Transfer Of 40K Research Articles

Transfer of 40K, 226Ra and 232Th from Soil to Water and Edible Plants and Associated Radiological Effects in Jos East and Jos South, Plateau State, Nigeria.

Transfer of 40K, 226Ra and 232Th from Soil to Water and Edible Plants and Associated Radiological Effects in Jos East and Jos South, Plateau State, Nigeria.

Soil-to-plant transfer of 40K, 238U and 232Th and radiological risk assessment of selected mining sites in Nigeria

One of the major route through which humans are exposed to ionizing radiation is via food chain, which is consequent of soil-to-plant transfer of radionuclides. This work reported the activity concentrations of 40K, 238U and 232Th in samples of water, soil and guinea corn grains collected from Beryllium and Gold mining sites in Kwara, Nigeria. In-situ measurements at approximately 1 m in the air was carried out using a well-calibrated portable Gamma Spectrometer (Super Spec RS-125), while the soil, water and the guinea corn samples were analyzed using a ‘3 × 3’ inch lead-shielded NaI (Tl) detector. The measured activity concentrations of the natural radionuclides in the soil from both mines are lower than the in-situ measurements. This was attributed to the contribution from other terrestrial materials on-site. The estimated mean transfer factors (TFs) for 40K, 238U and 232Th are 0.21, 0.17 and 0.31, and 0.46, 0.19 and 0.28 respectively for the Beryllium and Gold mining sites. While the TFs for 238U and 232Th exceeded the mean value of 0.0062 and 0.0021 for 238U and 232Th respectively, the TFs for 40K are well below the 0.74 for cereals grains provided by International Atomic Energy Agency (IAEA). The radiation impact assessment using the Monte Carlo simulations reveals values that were generally less than the global average values provided by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Hence, the risk of cancer inducement due to radiation exposure is within the acceptable limits for both mining sites.

Baseline radioecological data for the soil and selected bioindicator organisms in the temperate forest of Plitvice Lakes National Park, Croatia.

The aim of this study was to provide baseline radioecological data for the temperate forest ecosystem in Plitvice Lakes National Park. Emphasis was placed on the determination of naturally occurring radionuclides since there is an acknowledged lack of data for these radionuclides in non-accident conditions in wildlife, even for bioindicator organisms. Activity concentrations of 238U, 226Ra, 210Pb, 232Th, 40K, 134Cs, and 137Cs were measured by gamma spectrometry in soil and bioindicators: earthworms, conifer needles, mosses, and lichens. From the measured activity concentrations, concentration ratios were calculated to quantify the transfer of these radionuclides from soil to bioindicators. Our results show that soil activity concentrations are biased toward results from other studies conducted within the Dinaric mountain region. However, in moss and lichen samples, we measured higher activity concentrations of 226Ra and lower activity concentrations of 40K and 137Cs in comparison to similar studies. Also, we estimated lower concentration ratios for all radionuclides from soil to these organisms, except for 210Pb, in comparison to generic values. The transfer of 238U was generally low for all of the bioindicator organisms. For conifer needles, a correlation was found between activity concentrations of 226Ra and 137Cs in soil and related concentration ratios. Correlation was also found between the activity concentration of 40K in soil and transfer of 40K and 137Cs to mosses and lichens. A comparison with literature data highlighted the lack of 226Ra related concentration ratios for conifer trees and especially for earthworms. Therefore, the results of this study could supplement the sparse data currently available on radionuclide background data in similar ecosystems and related soil-to-wildlife transfer of radionuclides. Dose rate assessments, performed by the ERICA Tool, estimated that 96% of the overall exposure of wildlife in the Park area is due to the background dose rates, while 0.06μGyh-1 on average can be attributed as an incremental dose rate from 134Cs and 137Cs.

Transfer of 40K and 137Cs from diet into meat of ruminants: analogy or not?

The study of transfer coefficients and concentration ratios of 40K and 137Cs was performed in order to investigate the bioavailability and potential analogy relationships of observed radionuclides in the chain of animal production of ruminants. Sampling of material was performed at small individual farms situated inside the three regional livestock areas in Bosnia and Herzegovina. Transfer coefficients and concentration ratios of 40K and 137Cs were calculated for beef and sheep meat. Obtained results were in accordance with literature data with average transfer coefficient values for 40K and 137Cs in beef of 0.017 and 0.058 d kg-1, respectively; whilst the same values for the sheep meat were higher (0.104 and 0.341). Average values for concentration ratios of 40K and 137Cs were equilibrated between the species (beef: 0.125 and 0.418; sheep meat: 0.136 and 0.443). Obtained results indicated on the hidden analogy between observed radionuclides, covered by the homeostatic control of potassium in ruminants. The study confirmed the use of potasssium compounds for reduction of radiocesium contamination in ruminants.

Soil to rice transfer factors for 226Ra, 228Ra, 210Pb, 40K and 137Cs: a study on rice grown in India

India is the second largest producer of rice (Oryza sativa L.) in the world and rice is an essential component of the diet for a majority of the population in India. However, detailed studies aimed at the evaluation of radionuclide transfer factors (Fv) for the rice grown in India are almost non-existent. This paper presents the soil to rice transfer factors for natural (226Ra, 228Ra, 40K, and 210Pb) and artificial (137Cs) radionuclides for rice grown in natural field conditions on the West Coast of India. A rice field was developed very close to the Kaiga nuclear power plant and the water required for this field was drawn from the cooling water discharge canal of the power plant. For a comparative study of the radionuclide transfer factors, rice samples were also collected from the rice fields of nearby villages. The study showed that the 226Ra and 228Ra activity concentrations were below detection levels in different organs of the rice plant. The soil to un-hulled rice grain 40K transfer factor varied in the range of 6.5 × 10−1 to 2.9 with a mean of 0.15 × 101, and of 210Pb varied in the range of <1.2 × 10−2 to 8.1 × 10−1 with a mean of 1.4 × 10−1, and of 137Cs varied in the range of 6.6 × 10−2 to 3.4 × 10−1 with a mean of 2.1 × 10−1. The mean values of un-hulled grain to white rice processing retention factors (Fr) were 0.12 for 40K, 0.03 for 210Pb, and 0.14 for 137Cs. Using these processing retention factors, the soil to white rice transfer factors were estimated and these were found to have mean values of 1.8 × 10−1, 4.2 × 10−3, and 3.0 × 10−2 for 40K, 210Pb, and 137Cs, respectively. The study has shown that the transfer of 40K was higher for above the ground organs than for the root, but 210Pb and 137Cs were retained in the root and their transfer to above the ground organs of the rice plant is significantly lower.

Transfer of 40K, 238U, 210Pb, and 210Po from soil to plant in various locations in south of Syria

Transfer factors of 40K, 238U, 210Pb, and 210Po from soil to some agriculture crops in various locations in south of Syria (Dara'a and Assuwaydaa districts) have been determined. Soil and vegetable crops (green pepper, cucumber, tomato, and eggplant), legumes crops (lentil, chickpea, and broad bean), fruit trees (apple, grape, and olives) and cereals (barley and wheat) were collected and analyzed for 238U, 210Pb, and 210Po. The results have shown that higher transfer factors (calculated as Bq kg −1 dry wt. plant material per Bq kg −1 dry wt. soil) for 210Po, 210Pb and 238U were observed in vegetable leaves than fruits and cereals leaves; the highest values of transfer factor (TF) for 238U were found to be 0.1 for straw of chickpea. Transfer factors for 210Po varied between 2.8 × 10 −2 and 2 in fruits of eggplant and grain of barley, respectively. In addition, several parameters affecting transfer factors of the radionuclides were evaluated. The results can be considered as base values for TF of natural radionuclides in the region.

Impact of fertilizers on background radioactivity level in two newly developed desert areas

A survey of soils and plants was carried out to determine the environmental gamma background radiation levels in two newly developed desert areas. The materials and the standards were analyzed by gamma spectroscopy; a shielded high purity germanium detector was used to measure the natural concentration of 238U, 232Th and 40K activities in the samples. The radionuclide content in some commercial fertilizers was determined. The results of the analysis of specific activities in the fertilizers under study were 1.27–950.09 Bq/kg for 238U, 0.73–162.16 Bq/kg for 232Th and 10.22–23845.24 Bq/kg for 40K. All natural soil samples showed low-activity concen-trations. The concentrations of 238U (6.13–38.84 Bq/kg) and 232Th (2.58–25.69 Bq/kg) are quite similar, whereas that of 40K (113.91–9314.11 Bq/kg) are much higher for plant samples. Some of the results obtained are larger than the permissible international radioactivity levels. It is suitable in this regard to compare the activity values of the imported fertilizers and that fabricated in Egypt. The absorbed dose rate was found to be 1.91–1027 nGy/h and the radium equivalent activity concentration was 4.02–1840.98 Bq/kg for fertilizer samples. Soil and plant sample results were 11.86–415.29 nGy/h and 24.20–750.52 Bq/kg for the absorbed dose rate and the radium equivalent activity concentration, respectively. Banana plant contains the largest values. This article presents actual data from investigations of the soil–plant transfer of the primordial radionuclides for some fruits growing on these soils. The transfer factors of 0.35–1.821 for 238U, 0.227–0.480 for 232Th and 1.95–31.85 for 40K were obtained. The increase of the transfer of 40K reflects its great uptake to the fruits. Observed soil–plant factors vary widely, mainly as a result of different soil, vegetation types and environmental conditions. Taking into account the transfer factors of 137Cs to plants, the measured activity concentrations of this isotope should not endanger the health safety of the produced food.