Assessment of soil and soil-gas radon activity using active and passive detecting methods in Korea

Radon ((222)Rn) is a carcinogenic gas produced by the radioactive decay of radium ((226)Ra). It has been reported that soil and soil-gas are primary factors that could cause indoor radon problems. Six sites were selected for this study--Sanbook, Gangcheon, Jikyeong, Choojung, Geumsung and Homyoung--each was classified according to bedrock type. In order to investigate soil-gas radon activities and radon emanating power, innovated active and passive detecting methods were developed and applied under both field and laboratory conditions. Statistical analysis of results confirmed that the radon activity values measured using either active or passive methods under field or laboratory conditions could be interchangeable with each other.     

Application of a “closed-can” technique for measuring radon exhalation from mine samples of Punjab, Pakistan

Using the closed-can technique, radon exhalation rate measurements have been carried out for shale and coal samples collected from various mines located in the Chakwal and Makarwal areas of Pakistan. For the two areas, the measured average values of the exhalation rates from shale are 1.45±0.13 and 0.67±0.25 Bq m⁻² h⁻¹ and for coal are 1.0±0.03 and 0.65±0.32 Bq m⁻² h⁻¹, respectively. These values are much lower than the measured exhalation rates from alum-shale-based Nordic concrete which has values in the 50–200 Bq m⁻² h⁻¹ range. The lower values of the measured exhalation rates from the shale and coal deposits in the Chakwal and Makarwal areas are indicative of their lower uranium contents and mine workers in these areas do not face any abnormal health hazard due to radon since the exhalation rates have been found to be on the low side.     

Investigation of fault position and sources of radon by measurement of 238U decay series radionuclide activity in soil samples

North Derbyshire is designated a Radon Affected Area by the National Radiological Protection Board of Great Britain since more than 1% of the housing stock is estimated to have radon levels in excess of the 200 Bq m-3 Action Level. Enhanced radon emissions associated with geological faults make knowledge of their position important in relation to any potential residential or industrial development. A general survey of radionuclides present in the soils of north Derbyshire and their relationship to the underlying geology highlighted the difficulty of identifying the position of geological faults in the field. Using gamma-ray spectroscopy of soil samples the activity of three 238U decay series radionuclides (226Ra, 214Pb and 214Bi), which were taken as evidence of the presence of 222Rn which occurs in the same decay series, was measured to indicate the position of a fault by enhanced activity. The results also provided some evidence of the source of radon emitted at the fault. A comparison of this methodology with the more conventional soil gas analysis method is made.     

A statistical evaluation of the geogenic controls on indoor radon concentrations and radon risk

ANOVA is used to show that approximately 25% of the total variation of indoor radon concentrations in England and Wales can be explained by the mapped bedrock and superficial geology. The proportion of the total variation explained by geology is higher (up to 37%) in areas where there is strong contrast between the radon potential of sedimentary geological units and lower (14%) where the influence of confounding geological controls, such as uranium mineralisation, cut across mapped geological boundaries. When indoor radon measurements are grouped by geology and 1-km squares of the national grid, the cumulative percentage of the variation between and within mapped geological units is shown to be 34-40%. The proportion of the variation that can be attributed to mapped geological units increases with the level of detail of the digital geological data. This study confirms the importance of radon maps that show the variation of indoor radon concentrations both between and within mapped geological boundaries.     

Fracking and indoor radon: Spurious correlation or cause for concern?

Unconventional gas development (fracking) is controversial in large part because of environmental and health concerns. We consider the concern that fracking leads to more carcinogenic radon gas in nearby buildings. Our empirical approach estimates treatment effects where treatment is continuous (number of wells) and varies in intensity (distance to the wells) and in duration of exposure (the time since wells were drilled). The approach allows any potential effect of fracking to vary non-linearly with the distance between the well and test site and, holding distance constant, the time between drilling and testing. Our main model gives a precisely estimated zero effect of wells on radon concentrations in nearby buildings. It also reveals that energy firms drilled wells in places with higher pre-existing radon levels, which, if ignored, makes it appear that wells within 2 km increase indoor radon but wells 3 km away do not. This explains the finding of a prior study showing a link between drilling and indoor radon.     

环境中氡的水平及其对人体危害

氡是致人体天然辐射剂量贡献最大的核素,也是肺癌发病的重要因子,是净化空气要优先考虑的问题。为此,本文报告了环境氡的水平以及它对人体产生的危害,这些知识对净化环境,保护健康有重要意义     

Assessment of indoor radiation level in the environs of the uranium deposit area of West Khasi Hills District,Meghalaya, India

An estimation of the indoor background radiation dose distribution was carried out in dwellings of eleven villages located within and around the uranium mineralization area of Kylleng-Pyndensohiong, Mawthabah in West Khasi Hills District of Meghalaya, India. The ambient indoor gamma radiation level was monitored using Thermo Luminescence Dosimeters (TLDs) while the indoor radon and thoron concentration was measured using twin-cup dosimeters employing Solid State Nuclear Track Detectors (SSNTDs). Results obtained from the study reveals that the local inhabitants of villages located close to the mining site receive higher doses than those inhabitants of villages located at a much farther distance from the mining site. The average total annual effective dose was found to be varying from 1.2 mSv y⁻¹ in the village of Langpa to 3.4 mSv y⁻¹ in the village of Nongbah Jynrin. The data obtained will serve as a reference in documenting changes to environmental radioactivity if mining is to be carried out in the future.     

某铀矿山废石场及尾砂库氡污染调查

通过对某退役铀矿山的 14个废石堆放场及 3个尾砂库氡析出率的测量及内照射剂量的估算 ,表明 ,只有一个废石场的氡析出率超过国家规定的管理限值水平 ;尾砂库的氡析出率较高 ,个别测点的氡析出率超出管理限值水平近 7倍 ;因氡析出而使当地居民额外所受的年最大有效剂量当量为 0 0 5 8mSv。指出在尾砂库表面覆盖黄土 ,可以有效降低氡析出水平 ,当覆盖厚度达 0 5m时 ,可将氡析出水平降低 84%以上。     

贵阳地区氡浓度的连续观测

叙述用静电累积氡测量仪对贵阳地区环境氡浓度进行连续四年的观测，氡浓度季节性的变化受气温、降雨量等因素的影响较大，降雨不仅可使环境氡浓度降低，而且在降雨量相近的情况下降雨次数较多氡浓度也会相对偏低。     

The distribution of radon in tunnels with different geological characteristics in China

In China, as the economy is developing and the population is expanding, some underground buildings have been used as supermarkets, restaurants and entertainment places. Tunnels in mountains are one type of underground building, and the radon (²²²Rn) level in tunnels is an important issue. Radon levels in different type tunnels appear to differ, and relatively higher levels of ²²²Rn are associated with particular types of bedrock. The ²²²Rn levels in tunnels in five different geological characteristics were analyzed. Those built in granite had the highest ²²²Rn levels with a geometric mean (GM) of 280 Bq m⁻³, while those built in limestone (GM: 100 Bq m⁻³) and andesitic porphyry (GM: 96 Bq m⁻³) were lower. The sequence of ²²²Rn concentrations was: granite > tuff > quartz sandstone > limestone > andesitic porphyry, and the ²²²Rn in granite was statistically significantly higher than in limestone and andesitic porphyry. Tunnels built in granite, tuff, quartz sandstone, limestone tended to have higher ²²²Rn concentrations in summer than in winter, while the reverse tendency was true in andesitic porphyry tunnels. Only the difference in limestone was statistically significant.