| Autor: |
Hyun Koo Kim, Chan Ho Jeong, Hyeon Young Cho, Byung Uk Jo, Yu Jin Lee, Tae Seong Kim, Yong Cheon Lee, Moon Su Kim, Jae Ha Yang |
| Rok vydání: |
2016 |
| Předmět: |
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| Zdroj: |
The Journal of Engineering Geology. 26:261-276 |
| ISSN: |
1226-5268 |
| DOI: |
10.9720/kseg.2016.2.261 |
| Popis: |
The occurrence of natural radioactive materials such as uranium and radon-222 in groundwater was examined with hydrogeochemistry and geology at ○○ village in the Yongin area. Two rounds of 19 groundwater and 5 surface water sampling were collected for analysis. The range of pH value in groundwaters was 5.81 to 7.79 and the geochemical types of the groundwater were mostly Ca(Na)-HCO3 and Ca(Na)-NO3(Cl)-HCO3. Uranium and radon-222 concentrations in the groundwater ranged from 0.06 to 411 μg/L and from 5.56 to 903 Bq/L, respectively. Two deep groundwaters used as common potable well-water sources exceeded the maximum contaminant levels of the uranium and radon-222 proposed by the United States Environmental Protection Agency (US EPA). Three groundwater samples from residential areas contained unsuitable levels of uranium, and 12 groundwater samples were unsuitable due to radon-222 concentrations. Radioactive materials in the unsuitable groundwater are naturally occurring in a Jurassic amphibole- and biotite-bearing granitic gneiss. High uranium and radon-222 groundwater concentrations were only observed in two common wells; the others showed no relationship between bedrock geology and groundwater geochemical constituents. With such high concentrations of naturally occurring radioactive materials in groundwater, the affected areas may extend tens of meters for uranium and even farther for radon-222. Therefore, we suggest the radon-222 and the uranium did not originate from the same source. Based on the distribution of radon-222 in the study area, zones of higher radon-222 concentrations may be the result of diffusion through cracks, joint, or faults. Surface radioactivity and uranium concentrations in the groundwater show a positive relationship, and the impact areas may extend for ~200m beyond the well in the case of wells containing high concentrations of uranium. The highest uranium and thorium concentrations in rock samples were detected in thorite and monazite. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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