Transfer Of Natural Radionuclides Research Articles

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) under flooded and unflooded conditions in Hanoi, Vietnam

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) in Hanoi, Vietnam have been investigated using a low background gamma spectrometer with an HPGe detector (Model-GC5019). Twenty pairs of soil and water spinach samples in two environmental conditions, i.e., flooded and unflooded, were collected for measuring the activity concentrations and determining the soil-to-plant transfer factors (TFs) of natural radionuclides. For water spinach, stems and leaves were collected as the main parts for human consumption and livestock food. The TF of 40K is within the range of 0.32–2.49, which is greater than that of 228Ra (0.01–0.17) and 226Ra (0.01–0.13). The geometric means (geometric standard deviations) of the TFs are 1.17(1.89), 0.05(2.41) and 0.04(1.88) for flooded sites, and 0.89(1.73), 0.03(2.12) and 0.03(1.82) for unflooded sites, respectively. Comparing between the flooded and unflooded sites, the TFs are all greater at the flooded sites.

Transfer of Natural Radionuclides from Soil to Plants in Nasarawa, Nasarawa State, Nigeria.

Transfer of Natural Radionuclides from Soil to Plants in Nasarawa, Nasarawa State, Nigeria.

Effect of mineral fertilisers application on the transfer of natural radionuclides from soil to radish (Raphanus sativus L.)

Non-controlled usage of mineral fertilisers in agriculture land of Kazakhstan is a concerning issue, due to possible contamination of the soil by radionuclides. Pot experiment of growing of R. sativus with application of mineral fertilisers was carried out under natural conditions. Two commonly used mineral fertilisers, mono-potassium phosphate and ammonium nitrate, were chosen in the frame of current research to determine the impact of mineral fertiliser on transfer of natural radionuclides from soil to R. sativus edible part. For this goal, the activity concentrations of natural radionuclides U-234, U-238, Th-230, Th-232 and Ra-226, were determined in both R. sativus edible part and the investigated soil by using alpha-particle spectrometry. The highest activity concentrations were found for R. sativus edible part growing on soil that was fertilised by mono-potassium phosphate and were equal to 174 ± 17, 134 ± 15, 62 ± 4, 15 ± 2 and 2.8 ± 0.6 Bq/kg for U-234, U-238, Th-230, Th-232 and Ra-226, respectively. The results of soil-to- R. sativus edible part transfer factor for different radionuclides varied depending on the mineral fertiliser used. For evaluation of impact during consumption of R. sativus edible part by a population of Kazakhstan, annual effective ingestion dose and excess lifetime cancer risk were determined. The highest annual effective ingestion dose was found for R. sativus edible part cultivated in mono-potassium phosphate-fertilised soil and was equal to 4.4 μSv year−1.

Transfer of Natural Radionuclides in Terrestrial Food Chains-A Review of Investigations in Finland.

Transfer of natural radionuclides 210Pb, 210Po, 238U, and 228,230,232Th in subarctic food chains has been studied in Finland since the 1960s. The unique food chain lichen-reindeer-man related to Sami people in Finnish Lapland and other food chain options, from berries or mushrooms to man, have been explored and the activity concentrations of natural radionuclides in biological samples determined. The results from Finnish radioecological studies are summarized and differences in bioaccumulation between different radionuclides are discussed. It was found out that, although a substantial amount of activity concentration data exist from the research projects executed in Finland during the last 6 decades, more data, especially from U and Th, in biological environment and humans would be useful, e.g., for modeling purposes and for improved assessment of bioaccumulation and adverse effects (both radiological and chemical) of radionuclides.

Soil-to-crop transfer of natural radionuclides in farm soil of South Africa.

The activity concentration of natural radionuclides in farm soil and most common indigenous food crops (maize, potato, cowpea) in oil-producing (Philippi, Uitenhage, and Hertenbos farms) and non-oil-producing (Ukulinga farm) areas of South Africa was measured using a Hyper Pure Germanium detector. Consequently, the transfer of these radionuclides from soil-to-crops was estimated. The mean activity concentration of 226Ra, 232Th, and 40K for farm soil samples are 30.71 ± 11.77, 31.97 ± 8.90, 345.97 ± 98.62 Bq.kg-1 for Philippi; 18.67 ± 6.70, 31.55 ± 11.48, 191.93 ± 33.39 Bq.kg-1 for Uitenhage; 38.03 ± 17.44, 41.18 ± 31.54, 381.89 ± 163.40 Bq.kg-1 for Hartenbos; and 8.47 ± 2.87, 8.65 ± 3.52, 94.22 ± 25.97 ± 25.97 Bq.kg-1 for Ukulinga. The mean activity concentration of 226Ra, 232Th, and 40K for crop samples are 4.54 ± 1.47, 4.87 ± 1.69, 140.18 ± 35.38 Bq.kg-1 for Philippi; 9.17 ± 4.79, 3.85 ± 1.87, 136.75 ± 22.04 Bq.kg-1 for Uitenhage; 7.97 ± 2.91, 4.62 ± 2.40, 105.97 ± 48.65 Bq.kg-1 for Hartenbos; and 4.23 ± 1.63, 2.72 ± 1.19, 48.36 ± 15.55 Bq.kg-1 for Ukulinga. The activity concentration and soil-to-crop transfer factors for 40K were found to be much higher, possibly because this element is critical in crop growth. The results showed that the crop samples' transfer factor is in the order cowpea>potato>maize. This study showed that activity concentrations of 226Ra, 232Th, and 40K in crops and the corresponding transfer factors depend on activity concentrations of the same radionuclides in soil.

Transfer of natural radionuclides from soil to plants in Savar Dhaka

The radioactivity of environmental samples from nuclear reactor sites must be analyzed before the public is given free access to the plants grown in these soils. Plant and corresponding soil samples were collected from a sample site around the Savar research reactor near Dhaka (Bangladesh) and the activity concentrations of natural radionuclides <sup>226</sup>Ra (<sup>238</sup>U-chain), <sup>228</sup>Ra (<sup>232</sup>Th-chain) and non-chained <sup>40</sup>K were measured using gamma ray spectrometry. Soils of Savar contained more radioactive <sup>40</sup>K than <sup>226</sup>Ra and <sup>228</sup>Ra. The influence of certain soil properties on the activity concentrations and transfer factors (TF) of natural radionuclides were investigated by correlating the observed data with those of soil properties. The activity concentrations of <sup>40</sup>K were much higher than those of <sup>226</sup>Ra and <sup>228</sup>Ra in plants due to higher uptake from soils. The transfer factors for <sup>226</sup>Ra, <sup>228</sup>Ra and <sup>40</sup>K were found to range from 0.04 to 0.10, 0.12 to 0.32, and 0.24 to 0.72, respectively. The soil to plant transfer factors for <sup>40</sup>K was found to be much higher in plants, which might be due to this element being vital in plants. This study showed that activity concentrations of these radionuclides in plants and their plant transfer factors seem to depend on the activity concentrations of the same radionuclides in soil.</p><p><strong> </strong>

Transfer of Natural Radionuclides from Soil to Plants and Grass in the Western North of West Bank Environment- Palestine

The transfer factors of radionuclides (226Ra, 238U, 232Th, 40K and fallout radionuclides 137Cs) from soil to plant and grass collected from the north-west of West Bank environment – Palestine were measured. For soil to plant, the average transfer factor (TF) values were found to be 0.60, 0.50, 0.31, and 1.70 for 226Ra, 238U, 232Th and 40K respectively. For soil to grass the TF values were found to be 1.26, 1.12, 1.15 and 1.20 for 226Ra, 238U, 232Th and 40K respectively. For soil to plant, the average transfer factor values were found to be 0.27 for fallout radionuclides 137Cs. The TF showed wide variation in different species, while a few species of plants indicated preferential uptake of these radionuclides. TF average values from soil to grass were found to be higher than from soil to plant. Results showed that part of the total 226Ra in agricultural soils were from phosphate fertilizers. Because the species of plants were directly involved in the human food chain, information on the concentration level and transfer of radionuclides from soil to plants will provide important data for the environmental risk assessment in such zones. These results have been compared with those of different countries of the world.

Impact of natural radionuclides on geothermal exploitation in the Upper Rhine Graben

The deep geothermal fluids in the Upper Rhine Graben exhibit rather similar chemical compositions. They have a high NaCl content of about 100g/l. Circulation of geothermal fluid through the rock formations of the Upper Rhine Graben leads to chemical interactions at the liquid–solid interfaces. Some of these processes result in the transfer of natural radionuclides from solid to fluid. Due to the variation of the fluid's temperature and pressure as it passes through the surface plant during operation, solid deposits containing trapped radionuclides can accumulate in heat exchangers and filters causing health hazard, disposal cost and adverse effects on the surface installation. Radiological investigations at Bruchsal and Soultz-sous-Forêts were performed for the quantitative and qualitative determination of natural radionuclides that may occur in geothermal fluids and in the host rock with the aim to find a link between the specific activity of the source rock and the measured activity concentration in the fluid. The results of the fluid study show a distinct dominance of radium isotopes; however radium appears to be not supported by its parent nuclides. Thus, the geothermal fluid is in a state of radioactive imbalance. This phenomenon is observed for both geothermal sites at Bruchsal and Soultz-sous-Forêts. It seems that there are interaction processes for radium release in the reservoir fluids that are working for both geothermal sites despite of different reservoir rocks (sandstone at Bruchsal vs. granite at Soultz). Furthermore, radium could be transported into the geothermal power plant and incorporate in barium/strontium sulphate precipitations. By regular monitoring of the local dose rate all over the surface installation, the plant operator meets its obligation concerning employee safety. In addition, the operator receives site-specific information about the formation of scalings and their growth characteristics, which can be used to determine strategies to avoid precipitations.

Transfer of natural radionuclides from soil to the grass around uranium mine area Žirovski vrh, Slovenia

Uranium mine Žirovski vrh in Slovenia was closed in the year 1993. In the past years a lot of work was done for restoration of the area around the mine. There are two tailing sites, Jazbec and Borst, filled with material with high specific activity of 226 Ra. Tailings are covered by different layers of clay and soil in depth of 2 m for reducing radon exhalation rate. Gras, growing on the surface of tailing sites has been used as fodder for domestic animals. We were interesting about the amount of the specific activity of natural radionuclides 238 U, 226 Ra or 210 Pb, transferred from the covering soil on the tailing to the grass on the surface area. The transfer factors of naturally occurring radionuclides have not been studied to the same extent as their artificial counterparts, but some comprehensive investigations have been done by various institutions around the world. In case of 226 Ra calculated values are two times or four times bigger than measured. For 210 Pb measured values are up to hundred times bigger than calculated. The reason for that is radon in the air, decays to the 210 Pb, deposited on the grass and not 210 Pb coming from the soil.

Transfer of natural radionuclides from soil to plants in tropical forest (Western Ghats - India).

Soil and 2 wild plant species (Evodia roxburghiana and Eleaocarpus oblangus)have been collected from the western Ghats region and analysed for 210Po and238U. The radioactivity concentrations in plants and soil reflect the impact of the existence of igneous nature of rock in the area of study. Concentration ratios (CR) of these radionuclides, between plants and underlying soil, have been studied and the results shows that the concentration ratios (CR) seem to be depend on radionuclides in soil. Key words: Primordial radionuclides, western Ghats, monazite, igneous rock, CR-concentration ratio.

210Pb and stable lead content in fungi: Its transfer from soil

The uptake and transfer of natural radionuclides, other than 40K, from soil to mushrooms has been somewhat overlooked in the literature. Their contribution to the dose due to the consumption of mushrooms was considered negligible. But the contribution of 210Pb in areas unaffected by any recent radioactive fallout has been found to be significant, up to 35% of the annual dose commitment in Spain. More than 30 species of mushrooms were analyzed, and the 210Pb detected was in the range of 0.75–202 Bq/kg d.w. A slight difference was observed between species with different nutritional mechanisms (saprophytes ≥ mycorrhizae). The 210Pb content was correlated with the stable lead content, but not with its predecessor in the uranium radioactive series, 226Ra. This suggested that 210Pb was taken up from the soil by the same pathway as stable lead. The bioavailability of 210Pb in soil was determined by means of a sequential extraction procedure (NH 4OAc, 1M HCl, 6M HCl, and residue). About 30% of the 210Pb present in the soil was available for transfer to mushrooms, more than other natural radionuclides in the same ecosystem. Lycoperdon perlatum, Hebeloma cylindrosporum, and Amanita curtipes presented the highest values of the available transfer factor, ATF. As reflected in their ATF values, the transfer from soil to mushroom of some natural and anthropogenic radionuclides was in the following order: 228,230,232Th ≈ 40K ≥ 137Cs ≥ 234,238U ≈ 226Ra ≥ 90Sr ≥ 210Pb ≈ 239 + 240 Pu ≈ 241Am.

Transfer of natural radionuclides from soils to plants in a marsh enhanced by the operation of non-nuclear industries

Two sampling campaigns were performed in 1993 at the marsh area (Odiel marsh) located in southwestern Spain, in the city of Huelva. Spartina densiflora and substrate soil (5 cm deep) samples were collected in several locations across the area in each campaign. Activity concentrations of 210Po, U-and Th-isotopes were determined in the plant and the substrate samples. The production of phosphoric acid from phosphate mineral in the vicinity clearly enhances the concentrations of these radionuclides in certain areas of the marsh. Moreover, concentrations in plants are affected by the concentration of the same element in its substrate. Indeed, high concentration levels in plants are coincident with high concentration in soils. However, concentration ratios (CR), defined as the ratio between the concentration of an element in the plant and of that in its substrate, are higher when substrate concentrations are low, whereas low CR values are found in areas where substrate concentrations are high. Moreover, both variables (CR and soil concentration) seem to be non-linearly related, at least, in the case of radionuclides from the 238U decay chain.

Transfer of natural radionuclides from soils to plants in a wet marshland

Soils and two wild plant species ( Spartina densiflora and Spartina maritima) have been collected from the Odiel river marsh and analysed for 210Po and 238U. The radioactivity concentrations in plants and soils reflect the impact of the operation of two phosphoric acid production factories located close to the marsh. Concentrations ratios ( CR) of these radionuclides, between plant and underlying soil, have been studied. First results show that the concentration ratios ( CR) seem to be dependent on radionuclide soil concentration.