductive disturbances is high in epileptic patients with GTC convulsions despite the AEDs utilized. The risk for SD is further increased by poor seizure control and the frequently accompanied depressive manifestations. (2) It is possible that elevated E2 could increase the risk of SD by reducing active testosterone through negative feedback and the reduction of active testosterone could increase seizure intractability to antiepileptic medications.

Elemental characterization of Hazm El-Jalamid phosphorite by instrumental neutron activation analysis.

Instrumental neutron activation analyses (INAA) have been used to achieve accurate knowledge about the elemental analysis of phosphate ore deposits collected from Hazm El-Jalamid Northeast of Saudi Arabia. The samples were prepared for irradiation by thermal neutrons using a thermal neutron flux of 7×10(12)ncm(-2)s(-1) at ACT Lab Canada. The concentrations of 19 elements were determined. These included 12 major, minor and trace elements (Au, As, Ba, Br, Cr, Mo, Sb, Sc, Sr, Th, U and Zn) and 7 rare earth elements (REEs) (La, Ce, Nd, Sm, Eu, Yb and Lu). Major elements (Si, Al, Fe, Ca, Mg, Na, K, Cr, Ti, Mn, P, Sr and Ba) were determined using an inductively coupled plasma-mass spectrometer (ICP-MS). The comparison of the concentration of U and the REEs in the Hazm El-Jalamid phosphate samples with those of the Umm Wu'al phosphate from Saudi Arabia and El-Sibayia and El Hamrawein phosphate from Egypt shows that the contents of U and REEs are clearly higher in the Umm Wu'al, El-Sibayia and El Hamrawein phosphates than in the Hazm El-Jalamid phosphate samples. The results of major, trace elements, uranium and rare earth elements (REE) from El Jalamid phosphate have been compared with the global values of these elements. The concentrations for most of the elements studied are lower than the concentrations reported in the literature. The acquired data will serve as a reference for the follow-up studies to assess the agronomic effectiveness of the Hazm El-Jalamid phosphate rocks.

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.

Natural radioactivity and dose assessment for phosphate rocks from Wadi El-Mashash and El-Mahamid Mines, Egypt.

The activity concentrations of (226)Ra, (232)Th and (40)K have been measured by gamma spectroscopy (sodium iodide NaI(Tl) detector) in phosphate rock samples, collected from the Wadi El-Mashash, a site located in the central eastern desert, and El-Mahamid in the Nile valley, Egypt. The average activity concentrations of (226)Ra, (232)Th and (40)K (Bq kg(-1)) in phosphate rocks were 665.8+/-33.4, 329.4+/-17 and 587.6+/-29.4 for Wadi El-Mashash and 566.8+/-28.6, 217.3+/-11.8 and 560.1+/-28 for El-Mahamid, respectively. The corresponding values for shale rocks were 85.2+/-5.7, 93.3+/-5.6 and 303.1+/-15.2 Bq kg(-1), respectively. As a measure of radiation hazard to the occupational workers and public, the Ra equivalent activities, representative level index and dose rates due to natural radionuclides at 1 m above the ground surface were estimated. The calculated external gamma-radiation dose received by the workers of the phosphate mine are 538 and 418 microSv/y, which is far below the permitted dose of 20 mSv/y recommended by the International Commission of Radiation Protection [ICRP-60, 1990. Radiation Protection: 1990 Recommendation of the International Commission on Radiological Protection, Oxford, Pergamon Preis.] for workers.

Thyroid hormones, cholesterol and triglyceride levels in the camel.

Thyroxine, tri-iodothyronine, triglyceride and cholesterol were measured in the serum of clinically healthy male camels. Thyroxine and tri-iodothyronine levels, which were assayed by an immunoabsorbent method, were not correlated with either age or cholesterol levels.

Clinical aspects of malaria in the Asir Region, Saudi Arabia.

Three hundred and thirty-four cases of confirmed malaria seen in the Asir Central Hospital, Abha, in southwestern Saudi Arabia, were studied retrospectively. Two hundred and eighty-two of these (84.4%) were Saudis and the majority (72.2%) were living in the lowlands of Tihama. Transmission was found to occur throughout the year, with peaks following the rainy season and in the summer. In Saudis, falciparum malaria is more common than vivax (97.2% vs. 2.8%), while vivax malaria is more commonly seen in expatriates (46.2%). Poor response of falciparum malaria to chloroquine was more prevalent in expatriates than in Saudis (46.4% vs. 23%). Most of the expatriates gave a history of recent travel to countries known to be endemic with resistant malaria. The possibility of the emergence of chloroquine-resistant malaria in the southwestern region of Saudi Arabia was discussed.

Analytical approach for radioactivity correlation of disc sources with HPGe detector efficiency.

The HPGe detector efficiency is measured as a function of source to detector separation using disc sources of (131)I with diameter ranging from 10 to 400mm. Detector efficiencies are characterized using single photon point-like standard sources at different distances; the calculated efficiencies for disc sources were analyzed by utilizing the double point detector model (DPDM) and the efficiency transfer method. The developed approach provided satisfactory results. The axial variation and radial dependence for disc sources efficiency determination in gamma-ray spectrometry were described with both gamma ray standard sources and measured samples as their extended sources.

Skin dose measurements using radiochromic films, TLDS and ionisation chamber and comparison with Monte Carlo simulation.

Estimation of the surface dose is very important for patients undergoing radiation therapy. The purpose of this study is to investigate the dose at the surface of a water phantom at a depth of 0.007 cm as recommended by the International Commission on Radiological Protection and International Commission on Radiation Units and Measurement with radiochromic films (RFs), thermoluminescent dosemeters and an ionisation chamber in a 6-MV photon beam. The results were compared with the theoretical calculation using Monte Carlo (MC) simulation software (MCNP5, BEAMnrc and DOSXYZnrc). The RF was calibrated by placing the films at a depth of maximum dose (d(max)) in a solid water phantom and exposing it to doses from 0 to 500 cGy. The films were scanned using a transmission high-resolution HP scanner. The optical density of the film was obtained from the red component of the RGB images using ImageJ software. The per cent surface dose (PSD) and percentage depth dose (PDD) curve were obtained by placing film pieces at the surface and at different depths in the solid water phantom. TLDs were placed at a depth of 10 cm in a solid water phantom for calibration. Then the TLDs were placed at different depths in the water phantom and were exposed to obtain the PDD. The obtained PSD and PDD values were compared with those obtained using a cylindrical ionisation chamber. The PSD was also determined using Monte Carlo simulation of a LINAC 6-MV photon beam. The extrapolation method was used to determine the PSD for all measurements. The PSD was 15.0±3.6% for RF. The TLD measurement of the PSD was 16.0±5.0%. The (0.6 cm(3)) cylindrical ionisation chamber measurement of the PSD was 50.0±3.0%. The theoretical calculation using MCNP5 and DOSXYZnrc yielded a PSD of 15.0±2.0% and 15.7±2.2%. In this study, good agreement between PSD measurements was observed using RF and TLDs with the Monte Carlo calculation. However, the cylindrical chamber measurement yielded an overestimate of the PSD. This is probably due to the ionisation chamber calibration factor that is only valid in charged particle equilibrium condition, which is not achieved at the surface in the build-up region.