Gamma Spectrometry Research Articles

Assessment of Natural Occurring Radioactive Materials and Radiological Hazards Exposure in Soil of Ohia in Umuahia South Abia State Nigeria, Using High Purity Germanium (HPGe) Gamma Ray Spectrometry

Evaluation of natural occurring radioactive materials (NORMs) and radiological exposure are important. The main goal of this work was to determine the NORMs level and radiological exposure risk in Umuahia, using High Purity Germanium Gamma Ray Spectrometry at IPEN, Brazil. The radionuclides (RDNs) such as: 40K, 226Ra and 232Th and radiological parametric indices (RPIs) such as: Absorbed Dose Rate in Air (D), Outdoor and Indoor Annual Effective Dose Equivalent (AEDE), Radium Equivalent Activity (Raeq), Annual Gonadal Equivalent Dose (AGED) and Activity Concentration Index (I) were determined. The mean values of 40K, 226Ra and 232Th in Bq kg-1 were: 147, 28, and 31 while the RPIs mean values for D, ,, AGED, Raeq, and I are: 37 nGy h-1, 0.05 mSv y-1, 0.18 mSv y-1, 260 y-1, 83 Bq kg-1 and 0.29 respectively. Mean value of RDNs were found to be lower than 412 Bq kg-1, 32 Bq kg-1 and 35 Bq kg-1 average value while RPIs were also lower than 59 nGy h-1, 0.08 mSv y-1 for , 0.42 mSv y-1, 300 y-1 for AGED, 370 Bq kg-1 for Raeq, and 1 mSv y-1 respectively global safe limit or mean values. It is concluded that the soil is radiological safe for agriculture, building and construction purposes.

Assessment of Radionuclides Contents in Soil and Food Samples Due to Civil War in Enugu State, South-Eastern, Nigeria and Its Radiological Hazards

Human activities may influence the distribution of naturally occurring radioactive materials in the environment. This therefore, cause for concern radiological, as human are exposed to these radioactive materials without their consent. This study hereby evaluate the radionuclide contents from natural and artificially occurring radionuclides in soil samples and farm produce in Enugu. Gamma-ray spectroscopy was used to determine the radioactivity concentration level of the environmental radionuclides such as 238U, 232Th, and 40K and manmade radionuclides in soil, cassava, and bitter leaf samples within studied locations in Enugu State, Nigeria. The mean activity concentration of the radionuclides detected in the samples were 1136.74±27.07, 1118.53±4.85, 196.104±0.02 Bqkg-1 for 40K, 41.66±0.04, 22.99±0.38, Bqkg-1 for 238U and 36.44±0.04, 15.89±0.07, 7.69±0.02 Bqkg-1for 232Th. 137Cs ranged from 3.07 ± 0.01 – 7.81 ± 0.03 Bqkg-1. The radioactivity levels and estimated radiological indices were higher than the recommended limits. The values confirmed the reports of different fora on the radiological hazards due to exposure to high radiation in the region assayed.

Fabrication and Evaluation of Spectroscopic Grade Quasi-hemispherical CdZnTe Detector

Background: This study focuses on the fabrication and characterization of quasi-hemispherical Cd<sub>0.9</sub>Zn<sub>0.1</sub>Te (CZT) detector for gamma-ray spectroscopy applications, aiming to contribute to advancements in radiation measurement and research.Materials and Methods: A CZT ingot was grown using the vertical Bridgman technique, followed by proper fabrication processes including wafering, polishing, chemical etching, electrode deposition, and passivation. Response properties were evaluated under various external bias voltages using gamma-ray sources such as Co-57, Ba-133, and Cs-137.Results and Discussion: The fabricated quasi-hemispherical CZT detector demonstrated sufficient response properties across a wide range of gamma-ray energies, with sufficient energy resolution and peak distinguishability. Higher external bias voltages led to improved performance in terms of energy resolution and peak shape. However, further improvements in defect properties are necessary to enhance detector performance under low bias conditions.Conclusion: This study underscores the efficacy of quasi-hemispherical CZT detector for gamma- ray spectroscopy, providing valuable insights for enhancing their capabilities in radiation research field.

Изучение радиоактивности вод горных рек Кабардино-Балкарской Республики с использованием детектора NaI в низкофоновой защите

The results of studies of the radioactivity of the waters of the mountain rivers of the Kabardino-Balkarian Republic using the NaI detector in low-background protection are presented. The paper presents a method of low-background gamma-ray spectrometry for detecting radioactivity in drinking water, which is an effective method, has high sensitivity to radioactive radiation and allows you to accurately determine the level of radioactivity. The MULTIRAD MKS-01A spectrometric installation was used to measure radiation in samples under low background conditions. The identification and calculation of the volumetric activity of radionuclides was carried out using special software "Progress". Concentration levels and specific activity distribution of natural radionuclides 137Cs, 232Th, 40K, 226Ra and 222Rn were studied. Water samples were taken from the rivers of the Baksan, Cherek gorges and the Malka River of the Kabardino-Balkarian Republic. Studies have shown that radiation levels were within the norm set for drinking water.

Can metals and radionuclides in Shiveluch (Kamchatka) volcanic ash affect human health?

Volcanic eruption is associated with the release of large volumes of pollutants in the environment, which can pose a risk to humans and other living organisms. The elemental and radioisotope composition of ash released during the Shiveluch Volcano eruption in 2023 was analyzed using ICP-MS and low-background gamma spectrometry. The ash consisted of 59% SiO2, 16.7% Al2O3, 5.3% CaO, 4.6 % Na2O, 4.5% Fe2O3, 1.4% K2O, 0.48% TiO2, 0.17% P2O5, 0.15% S, 0.078% MnO and 44 trace elements. Hazard Quotient and Hazard Index were calculated in order to evaluate the potential health risks to children and adults due to exposure to contaminants via inhalation, ingestion, and dermal contact. All values were below the unit, indicating a low probability of non-carcinogenic and cancerogenic risk occurrence in target groups. The average activity concentrations of the natural radionuclides were 350, 12.4 and 4.84 Bq/kg for 40K, 226Ra and 232Th. Radiological indices, including external and internal risk assessment, radium equivalent activity, annual effective dose, gamma index, and excess lifetime cancer risk were calculated to estimate the radiological hazard for the population. The values of all indices were below the recommended safety limits, indicating a low level of hazard for the exposed population.

Determination of the type of radioactive nuclei and gamma spectrometry analysis for radioactive sources

Determining the type of radioactive nuclei is the second activity after the inventory of radioactive waste in Kosovo, their location and the number of radioactive sources. Before starting any type of radioactive waste action, it is necessary to determine the content of their activity, the type of radioisotope, physical and chemical form and the risks associated with their management. The realization of this is achieved as a combination of quality assurance processes, the inventory of the radioisotope and its activity that is present in the waste, the composition of the waste material and direct measurements. This serious activity was carried out entirely in the field and was undertaken due to the lack of source certification or any other indication of their classification and activity. The process of determining the type of radioactive nuclei helps to realize a more effective characterization of them as well as to determine the path of waste management. The probability that a gamma radiation detector interacts with it to produce a pulse represents the effectiveness of the detector.

Determination of Natural Radioactivity Levels and Radiation Hazards from the Soil of Tin Mining in Kyerwa District, Tanzania

Gamma spectrometry was used to determine the activity concentrations of the natural radionuclides 226Ra, 232Th, and 40K in soil samples from the Tin mining in Kyerwa District, Tanzania. The study findings revealed that the mean activity concentrations of 226Ra, 232Th, and 40K were 90.68, 65.45, and 630.95 Bq/kg, respectively. These values were all greater than the average global activity concentrations for 226Ra, 232Th, and 40K which are 32 Bq/kg, 45 Bq/kg, and 420 Bq/kg, respectively. Assessments of the radiological risks associated with these naturally occurring radionuclides were done. In this case, the radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), and radioactivity level index (Iγ) were calculated. The results show that the mean values of Raeq, Hex, Hin, and Iγ were 230.6 Bq/kg, 0.628, 0.861, and 0.831, respectively. These results were below the global criteria levels for Raeq, Hex, Hin, and Iγ, which are 370 Bq/kg, 1, 1, and 2, respectively. Estimates for the absorbed dose rate in the air (DR), the annual effective dose equivalent (AEDE), and the annual gonadal equivalent dose (AGED) were also made. The findings revealed that the corresponding mean values for DR, AEDE, and AGED were 106.8 nGy/h, 1.07 mSv/y, and 744.4 μSvy-1. The mean values exceeded the global average value of 57 nGy/h for DR, 0.07 mSv/y for AEDE, and 2984 Sv/y for AGED. Therefore, Tin mining activities in the Kyerwa District could endanger the mining community from natural radioactive sources. In this study, therefore, we recommend performing a periodic inspection of the mining areas, monitoring the mining workers, and determining the level of activity and concentrations of different radionuclides in the mining area.

Qualitative and quantitative imaging of alpha‐emitting radiopharmaceuticals

AbstractTargeted alpha (α) therapy (TAT) is an emerging therapeutic strategy for cancer treatment. To evaluate the safety and efficacy of targeted α‐therapy, the biodistribution and internal radiation dose of α‐emitting radionuclides should be determined. In vivo imaging of these radionuclides often involves the detection of gamma rays, X‐rays, and positrons generated during their complex decay processes. This review aims to classify the α‐emitting radionuclides (astatine‐211, actinium‐225, radium‐223, bismuth‐212, bismuth‐213, thorium‐227, and terbium‐149) according to their imageable signals. Additionally, this study summarizes various imaging modalities, including gamma camera imaging, single‐photon emission computed tomography, positron emission tomography, Compton imaging, bremsstrahlung imaging, and Cerenkov luminescence imaging, which hold potential for imaging α‐emitting radionuclides, to explore their biomedical applications in qualitative nuclide tracing and diagnosis, quantifying pharmacokinetics, and assessing prognosis and response to therapy.

Integration of beta counting system with ORION-DSP coupled to NaI(Tl) detector-a comparative study with an HPGe detector.

The integration of the ORION digital signal processing-based MCA system coupled with a 3″ × 3″ NaI(Tl) detector assembly with a GM detector for counting beta (β) has eliminated the need for a standalone β-γ method in which U3O8 is determined by gross β and gross γ counting. Uraniferous and mixed U-Th samples were taken up for study and compared with the results obtained from Canberra p-type coaxial high resolution gamma ray spectrometry detector. In uraniferous samples, U3O8 values obtained are within ±10%, whereas in the case of mixed U-Th samples, U3O8 values are within ±15%. Regression graphs drawn between the outcomes from the two analytical systems indicate R2>0.95 for Ra(eU3O8) and ThO2. In uraniferous samples, the R2 value for U3O8 was found to be > 0.99, but in mixed U-Th samples, it is 0.92. The closeness of agreement between the results obtained from two methods at various concentrations over the analytical range shows that the integrated system is suitable for the quantitative determination of eU3O8, U3O8, Ra(eU3O8), ThO2 and K in geological rock samples.

The Bacau (Romania) phosphogypsum stacks as a source of radioactive threat: a case study

ABSTRACT For a detailed characterization of the 5.7 106 mt phosphogypsum (PG) stack in the vicinity of Bacau city, Romania, the air dose rate (ADR) was measured in 72 points covering the stack surface, while 10 samples of stack material were collected for future analysis. Radiometric determinations showed for the ADR values varying between 364 ± 53 and 489 ± 8 nSv/h, with some extreme values of 2775 ± 734 nSv/h, significantly exceeding 90 nSv/h, the average value reported for the Romanian territory. High-resolution gamma-ray spectroscopy (HRGS), performed on 10 samples collected from the entire PG stack evidenced only the presence of 226Ra as the major radioactive element with a specific activity varied between 820 ± 150 and 5278 ± 264 Bq/kg for hot spots. Further analysis performed on a similar number of samples by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDX), evidenced, beside gypsum as the main component, traces of brushite (CaHPO4·2H2O) and ardealite (Ca2(PO3OH)(SO4)·4H2O), as well as the presence of small acicular celestine (SrSO4) agglomerates. XRF determinations of the mass fractions of major elements evidenced values such as SiO2 (2.31 ± 0.73 %), TiO2 (0.07 ± 0.01 %), Al2O3 (0.17 ± 0.04 %), Fe2O3 (0.87 ± 0.18 %), MnO (0.01 ± 0.01 %), MgO (0.17 ± 0.02 %), CaO (32.5 ± 0.82 %), Na2O (0.04 ± 0.04 %), K2O (0.05 ± 0.01 %), P2O5 (2.12 ± 0.51 %), LOI (20.2 ± 0.3 %), i.e. closer to literature reported data for PG of different provenience while the data concerning the distribution of 20 trace elements, including incompatible Sc, La, Ce, and Th were relatively closer to the upper continental crust (UCC).

Low and high-resolution gamma-ray spectroscopy for the characterization of uranium contamination

Decommissioning is the last step in the life cycle of a nuclear facility. After the evacuation of the facility components, the remaining structures such as concrete walls and floors must be controlled to ensure that no residual contamination remains. As it is a costly and time consuming activity, CEA develops fast measurement methods allowing a complete scanning of very large areas (hundreds of thousands of square meters) in legacy uranium enrichment plants based on gas diffusion, at Pierrelatte nuclear site, France. After fast alpha and beta measurements, HPGe and NaI gamma-spectroscopy detectors are used to characterize more precisely uranium contamination. HPGe has excellent energy resolution but requires very long acquisition times. On the contrary, NaI(Tl) detectors enable rapid measurement, but extracting the contamination signal from the natural background is difficult due to their low resolution. Using an innovative approach based on energy bands of the NaI spectra, contamination activity and enrichment are consistent with that measured with HPGe but in only 15 min vs. 65 h, and with a sufficiently low relative uncertainty of about 15 % and 20 %, respectively, on activity and enrichment. Large area NaI(Tl) detectors will allow cost-effective scanning of the Gaseous Diffusion Plant (UDG) nuclear site (hundreds of thousands of squared meters) within practical times, in complement to alpha and beta contamination detectors.

Removal of 177Lu from radioactive wastewater using Montmorillonite clay

Because radioactive 177Lu has a wide range of possible applications in radiopharmaceuticals, its removal from medical wastewater is particularly important. Montmorillonite clay was employed as an adsorbent in this study. Radioactive solutions were prepared with dilutions of the solution containing 177Lu at various concentrations, in which it was present as Lu3+. ULEGe detector in gamma spectrometer was used to measure 177Lu gamma rays emitted from the radioactive aqueous solutions. The results obtained showed that it is possible to remove 177Lu with a high yield of approximately 90% and it is effective in a period of 90 min under acidic conditions. From the findings, it can be argued that Montmorillonite clay, as an abundant and sustainable adsorbent, may also be suitable for the disposal of different radioactive medical wastes such as 131I and 99mTc, and also the technique based on gamma ray spectroscopy can be used for fast and practical measurements of radioactive material amounts.

Gamma-rays and X-rays spectrometries applied to evaluate soil redistribution

This work responds to the growing global demand for food, which requires improvements in agricultural production and sustainable management of natural resources. The focus is on soil erosion as a critical element in preserving agricultural productivity. From this perspective, the levels of radionuclides and chemical elements present in the soil, quantified through Gamma-Rays Spectrometry (GRS) and Energy Dispersive X-ray Fluorescence (EDXRF), were used to investigate soil redistribution over time. 27 soil samples ranging from 0 to 30 cm in depth were collected in an agricultural plot located in southern Brazil. Quantitative analysis indicated high mean concentrations of Fe (161 ± 7 gkg−1), Al (110 ± 17 gkg−1), Ca (2.6 ± 0.5 gkg−1), Mn (2.4 ± 0.3 gkg−1) and K (543 ± 165 mgkg−1) in comparison with the other detected elements. The quantification of 137Cs provided a mean inventory of 27 ± 17 Bqm−2. Using the proportional model, an estimated gross erosion rate of 28.2 tonha−1year−1 and a net soil deposition of 6.6 tonha−1year−1 were calculated. Therefore, a net soil loss of 21.6 tonha−1year−1 was experienced within the agricultural plot studied. The data set combination of both techniques with Principal Component Analysis (PCA) revealed correlations between the variables studied and the soil erosion dynamics. The PCA showed a tendency to separate the samples according to their sampling depth. Moreover, 137Cs behavior in soil proved to be similar to the behavior of elements found in fertilizers, like K. On the other hand, the individual influence of 137Cs was not enough to cause significant changes in the samples distribution in the scores plot, highlighting EDXRF as a promising technique to complement soil erosion studies.

Radiological impact of 226Ra, 232Th and 40K in fodders from Penang, Malaysia

The plant acts as an important route for the transfer of radionuclides from the soil to animals, leading to the transfer of radiation to human food products such as beef and milk. Therefore, the level of radioactivity in fodder plays a crucial role in deciding whether cattle may be allowed to graze in a certain area. In this study, the activities of 226Ra, 232Th and 40K were measured via gamma-ray spectrometry on different fodder samples, including napier leaves, rice straw, corn stalks, guinea grass, mixed pasture, palm oil leaves and palm kernel collected from Penang, Malaysia. Theoretical calculations were also conducted to estimate the levels of these radionuclides in caw's products (beef and milk), as well as their potential radiological impact on local consumers. On average, the annual effective dose due to ingestion of radionuclides in milk was 11.39 μSv y−1, whereas in beef it was 5.63 μSv y−1. These values are significantly lower than the worldwide average of 290 μSv y−1. Research confirmed that farmers' usage of the aforementioned feeds did not cause any radiation-related health risks.

Analysis of radon progeny contamination

ABSTRACT In the present work, the radon contamination has been investigated with a high-purity germanium detector and dual ‘gamma + beta’ and ‘alpha’ contamination metre. Radioactive radon (222Rn) and products of its decay were collected by well-known swiping technique. Naturally occurring dust deposited on a plastic surface was collected and the radiation emissions coming from the collected sample were measured and analysed. The main radioactive isotopes contributing to the gamma spectrum were determined. The time behaviour of radon progeny contributing to gamma and alpha activities was investigated and compared with a modelled forecast. The minimal detectable activity when the radon progeny could be determined with a high-purity germanium gamma spectrometer has been established. Also, the minimum activity, measured with a dual contamination metre, has been recognised at which the presence of radon progeny contamination can be determined using gamma spectrometry. A new method is proposed for determining the duration of radon contamination and the time when the contamination occurred. The method is based on the analysis of the relative gamma activities of radon progeny (214Pb and214Bi) measured at different times after the radon contamination.

Americium-241 in peat bogs as a global marker of the beginning of the Anthropocene: examples from Europe and North America

Fallout radionuclides are being considered as potential global indicators of the beginning of the Anthropocene, yet questions persist about their preservation in bogs. This study assessed the reliability of 241Am records in peat cores from acidic, ombrotrophic bogs. The source of 241Am (half-life 432.7 years) in these natural archives is radioactive decay of the short-lived plutonium isotope 241Pu (half-life 14.329 years) present in fallout from the atmospheric testing of nuclear weapons. We leveraged previously gathered data to gauge the congruence of 241Am records with 210Pb dates, examining the alignment of the 241Am activity peak with the depth corresponding to the year AD 1963, as determined using the 210Pb constant rate of supply (CRS) model. Our analysis employed 35 peat cores from 30 sites across Europe and North America, collected over the last three decades for trace metal deposition studies. Each core underwent independent 210Pb dating. Among the 35 cores, 10 were excluded because of significant uncertainty in 241Am peak quantification. Among the remaining 25 cores, 22 displayed a single 241Am peak and 3 exhibited two peaks with similar 241Am activities. Of the 22 cores with a single peak, 18 were within 10 years of AD 1963, with 10 of those being within 5 years. For 10 of the 22 cores, 14C dates obtained from the atmospheric bomb pulse curve enabled comparison, with 9 showing ≤10 years of difference and 7 of those showing ≤5 years from the 210Pb CRS model AD 1963. Factors contributing to age discrepancies included (i) analytical limitations of 241Am measurements in peat using gamma spectrometry, (ii) the impact of peat accumulation rates on 241Am activities, i.e., dilution effects, (iii) post-depositional migration of 241Pu and (or) 241Am, (iv) uncertainties introduced during 210Pb age-modelling, and (v) the limited number of samples dated using 14C. The usefulness of 241Am as an Anthropocene marker (assuming AD 1963) hinges on the accepted uncertainty level in defining this epoch. Detection of 241Am through gamma spectrometry was statistically validated as a real peak in 22 out of a total of 35 cores: this fraction (63%) is within the range reported in other studies. Given that the cores were gathered from 16 European and 14 North American sites, these peaks can be taken to denote the hemispheric onset of the Anthropocene. Lastly, common post-depositional migration of 137Cs in ombrotrophic peatlands contrasts with its immobility in minerotrophic peatlands, where the presence of mineral matter and neutral pH inhibit its movement. This observation suggests that fens and swamps, characterized by minerotrophic conditions, may also serve as repositories of nuclear weapons test fallout, including 241Am.

Comparing 3D printing techniques (SLA vs. FDM) for their use in radionuclide metrology

This paper presents a comparative analysis, in which we evaluate the parameters of SLA and FDM printing technologies, for the production of radioactive standard sources in the SARPAGAN geometry, frequently encountered in radionuclide metrology. Aspects such as material compatibility, dimensional accuracy, radiation stability and the influence of 3D printing technology on the reliability of the final product will be addressed. Furthermore, the results obtained by gamma-ray spectrometry on a sample of 99mTc, using the standard SARPAGAN geometry, in comparison with the two 3D printed SARPAGAN geometries (SLA and FDM), were analyzed to evaluate how both the material and the technique printing of the geometry influences the results.

Soil –plant transfer factors of radionuclide in cassava (Manihot esculenta) around a cement factory in Kogi State, Nigeria

Mathematical models are typically used to predict how naturally occurring radionuclides migrate from soil to plants. A transfer factor (TF) is the ratio of radionuclide concentration (Bq kg−1) of plant to soil in dry weight. This research aimed at determining the soil to plant transfer factor of radionuclide, in order to access the level of migration of natural radionuclide from soil to a selected cultivated crop (cassava), due to cement production activity around a cement factory. Soil and cultivated plant samples were collected randomly at different locations around the factory. The collected samples were analyzed using NaI (Tl) gamma (γ) spectroscopy. The average transfer factor (TF) from soil to plant was found to be 0.428, 0.531 and 0.398 for 226Ra, 232Th and 40K, respectively. The TF indicates that about 42.8%, 53.1% and 39.8% of 226Ra, 232Th and 40K, respectively, were transferred from soil to cassava and varies in the order of 232Th (0531) > 226Ra (0.428) and 40K (0.398). All the transfer factors were below the world standard of unity. There exists a positive Pearson correlation among the three radionuclides in the soil and plant samples. The three radionuclides were detected in soil and food samples, and a positive correlation between them suggests that they originated from the same source for each environmental matrix. The results determined the value of TF of soil to cassava (Manihot esculenta) is at a safe level to the farmland around the cement factory and have no immediate radiological health implications due to cement production.

Radiation protection for Gabes phosphate area residents: Assessing natural radioactivity in soil and potable water samples

Phosphate mining activities are recognized to be one of various industrial processes generating enhanced Naturally Occurring Radioactive Materials (NORM) by introducing natural radionuclides into the surrounding soils and water bodies, posing a risk to human health.This study was carried out to assess the level of natural radionuclides in soils and potable waters collected from the phosphate area of Gabes city, located in southeastern Tunisia, and to evaluate radiation protection measures by estimating radiological health hazard parameters. Gamma spectrometry system employing an HPGe detector was used in this study to assess 40K, 232Th and 226Ra activity concentration in soils. The average values were found to be 163.7, 14.5, and 7.7 Bq kg−1, respectively, which were lower than worldwide average values. The radiological hazard parameters assessed in this study were radium equivalent activity (Ra-eq), external hazard index (Hex), external gamma absorbed rate (GDR), external annual effective dose (Deff) and excess lifetime cancer risk (ELCR). The calculated average values of the above-mentioned parameters were of 41 Bq kg−1, 0.1, 20.2 nGy h−1, 24.8 μSv y−1 and 8.7 × 10−5 all of which were found to be below their permissible standards.For potable water samples, the activity concentrations of radium were analyzed using an HPGe detector and those of uranium were determined by alpha spectrometry. The average activity concentrations of uranium and radium isotopes in underground water samples were found to be higher than those obtained in tap water samples. For both types of water, the average values for all radionuclides were found to be below their respective reference limits.The annual ingestion effective doses were also estimated in this study. The estimated average values for infant and children for underground water samples were higher than the permissible limit of 100 μSv y−1 set by WHO. The 226Ra was the main contributor to the effective doses for different age categories, followed by 228Ra.

Historical trends of heavy metals applying radio-dating and neutron activation analysis (NAA) in sediment cores, Burullus Lagoon, Egypt

Burullus lagoon is part of Egypt’s protected area network. The lagoon serves as a reservoir for drainage water discharged from agricultural areas, and the lake’s sediments provide a unique opportunity to record environmental behavior and reconstruct of the heavy metal contamination history. In the present study, the sediment chronology, sedimentation rates, and metal accumulation fluxes were estimated in four sediment cores using 210Pb dating models to evaluate how human activities have affected the coastal environment. Using the radioisotopes 210Pb and 137Cs, radiometric dating was carried out using gamma-ray spectrometry. At the Egypt Second Research Reactor (ETRR-2), the element concentrations were determined using the instrumented neutron activation analysis (INAA- k0 method). Our findings show that the constant rate of supply (CRS), which has been verified with the peak of artificial radionuclide 137Cs, is the best model performed for the chronology of Burullus Lagoon. The average sedimentation rate, according to 210Pb dating models, is 0.85 cm/year. The large variation in sedimentation rates, especially after the 1990s, is consistent with an increase in the anthropogenic flux of heavy metals. This may be led into a significant environmental problem such as reducing the size of the lake and degrading the quality the water in Burullus Lagoon. Enrichment factor (EF) of the studied elements displayed the following order: Cl > Ca > Na > Br > Zn > Ta > Ti > V > Cr > Sc > Mg > Mn > Fe > Hf which is higher than unity. Furthermore, the Nemerow pollution index (PI Nemerow) revealed that pollution was increasing in the direction of the drains and slightly polluted. Consequently, pollutant indices showed that urbanization and industrial development may have increased the depositional fluxes of the metals in sediments over time.