Measurement of Natural Radioactivity and Radon Exhalation Rate in Coal Ash Samples from a Thermal Power Plant

Coal is the main energy source for electricity generation in the world. In Morocco, 37% of electricity generation comes from combustion coal in thermal power plants. This combustion process generates large amounts of fly and bottom ashes. In recent years, these ashes became a great topic of interest because of their different uses and especially in construction materials. In this work, we assess radiation risks due to natural radioactivity in samples of fly and bottom ashes collected from JLEC (Jorf Lasfar Energy Company) thermal power plant, and different analyses are performed through two nuclear techniques such as gamma spectrometry and alpha dosimetry based on the use of LR115 films detectors. Our analysis shows that 226Ra activities and 232Th in both ash samples are well above the permissible activity. The values of the external risk index (Hex) and internal one (Hin) for these ashes are below unity, with the exception of 1.28 in fly ash for Hin. The obtained values for the equivalent radium Raeq and annual effective doses Ėin fly and bottom ashes are 324 Bq/kg and 210 Bq/kg, and 0.18 mSv/y and 0.11 mSv/y, respectively. The surface radon exhalation rates for the samples of fly and bottom ashes are 276 mBq⋅m-2⋅h-1 and 381 mBq⋅m-2⋅h-1, respectively. Based on these results, we have shown that fly ash and bottom one from thermal power plant JLEC didn’t have, in any case, a health risk to the public so it can be effectively used in various construction activities.

Measurement of Natural Radioactivity in Lagoon Sands Used in Construction in the District of Abidjan, Côte d’Ivoire

Sand is an important natural material for the construction of houses, work buildings and other public spaces. This work, which is one of the first contributions to the environmental quality of construction materials, concerns the measurement of natural radioactivity in the lagoon sands collected in the district of Abidjan. Nineteen (19) samples of these sands are analyzed by gamma-ray spectrometry equipped with HPGe detector. The mean values obtained for 226Ra, 232Th and 40K are respectively 7.76 ± 1.84 Bq·kg-1, 5.21 ± 1.36 Bq·kg-1, and 217.31 ± 5.03 Bq·kg-1. The estimated average value of radium equivalent (Raeq) is 31.94 Bq·kg-1. The results show that the average values obtained are far lower than the global limits of 35, 30, and 400 Bq·kg-1 for the concentrations of 226Ra, 232Th and 40K, respectively, and 370 Bq·kg-1 for the equivalent radium established by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Therefore, the use of the analyzed lagoon sand samples in the different construction sectors should not cause serious radiological effects on the populations living in the District of Abidjan. Our results provide new data on building materials radioactivity in Côte d’Ivoire and all over the World. They can also be used as a reference for future work.

Fertility Cancer and Hereditary Risks in Soil Sample of Nasarawa, Nasarawa State, Nigeria

A survey of Fertility Cancer and Hereditary Risks in Soil Sample of Nasarawa was carried out.This study assessed the level of Fertility Cancer and Hereditary Risks from the naturally occurring radionuclides;^(232)Th,^(226)Ra and ^(40)K.12 soil samples collected from the respective part of the Nasarawa were analyzed using the gamma-ray spectrometry NaI(Tl)detector system.The mean concentration for ^(40)K was 645.29±07.32 Bq/kg,for ^(226)Ra was 28.43±4.8422 Bq/Kg and for ^(232)Th was 66.84±2.0201 Bq/Kg.The average effective dose due to the ingestion was 0.36±0.1μSv/y which was approximately 1000 times lower than the world average effective dose.Radium equivalent activity Ra_(eq)(Bq/kg),alpha index and total cancer risk were found to be 161.44±8.08 Bq/kg,0.142±0.02 and(0.21±0.05)×10^(-5) respectively.UNSCEAR/USEPA stipulated that;radium equivalent activity,alpha index,effective dose and total cancer risk should not exceed the limit of 370 Bq/kg,unity,300μSv/y and 1×10^(-4) respectively.Hence the values obtained in this work were within the acceptable limits.This implies that the ingestion or inhalation of soil is not associated with any radiological risk of concern.