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(searched for: doi:10.4236/wjnst.2016.63017)
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Saad Ouakkas, Aziz Boukhair, Maged Ahmed Saleh Abdo, Mohammed Benjelloun
Published: 3 April 2022
Indoor and Built Environment, Volume 31, pp 1482-1492; https://doi.org/10.1177/1420326x211059134

Abstract:
In order to assess the radiological impact of radon on >250,000 students, the total annual effective dose was estimated inside 204 Moroccan primary schools sampled in the Doukkala-Abda region. The measurement of indoor radon concentrations was conducted using the LR115 detector for each month, each season and throughout the year. The evolution of indoor radon concentrations showed a decrease in annual average radon concentrations of 20–26% and 10–14%, respectively, compared to the monthly and seasonal annual average radon concentrations. For this purpose, a corrective model of short-term radon concentrations was developed to calculate the seasonal correction factors in order to estimate the annual indoor radon concentrations. For the qualitative evaluation of these factors, a percentage of deviation between the measured and estimated annual radon concentrations was calculated. Almost half of the estimated annual concentrations were 10% less than the measured concentration and the majority of these estimated values were within 40%. The estimated total annual effective doses received by students, except those in the Sidi Bennour city, were higher than the world average (1.15 mSv/y). Nevertheless, all these doses remained below the permissible limit recommended by the International Commission on Radiological Protection (3–10 mSv/y).
Fatima Ezzahra Arhouni, Mohammed Hakkar, Ahmed Mahrou, Laila Belahbib, Hamid Mazouz, , , , Aziz Boukhair, Saad Ouakkas, et al.
Journal of Radioanalytical and Nuclear Chemistry, Volume 331, pp 1609-1617; https://doi.org/10.1007/s10967-022-08235-y

Abstract:
Reactive silica additives, such as clays, can increase the filterability of phosphogypsum (PG) during wet phosphoric acid production from phosphate rock (PR). In this study, the effect of adding inexpensive fly ash waste (34 kg per t PR) together with lower quantities of pure silica (8.5 kg per t PR) on the radioactivity of PG was investigated. The addition of fly ash waste/pure silica reduced the radiological activity of the PG by roughly 30%. The reduction was attributed to decreased activities from 238U (60% reduction) and 226Ra (30% reduction) in PG. Besides, P2O5 losses were slightly decreased.
Miguel Ángel Sanjuán
Published: 18 March 2022
The publisher has not yet granted permission to display this abstract.
Saad Ouakkas, Fatima Ezzahra Arhouni, Mohammed Hakkar, Maged A. S. Abdo, Aziz Boukhair, Aafaf Essedaoui, Mohammed Benjelloun
Journal of Hazardous, Toxic, and Radioactive Waste, Volume 26; https://doi.org/10.1061/(asce)hz.2153-5515.0000661

Abstract:
The present study aims to evaluate simultaneously, for the first time in the Doukkala region (Morocco), the degree of physicochemical and metallic contamination as well as the concentration of 222Rn radionuclides in freshwaters from the sources to the households. From March to June 2019, 23 water samples were collected from the Oum Er-Rbia River, wells located in the town of Ouled Ghanem, Sidi Abed, and El Oualidia, water treatment stations (before and after treatment), water towers, the irrigation canal of Sidi Bennour, and dwellings. Physicochemical parameters [temperature, conductivity, turbidity, pH, chlorides, alkalinity (TAC), total hardness (TH), oxidizability, nitrites, nitrates, ammoniums, and sulfates], heavy metal parameters [copper (Cu), zinc (Zn), and cadmium (Cd)], and radioactive measurements (222Rn) were determined for each sample. The results of the physicochemical analyzes of the water collected from the Oum Er-Rbia River showed that most of the values of the physicochemical parameters, namely conductivity (44,800 μS/cm), turbidity (17.41 NTU), sulfates (2,506.5 mg/L), and chlorides (18,105 mg/L), exceed the Moroccan and World Health Organization (WHO) standards. For the water collected from treatment stations and wells, the analyses showed that some parameters exceed the acceptable limits of drinking water in the towns of Ouled Ghanem, Sidi Abed, and Sidi Daoui station. In dwellings, almost all the water sampled is drinkable except a few ones in the towns of Ouled Ghanem and Sidi Abed. As for heavy metals, the concentrations of Cu, Zn, and Cd varied, respectively, from (0.002 to 0.061 mg/L), (0.02 to 7.5 mg/L), and (0.002 to 0.086 mg/L). These concentrations were within the national permissible limits for drinking water except for the water of Oum Er-Rbia River for Zn and the water in a dwelling of Sidi Abed for Cd. The mean volume activities of radon in the water samples ranged from 29.64 to 130.72 Bq/m3 and do not show any significant difference except for the water in the Ouled Ghanem dwellings. All the radon volume activities were within the admissible limit which is about 11.1 Bq/L set by WHO.
, Biljana Angjusheva, Vojo Jovanov, Pece Murtanovski, Ljubica Vladiceska, Nikolina Stamatovska Aluloska, Jelena Krneta Nikolic, Andrej Ipavec, Katarina Šter, Maruša Mrak, et al.
Published: 18 September 2021
Journal of Radioanalytical and Nuclear Chemistry, Volume 330, pp 685-694; https://doi.org/10.1007/s10967-021-07980-w

Abstract:
Huge quantities of fly ash and bottom ash are generated from thermal power plants and it presents great concern for country, mainly due to the environmental effects. In this study, fly ashes and bottom ash were characterized from technical and radiological aspects. Health effect due to the activity of radionuclides 226Ra, 232Th and 40K was estimated via radium equivalent activity (Raeq), external hazards index (Hex), the external absorbed dose rate (D) and annual effective dose rate (EDR). The specific surface area (40.25 m2 g−1), particle density (1.88 g cm−3) and LOI (23.49%) were typical for bottom ash. Siliceous fly ash contained 32% reactive silica. The annual effective dose rate for all ashes is ≤ 0.2 mSv y−1. Both, fly ash and bottom ash present potential secondary raw materials to be used for building purposes as result of their technological and radiological assessment.
Maged Ahmed Saleh Abdo, , Mohammed Fahad, Saad Ouakkas, Fatima Ezzahra Arhouni, Mohammed Hakkar, Laila Belahbib, Musherah Naji Al-Suhbani
Published: 11 June 2021
Journal of Environmental Radioactivity, Volume 237; https://doi.org/10.1016/j.jenvrad.2021.106665

The publisher has not yet granted permission to display this abstract.
Journal of Material Cycles and Waste Management, Volume 23, pp 1102-1113; https://doi.org/10.1007/s10163-021-01201-y

The publisher has not yet granted permission to display this abstract.
, José A. Suarez-Navarro, Cristina Argiz, Esteban Estévez
Journal of Radioanalytical and Nuclear Chemistry, Volume 327, pp 1045-1054; https://doi.org/10.1007/s10967-020-07578-8

The publisher has not yet granted permission to display this abstract.
Devi Swasti Prabasiwi, Sri Murniasih, Kharistya Rozana, Dewi Puspa Ariany
Published: 1 January 2021
Abstract:
The main objective of this research is to assess the air quality around Rembang Steam Power Plant, through the mass concentration of Total Suspended Particulate (TSP), identification of heavy metals and radionuclides using nuclear analysis technique. Identification of heavy metals (Zn, Cu, Cr, Cd, Sb and As) was determined by instrumental neutron activation analysis (INAA) method using thermal neutrons from the Kartini nuclear research reactor, while for radionuclide identification (Ra-226, Ra-228, Th- 232 and K-40) was determined using gamma spectrometry. The characteristics of TSP mass concentrations at six locations ranged from 41.9 - 61.6 µg/m3, these values have met the requirement of WHO air quality. For radionuclide activity, the lowest value was 3.35 µBq/m3 of Th-232 and the highest value was 62.17 µBq/m3 of K-40. According to Nuclear Energy Regulatory Agency of Indonesia, the recommendation value for Th-232 radioactivity is below 2300 µBq/m3. Analysis of heavy metal using NAA method showed that heavy metal concentration ranged from 0.14 µBq/m3 for Arsenic (As) until 7.83 µBq/m3 for Zinc (Zn). This result indicates that heavy metal concentration is below average threshold standard of heavy metals in air set by WHO. This research indicates that air quality around Rembang Steam Power Plant with a distance of about 1 until 2.3 km from flue gas stuck are still under control.
Imane Rhouch, Saad Ouakkas, Abdelghani Laamyem, Elhachmi Essadiqi, Mustapha Faqir
Journal of Hazardous, Toxic, and Radioactive Waste, Volume 25; https://doi.org/10.1061/(asce)hz.2153-5515.0000558

Abstract:
Sewage sludge resulting from wastewater treatment process by infiltration/percolation using a matrix of adsorbent (coal ash waste/sand) was found to contain harmful elements. As an alternative approach for a sustainable valorization of this sludge, the present study intends to study the possibility of partially substituting clay in fired clay brick for sludge. Different bricks were manufactured incorporating a varied rate of sludge (5%, 10%, 15%, 20%, and 25%, by dry weight), as well as a reference brick that includes only the conventionnel raw materials. To evaluate their suitability as engineering building materials, the bricks specimens have been submitted to a set of trial experiments; linear drying shrinkage; absorption by capillarity, bulk density, mechanical resistance strength; and radiological proprieties. Bulk density and compressive strength were found to be inversely proportional to the amount of sewage sludge, and the results are respectively ranged from 1,882.81 to 1,921.87 kg/m3, and from 5.78 to 16.1 MPa. Specimens meet the Moroccan norm that requires a minimum of 5 MPa in compressive strength resistance for brick type class RC 50. Sludge/clay bricks favor the reduction of linear shrinkage, and specimens including up to 25% of waste sludge are improved on an order of 38.04% compared to the reference. The radiological assessment of sludge bricks ensures their safety since they are far below the required limits (less than 10 mSv · y−1). According to results, incorporating up to 25% of sludge in bricks is suitable for building purposes.
Maged Ahmed Saleh Abdo, , Mohammed Fahad, Saad Ouakkas, Mohammed Benjelloun
Published: 27 August 2020
Air Quality, Atmosphere & Health, Volume 14, pp 129-137; https://doi.org/10.1007/s11869-020-00919-2

The publisher has not yet granted permission to display this abstract.
, Sri Murniasih, Devi Swasti Prabasiwi
Published: 1 January 2020
Journal of Physics: Conference Series, Volume 1436; https://doi.org/10.1088/1742-6596/1436/1/012134

Abstract:
Around Rembang Power Plant, ambient air samples of PM2.5 and PM10 has been taken. Result of this study can be useful as information for stakeholder and also people around Rembang power plant. Total characterization of average mass concentration in 6 locations for PM 2.5 and PM10 are 17.08 μg/m3 and 27.38 μg/m3 respectively. Those values are below air quality requirement by WHO. According to WHO, PM 2.5 should not exceed 25 μg/m3 and PM10 is not more than 50 μg/m3. Mass of PM 2.5 was around 63% from PM10 mass. This data shows that fossil fuel is main source of suspended particulate matter around Rembang power plant. Radioactivity analysis was done using gamma spectrometry, HPGe detector, radioactive sources (Eu-152 and Cs-137) and also Maestro 2 software. Radioactivity of Ra- 226 for PM2.5 and PM10, are 5.72 μBq/m3 and 7.30 μBq/m3 respectively. Radioactivity of Th-232 for PM2,5 and PM10 are 1.17 μBq/m3 and 2.59 μBq/m3 respectively, while radioactivity of K-40 for PM2.5 and PM10 are 17.68 μBq/m3 and 25.58 μBq/m3, respectively. Those values of radioactivity are below recommended values released by Regulation of Nuclear Regulatory Agency Head Number 7 Year of 2017 About Radioactivity Level in Air. According to this law, radioactivity of Ra-226 is below 1800 μBq/m3 and for Th-232 is below 2300 μBq/m3.
Ahosan Habib, Triyono Basuki, Sunao Miyashita, Wiseman Bekelesi, Satoru Nakashima, , , Abdul Baquee Khan Majlis,
Published: 27 December 2018
Environmental Monitoring and Assessment, Volume 191; https://doi.org/10.1007/s10661-018-7160-y

Abstract:
To study the level of radioactivity concentrations from a coal-based power plant (Barapukuria, Bangladesh) and to estimate the associated radiological hazards, coal and associated combustion residuals from the power plant were analyzed by gamma-ray spectrometry with high-purity germanium (HPGe) detector. The results reveal that the mean radioactivity (Bq kg−1) concentrations in feed coal samples are 66.5 ± 24.2, 41.7 ± 18.2, 62.5 ± 26.3, and 232.4 ± 227.2 for U-238, Ra-226, Th-232, and K-40, respectively, while in coal combustion residuals (CCRs), they are 206.3 ± 72.4, 140.5 ± 28.4, 201.7 ± 44.7, and 232.5 ± 43.8, respectively. With the exception of K-40, all the determined natural radionuclides are considerably higher in the investigated feed coal and associated combustion residues as compared with the world soil and world coal mean activities. On the average, CCRs contains 3.10–3.37 times more natural radionuclides than the feed coal, except for K-40. The radioactivity of fly ash and bottom ash is fractionated, and ratio ranges from 1.40 to 1.57. The mean values of the radiological hazard indices in the coal and their associated residuals are 153.1 and 446.8 Bq kg−1 for radium equivalent activity, 0.41 and 1.21 for the external hazard index, 70 and 200.1 nGy h−1 for the absorbed gamma dose rate, 0.09 and 0.25 mSv year−1 for the annual effective dose rate, and 3.0 × 10−4 and 8.6 × 10−4 Sv−1 for the excess lifetime cancer risk, respectively, most of which exceed the UNSCEAR-recommended respective threshold limits. The outcome of this study suggests a potential radiological threat to the environment as well as to the health of occupational workers and nearby inhabitants from the examined samples.
, A. Laamyem, A. Boukhair, E. Essediqi, M. Monkade, A. Zrabda
Journal of Radiation Research and Applied Sciences, Volume 11, pp 217-224; https://doi.org/10.1016/j.jrras.2018.01.006

The publisher has not yet granted permission to display this abstract.
, Elif Gören, Ahmed M.K. Garad, Aydan Altıkulaç, , Celalettin Duran, , Volkan Altunal, , Adnan Özdemir
Published: 1 February 2018
Radiochimica Acta, Volume 106, pp 611-621; https://doi.org/10.1515/ract-2017-2863

Abstract:
Lignite coal (LC) is a key energy source for electricity generation in Turkey. During lignite burning, huge amounts of fly ash (FA), bottom ash and slag are produced as by-products which contain radionuclides in the natural radioactive series of uranium and thorium, and radioactive potassium. These radionuclides may lead to radiological exposure of workers and the public and cause environmental problems. Therefore, finding diverse uses for the by-products in the construction sector and earthwork applications has considerable economic and environmental importance. In this study, the activity concentrations of 226Ra, 232Th and 40K in and radon emanating power (EP) and radon mass exhalation rate (EXRM) from LC, slag and FA obtained from the Kangal lignite-burning power plant with a power of 457 MWe were measured using gamma-ray spectroscopy. The major chemical components (SiO2, Al2O3, Fe2O3, CaO and MgO) of fly ash samples were analysed using an energy dispersive X-ray fluorescence spectrometer. The annual effective doses received by workers and members of the public were estimated using different scenarios specified in Radiation protection 122. The average activity concentrations of 226Ra, 232Th and 40K in LC, slag and FA samples were 187±21, 16±1 and 99±9 Bq kg−1, 620±18, 41±2 and 330±13 Bq kg−1, and 937±30, 38±2 and 272±17 Bq kg−1, respectively. The average values of EP and EXRM of the lignite, slag and FA samples were 8 %, 7 % and 10 %, and 0.1, 0.3 and 0.7 Bq kg−1 h−1, respectively. The highest average of the total annual effective dose is estimated at 153 μSv for members of the public and 74 μSv for workers, lower than the recommended annual limit of 1000 μSv.
Bouchaib Kassi, Aziz Boukhair, Khadija Azkour, Mohamed Fahad, Mohammed Benjelloun, Abdel-Mjid Nourreddine
World Journal of Nuclear Science and Technology, Volume 08, pp 176-189; https://doi.org/10.4236/wjnst.2018.84015

Abstract:
The aim of our present work is to measure the specific activities of the radionuclides 226Ra, 232Th, 40K and the exhalation rates in terms of area and mass of 222Rn in some samples of building materials commonly used in Morocco in order to evaluate the radiological risk caused by natural radioactivity. To this end, the analyses were carried out, using two nuclear techniques, namely high resolution gamma spectrometry and alpha dosimetry based on the use of LR115, on 50 samples collected from large commercial suppliers in Morocco. The results of these analyses show that the average specific activities of 226Ra, 232Th and 40K in these materials vary from 9 to 52 Bq/kg, 3 to 63 Bq/kg and 68 to 705 Bq/kg respectively. These activities remain within the permissible limits of 35 Bq/kg, 30 Bq/kg and 370 Bq/kg respectively, with the exception of a few samples of red brick, gray cement, ceramic and granite. The activity of the radium equivalent (Raeq), the internal (Hin) and external (Hex) hazard indices, the absorbed dose rate, the total annual effective dose , the excess lifetime cancer risk (ELCR) as well as volumic activities, exhalation rates in terms of area (ES) and mass (EM) are calculated for the samples analyzed in this work in order to assess the radiological risks resulting from the use of these materials in various construction activities. It seems that the values of these indices vary from 19 to 196 Bq/kg, 0.08 to 0.67, 0.05 to 0.53, 9 to 91 nGy/h, 0.05 to 0.56 mSv/y, 0.19 × 10−3 to 1.96 × 10−3, 72 to 350 Bq/m3, 56 to 273 mBq⋅m−2⋅h−1 and 3 to 15 mBq⋅kg−1⋅h−1 respectively. The lowest values are identified for gypsum, while the highest are attributed to granite. All of the obtained results of these indices respect the permissible limits except for the Raeq in some granite samples, the ELCR index in all samples except gypsum and the radon volumic activity in some gray cement samples, ceramic and granite. As a result, the different types of building materials analyzed in our work do not present a health risk to the public and can be used in various construction activities, with the exception of a few samples of red brick, gray cement, ceramic and granite. The choice of the use of red brick, gray cement and ceramic should be monitored and adapted according to the criteria of the limitation of the doses whereas the use of the granite must be moderate in order to limit over time the health risk which increases with the duration of exposure of humans to these building materials.
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