Manny Mathuthu

Transfer Rates of 238U and 232Th for E. globulus, A. mearnsii, H. filipendula and Hazardous Effects of the Usage of Medicinal Plants From Around Gold Mine Dump Environs

Medicinal plant consumption can be a source of human exposure to radioactive elements such as 238U and 232Th, which can lead to internal radiation doses. The uptake of 238U and 232Th from soils to the leaf samples of three different medicinal plant species (Eucalyptus globulus, Acacia mearnsii and Hyparrhenia filipendula) from the purlieu of the Princess gold mine dump, an abandoned contaminated tailings storage site (TSS), located at longitude 27°55′00″E and latitude 26°09′30″S in Davidsonville (Roodepoort, west of Johannesburg, South Africa) was measured. This was done using ICP-MS spectrometry and substantial differences were observed in the soil-plant transfer factor (TF) values between these radionuclides. The plant species E. globulus exhibited the highest uptake of 238U, with an average TF of 3.97, while that of H. filipendula was 0.01 and the lowest TF of 0.15 × 10−2 was measured for A. mearnsii. However, in the case of 232Th, the highest average TF was observed for A. mearnsii (0.29), followed by E. globulus (0.10) and lowest was measured for H. filipendula (0.27 × 10−2). The ratio of TF average value i.e., 238U to 232Th in the soil-plant leaves was 38.05 for E. globulus, 0.01 for A. mearnsii and 4.38 for H. filipendula.

Determination of lead isotope ratios in uranium mine products in South Africa by means of inductively coupled plasma mass spectrometry

Nuclear terrorism has led to newer investigative methods for building national nuclear forensic libraries. The objective of this work was to resolve these signatures by applying the ICP-MS for isotope ratio (IR) analysis on uranium containing samples. Lead (Pb) isotope ratios for the studied gold mine has 207Pb/204Pb values between 13–20 and 206Pb/204Pb values ranging from 16–25, which confirm that the Carletonville gold fields are of uraninite detrital pyrite deposits. Trace elemental concentrations indicated a pyrite type of uranium deposit. Uranium in the deposit exhibits geochemical signatures of the radiogenic formations of the ore enhanced in 206Pb.

Chemical Toxicity of Surface-Based Drinking Water Sources Due to Natural Uranium Pollutant Around Princess Gold Mine Environs in Roodepoort, South Africa

The activity level of natural uranium pollutant in surface-based water around Princess Gold Mine in Roodepoort, South Africa was measured using inductively coupled plasma mass spectrometry. The highest activity level of 6.39E+04xa0mBq/L is reported in the reddish brown ochre surface water from tailing (SWA-RB) close to the houses, whereas the lowest value of 1.92E+03xa0mBq/L is reported in the flowing surface water (SRWA-5) 1xa0km away from the dump. Along the path high values of 1.56E+04, 1.07E+04, 1.57E+04 and 8.46E+03xa0mBq/L were reported at SRWA-2, SRWA-3 and SRWA-4, respectively. The inhabitants living around the tailings use the surface water for daily consumption. Based on the annual limit guideline for drinking water recommended by World Health Organization (731xa0L/year), this study revealed that, the community around this vicinity receives 2.10xa0mSv as the highest annual collective effective dose due to 238U in the drinking surface water. The radiological-health risks of 238U in the water samples analysed revealed the highest cancer mortality and morbidity values of 2.40E+03 and 3.67E+03, respectively. The mean chemical toxicity risk for the natural uranium over the lifetime consumption is 5.31E+05xa0μg/kg/day which shows that the main human risk may likely be due to the chemical toxicity of natural uranium.

Heavy metal concentration in soil in the tailing dam vicinity of an old gold mine in Johannesburg, South Africa†

Abstract: Soil contamination with heavy metals is a serious concern to food production and human health. The present study was conducted to evaluate the impact of tailings from an old mining site on heavy metal contamination of soil. Using a GPS to map out different sites around the tailing dam, soil samples were taken from under grassland at the different sites, at depths of 15 cm and 1 m, using a shovel and handheld auger. The samples were prepared, acid digested, and analyzed for a multi-element suite by inductively coupled plasma atomic emission spectrometry. Results showed heavy metal concentration in the order of Cr > Zn > As > Mn > Cu > Pb > Ni > Sr > Hg. Most of the soil samples contained high concentration of As (13.46-234.6 mg kg-1). Soil concentrations of As, Hg, Cr, and Mn also decreased with distance from the dump material. Single contamination index of each pollutant, calculated according to the South African Soil Quality Standards revealed very high and medium pollution grades for As (index = 7.39) and Cr (index = 2.16), respectively. Arsenic is a metal associated with gold ore and soil pollution by such metals can make it infertile and unsuitable for plants.

Exposure Risks Assessment Due to Gamma Emitting Radionuclides in Soils and Consumable Waters Around Princess Gold Mine Dump in Roodepoort, South Africa

This study evaluated the activity concentration of 238U, 226Ra, 232Th, and 40K around the Princess Gold Mine dump in Roodepoort, South Africa using gamma spectrometry and ICP-MS. The soil contained a high concentration of 238U at a depth of 1xa0m and at the surface. Doses due to ingestion of the untreated water were estimated as being far above the limit of 0.10xa0mSv/a set by the World Health Organization. The South African National Nuclear Regulator’s reference value of 0.25xa0mSv/a was also exceeded by almost all of the analyzed water samples. Thus, the dose the public could receive from drinking this water poses a potential radiological health risk.抽象利用伽马光谱和ICM-MS评价了Princess金矿尾矿堆(Roodepoort, 南非)附近土壤的238U、226Ra、232Th和40K活性浓度。地表及1m深土壤都含有较高浓度238U。居民饮用未处理水而摄入放射性核素的剂量将远高于世界卫生组织规定的0.10 mSv/a标准。几乎所有水样测试值都超过南非规定的核素摄入量参考值0.25mSv/a。因此,饮用研究区水存在摄入过量放射性核素的健康风险。ZusammenfassungDiese Studie untersuchte die Aktivitätskonzentration von 238U, 226 Ra, 232Th und 40K im Umfeld der Kippe der Princess Gold Mine in Roodeport, Südafrika mittels Gammaspektrometrie und ICP-MS. Der Boden enthielt in einer Tiefe von 1 m und an der Oberfläche eine hohe Konzentration von 238U. Es wurde eingeschätzt, dass die Dosen auf Grund der Einnahme des unbehandelten Wassers weit über dem Grenzwert der Weltgesundheits¬organisation von 0,1 mSv/a liegend. Der Referenzwert des Süd¬afrikanischen Nuklearen Regelwerkes von 0,25 mSv/a wurde ebenfalls in fast allen analysierten Wasserproben überschritten. Damit stellt die Dosis, die die Öffentlichkeit beim Trinken des Wassers erhalten kann, ein mögliches radiologisches Gesundheitsrisiko dar.ResumenEste estudio evaluó la actividad de 238U, 226Ra, 232Th y 40K cerca del vertedero de la mina de oro Princess en Roodepoort, Sudáfrica usando espectrometría gama y ICP-MS. El suelo contenía una alta concentración de 238U a una profundidad de 1 m y en la superficie. Se estimaron las dosis debido a la ingestión de agua no tratada que estuvo muy por encima del limite de 0,10 mSv/a indicado por la Organización Mundial de la Salud. Casi todas las muestras de agua analizadas excedieron también el valor de referencia de 0,25 mSv/a de la Regulador Nacional Nuclear de Sudáfrica. Así, la dosis que el público podría recibir consumiendo esta agua posee un potencia riesgo radiológico para la salud.

Analysis of reaction cross-section production in neutron induced fission reactions on uranium isotope using computer code COMPLET

This study provides current evidence about cross-section production processes in the theoretical and experimental results of neutron induced reaction of uranium isotope on projectile energy range of 1-100u202fMeV in order to improve the reliability of nuclear stimulation. In such fission reactions of 235U within nuclear reactors, much amount of energy would be released as a product that able to satisfy the needs of energy to the world wide without polluting processes as compared to other sources. The main objective of this work is to transform a related knowledge in the neutron-induced fission reactions on 235U through describing, analyzing and interpreting the theoretical results of the cross sections obtained from computer code COMPLET by comparing with the experimental data obtained from EXFOR. The cross section value of 235U(n,2n)234U, 235U(n,3n)233U, 235U(n,γ)236U, 235U(n,f) are obtained using computer code COMPLET and the corresponding experimental values were browsed by EXFOR, IAEA. The theoretical results are compared with the experimental data taken from EXFOR Data Bank. Computer code COMPLET has been used for the analysis with the same set of input parameters and the graphs were plotted by the help of spreadsheet & Origin-8 software. The quantification of uncertainties stemming from both experimental data and computer code calculation plays a significant role in the final evaluated results. The calculated results for total cross sections were compared with the experimental data taken from EXFOR in the literature, and good agreement was found between the experimental and theoretical data. This comparison of the calculated data was analyzed and interpreted with tabulation and graphical descriptions, and the results were briefly discussed within the text of this research work.

Developing Nuclear Forensics Signaturesand National Nuclear Forensics Librariesfor the African Continent: A Case Reviewfor South Africa

Nuclear terrorism has led to the development of National Nuclear Forensics Libraries (NNFL) from signatures by each Member State of the International Atomic Energy Agency (IAEA). The objective of this Review is to highlight the need for Africa States especially South Africa to set-up their own Nuclear Forensic Laboratories that will apply available techniques to develop NNFL for their nuclear material. An overview of some applicable techniques is given as well as a few demonstrative results.

Radionuclides and toxic elements transfer from the princess dump to water in Roodepoort, South Africa

High concentrations of radionuclides and toxic elements in gold mine tailings facilities present a health hazard to the environment and people living near that area. Soil and water samples from selected areas around the Princess Mine dump were collected. Soil sampling was done on the surface (15 cm) and also 100 cm below the surface. Water samples were taken from near the dump, mid-stream and the flowing part of the stream (drainage pipe) passing through Roodepoort from the mine dump. Soil samples were analyzed by gamma-ray spectroscopy using a HPGe detector to determine the activity concentrations of (238)U, (232)Th and (4) (u200b40)K from the activities of the daughter nuclides in the respective decay chains. The average activity concentrations for uranium and thorium in soil were calculated to be 129 ± 36.1 Bq/kg and 18.1 ± 4.01 Bq/kg, respectively. Water samples were analyzed using Inductively Coupled Plasma Mass Spectrometer. Transfer factors for uranium and thorium from soil to water (at point A closest to dump) were calculated to be 0.494 and 0.039, respectively. At point Z2, which is furthest from the dump, they were calculated to be 0.121 and 0.004, respectively. These transfer factors indicate that there is less translocation of the radionuclides as the water flows.