氡气灾害调查的一些结果

氡气灾害是一种广泛分布的地质灾害。室内氡气浓度偏高会使居民患肺癌的几率增高，而室内氡气主要来自房屋地基所在的地质单元。笔者在美国犹他大学研究所工作期是，研究了瑞丁普朗花岗片麻岩带近地表氡的浓度与铀含量的关系以及铀的分布与居民癌症死亡率之间的相关关系。铀的区域性分布是利用航空伽马能谱测量资料求得的，说明利用航空伽马能谱测量资料开展氡气灾害区域评价的可能性。文中还举例说明氡气调查在制定建设规划方面的作     

有限差分算法求解砂岩型铀矿体氡气场分布初探

介绍了有限差分方法的原理,叙述了砂岩型铀矿体上氡气场的分布,并建立了氡气场分布的理论方程,通过有限差分算法求解氡气场分布方程,为砂岩型铀矿体上氡气场的正演研究提供了数值计算方法。针对砂岩型铀矿体上氡气场低值区对应矿体而高值异常场对应矿体两端的特点,以矿体端点高值异常峰值点为中心进行二维等步长剖分,得出差分方程,为问题的进一步研究提供一种算法思路。     

汶川地震小鱼洞活动断裂氡气异常及其水文地质意义

利用氡气测量的方法标定断裂(裂隙)构造及其开启程度,并反应断裂(裂隙)的水文地质特征是一种有效而且快速的方法。选取小鱼洞活动断裂三个试段进行了氡气(RaA)测量,并利用统计方法对测量数据进行分析,确定研究区氡气的背景值和异常值。根据氡气异常等级对小鱼洞活动断裂开启性进行了划分,并对其水文地质意义进行了讨论。在基岩裂隙地区可用氡气测量技术圈定蓄水构造,从而确定找水的有利孔位。     

氡气测量在骊山北坡坡体病害工程地质研究中的应用效果

本文以陕西临潼骊山北坡坡体病害地区进行氡气测量的实例，介绍了氡气测量用于解决工程地质问题的技术方法，文中具有论述了氡气测量的适用条件和探测技术，通过氡气异常特征的地质解释及验证说明了氡气测量技术的实际应用效果。     

氡气测量在栗木锡铌钽矿外围的找矿效果

虽然氡气测量法在多个领域应用广泛,但用氡气测量法寻找隐伏有色金属矿却少有报道.为了扩大氡气测量法的应用范围,为寻找隐伏有色金属矿提供新的勘查方法,我们用美国产RAD7型电子测氡仪在广西栗木锡铌钽矿上进行了试验.结果在三个黄牛和水溪庙锡铌钽矿体上方土壤中除有很好的氡气异常反映,氡气异常特征与深部隐伏锡铌钽矿在空间上和规模上具有很好的对应关系外,对矿区外围2个氡气异常地段进行钻探验证也取得了良好的找矿效果,这为该区外围找矿、扩大矿产资源储量提供了一种有效的勘查方法.     

峨眉山柿子坪热田地表氡气异常特征

本文通过柿子坪地区地表氡气测量,对热田地表氡气异常特征作了初步分析。该区地表氡气高值异常呈环状产出,并严格受构造控制。同时指出地表氡气测量是热田勘查的有效途径。     

民用建筑工程中土壤氡浓度检测的实践

近年来,随着社会的不断发展,由于土壤氡元素污染引发的民用建筑内部环境污染问题在逐年增多,逐渐成为了影响群众身体健康的重要因素;氡是一种放射性气体,是危害人类身体健康的辐射源之一;氡经过衰变,形成一系列的带辐射微粒,当这些微粒被吸入肺部,部分会堆积聚集,并继续散发辐射,容易令吸入者患上肺癌。天然氡气的散发出自泥土、岩石或者黄岗岩制造的混凝土能建筑材料,从墙壁、地板、或经由地面上的裂缝进入建筑物的内部。由于部分建筑物通风不足,氡气会滞留堆积在房间内部;氡气的超标,则会对长期呆在室内的人们造成健康隐患,因此。对土壤中氡元素的检测变得越来越重要。     

地裂缝氡值测试及形成机制初探

本文从氡气测量的基本原理和地裂缝的形成机制入手，通过分析地裂缝氡气剖面曲线，对地裂缝氡气异常的特点及其形成的地质背景提出了一些看法，给出了地裂缝氡气异常的判据。     

四川阿坝土壤与空气中氡气浓度及分布调查

采用IED-3000R轻便型测氡仪,对四川阿坝地区土壤、空气中的氡气浓度开展初步调查。结果表明：(1)测区空气中氡气浓度较高,均在平均值185 Bq/m3附近;(2)所测得土壤的氡气浓度范围为2 736～93 486 Bq/m3,平均值为26 021 Bq/m3,远远高于全国城市土壤中氡气浓度7 300 Bq/m3的平均值,同时在156个土壤氡气浓度被测点中共有91个测点氡气浓度值超过20 000 Bq/m3,而按照国家标准,对于民用建筑工程土壤中氡气浓度超过20 000 Bq/m3要进行不同程度的防氡工程;(3)地质环境、土壤松散度、岩土性质、土壤含水率为影响阿坝地区土壤氡气浓度的主要因素。     

氡气测量方法在礼贤断裂勘查中的应用

利用氡气测量方法对礼贤断裂的位置进行勘查,通过对测量数据的分析,圈定氡气浓度的异常区,从而作为判定礼贤断裂位置的重要依据。     

北京广东典型地区室内氡气浓度与地质背景关系

为了解不同地质背景条件室内氡浓度水平,采用脉冲电离室测氡仪AlphaGUARD测量了北京广东不同地质背景典型测点的室内氡浓度,同时对广东某一测点进行了长期的室内氡监测。测量和研究结果表明：地表岩性是影响室内氡浓度高低的重要因素之一。地处花岗岩地区的建筑物内氡浓度高于其他岩性地区的室内氡浓度,广东室内氡水平明显高于北京地区,广东北京花岗岩地区的平均室内氡浓度分别为69.98 Bq/m^3和43.97 Bq/m^3,第四系覆盖地区的平均室内氡浓度分别为43.60 Bq/m^3和35.74 Bq/m^3。民用住宅卧室内的室内氡浓度略高于公共建筑物办公室内的室内氡浓度。因此,结合地质背景研究室内氡的水平与分布对指导开展室内氡调查中确定抽样方案、选择测点及进行区域尺度室内氡评价有重要的实用价值。     

Geological and geochemical factors affecting radon concentrations in dwellings located on permeable glacial sediments—a case study from Kinsarvik,Norway

In 1996–1997, indoor radon values of more than 40,000 Bq/m³ and large seasonal and geographical variations in indoor air radon were reported from a residential area located on a highly permeable ice-marginal deposit. Geochemical analyses of bedrock, groundwater and sediments and comparisons between indoor radon values and soil radon values indicate that the indoor radon concentrations in this area are strongly affected by subterranean airflows caused by temperature differences between soil air and atmospheric air. The airflows concentrate the radon-laden soil air towards the topographic highest part of the deposit in winter and towards the topographic lowest part in summer. In areas where subterranean airflows are likely to occur, radon measurements performed both in summer and in winter provide the best estimate of annual average indoor radon concentrations, and assessments of indoor radon concentrations based on single soil gas measurements are not recommended.     

Radon reduction in homes constructed on saprolite in the Central Appalachians

 A 3-year study of indoor radon in more than 1000 homes in northern Virginia and southern Maryland was conducted using 3-month exposure alpha-track monitors. In a study set of 200 homes, first-floor indoor radon concentrations, which most closely approximates home exposure levels, averaged slightly more than 3 pCi/l. In a study set of 100 homes, sub-slab ventilation was used to reduce indoor radon concentrations. Interest in remediation was related to public perception of the hazardous nature of radon; people living in homes with indoor radon measurements of more than 4 pCi/l were more likely to participate in the remediation phase of the project. Sub-slab ventilation was successful in more than 90% of the homes in reducing indoor radon from concentrations as high as 30 pCi/ to less than 4 pCi/l, at least for the entire year of post-remediation radon measurements. Received: 29 February 1996 · Accepted: 29 May 1996     

Relationship between radon concentrations in indoor air and in soil gas

In the Ljubljana region, 53 schools were selected for measurements of radon concentrations in soil gas close to a school building, and indoor radon concentrations in one of the ground-floor classrooms of each building. The aim was to establish a relationship between radon concentrations in indoor air and in soil gas from the ground on which the building is situated. Soil gas radon concentrations between 2 and 14 kBqm^-3 were found. Indoor radon concentrations ranged from 20 to 1,440 Bqm^-3, with seven values exceeding 200 Bqm^-3. It is concluded that good quality of the construction elements ensure low indoor radon concentration, regardless of high soil gas radon level.     

Radon distributions in the Hail Region of Northern Saudi Arabia

Indoor radon measurements were carried out in a total of 420 dwellings and 17 schools in Hail region of Saudi Arabia, using NTDs based radon dosimeters. The duration of the measurements was one year, from April 2008 to April 2009. The indoor radon concentrations varied from 4 to 513 Bq/m³ with an overall average of 45 Bq/m³ for all surveyed dwellings. These passive measurements were confirmed by the active measurements. The anomalous concentrations above 200 Bq/m³ were observed in 13 dwellings, representing 3.1 % of the total surveyed dwellings. In Inbowan village alone, it was found that 7.6 % of the dwellings have indoor radon concentration above 200 Bq/m³. The highest average indoor radon concentration of 64 Bq/m³ was found in Inbowan village while the lowest average of 24 Bq/m³ was found in Majasah village. The city of Hail showed an average indoor radon concentration of 49 Bq/m³. The average indoor radon concentration in one area located at the edge of the Aja Mountain in Hail city was 111 Bq/m³. The elevated indoor radon concentrations in many dwellings in the Hail region, prompted us to measure outdoor ground radon in such locations using gas monitor. It was found that radon concentrations at a depth of 0.5 m varied significantly from place to place ranging from 1.2 to 177 kBq/m³. The outdoor radon concentrations are generally correlated with the indoor radon measurements. Radon exhalations from construction materials and soil samples from the Hail region were also measured. It was found that radon exhalations from soil samples are higher than that of construction materials by a factor of at least 3 and reaching up to 11. These results indicate that soil is the main source of indoor radon. Geological interpretations of the results are also given.     

Impact of the deeper geological basement on soil gas and indoor radon concentrations in areas of Quaternary fluvial sediments (Bohemian Massif,Czech Republic)

The relationship of soil gas radon Rn²²² and indoor radon was studied within the Quaternary fluvial sediments of the Czech Republic. The processing of data selection from the radon database of the Czech Geological Survey and indoor radon data (database of the National Radiation Protection institute) has proved the concentration dependence of radon in Quaternary fluvial sediments on deeper bedrock. The ArcGIS processing was accompanied by the field verification in five profiles, intersecting the granitoid Central Bohemian Plutonic Complex and its rim rock types. Both theoretical and experimental results show dependence of soil gas radon and indoor radon concentrations in Quaternary fluvial sediments on deeper geological basement, thus leading to the conclusion that the lateral transport of Quaternary sediments does not play such a dominant role in radon concentrations, as was thought previously. This fact will enable to determine precisely the radon index of Quaternary sediments (in the Czech radon mapping classified as an intermediate index) into three categories according to the lithology of their geological basement.     

From radon hazard to risk prediction-based on geological maps,soil gas and indoor measurements in Germany

Mapped geological units can be regarded as proxies standing for a complex series of subsoil geochemical and physical properties including the assigned radon activity concentration in soil gas, which is taken as best estimator of the regional geogenic radon potential. Areal distribution of measuring sites for soil gas in Germany is adapted to spatial variation of geology. A grid-based and distance-weighted interpolation procedure is applied, following geologically defined neighbourhood relations of measuring sites and accounting for isolated outcrops of known geology but without measurements. To investigate the statistical relationship between indoor radon, house type and building ground specifications, measurements of the indoor radon concentration have been carried out in more than 10,000 dwellings in different regions of Germany. Multiple regression analyses of variance reveal that besides region-specific geological properties and building characteristics, various house type and living style variables significantly contribute to the explained variance for ground floor radon concentrations. These parameters are also dominant in controlling the radon transfer relation from soil gas to indoor air. Risk prediction maps for radon in houses indicating the probability to exceed certain indoor threshold values can be useful especially for regions with no or only a few measurements of indoor radon.     

A preliminary design of a radon potential map for Canada: a multi-tier approach

Canada is a vast country with most of the population living on a small portion of the land. However, for a national radon potential map, it is mandatory to cover the entire country including sparsely populated areas. Because of these characteristics, the radon map development for Canada is challenging. After briefly reviewing of radon map development in the world, this study considers a multi-tier approach to best use available however limited resources and to generate a national radon map in a timely fashion. In summary, radon potential maps for highly populated areas should be determined by direct indoor radon measurements where enough indoor radon data are available. In areas where indoor radon measurements are limited or not yet available, the radon potential maps could be developed from various data sources with a multi-factor scoring system including geological information on soil permeability, soil gas radon concentration and ground uranium concentration. In sparsely populated areas, radon potential maps can only be generated with geological predictive tools, especially in those areas where no houses have yet been built. Because indoor radon measurement data and geological information relevant to radon are very limited in Canada, a multi-step strategy is also worth considering in addition to the multi-tier approach.     

环境中氡及其子体的危害与控制

简要回顾氡致肺癌的长时间认识过程和研究历史,简述了当年铀矿工人和矿工吸入氡及其子体与肺癌发病率的关系,指出环境中氡的危害。重点讨论了国内外室内氡和地下建筑物中氡浓度分布及其来源,从而启发人们研究环境中氡的地质来源以及控制室内氡水平的基本措施;进一步阐述了我国室内氡研究的成果和需要进一步研究的问题。     

氡地质潜势规律研究方法探讨

氡的地质潜势是环境氡研究的重要内容,也是从地质背景出发快速评价氡浓度水平的有效方法,氡析出率是反映氡地质潜势的最好参数,根据放射性元素分布规律,地质背景及放射性元素衰变等,建立了计算氡析出率的理论公式。理论计算结果表明,北京市区氡的地质潜势分为四个不同的区,不同潜势区中室内氡浓度水平发生相应变化。说明通过氡地质潜势规律研究,可以确定室内氡浓度水平潜在高值区。