• Environmental Analysis Health and Toxicology
• /
• v.17 no.4
• /
• pp.273-284
• /
• 2002

At present, the health risks associated with the natural radionuclides of ground water have become a concern as potential social problems. However, there are no regulatory actions or control strategies for such risks. Therefore, we have investigated and discussed the risks and associated management strategies for radionuclides in other countries. US EPA has proposed MCL (300 pCi/L) and AMCL (4,000 pCi/L) for radon, and 30 ppb for uranium, 15 pCi/L for gross-alpha and 5 pCi/L for radium as final MCLs. Also, Canada, WHO and European countries have their inherent management levels. Finally, we suggested several criteria for setting guidelines in our countries including exposure related criteria such as geological distribution, occurrence, exposure probability distribution, exposure population and multimedia exposure assessment, acceptable risk, and cost -benefit analysis. The national-scale exposure and risk assessment, and economic analysis should be conducted for producing and aggregating the representative information on these criteria.

• Journal of Environmental Science International
• /
• v.24 no.3
• /
• pp.275-280
• /
• 2015

In order to measure the Radionuclides and Concentration, the directly grinded land samples (river soil, pine leaves and mugwort) among the environment samples around the nuclear power plant were filled in a 450 mL Marinelli beaker and weighed to obtain the dry mass ratio of the samples. Then the background and land samples were measured for 80,000 sec. The analysis of the collected land samples showed that most of them contained less radiation nuclide than the detection minimum limit in the 'Ministry of Education, Science and Technology Public Notice No. 2010-32.'In others, the natural radionuclides $^{40}K$ were detected. Of the products of nuclear reaction discharged by a nuclear reaction, $^{134}Cs$ and $^{137}Cs$ are more easily detected, and their discharge sources can be traced using the relative ratio. Although the radioactive concentration in the vicinity of Kori Nuclear Power Plant, which is more than 1,100km away from Fukushima, the Japanese nuclear accident site, continuous monitoring is needed as the radionuclides can still be accumulated in the soil or animals and plants.

• Journal of the Korean Society of Groundwater Environment
• /
• v.1 no.2
• /
• pp.100-104
• /
• 1994

The rock matrix diffusion provides a retarding mechanism for sorbing and especially non-sorbing radionuclides. It has to be verified not only theoretically and experimentally but also from natural phenomena, before the mechanism can be incorporated fully into transport codes. The natural analogue studies, such as the concentration variation of radionuclides in profiles perpendicular to fluid-conducting fractures and to intrusive contact zones, have been believed to provide a validation. In thermal alteration zones of Naeduckri granite intruded by a pegmatite, large alkali and alkaline earth elements such as K, Rb, Sr, and Ba were moderately migrated during thermal alteration. Li, V. and Nb were also migrated about 9cm in width from the contact between the granite and the pegmatite. The concentration variation of these elements in thermally altered zones seems to be resulted from the local migration due to the re-equilibration among the elements released from the breakdown of primary minerals in the granite. Most of these natural analogue studies simply show only the concentration variation of elements without detailed informations on the diffusion time and other important data fir interpreting the behaviour of radionuclides, because of the absence of appropriate minerals for age data. Despite this problem, natural analogue studies will be needed for transport models of radionuclides in safety assessment.

• Proceedings of the KSEEG Conference
• /
• 2002.06a
• /
• pp.81-100
• /
• 2002

While most of regulatory communities in abroad recognize ' 'natural attenuation " to include degradation, dispersion, dilution, sorption (including precipitation and transformation), and volatilization as governing Processes, regulators prefer "degradation" because this mechanism destroys the contaminant of concern. Unfortunately, true degradation only applies to organic contaminants and short- lived radionuclides, and leaves most metals and long-lived radionuclides. The natural attenuation Processes may reduce the potential risk Posed by site contaminants in three ways: (i)contaminants could be converted to a less toxic form througy destructive processes such as biodegradation or abiotic transformations; (ii) potential exposure levels may be reduced by lowering concentrations (dilution and dispersion); and (iii) contaminant mobility and bioavailability may be reduced by sorption to geomedia. In this review, authors will focus will focul on "sorption" among the natural attenuation processes of hazardous inorganic contaminants including radionuclides. Note though that sorption and transformation processes of inorganic contaminants in the natural setting could be influenced by biotic activities but our discussion would limit only to geochemical reactions involved in the natural attenuation. All of the geochemical reactions have been studied in-depth by numerous researchers for many years to understand "retardation" process of contaminants in the geomedia. The most common approach for estimating retardation is the determination of distrubution coefficiendts ($K_{d}$) of contaminants using parametric or mechanistic models. As typocally used in fate and contaminant transport calculations such as predictive models of the natural attenuation, the $K_{d}$ is defined as the ratio of the contaminant concentration in the surrounding aqueous solution when the system is at equilibrium. Unfortunately, generic or default $K_{d}$ values can result in significant error when used to predict contaminant migration rate and to select a site remediation alternative. Thus, to input the best $K_{d}$ value in the contaminant transport model, it is essential that important geochemical processes affecting the transport should be identified and understood. Precipitation/dissolution and adsorption/desorption are considered the most important geochemical processes affecting the interaction of inorganic and radionuclide contaminants with geomedia at the near and far field, respectively. Most of contaminants to be discussed in this presentation are relatively immobile, i.e., have very high $K_{d}$ values under natural geochemical environments. Unfortunately, the obvious containment in a source area may not be good enough to qualify as monitored natural attenuation site unless owner demonstrate the efficacy if institutional controls that were put in place to protect potential receptors. In this view, natural attenuation as a remedial alternative for some of sites contaminated by hazardous-inorganic components is regulatory and public acceptance issues rather than scientific issue.

• Journal of Radiation Protection and Research
• /
• v.43 no.3
• /
• pp.85-96
• /
• 2018

Background: A variety of inorganic scintillators have been developed and improved for use in radiation detection and measurement, and in situ gamma-ray spectrometry in the environment remains an important area in nuclear safety. In order to verify the feasibility of promising scintillators in an actual environment, a performance test is necessary to identify gamma-ray peaks and calculate the radioactivity from their net count rates in peaks. Materials and Methods: Among commercially available scintillators, $LaBr_3(Ce)$ scintillators have so far shown the highest energy resolution when detecting and identifying gamma-rays. However, the intrinsic background of this scintillator type affects efficient application to the environment with a relatively low count rate. An algorithm to subtract the intrinsic background was consequently developed, and the in situ calibration factor at 1 m above ground level was calculated from Monte Carlo simulation in order to determine the radioactivity from the measured net count rate. Results and Discussion: The radioactivity of six natural radionuclides in the environment was evaluated from in situ gamma-ray spectrometry using an $LaBr_3(Ce)$ detector. The results were then compared with those of a portable high purity Ge (HPGe) detector with in situ object counting system (ISOCS) software at the same sites. In addition, the radioactive cesium in the ground of Jeju Island, South Korea, was determined with the same assumption of the source distribution between measurements using two detectors. Conclusion: Good agreement between both detectors was achieved in the in situ gamma-ray spectrometry of natural as well as artificial radionuclides in the ground. This means that an $LaBr_3(Ce)$ detector can produce reliable and stable results of radioactivity in the ground from the measured energy spectrum of incident gamma-rays at 1 m above the ground.

• Nuclear Engineering and Technology
• /
• v.54 no.11
• /
• pp.4253-4264
• /
• 2022

Since the implementation of the phosphate project in Bled El-Hadba (BEH) deposit, western region of Tébessa, no detailed study has been conducted to assess the natural radioactivity distribution and the associated radiological risk parameter for this open-pit mine. For the sake of determining a credible premining reference database for the region of interest, 21 samples were collected from different geological layers of the above-mentioned deposit. Gamma Spectrometry was applied for measuring radioactivity using a high resolution HPGe semiconductor detector. The obtained activity results have shown a significant broad variation in the radioactive contents for the different phosphate samples. The total average concentrations (in Bq·kg^-1) for ²²⁶Ra, ²³⁸U, ²³⁵U, ²³²Th and ⁴⁰K computed for the different type of phosphate layers were found to be 570 ± 169, 788 ± 280, 52 ± 18, 66 ± 6 and 81 ± 18 respectively. The mean activity concentrations of the measured radionuclides were compared to other regional and worldwide deposits. The ratios between the detected radioisotopes have been calculated for spatial distribution of natural radionuclides in the study area. Based on the aforementioned activity concentrations, the corresponding radiation hazard parameters were assessed. Correlations between the obtained parameters were drawn and a multivariate statistical analysis (Pearson Correlation, Cluster and Factor analysis) was carried out in order to identify the existing relationships.

• Journal of Radiation Industry
• /
• v.17 no.2
• /
• pp.151-160
• /
• 2023

The International Atomic Energy Agency (IAEA) proposes 11 industries that handle Naturally Occurring Radioactive Material (NORM) that are considered to need management. A water treatment facility is one of the above industries that takes in groundwater and produces drinking water through a water treatment process. Groundwater can accumulate natural radionuclides such as uranium and thorium in raw water by contacting rocks or soil containing natural radionuclides. Therefore, there is a possibility that workers in water treatment facilities will be exposed due to the accumulation of natural radionuclides in the water treatment process. The goal of this study is to evaluate the external radiation dose according to the working type of workers in water treatment facilities. In order to achieve the above goal, the study was conducted by dividing it into 1) analysis of the exposure environment, 2) measurement of the external radiation dose rate 3) evaluation of the external radiation dose. In the stage of analyzing the exposure environment, major processes that are expected to occur significantly were derived. In the measurement stage of the external radiation dose rate, a map of the external radiation dose rate was prepared by measuring the spatial radiation dose rate in major processes. Through this, detailed measurement points were selected considering the movement of workers. In the external radiation dose evaluation stage, the external radiation dose was evaluated based on the previously derived external radiation dose rate and working time. As a result of measuring the external radiation dose rate at the detailed points of water treatment facilities A to C, it was 1.90×10^-1 to 3.75×10⁰ μSv h^-1, and the external radiation dose was analyzed as 3.27×10^-3 to 9.85×10^-2 mSv y^-1. The maximum external radiation dose appeared during the disinfection and cleaning of activated carbon at facility B, and it is judged that natural radionuclides were concentrated in activated carbon. It was found that the external radiation dose of workers in the water treatment facility was less than 1mSv y^-1, which is about 10% of the dose limit for the public. As a result of this study, it was found that the radiological effect of external radiation dose of domestic water treatment facility workers was insignificant. The results are expected to contribute as background data to present optimized safety management measures for domestic NORM industries in the future.

• Journal of Soil and Groundwater Environment
• /
• v.18 no.1
• /
• pp.36-45
• /
• 2013

We analyzed natural radionuclides in 80 wells in volcanic rock areas and investigated environmental characteristics. Uranium and radon concentrations ranged from ND to $9.70{\mu}g/L$ (median value: 0.21) ${\mu}g/L$, 38~29,222 pCi/L (median value: 579), respectively. In case of gross-${\alpha}$, 26 samples exceeded MDA (minimum detectable activity, < 0.9 pCi/L) value and the activity values ranged from 1.05 to 8.06 pCi/L. The radionuclides concentrations did not exceed USEPA MCL (maximum contaminant level) value of Uranium ($30{\mu}g/L$) and gross-${\alpha}$ (15 pCi/L). But Rn concentrations in 4 samples exceeded USEPA AMCL (Alternative maximum contaminant level, 4,000 pci/L) and one of them showed a significantly higher value (29,222 pCi/L) than the others. The levels of uranium concentrations in volcanic rock aquifer regions were detected in order of andesite, miscellaneous volcanic rocks, rhyolite, basalt aquifer regions. Radon, however, was detected in order of miscellaneous volcanic rocks, rhyolite, andesite, basalt aquifer regions. The correlation coefficient between uranium and radon was r = 0.45, but we found that correlations of radionuclides with in-situ data or major ions were weak or no significant. The correlation coefficient between the depth of wells and uranium concentrations was a slightly higher than that of depth of wells and radons. Radionuclide concentrations in volcanic rock aquifers showed lower levels than those of other rock aquifers such as granite, metamorphic rock aquifers, etc. This result may imply difference of host rock's bearing-radioactive-mineral contents among rock types of aquifers.

• Nuclear Engineering and Technology
• /
• v.55 no.7
• /
• pp.2650-2655
• /
• 2023

In the process of growth and development, plants not only absorb essential nutritional elements, but also absorb radioactive and non-essential elements from the environment, and their distribution varies in different parts of the plant. In this study, neutron activation analysis and gamma spectrometry were performed on stems, roots, and leaves of vegetables. The results indicate that the accumulation of radionuclides and multi-elements depends on the plant type and plant parts. Activity concentrations of ²²⁶Ra and ²³²Th in plants were accumulated in the following order: Roots > Stems > Leaves. The highest concentrations of ⁴⁰K and ²¹⁰Pb were observed in the stems and leaves of plants, respectively. Essential nutrient requirements of plants are in the following order: K > Ca > Mg > Fe > Zn > Mn. Among the nonessential metals, the concentration of Na in the vegetable sample was much greater than those of the other elements. The K/Na ratio in the plant depends on the type of plant and the translocation within the plant.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2018.05a
• /
• pp.375-376
• /
• 2018