共查询到17条相似文献，搜索用时 234 毫秒
1.
四平市区土壤中氡的分布规律 总被引：3，自引：0，他引：3
在国内对测量天然条件下城市土壤中氡还为数不多的情况下，利用静态活性炭吸附法，对四平市区土壤中氡进行了测量，分析了四平土壤中氡的分布规律。区内土壤中氡浓度的变化范围为0.1-46.7Bq/l，个别点测值高出世界土壤中氡浓度平均值（7.4Bq/l)的8．6倍。根据土壤中镭的含量计算了空气中氡的变化规律，在距地表1m高的空气中氡浓度平均值为3.54Bq/l，此值在世界正常值范围（1－10Bq/l)内。 相似文献
2.
经过10年对3个不同测点氡季节性变化的调查，以及幼儿园，学校，防空掩蔽所和地窖氡浓度的测量后，对奥西耶克（东克罗地亚，130000户居民）的住宅（住宅建筑）进行了系统的室内氡测量，用LR－115固态径迹探测器在城镇48个测点上测量了室内氡，给出了算术平均值为71．6Bq.m^-3,标准偏差为44．0Bq,m^-3,和几何平均值为60．1Bq.m6-3，其冬浓度范围从22．7到186．5Bq.m^-3,由Radhome硅探测器进行的氡测量差异并不大，氡浓度的经验频率分布（分组宽度20Bq.m^-3)与x^2检验示出的理论对数正态分布相一致，氡图指指出了由地质土壤构造造成的氡浓度较高的区域（该城镇的中部）。上述提及住宅中氡及其子体的平衡因子为0．44，有些氡模型的有效剂量当量估计数接近2mSv.a^-1. 相似文献
3.
对长约70 km引水工程洞线上进行的地面伽马能谱测量、陆地伽马剂量率测量、土壤氡浓度测量、岩石表面氡析出率测量以及钻孔岩芯样品的放射性元素U、Ra、Th、K含量分析的综合放射性地质调查,并对获得的测量数据进行分析研究。结果表明,测区引水沿线地质体放射性核素当量含量平均值为：U 1.56×10-6,Th 14.12×10-6,K 2.16×10-2;钻孔岩芯放射性元素分析含量平均值为：U 32.34 Bq/kg,Ra 35.68 Bq/kg,Th 35.29 Bq/kg,K 865.65 Bq/kg。陆地伽马剂量率为90.42 nGy/h;土壤氡浓度平均值为4 272.1 Bq/m3;岩石表面析出率平均值为4.01×10-2 Bq/m2·s。根据测量结果,利用内照射和外照射辐射剂量计算了对施工人员造成的辐照剂量为0.759 mSv,低于国家对公众的剂量限值1 mSv/a,表明引水工程输水隧洞的施工在安全辐射范围内。 相似文献
4.
在广东珠海地区采用便携式半导体测氡仪进行了大比例尺土壤氡浓度调查,测点数469个,面积大于100km2。珠海地区地下0.6 m处的平均土壤氡浓度为55.94±58.54 kBq/m3,其中在珠海斗门的第四纪沉积物地区、沉积物和风化花岗岩混合地区,以及风化花岗岩地区的土壤氡浓度分别是7.14±8.75,37.64±25.92和151.25±196.23 kBq/m3。高氡潜势区主要分布在黑云母花岗岩、风化花岗岩地区和新的工业开发区,且表现出与当地岩性密切相关。城市化和工业化改变了原有的天然辐射背景。珠海市区的平均土壤氡浓度分别为广州、泉州和晋江市平均值的8.3倍和15倍。研究结果表明：珠海是一个氡潜势较高的区域,需要进一步开展辐射防护目的的氡测量。 相似文献
5.
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。 相似文献
6.
固体径迹探测技术在环境氡监测中的应用 总被引：1，自引：0，他引：1
对醋酸纤维素和CR-39探测器进行比较研究,在确定两种探测器的蚀刻条件和改进径迹计数方法的基础上,对CR-39探测器进行刻度,刻度系数为0.035 Tc/cm2/Bq.h/m3。应用固体径迹测氡方法对安阳地区和成都市室内外氡浓度进行测量,结果表明安阳地区室内外氡浓度范围在13.0 Bq/m3~54.2 Bq/m3之间,成都市室内外氡浓度范围14.1 Bq/m3~43.2 Bq/m3之间,低于GB/t16146-1995规定的氡浓度标准。监测过程发现,装饰地板材料是影响室内氡浓度的一个主要因素,水泥厂、钢铁厂等工业污染是影响室外氡浓度水平的重要因素。 相似文献
7.
自2001年12月连续逐周在贵阳观风山附近对近地面空气210Pb-7Be浓度和沉降量的观测表明:区域性降水和气温制约近地面空气210Pb具高浓度"U"型年分布;降水量和平流层向下输送影响近地面空气7Be月均浓度的季节性变化;210Pb/7Be月均浓度比率受控于210Pb变化和富7Be气团下沉的影响.观风山与瓦里关山之间因纬度和海拔的关系,7Be比率急剧震荡,显示出海洋性贫7Be气团入侵对观风山地区的明显影响.2002-2008年间贵阳观风山近地面空气210Pb的年均浓度(2.8±0.6)mBq/m3,约为全球若干站点中最高平均浓度值的4倍;而7Be的年均浓度(4.8±0.6)mBq/m3,与全球高海拔站点长期观测的平均值相当,大约为北半球中纬度对流层顶部附近7Be浓度值(18.0 mBq/m3)的1/3.8,显示出低纬度、较高海拔地区的预期水平.2003年,瓦里关山和观风山近地面空气7Be的年均浓度比为3.8,与预期的大气输送和混合作用基本一致.7Be月均浓度的增大趋势反映出受太阳黑子数减少的变化关系,其影响底线大约为4 mBq/m3;7Be年均浓度波动的增大趋势反映出受太阳黑子数降低的可能影响.贵阳观风山降水中7Be和210Pb的体积加权浓度分别为0.72 Bq/L和0.27 Bq/L;年沉降通量分别为0.080 Bq/(cm2·a)和0.031 Bq/(cm2·a).数值模拟显示出全球空气210Pb高浓度区和高沉降通量环带分布,印证了洱海和红枫湖沉积物7Be和157Cs蓄积的模拟结果. 相似文献
8.
9.
10.
为了研究区域土壤氡填图的方法,利用RAD7电子测氡仪和RADON-JOK土壤气体渗透率仪在广东省中山市进行了面积为1 800 km2的测量工作,有效测点数为67个。中山市的平均土壤氡浓度为(100.41±154.64)kBq/m3;最大值和最小值分别为0.74 kBq/m3和1 199.24 kBq/m3。土壤气体渗透率测量结果表明,在风化花岗岩地区,高渗透率和中渗透率占优势;而第四纪沉积物地区大部分土壤气体渗透率较低。基于此,结合研究区土壤氡浓度和土壤气体渗透率,对研究区土壤氡风险进行了分级评价。为土壤氡风险分级的方法研究提供了有参考价值的研究实例。 相似文献
11.
1Introduction Radonisaradioactivegasarisingfromtheurani umdecaychain,andisthelargestsinglesourceofra diationexposuretothepopulation(Fovtetal.,1999).Highradonexposureshavebeenshownto causelungcancer(JonMiles,1998),anditiscom monlybelievedthatthegreatertheexposureofradon radiation,thegreatertheriskofdevelopinglungcanc er(YangWenjieetal.,1999).Theairradoncomes mainlyfromundergroundsoilandconstructionmateri als.Ingeneral,222Rnhasthehighestlevelinthebase mentsandundergroundspacesthatareincontact… 相似文献
12.
M. I. Al-Jarallah K. Abdalla D. Al-Azmi M. Azadul Islam A. Sahin 《Arabian Journal of Geosciences》2016,9(8):523
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. 相似文献
13.
Correlation between geology and radon levels in groundwater, soil and indoor air in Bhilangana Valley, Garhwal Himalaya, India 总被引：2，自引：1，他引：2
Radon concentrations were measured in soil, air and groundwater in Bhilangana Valley, Garhwal Himalaya, India by using an
LR-115 plastic track detector and radon emanometer. Radon concentrations were found to vary from 1 KBq/m3 to 57 KBq/m3 in soil , 5 Bq/l to 887 Bq/l in water and 95 Bq/m3 to 208 Bq/m3 in air. The recorded values are quite high due to associated uranium mineralization in the area. Radon concentration was
also found to depend on the tectonic structure and geology of the area.
Received: 22 July 1996 · Accepted: 8 January 1997 相似文献
14.
Indoor radon is considered as one of the potential dangerous radioactive elements. Common building materials and soil are the major source of this radon gas in the indoor environment. In the present study, the measurement of radon exhalation rate in the soil and building material samples of Una and Hamirpur districts of Himachal Pradesh has been done with solid state alpha track detectors, LR-115 type-II plastic track detectors. The radon exhalation rate for the soil samples varies from 39.1 to 91.2 mBq kg?1 h?1 with a mean value 59.7 mBq kg?1 h?1. Also the radium concentration of the studied area is found and it varies from 30.6 to 51.9 Bq kg?1 with a mean value 41.6 Bq kg?1. The exhalation rate for the building material samples varies from 40.72 (sandstone) to 81.40 mBq kg?1 h?1 (granite) with a mean value of 59.94 mBq kg?1 h?1. 相似文献
15.
16.
利用 PRM-2100氡子体监测仪对重庆市丰都县雪玉洞氡子体平衡当量浓度进行连续12个月的监测。研究表明：（1）雪玉洞洞内氡子体平均平衡当量浓度为2135.7 Bq/m3;取平衡因子为0.5,则其平均氡浓度为4271.4 Bq/m3;（2）氡子体平衡当量浓度总体呈现出夏季高、冬季低及洞层越高,浓度越高的特点,而且氡子体平衡当量浓度变化与洞内温度变化相关性不明显,但与洞外的相关性则较强;（3）雪玉洞游客因吸入氡子体所致的年均有效剂量当量为0.02 mSv/a,只是联合国原子辐射效应科学委员会（UNSCEAR）估计的氡子体对公众产生危害的年有效剂量界限值（1.30 mSv/a）的1.54%,因此短时间游览对游客的健康不会产生影响。但是,由于洞穴讲解员、保安、拍照人员在洞内工作时间较长,接受氡子体照射的年均有效剂量当量分别为7.69 mSv/a、11.96 mSv/a、59.48 mSv/a,均高于UNSCEAR 的年有效剂量。因此,需要合理安排洞穴内工作人员工作时间和科学地制订出他们的年工作时间上限;加强氡危害相关知识的普及与洞穴工作人员的个人防护;在高氡浓度析出区域进行屏蔽防护或在适当位置安装空气净化器;与此同时,还要加强氡及其子体浓度的分析和监测等。 相似文献
17.
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. 相似文献