Analysis of the different source terms of natural radionuclides in a river affected by NORM (Naturally Occurring Radioactive Materials) activities (original) (raw)
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Radioactivity in Iberian Rivers with Uranium Mining Activities in their Catchment Areas
Procedia Earth and Planetary Science, 2014
Rivers flowing through the uranium mining region of Portugal, such as the Mondego and Zêzere rivers, receive drainage from areas of old uranium mines. The international River Águeda, a tributary to River Douro, has also important uranium mining and milling facilities in its catchment basin in Spain. In order to assess the radioactive contamination of these river basins resulting from uranium mining waste, uranium series radionuclides were measured in water, suspended particulate matter, and riverbed sediments. Results showed that significant radioactivity enhancement took place in sections of these rivers. This contamination persisted long time after environmental remediation implemented at some mine sites and cessation of mine discharges. The persistent risk of waste leaching and dam failure requires continued monitoring of radioactivity levels in these rivers.
Natural radioactivity in waters and sediments from a Spanish mining river
Radiation Physics and Chemistry, 2001
The environmental problem of naturally occurring radioactive materials (NORM) is omnipresent on earth and their radioactivity may become concentrated as a result of human activities. Various industries produce concentrated radioactivity in their by-products. Mining originating industries such as the coal industries, petroleum extraction and processing and natural gas, mining enrichment waste, phosphate, etc have been well known and widely investigated. The Environmental Protection Agency (EPA) describes NORM wastes from the mining and processing of three categories of metals: Rare earth metals, special application metals and metals produced in bulk quantities by industrial extraction processes. Moreover, NORM has a lot of negative effects on the natural resources (water supplies, soils, air, etc.) and living organisms (human, animals, plants, microorganisms, etc.). In this study, we investigated NORM levels that originated from mining industry and the concentration of NORM in drinking water supplies. NORM parameter of gross alpha and gross beta were also in this study, seasonal changes in gross alpha and gross beta were investigated. The obtained results showed that, natural activity concentrations of αand β-emitting radionuclides in all water samples did not exceed World Health Organisation (WHO) and Turkish Standards of Drinking Water (TS 266) recommended levels (Table 1). Concentrations ranging from 0.0062 Bq/l to 0.79 Bq/l and from 0.004 to 0.18 Bq/l were observed for the gross α and gross β activities, respectively. For all samples, the gross β activities were higher than the corresponding gross α activities.
Artificial radionuclides in waters of the lower section of the river Ebro (Northeast Spain)
2000
The river Ebro, in Northeast Spain, discharges into the Mediterranean Sea after flowing through several large cities and agricultural, mining and industrial areas. The Ascó nuclear power plant (NPP) is located in the lower river section and comprises two pressurised-water reactor (PWR) units, from which low-level liquid radioactive waste is released to river waters under authority control. During the period 1989 to 1993, we carried out 29 sampling campaigns in order to determine 3 H, 90 Sr, 134 Cs, 137 Cs, 238 Pu and 239,240 Pu in Ebro river waters at different locations, both upstream and downstream from the Ascó NPP. 3 H, 134 Cs and 137 Cs activities showed large variability as they ranged from <1.4 to 117±3 Bq L −1 , <0.27 to 22±1 mBq L −1 and <0.36 to 35±1 mBq L −1 , respectively. This behaviour, especially remarkable for tritium, was due to the detection of tank releases travelling downstream. The characteristic NPP 134 Cs/ 137 Cs ratio was found to be 0.61±0.02 (N = 22). In the estuarine area, 137 Cs traces from Mediterranean waters were observed and relatively enhanced tritium activities might possibly be present due to the accumulation of activity in the estuary. 90 Sr and 239,240 Pu activities were homogeneous both in respect to time and space, showing mean activities 6.9±0.2 mBq L −1 (N = 10) and 1.36±0.10 mBq m −3 (N = 3), respectively. These levels could only be attributed to nuclear weapons fallout leached by continental waters, as the impact from the plant appears to be negligible and no other sources are present in the area.
Water, Air, & Soil Pollution, 2017
Water quality was evaluated in a coal mining area in the city of Figueira, Paraná State, Brazil, where uranium was associated with the coal deposit. Upstream the mine, groundwaters were more acid and some elements and compounds, such as iron, aluminum, and sulfate, were in higher concentration, possibly because of acid mine drainage (AMD) generation in tailing pit. 238 U and 234 U activity concentrations exceeded the standards proposed by the World Health Organization in two sampling periods in effluent samples and in some groundwater samples, indicating that waters from this aquifer system were unhealthy for human consumption. Uranium isotopes were more elevated in groundwaters in the rainy month probably because of a higher leaching and transport rate of this element from rocks/ tailings pit to waters. The average radon activity concentration in groundwater was higher than in surface waters and effluents in both periods studied, possibly due to the enhanced presence of uranium and radium in the aquifer rocks that would favor the radon accumulation and entrapment. The effects of the mining activities on the groundwater quality were displayed in terms of activity ratios (234 U/ 238 U, 226 Ra/ 238 U), which showed different behaviors upstream the mine area relatively to areas downstream the mine.
Water Quality, 2017
The Yenisei River is one of the largest rivers in the world. There is Mining and Chemical Combine (MCC) of Rosatom located at Krasnoyarsk, on the bank of the River Yenisei, 50 km downstream of the city of Krasnoyarsk. Since 1958 MCC used river's water for cooling of industrial nuclear reactors for the production of weapon plutonium-238 Pu. Besides the pollution caused by industry-related radionuclides, pollution by natural radionuclide-uranium and its isotopes-are also investigated. Besides the natural uranium isotopes (234 U, 235 U, 238 U), exclusive artificial isotope-236 U was also found. Yenisei water was also polluted by high tritium content: from 4 Bq/L (back road value) to 200 Bq/L (some sample of water). The total amount of radionuclides investigated was about 20 radioisotopes. These radionuclides have different physical and chemical properties, different half-lives, and so on. Thus, the data on artificial radionuclides entering the Yenisei River water were obtained by long-term monitoring, which is likely to be connected with the activity of the industrial enterprises located on the river's banks of the studied area.
The article summarizes the activity concentrations data of 226 Ra and the sum of uranium isotopes (∑U) in samples of drinking underground water for different regions of Ukraine studied during 1998-2023 in the radiation monitoring laboratory of the State Institution "O.M. Marzieiev Institute of Public Health National Academy of Medical Sciences of Ukraine. Arithmetic mean and standard deviations, minimum and maximum values for 226 Ra and ∑U activity concentrations are presented for the entire 1240 sample set and for each region separately. Collected data show that the established state permissible level for drinking water of 1.0 Bq/l is exceeded for 226 Ra in 1.1% of the studied samples, and for ∑U-in 3.9% correspondingly. The detected high levels of 226 Ra and ∑U activity concentrations correspond to certain regions belonging to the Ukrainian crystalline shield territory. A comparison of the current data with the data of previous studies held during of 1989-1991 indicates a significant difference: for the previous studies the average and standard deviations are much higher. We attribute this to the fact that the centralized sampling of previous studies was random, and it was related exclusively to communal water supply systems. At the same time, the current sample set covers a much larger number of regions, different water consumers; the data set includes the results of repeated studies for a large number of sources, in particular, sources with purified water. Hypothetical exposure doses caused by consumption of 226 Ra and ∑U in water for the current sample set were estimated for different age groups for each sample studied, as is, without taking into account the pattern of water consumption. The corresponding dose exceeds the WHO recommended value of 0.1 mSv per year for children under the age of one year for 220 cases (17.7%). This dose limit excess for other age groups corresponds-for children: aged 12-17 years-13.1%, aged 1-2 years-7.4%, 7-12 years old-5.6%, 2-7 years old-3.9% and for adults-4.1%. Protection of underground water is commonly much higher than for surface water with regard to chemical and microbiological pollutants, which sets the priority of its use as drinking water source 1. At the same time, underground water contains natural radionuclides of the U and Th series. The radioactivity concentration in water is formed by the radioactive composition of the rocks, the level of fissuring of the rocks, the chemical properties of the water and the contact time of the water with the rocks 2. Author shoved scatted plot of uranium versus 226 Ra in random Australian ground water illustrating the lack of correlation between parent and decay product. The introduction of natural radionuclides into water occurs due to diffusion of gas (222 Rn) or leaching (U, Ra) from the surface of rocks. The chemical composition of water defines the intensity and priority of certain radionuclides leaching. High levels of natural radionuclides in drinking water are observed primarily for artesian wells with a depth of several tens to hundreds of meters, although in some places favorable conditions for the entry of natural radionuclides into water present even for aquifers with a depth of only a few meters or even for surface streams 3. In addition, high levels of natural radionuclides in surface water can form discharges from mining and processing industrial enterprises, mines.
Radionuclides release to three rivers by ore treatment unit at Caldas, Minas Gerais-Brazil
The Ore Treatment Unit (OTU) is a uranium mining and milling plant, situated at Caldas city, Minas Gerais, Brazil that was disabled in the mid 90's. This unit releases controlled effluents to three rivers: Ribeirão das Antas (at point 014, influenced by the waste pile), Ribeirão Soberbo (point 025, influenced by the waste pond) and Córrego da Consulta (at point 076, influenced by the open pit mine). Water samples collected at these points were analyzed for U nat , 226 Ra, 210 Pb, 232 Th and 228 Ra content in the particulate and soluble fractions, and the behavior of radionuclide releases and their fractions was investigated. U nat and 228 Ra showed identical behaviors at these three points. U nat at point 014 (waste pile) behaved different from described in recent literature data. The isotopes of Ra should exhibit the same behavior at each point, but this was not observed at point 025 (waste pond). 232 Th release showed equal activity concentration near the waste pile (point 014) and near the waste pond (point 025), whilst near the open pit mine (point 076) the soluble fraction showed a concentration of activity greater than the particulate fraction. Finally, 210 Pb showed a different behavior at each point. Due to the great differences in behaviors of each radionuclide, it was not possible to establish a temporal pattern of release which requires assessment over a longer period of time.
Natural radionuclides in waste water discharged from coal-fired power plants in Serbia
Water Science and Technology, 2016
Investigation of the natural radioactivity levels in water around power plants, as well as in plants, coal, ash, slag and soil, and to assess the associated radiation hazard is becoming an emerging and interesting topic. This paper is focused on the results of the radioactivity analysis in waste water samples from five coal-fired power plants in Serbia (Nikola Tesla A, Nikola Tesla B, Kolubara, Morava and Kostolac), which were analyzed in the period 2003–2015. River water samples taken upstream and downstream from the power plants, drain water and overflow water were analyzed. In the water samples gamma spectrometry analysis was performed as well as determination of gross alpha and beta activity. Natural radionuclide 40K was detected by gamma spectrometry, while the concentrations of other radionuclides, 226Ra, 235U and 238U, usually were below the minimum detection activity (MDA). 232Th and artificial radionuclide 137Cs were not detected in these samples. Gross alpha and beta activ...
Bulletin of Environmental Contamination and Toxicology, 2009
Two large uranium mines, Quinta do Bispo and Cunha Baixa, district of Viseu, North of Portugal, were exploited until 1991. Sulfuric acid was used for in situ uranium leaching in Cunha Baixa mine and for heap leaching of low grade ores at both mines. Large amounts of mining and milling residues were accumulated nearby. Since closure of mines, the treatment of acid mine waters has been maintained and treated water is released into surface water lines. Analysis of radionuclides in the soluble phase and in the suspended matter of water samples from the uranium mines, from the creeks receiving the discharges of mine effluents, from the rivers and from wells in this area, show an enhancement of radioactivity levels. For example, downstream the discharge of mine effluents into Castelo Stream, the concentrations of dissolved uranium isotopes and uranium daughters were up to 14 times the concentrations measured upstream; 238 U concentration in suspended particulate matter of Castelo Stream reached 72 kBq kg -1 , which is about 170 times higher than background concentrations in Mondego River. Nevertheless, radionuclide concentrations decreased rapidly to near background values within a distance of about 7 kilometers from the discharge point. Enhancement of radioactivity in underground waters was positively correlated with a decrease in water pH and with an increase of sulfate ion concentration, pointing out to Cunha Baixa mine as the source of groundwater contamination. The radiotoxic exposure risk arising from using these well waters as drinking water and as irrigation water is discussed and implementation of environmental remediation measures is advised.