山东省环境中氡及其子体浓度与所致剂量的研究

本文采用闪烁法和Thomas三段法测量了山东省室外148个测量点的氧浓度、92个测量点的氧子体浓度, 其几何均值分别为4.76Bq·m^-3、1.54×10^-3J·m^-3 F值为0.60；室内46个测量点的氡及其子体浓度, 几何均值分别为18.0Bq·m^-3、4.50×10^-8·Jm^-3 F值为0.45。室内、外氡及其子体浓度均遵从对数正态分布。垒省每个居民吸八氧及其子体所致年有效剂量当量为0.58mSv。     

陕西省氡浓度水平及内照射剂量研究

我们使用FDT-84型气球法测氡仪器, 以抓测方式, 对欧西省室内外氧及氧氲子休浓度进行了4500次采样测量, 同时,给出西安地区氧的昼夜、季节及高度变化规律。估算出居民成人年有效剂量当量为1.73mSv·a^-1,全省居民集体年有效剂量当量为5.09×10⁴man·Sv·a^-1.浓度水平及剂 量在UVSCEAR近年报告书中各国水平之间,属正常本底范围.     

氡及其子体对大鼠肺及其支气管的损伤作用

[目的 ]研究大鼠吸入氡及其子体后肺及支气管组织的生物学变化。 [方法 ]雄性SD大鼠吸入氡及其子体的累积剂量分别达 66、111、174工作水平月 (workinglevelmonth ,WLM )后 ,收集支气管肺灌洗液 (bronchialveolarlavageflu ids ,BALF) ,观察BALF中细胞计数和分类的变化。采用SCGE技术 ,检测BALF和肺细胞的DNA链断裂情况。同时观察大鼠气管、支气管、细支气管和肺泡的病理组织学变化。 [结果 ]大鼠吸入氡及其子体后 ,各染毒组BALF中细胞总数有增加趋势 ,但仍在正常范围之内 ,淋巴细胞比例明显减少 ,而粒细胞增多 (P <0 0 5 )。各染毒组细胞DNA链断裂的迁移长度显著增加 ,且存在剂量 效应关系。病理结果观察到 174WLM剂量组肺组织慢性炎细胞浸润明显 ,部分区域浸及肌层 ,肺泡上皮大片脱落 ,出现灶性肺气肿。 [结论 ]在本实验的染毒剂量下 ,氡及其子体可降低BALF中淋巴细胞比例 ,增加粒细胞比例 ;能引起BALF和肺细胞的DNA链断裂的损伤     

Lung cancer risk at low radon exposure rates in German uranium miners

Background:

A determination of the risk of lung cancer at low levels of radon exposure is important for occupational radiation protection.

Methods:

The risk of death from lung cancer at low radon exposure rates was investigated in the subcohort of 26 766 German uranium miners hired in 1960 or later.

Results:

A clear association between lung cancer mortality (n=334 deaths) and cumulative exposure to radon in working level months (WLM) was found. The excess relative risk per WLM was 0.013 (95% confidence intervals: 0.007; 0.021).

Conclusions:

The present findings provide strong evidence for an increased lung cancer risk after long-term exposure to low radon exposure rates among Wismut miners. The results are compatible to those from residential radon studies and miner studies restricted to low levels.     

Biological effects of alpha particle radiation exposure on human monocytic cells

Radon ((222)Rn) gas produces decay progeny that emits high energy alpha (α)-particles. Epidemiological studies have shown that exposure to (222)Rn is linked with elevated risk of developing lung cancer, however clear mechanisms leading to such effects have not been delineated. Cytokines play a critical role in inflammation and their dysregulated production often contributes to disease pathogenesis. In this study, Bio-plex multiplex technology was employed to investigate modulations of 27 pro-inflammatory cytokines following exposure of human monocytic cells to 1.5 Gy of α-particle radiation. Concurrently, DNA damage was assessed by examining the formation of phosphorylated H2A histone family X (γ-H2AX) sites. Of the 27 cytokines assessed, 4 cytokines were shown to be statistically downregulated by ～2 fold relative to the untreated controls and included the interleukin (IL) family of proteins (IL-2, IL-15 and IL-17) and macrophage inflammatory protein 1 beta (MIP-1b). Interferon-inducible protein-12 (IP-12), vascular endothelial growth factor and regulated on activation normal T cell expressed and secreted (RANTES) were shown to be high expressors and upregulated. Cells irradiated with α-particles ranging from 0.27 to 2.14 Gy showed statistically significant, dose-dependant increases in γ-H2AX formation. These data suggest that α-particle radiation causes dysregulation in the production of a number of pro-inflammatory cytokines and results in significant DNA damage.     

Dosimetry of radon progeny deposited on skin in air and thermal water

It is held that the skin dose from radon progeny is not negligibly small and that introducing cancer is a possible consequence under normal circumstances as there are a number of uncertainties in terms of related parameters such as activity concentrations in air and water, target cells in skin, skin covering materials, and deposition velocities. An interesting proposal has emerged in that skin exposure to natural radon-rich thermal water as part of balneotherapy can produce an immune response to induce beneficial health effects. The goal of this study was to obtain generic dose coefficients with a focus on the radon progeny deposited on the skin in air or water in relation to risk or treatment assessments. We thus first estimated the skin deposition velocities of radon progeny in air and thermal water based on data from the latest human studies. Skin dosimetry was then performed under different assumptions regarding alpha-emitting source position and target cell (i.e. basal cells or Langerhans cells). Furthermore, the impact of the radon progeny deposition on effective doses from all exposure pathways relating to ‘radon exposure’ was assessed using various possible scenarios. It was found that in both exposure media, effective doses from radon progeny inhalation are one to four orders of magnitude higher than those from the other pathways. In addition, absorbed doses on the skin can be the highest among all pathways when the radon activity concentrations in water are two or more orders of magnitude higher than those in air.     

青海省环境中氡及其子体浓度所致居民内照射剂量

本文对青藏高嫌北部的青海省室内外氡-222及其子体进行了测量。采用闪烁法测氡浓度, 托马斯三段法测氡子体α潜能浓度。测量了162个居室和161个室外的氡及其子体浓度。全省室内外氡的平均浓度分别为：20.94Bq·m^-3和8.01mq·m^-3。     

河南省环境氡水平及所致公众剂量

用闪烁室法测量了河南省室内外空气中氡浓度。结果表明, 室内外环境氡浓度量对数正态分布, 95%的居室氡浓度小于55Bq·m^-3。全省室内外平均氡浓度分别为21.5Bq·m^-3和16.4Bq·m^-3。若室内外平衡因子F分别米取0.5和0.6, 则氡子体所致公众年有效剂量为0.97mSv, 年集体有效剂量约为7× 10⁴man·sv。     

银川市26户居室内氡污染水平调查

目的 了解银川市居民住宅氡污染水平，探讨室内氡的变化规律。方法 采用现场监测的方法，对居室内氡、TSP等指标进行24h连续监测。结果 本地区室内氡浓度平均水平较全国其他地区高；未发现室内氡浓度与建筑类型、装修材料、楼层有明显关系；室内氡浓度与TSP浓度、空气湿度呈正相关，与气温呈负相关。室内氡浓度日变化是清晨6时最高、下午17时最低。结论 建筑材料可能是导致室内氡浓度升高的主要原因；室内TSP浓度、空气湿度、温度的改变可影响室内氡浓度水平。