Natural radioactivity levels and radiological hazards indices of chemical fertilizers commonly used in Upper Egypt

Assessment of radioactivity level and associated radiological hazard in fertilizer from Dhaka

Miners, factory workers, traders, end-users, and foodstuff consumers all run the risk of encountering health hazards derived from the presence of elevated levels of radiation in fertilizers, as these groups often come into direct or indirect contact with fertilizers as well as raw materials throughout various linked processes such as mineral extractions, fertilizer production, agricultural practices. A total of 30 samples of various kinds of fertilizer produced in different factories in Dhaka megacity were analyzed to quantify the concentrations of primordial radionuclides using HPGe detector. Among the analyzed samples, average (range) concentration of 40K was found to be 9920 ± 1091 (8700 ± 957-11,500 ± 1265), 9100 ± 1001 (8600 ± 946-9600 ± 1056), 2565 ± 282 (2540 ± 279-2590 ± 285), and 3560 ± 392 (2620 ± 288-4500 ± 495) Bq/kg in the samples of Muriate of Potash Fertilizer, Sulphate of Potash Fertilizer, Humic Acid Fertilizer, and NPKS Fertilizer, respectively. Elevated concentration of 226Ra was found in Triple Super Phosphate Fertilizer with a mean (range) of 335 ± 37 (290 ± 32-380 ± 42) Bq/kg. The higher activity of 40K can be linked to the greater levels of elemental potassium in phosphate fertilizer. Elevated concentrations of radionuclides may also result from variations in chemical processes as well as the local geology of the mining areas where the raw materials were extracted for fertilizer production. Numerous fertilizer brands surpass prescribed limits for various hazardous parameters, presenting significant health risks to factory workers, farmers, and consumers of agricultural products. This study provides baseline information on the radioactivity of fertilizers, which could be used to develop mitigation methods, establish national fertilizer usage limits, justify regulatory frameworks, and raise public awareness of fertilizer overuse. The findings of the study could potentially help to explore the impact of fertilizer on the food chain.

ASSESSMENT OF GAMMA DOSE AND ANNUAL EFFECTIVE DOSE RATE FOR COMMONLY USED FERTILIZER SAMPLES IN AGRICULTURE FIELD WITH A STATISTICAL APPROACH

In this present study, the activity concentration of the naturally occurring radionuclides 238U, 232Th and 40K have been measured in commonly used chemical fertilizers for agriculture by using gamma-ray spectrometry with NaI (TI) detector. Radiological hazard parameters have been calculated for samples. The mean specific activity concentration of the 238U, 232Th and 40K is 176, 5.75 and 4136 Bq kg-1, respectively. Particularly, the mean value of 238U, as well as 40K, is higher than the world recommended value. Also, the average value of radium equivalent activity is 503 Bq kg-1 and the absorbed dose rate (DR) is 282.93 nGyh-1, which is greater than the permissible limit, whereas the annual effective dose rate (AEDR) is 0.316 mSvy-1, which is lower than the world recommended value. Therefore, collected fertilizer samples significantly increase the activity concentration of natural radionuclides in the agricultural soils. Multivariate statistical techniques such as Pearson correlation and factor analysis are carried out for radioactive variables to understand the existing relationship between them. From obtained results reveals that these fertilizer samples increases the probability of adverse health effects due to natural radioactivity.

Assessment of radiation hazard indices due to natural radioactivity in soil samples from Orlu, Imo State, Nigeria

The use of a Radiation Alert Inspector device and a gamma-spectrometry system fitted with a Sodium Iodide (NaI) detector was used to determine the radioactivity concentration level of natural radionuclides ²³⁸U, ²³²Th, and ⁴⁰K in soil in several locations in Orlu, Imo State, Nigeria. 19 soil samples were collected for analysis from several locations of factories, agricultural farming-lands, gullies and water eroded areas, and soil deposits very close to flowing waters from rocks, due to environmental concerns arising from human activities in this region. The activity concentration values for ²³⁸U, ²³²Th, and ⁴⁰K were found to range from 0.14 to 9.34 Bq.kg⁻¹, 0.03–3.75 Bq.kg⁻¹, and 16.83–783.06 Bq.kg⁻¹, respectively, with average mean values of 4.15, 1.64, and 134.13 Bq.kg⁻¹. Radium equivalent activity, absorbed dose rate, and gamma index mean values for the samples were 16.822 Bq.kg⁻¹, 8.528 nGyh^-1, and 0.133 mSv respectively, the obtained values were below the safe limit values set by the United Nations Scientific Committee on the Effects of Atomic Radiation of 370.0 Bq.kg⁻¹, 59.0nGyh⁻¹, and 1.0 mSv. According to the findings, the regions under study are reasonably safe for human outdoor activities such as agriculture, construction, and factory operations.

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Study area is devastated by landslides & water erosion, enhancing radio-exposure.

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Aim of research is to measure Soil radionuclides; ²³⁸U, ²³²Th & ⁴⁰K, in Orlu L.G.A.

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Laboratory analysis was carried out at NIRPR, University of Ibadan, Nigeria.

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The activity concentration of ⁴⁰K exceeds the values of both ²³⁸U and ²³²Th.

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Planting of bamboo trees in this regions should be encouraged.

Accumulation rates of natural radionuclides (40K, 210Pb, 226Ra, 238U, and 232Th) in topsoils due to long-term cultivations of water spinach (Ipomoea Aquatica Forssk.) and rice (Oryza Sativa L.) based on model assessments: A case study in Dong Nai province, Vietnam

In topsoils, the activity concentrations of natural radionuclides (hereafter NRs) increase due to the addition of NRs from fertilizers, irrigation water, and air dust pollution. On the other hand, various physical-chemical and environmental processes such as radioactive decay, volatilization, leaching, erosion, and plant uptake were responsible for the decrease of the activity concentrations of NRs in the topsoils. In this study, behaviours of ⁴⁰K, ²¹⁰Pb, ²²⁶Ra, ²³⁸U, and ²³²Th in topsoils were modelled by the CEMC soil model and the HYDRUS-1D model. An exponential equation was proposed for estimating the accumulation rates of these radionuclides in the topsoils. Long-term accumulation of radionuclides was assessed for water spinach (Ipomoea Aquatica Forssk.) soil (hereafter VES) and rice (Oryza sativa L.) soil (hereafter RIS). We found that the current agricultural practices caused the increase of ⁴⁰K activity concentration in the water spinach soil, and ⁴⁰K, ²¹⁰Pb, ²²⁶Ra, and ²³²Th activity concentrations in the rice soil. The accumulation rates of radionuclides were in the order ²³⁸U < ²³²Th < ²²⁶Ra < ²¹⁰Pb < ⁴⁰K. 25 years of cultivation with water spinach can increase/decrease + (165 ± 6) Bq of ⁴⁰K, - (8.2 ± 0.7) Bq of ²¹⁰Pb, - (4.3 ± 0.2) Bq of ²²⁶Ra, - (7 0.3 ± 0.3) Bq of ²³⁸U, and - (1.8 ± 0.1) Bq of ²³²Th in 1 kg soil. For rice cultivation, these values are + (1004 ± 39), + (3.3 ± 0.2), + (3.0 ± 0.2), - (5.1 ± 0.3), (2.2 ± 0.1) Bq kg^-1 for ⁴⁰K, ²¹⁰Pb, ²²⁶Ra, ²³⁸U, and ²³²Th, respectively.

Natural radioactivity and radiation hazard assessment of industrial wastes from the coastal phosphate treatment plants of Gabes (Tunisia, Southern Mediterranean Sea)

This work is a first contribution to the knowledge of natural radionuclides (²²⁶Ra, ²³⁸U, ⁴⁰K, and ²³²Th) activities in phosphate rock (NORM), phosphogypsum, and phosphogypsum foam (TENORM) from the coastal fertilizer plants of Gabes (Southeastern Tunisia) and the assessment of their radiation hazards on human health and the surrounding environment. In the three studied materials, activities were found to be in the range of 35.4 (⁴⁰K)-375.1 (²²⁶Ra), 10.0 (⁴⁰K)-220.2 (²²⁶Ra), and 79.2 (²³²Th)-1168.6 Bq kg^-1 (²²⁶Ra), respectively. Considering the studied radionuclides and materials, the corresponding decreasing activity orders were found to be ²²⁶Ra > ²³⁸U > ⁴⁰K > ²³²Th and PGF > PR > PG, respectively. All human health hazard indices exceeded the worldwide recommended safety limits, which show that the workers in Gabes phosphate fertilizer plants as well as the neighboring human community may potentially be exposed to significant radiation, which may cause several diseases and malformations. It is therefore recommended to avoid and/or reduce the potential fertilizer industry radioactive impact in the area.

Radioactivity of Five Typical General Industrial Solid Wastes and its Influence in Solid Waste Recycling

The level of radionuclides is an important index for the preparation of building materials from industrial solid waste. In order to investigate the radiological hazard of five kinds of typical general industrial solid wastes in Guizhou, China, including fly ash (FA), red mud (RM), phosphorus slag (PS), phosphogypsum (PG), and electrolytic manganese residue (EMR), the radiation intensity and associated radiological impact were studied. The results show that concentrations of 238U, 235U, 232Th, 226Ra, 210Pb, and 40K for different samples vary widely. The concentration of 238U was both positively correlated with 235U and 226Ra, and the uranium contents in the measured samples were all of natural origin. The radiation levels of PG, EMR, EMR-Na (EMR activated by NaOH), and EMR-Ca (EMR activated by Ca(OH)2) were all lower than the Chinese and the world’s recommended highest levels for materials allowed to be directly used as building materials. The values of the internal and external illumination index (IRa and Iγ, respectively) for FA and RM were higher (IRa > 1.0 and Iγ > 1.3 for FA, IRa > 2.0 and Iγ > 2.0 for RM). The radium equivalent activity (Raeq), indoor and outdoor absorbed dose (Din and Dout, respectively), and corresponding annual effective dose rate (Ein and Eout) of RM, PS, and FA were higher than the recommended limit values (i.e., 370 Bq/kg, 84 nGy/h, 59 nGy/h, 0.4 mSv/y, and 0.07 mSv/y, respectively), resulting from the higher relative contribution of 226Ra and 232Th. The portion of RM, FA, and PS in building materials should be less than 75.44%, 29.72%, and 66.01%, respectively. This study provides quantitative analysis for the safe utilization of FA, RM, PS, PG, and EMR in Guizhou building materials.

Environmental radioactivity of soils and sediments: Egyptian sector of the Nile valley

The activity concentrations of natural ⁴⁰K, ²³²Th, and ²³⁸U in 89 soil and 84 sediment samples collected over the entire Egyptian Nile River basin including the Nile delta are reported based on the results of epithermal neutron activation analysis. The average activity concentrations of ⁴⁰K, ²³²Th, and ²³⁸U equal to 15.3 ± 6.6, 15.6 ± 11.1 and 220 ± 31 Bq/kg, respectively, are significantly lower than those reported for the Upper Continental Crust, World Average Sediments as well as World Average Soils, suggesting the presence of a considerable portion of mafic material, most probably originating from the Ethiopian High Plateau. Their average activity concentrations are statistically the same in soil and sediments, indicating that the Nile sediments and soil material are of the same origin. The main goal of this study was not only to estimate the radiological hazards but also to show the influence of sedimentary material transportable by the Blue Nile from the Ethiopian High Plateau. The different hazard indices like the radium equivalent, gamma index, external hazard as well as the internal hazard show a low radiological exposure either on direct contact or if local mud bricks are used in the construction of dwellings.

Radiological investigation of phosphate fertilizers: Leaching studies

The raw materials of the phosphate fertilizer industry are the various apatite minerals. Some of these have high levels of natural radionuclides, and thus phosphate fertilizers contain significant amounts of U-238, K-40 and Ra-226. These can leach out of the fertilizers used in large quantities for resupplying essential nutrients in the soil and can then enter the food chain through plants, thereby increasing the internal dose of the affected population. In the current study, the radiological risk of eight commercially available phosphate fertilizers (superphosphate, NPK, PK) and their leaching behaviours were investigated using different techniques (gamma and alpha spectrometry), and the dose contributions of using these fertilizers were estimated. To characterize the leaching behaviour, two leaching procedures were applied and compared -the MSZ 21470-50 (Hungarian standard) and the Tessier five-step sequential extraction method. Based on the evaluation of the gamma-spectra, it is found that the level of Th-232 in the samples was low (max.7 ± 6 Bq kg^-1), the average Ra-226 activity concentration was 309 ± 39 Bq kg^-1 (min. 10 ± 8 Bq kg^-1, max. 570 ± 46 Bq kg^-1), while the K-40 concentrations (average 3139 ± 188 Bq kg^-1, min. 51 ± 36 Bq kg^-1) could be as high as 7057 ± 427 Bq kg^-1. The high K-40 can be explained by reference to the composition of the investigated fertilizers (NPK, PK). U concentrations were between 15 and 361 Bq kg^-1, with the average of 254 Bq kg^-1, measured using alpha spectrometry. The good correlation between P₂O₅ content and radioactivity reported previously is not found in our data. The leaching studies reveal that the mobility of the fertilizer's uranium content is greatly influenced by the parameters of the leaching methods. The availability of U to water ranged between 3 and 28 m/m%, while the Lakanen-Erviö solution mobilized between 10 and 100% of the U content.

Radionulide analyses of ingested water from some estuaries within the coastal area of Akwa Ibom State, Nigeria

Radionuclide analyses of ingested water from three selected estuaries within the coastal areas of Akwa Ibom State, Nigeria have been carried out. Fifteen water samples collected at strategic points from the estuaries were pre-treated and each placed on the sodium iodide NaI (Tl) -model 802 detector for 3600 s to obtain the gamma radiation count rate. The activity concentrations and other radiological risk parameters were computed. The effective dose rate of radiation due to ingested water (E.D.I.W.) ranged between 0.25 and 1.86 mSv yr^-1, the effective equivalent dose rate due to absorbed radiation in air (Deq) ranged between 0.0065 and 0.0369 mSv yr^-1 and the total equivalent dose rate of radiation ranged between 0.257 and 1.87 mSv yr^-1. The E.D.I.W exceeded the International Commission on Radiological Protection (ICRP) permissible limit of 0.1 mSv yr^-1 set for ingested radionuclides from food. Most surveyed points had their total equivalent dose rate of radiation greater than the ICRP permissible dose limit of 1 mSv yr^-1 for radiation exposure from all internal and external sources. The annual gonadal dose equivalent ranged between 0.008 and 0.041 mSv yr^-1 and are below the world average value of 0.3 mSv yr^-1. The excess lifetime cancer risk ranged between 0.7 × 10^-3 and 5.07 × 10^-3 and are above the world average value of 0.29 × 10^-3. The elevation of most of the radiation risk parameters over the standard limits shows that oil production activities may have raised the background radiation levels of the area. This research also revealed that computing only the Deq and neglecting the E.D.I.W would mean under estimating the radiation doses received by an impacted person by 97.4%-98.3%. Water consumed from these sources could enhance the radionuclide content and the percentage probabilities of developing cancer by impacted persons.

Radiological impact of natural radioactivity in Egyptian phosphate rocks, phosphogypsum and phosphate fertilizers

In this study, the activity concentrations of the natural radionuclides in phosphate rocks and its products were measured using a high- purity germanium detector (HPGe). The obtained activity results show remarkable wide variation in the radioactive contents for the different phosphate samples. The average activity concentration of ²³⁵U, ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K was found as (45, 1031, 786, 85 and 765Bq/kg) for phosphate rocks, (28, 1234, 457, 123 and 819Bq/kg) for phosphate fertilizers, (47, 663, 550, 79 and 870Bq/kg) for phosphogypsum and (25, 543, 409, 54 and 897Bq/kg) for single super phosphate respectively. Based on the measured activities, the radiological parameters (activity concentration index, absorbed gamma dose rate in outdoor and indoor and the corresponding annual effective dose rates and total excess lifetime cancer risk) were estimated to assess the radiological hazards. The total excess lifetime cancer risk (ELCR) has been calculated and found to be high in all samples, which related to high radioactivity, representing radiological risk for the health of the population.