我国31个城市饮用水氡浓度初步调查

目的:初步调查我国城市饮用水氡水平、分布特征及其影响因素。方法:按照行政区域采样,选择我国31个省会城市和直辖市,采集市政供水管网末梢水样品406份,基于RAD7 H 2O测量装置,采取闭合回路液—气平衡法,利用抓取模式,通过半导体探测器探测气体回路中氡浓度,经过4个循环周期,推算饮用水氡浓度。 ...     

Public exposure to radon in drinking water in SERBIA

Radon is the main source of natural radiation that is received by population. The results of radon activity measurements in water from public drinking fountain, from bottled drinking water and from tap water in the city of Novi Sad, Serbia, are presented in this paper. The measurements were performed by RAD 7 radon detector manufactured by DURRIDGE COMPANY Inc. The corrected value of radon concentration in one sample exceeded the European Commission recommendation reference level for radon in drinking water of 100 Bq l⁻¹. In order to make the correlation between radon and radium concentrations in the tap water and in the water from public drinking fountain, the gamma-spectrometric measurements were performed. The results of ²²²Rn activity concentration measurements from soil in the city of Novi Sad using RAD 7 detector are presented.     

Groundwater treatment as a source of indoor radon

New Viimsi Parish water treatment plant (Northern Estonia) was investigated in order to determine whether the open filter columns serve as a source of ²²²Rn generation in the treatment process and whether they influence indoor air ²²²Rn activity concentrations. ²²²Rn measurements of indoor ²²²Rn were performed at different locations of the treatment plant; water samples from incoming raw water, from all the purification stages, consumers water and solid filter material from two filtration stages were analyzed.     

The effect of uranium migration on radionuclide distributions for soil samples at the El-Gor area,Sinai, Egypt

The concentrations and distributions of the activity of natural radionuclides in soil samples were investigated in fifteen soil samples at El-Gor area representing two profiles (A and B) using a HP–Ge detector and alpha counting by SSNTD (CR-39), respectively. The average concentrations of the radionuclides ²³⁸U, ²²⁶Ra, ²³⁵U, ²³²Th and ⁴⁰K are 203.4, 177.23, 9.77, 43.33 and 386.22 Bq kg⁻¹ (dry weight), respectively, and profile A and ²³⁸U, ²²⁶Ra, ²³⁵U, ²³²Th and ⁴⁰K have average concentrations of 232.58, 246, 11.7, 31.7, and 277.07 Bq kg⁻¹ for profile B, respectively. The eTh and eU were estimated to detect the migration process of uranium into or out of an area or uranium to or from the studied profiles. The results indicate a migration of uranium by 29% for profile A and 65.37% for profile B. The activity ratio (²³⁸U/²²⁶Ra) was found to be 0.9 in profile A and 1.15 in profile B. These ratios coincide with the uranium migration processes. The responsible mass corresponding to the measured ²²⁶Ra activity was also calculated. The radon activity concentrations for the two profiles are nearly 300 Bq m⁻³. The emanation coefficient (η) was calculated from the ratio of the expected radon activity to the measured radon for the studied soil samples. The value of η was found to depend only on the radium activity regardless to soil formation.     

我国部分城市地下水饮用水氡含量及剂量贡献研究

目的 初步调查我国典型城市地下水饮用水氡水平和分布特征,估算生活用水地下水氡释放所致居民有效剂量。方法 选择北京、内蒙古、宁夏、陕西、河南、辽宁和黑龙江共7个省(自治区、直辖市)的12个典型城市,采集市政地下水供水共73个水样,采用连续测氡仪水氡测量装置测量水氡含量,估算生活用水地下水氡释放所致居民有效剂量。结果 7个省(直辖市)12个城市的地下水饮用水氡含量均值为11.8 Bq/L,范围为1.0~63.8 Bq/L,有37%的样品氡含量超过了美国环境保护部(EPA)推荐的饮用水氡浓度限值11.1 Bq/L。全部样品氡含量低于世界卫生组织(WHO)建议的公共饮用水氡浓度参考水平100 Bq/L。生活用水地下水氡释放所致居民年有效剂量均值为29 μSv(2.4~160 μSv)。结论 通常情况下,生活用水地下水氡释放对居民的剂量份额较低,可以忽略。但是,在一些花岗岩地区,生活用水过程地下水氡释放所致居民的剂量贡献应该引起重视。     

氡气暴露后对机体肺功能及金属元素含量的影响

目的 探索暴露于高浓度氡气后对机体肺功能的影响及金属元素水平的扰动。方法 按随机数表法将小鼠分为对照组、氡暴露30 WLM组、60 WLM组、120 WLM组,每组10只。达到累积剂量后,用无创肺功能检测仪检测小鼠肺功能,采集各组小鼠血样、肺、心脏、肝脏、肾脏、脾脏组织。HE染色观察染氡小鼠肺组织病理改变,用电感耦合等离子体质谱(ICP-MS)检测组织中金属元素含量,包括机体必需微量元素:铬(Cr)、钼(Mo)、钴(Co)、硒(Se)、铜(Cu)、锌(Zn)、锰(Mn)、镍(Ni),以及具有潜在毒性的元素:砷(As)、锡(Sn)、铅(Pb)、铝(Al)、汞(Hg)、镉(Cd)、银(Ag)的含量。结果 与对照组相比,染氡组小鼠肺通气功能降低,肺泡结构破坏,肺部金属元素Cr、Al、Pb、Sn(F=0.34、0.66、3.14、1.16,P＜0.05)以及血液中必需微量元素Mn、Cr、Zn、Mo(F=0.65、1.44、0.97、2.08,P＜0.05)含量降低,而肺部Cu、Mo、Se、As元素升高(F=1.31、1.26、0.81、2.04,P＜0.05),其余组织中元素含量也有波动。结论 吸入一定累积剂量的氡气会降低小鼠的肺通气功能,破坏肺泡结构,并使肺和血液中必需微量元素含量降低,体内金属元素含量出现波动。     

Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin

The objective of this work was to establish a new procedure for ²²⁸Ra determination of natural waters via preconcentration of radium on MnO₂ and separation of its daughter, ²²⁸Ac, using Diphonix ion exchange resin. Following removal of potential interferences via passage through an initial Diphonix Resin column, the first daughter of ²²⁸Ra, ²²⁸Ac, is isolated by chromatographic separation via a second Diphonix column. A holding time of >30 h for ²²⁸Ac ingrowth in between the two column separations ensures secular equilibrium. Barium-133 is used as a yield tracer. Actinium-228 is eluted from the second Diphonix Resin with 5 ml 1 M 1-Hydroxyethane-1,1-diphosphonic acid (HEDPA) and quantified by addition of scintillation cocktail and LSC counting. Radium (and ¹³³Ba) from the load and rinse solutions from the 2nd Diphonix column may be prepared for alpha spectrometry (for determination of ²²³Ra, ²²⁴Ra, and ²²⁶Ra) by BaSO₄ microprecipitation and filtration. Decontamination tests indicate that U, Th, and Ra series nuclides do not interfere with these measurements, although high contents of ⁹⁰Sr (⁹⁰Y) require additional treatment for accurate measurement of ²²⁸Ra. Addition of stable Sr as a “hold back” carrier during the initial MnO₂ preconcentration step was shown to remove most ⁹⁰Sr interference.     

土壤物理性质对土壤氡浓度及地表氡析出率的影响

目的探讨土壤性质对土壤氡浓度及地表氡析出率的影响。方法在北京、贵阳、呼和浩特的31个测量点进行土壤氡浓度及析出率的现场实测。采集土壤样品，在实验室进行土壤镭含量、含水量、孔隙度和粒径分布等物理性质测量。用线性拟合方法分析了实测土壤氡、析出率数据之间的相关性，以及它们与土壤镭含量的关系。结果地表氡析出率与土壤氡浓度和土壤镭含量有正相关关系；土壤含水饱和度过高或过低均会使析出率和土壤氡浓度降低；贵阳地区土壤镭含量较高，但其粉砂黏土壤的特性使土壤氡浓度很难准确采样，导致结果偏低。结论地表氡析出率和土壤氡浓度虽然与土壤镭含量有正相关关系，但在实际环境中易受含水量等多因素影响，而且土壤氡浓度的准确测量受土壤特性限制较大。     

International intercomparisons of integrating radon detectors in the NIRS radon chamber

An international intercomparison of integrating detectors was conducted at NIRS (National Institute of Radiological Science, Japan) with a 24.4 m³ inner volume walk-in radon chamber that has systems to control radon concentration, temperature and humidity.During the first intercomparison (05.2007) four groups participated from four countries and for the second intercomparison (10.2007) 17 participants were involved from 11 countries.Most of detectors are in good agreement with each other when compared to the radon level provided by the radon chamber. It appeared that the 70% of detectors are unified within the 20% margin of uncertainty.     

过滤室内空气对降低居民室内氡照射的效果研究

目的 研究空气净化器过滤室内空气对室内氡子体行为的影响,探讨该方法对降低居民室内氡照射的效果。方法 构建理论模型计算室内空气过滤前后室内氡子体的浓度,基于结合态和未结合态氡子体的剂量转换系数,评估过滤室内空气对居民氡照射剂量的降低效果,并在密闭房间内进行部分实验验证。结果 室内空气的过滤速率越大,氡子体的去除效率越明显。在一个气溶胶初始浓度为10 000 cm^-3的密闭室内,当过滤速率>10 h^-1时,氡子体总浓度可下降90%以上。但不同过滤速率下,未结合态氡子体浓度均有所增高。室内氡子体浓度变化和居民氡照射剂量下降与净化器的过滤速率密切相关,过滤速率越大,降低剂量的效果越快越好。当过滤速率>5 h^-1时,净化器可降低居民内照射剂量70%以上。结论 空气净化器过滤室内空气虽然会导致未结合态氡子体浓度上升,但仍能有效地降低氡子体所致居民的暴露剂量。     

氡暴露致小鼠骨髓细胞的DNA损伤

目的 研究氡暴露致小鼠骨髓细胞的DNA损伤。方法 采用雄性BALB/C小鼠24只,随机分为4组,每组6只,除对照组外,处理组小鼠整体暴露于多功能生态氡室,吸入氡及其子体的累积剂量分别为27(低剂量组)、52(中剂量组)和105(高剂量组)工作水平月(WLM)。采用单细胞凝胶电泳(SCGE)、微核(MN)实验、激光共聚焦显微镜(LSCM)检测小鼠骨髓细胞的DNA链断裂、微核细胞率及凋亡率,观察氡暴露致小鼠骨髓细胞的DNA损伤。结果 高剂量氡暴露可造成小鼠骨髓细胞DNA断裂,尾长和尾DNA百分含量与对照组相比,差异有统计学意义(F=201.9,40.78,P<0.05);微核率和凋亡率增加差异有统计学意义(F=16.28,41.62,P<0.05)。而中、低剂量组则无明显改变。结论 高剂量氡暴露引起DNA损伤,从而对小鼠骨髓细胞产生毒效应。     

急性高氡暴露对小鼠生物效应的研究

目的 研究急性高氡暴露对小鼠的生物效应。方法 将6 ~ 8周龄BALB/c雄性小鼠一次性暴露于平均氡浓度7×10⁵ Bq/m³的HD-3型生态氡室中10 h,分别在其暴露后1、2、3个月时称重并收集小鼠肺组织与血液样本,每个时间点均设置相应的对照组,每组4只。使用苏木精-伊红(HE)染色法观察小鼠肺组织病理、血液分析仪检测血常规、超氧化物歧化酶(SOD)、丙二醛(MDA)检测试剂盒分别测量血清与肺组织SOD与MDA含量。结果 HE染色结果表明,实验组较对照组出现肺泡壁增厚与粒细胞浸润增多,但其程度随时间逐渐降低,且在3个月时未观察到明显差异。实验组与对照组的体重及血常规各指标无明显改变。SOD含量检测显示,氡暴露后2个月,肺组织SOD含量下降[对照组(11.34 ±1.03) U/mgprot,实验组(9.75 ±0.71) U/mgprot,t = 2.54,P < 0.05]。MDA含量检测显示,氡暴露后1个月,肺组织MDA含量增加[对照组(2.30 ±0.24) nmol/mgprot,实验组(2.77 ±0.29) nmol/mgprot,t = 2.49,P< 0.05]。氡暴露后3个月,实验组与对照组SOD与MDA含量无明显差异(P > 0.05)。结论 小鼠急性高氡暴露后,肺组织出现一定程度的损伤并且可以检测到氧化应激指标的变化。但在暴露后3个月内,损伤逐渐被修复,氧化应激指标也恢复正常。此外,急性高氡暴露未引起小鼠体重和血常规的明显改变。     

室内氡暴露居民外周血淋巴细胞DNA损伤及微核细胞发生率

目的：观察室内氡暴露居民外周血淋巴细胞DNA损伤及微核细胞发生率。方法：采用单核细胞凝胶电泳和微核检测两种方法。观察了我国甘肃省窑洞内氡暴露居民及对照居民外周血淋巴细胞DNA损伤及微核细胞发生率。结果：窑洞和普通住房居民（室内空气中氡浓度分别为200－350Bq.m^－3及37．5-77.1Bq.m^－3)的细胞迁移发生率分别为1．68％和1．43％，人发生细胞迁移百分别为57．1％和54．3％。50岁以上窑洞和普通住房居民细胞迁移和人发生细胞迁移率分别为2．14％、75．0％和2．00％、64．7％。窑洞和普通住房居民微核细胞发生率分别为1．07％和0．78％。结论：窑洞居民外周血淋巴细胞DNA损伤及微核细胞发生率略高于普通住房居民，P值接近0．05。     

基于EPA/BEIR-VI模型的我国居室内氡致肺癌风险估计

目的:估计我国居室内氡导致的居民肺癌归因份额。方法:利用较为权威且适用的EPA/BEIR-VI风险模型,基于我国2015年肺癌死亡率、全死因死亡率以及有代表性的吸烟率和居室内氡平均浓度,预测我国居室内氡浓度水平致肺癌死亡风险。结果:非吸烟男性人群居室内氡致肺癌死亡超额相对危险(ERR)高于吸烟人群,且达到年龄为50岁时...     

Earthquake precursory studies in Kangra valley of North West Himalayas, India, with special emphasis on radon emission

The continuous soil gas radon monitoring is carried out at Palampur and the daily monitoring of radon concentration in water is carried out at Dharamshala region of Kangra valley of North West Himalayas, India, a seismic zone V, to study the correlation of radon anomalies in relation to seismic activities. In this study, radon monitoring in soil was carried out by using barasol probe manufactured by Algade France, whereas the radon content in water was recorded using RAD 7 radon monitoring system of Durridge Company USA. The effect of meteorological parameters viz. temperature, pressure, wind velocity, rainfall, and humidity on radon emission has been studied. The seasonal average value and standard deviation of radon in soil and water is calculated to find the radon anomaly to minimize the effect of meteorological parameters on radon emission. The radon anomalies observed in the region have been correlated with the seismic events of M≥2 reported by Wadia Institute of Himalayas Geology Dehradoon and Indian Meteorological Department, New Delhi in NW Himalayas within 250 km distance from the monitoring stations.     

Radon leakage as a source of additional uncertainty in simultaneous determination of 226Ra and 228Ra by gamma spectrometry—Validation of analysis procedure

A series of validation experiments was carried out to assess robustness, repeatability, and trueness of an analysis procedure for simultaneous determination of ²²⁶Ra and ²²⁸Ra in water samples. The study revealed instabilities in the radon holding capacity of the sample matrix (epoxy resin). The discovered effect is a new additional component in the uncertainty budget which should be considered when ²²⁶Ra is measured via its progeny in similar sample matrices.     

The influence of uncertainties of radon exposure on the results of case-control epidemiological study

Abstract

Purpose: Simulation of large-scale epidemiological study to identify the influence of uncertainties of radon exposure assessment on the excess relative risk of lung cancer.

Materials and methods: Analysis of sources of uncertainties arising during radon epidemiologic case-control studies. Assessment of the uncertainties due to influence of long-term variations of radon concentration, exposure to radon in other places of human presence, except dwellings, quality of radon concentration measurements etc. Simulation by Monte Carlo technique of radon epidemiologic study, comparable to the pooled European radon case-control study, and assessment of uncertainties, which affect the evaluation of dose-effect dependence.

Results: The uncertainties of personal exposure to radon are generally caused by the combined effect of long-term variations of radon concentration and the differences in the levels of radon concentration in homes and other places of human presence. The logarithmic standard deviation of this uncertainty is from 0.70 to 0.90. This value is ～2 times higher than the uncertainty, applied for correction of the results in the pooled European radon case-control study. It is shown that for σ_err?<?1.0 regression calibration technique allows to make full correction of the uncertainty. The error in assessment of uncertainties of the exposure to radon concentration in the pooled European radon case-control study has led to an underestimation of excess relative risk of lung cancer incidence at least by 1.5 times.

Conclusion: The error in an assessment of uncertainties of radon exposure in the pooled European radon case-control study has led to an underestimation of relative risk of lung cancer incidence at least by 1.5 times.     

室内氡暴露居民肺癌p53和k-ras基因突变

目的：检测室内高氡暴露地区居民肺癌P53和k-ras基因突变,方法：采用PCR扩增,PCR－SSCP电泳和序列分析方法。结果：9例标本中有5例p53PCR-SSCP电泳呈阳性结果,其中3例经克隆测序发现有碱基置换,结论：室内氡浓度在200－350Bq.m^-3.a^-1范围内的7例肺癌病例中有5例发生P53基因突变,P53基因突变还可能与肺癌患者的年龄吸烟史有关。     

吸入氡致大鼠肺蛋白质组表达变化的分析

目的 从蛋白质组学角度分析氡染毒后大鼠肺组织蛋白质表达谱的变化。方法 雄性Wistar大鼠氡吸入染毒累积剂量分别达100、200、400工作水平月(WLM)后,取大鼠肺组织,裂解提取其总蛋白;双向电泳(2-DE)分离总蛋白,ImageMaster 2D Platinum软件分析差异表达蛋白,切取差异蛋白点,胶内酶解并进行质谱(MALDI-TOF-MS)鉴定。结果 正常对照组和氡染毒组大鼠肺组织的2-DE图谱有明显差异,差异表达点中与氡染毒呈剂量变化关系的点有14个表达上调,9个表达下调,质谱鉴定出其中的15个差异蛋白点。结论 氡染毒组大鼠肺组织的蛋白表达谱发生了一定的差异性,氡吸入致靶器官肺损伤可能与多种蛋白相关。     

The implications of particle energy and acidic media on gross alpha and gross beta determination using liquid scintillation

The interaction of humans with radioactivity present in the environment from natural and artificial sources necessitates an evaluation of its risk on human health. Gross alpha and gross beta activities can provide a rapid evaluation of the radioactive content of a sample and can be simultaneously determined by using liquid scintillation counters. However, calibration of the liquid scintillation counter is required and is affected by many factors, such as particle energy and the acidity of the media. This study investigates what effect the particle energy used for calibration has on misclassification and how to account for this misclassification in routine measurements.The variability in measurement produced by the final pH, as well as any acids used in sample treatment, was also studied. These results showed that the most commonly used acid for these types of analyses, HNO₃, produced a high amount of misclassifications at very low pH. The results improved when HCl was used to adjust the sample to low pH.