An epidemiological study of salt miners in diesel and nondiesel mines

A cross-sectional study of 5 NaCl mines and 259 miners addressed the following questions: 1) Is there an association of increased respiratory symptoms, radiographic findings, and reduced pulmonary function with exposure to nitrogen dioxide (NO₂) and/ or respirable particulate (RP) among these miners? 2) Is there increased morbidity of these miners compared to other working populations? Personal samples of NO₂ and respirable particulate for jobs in each mine were used to estimate cumulative exposure. NO₂ is used as a surrogate measure of diesel exposure. Cough was associated with age and smoking, dyspnea with age; neither symptom was associated with exposure (years worked, estimated cumulative NO₂ or RP exposure). Phlegm was associated with age, smoking, and exposure. Reduced pulmonary function (FVC, FEV₁, peak, flow, FEF₅₀, FEF₇₅) showed no association with exposure. There was one case of small rounded and one case of small irregular opacities; pneumoconiosis was not analyzed further. Compared to underground coal miners, above ground coal miners, potash miners, and nonmining workers, the study population after adjustment for age and smoking generally showed no increased prevalence of cough, phlegm, dyspnea, or obstruction (FEV₁/FVC<0.7). Obstruction in younger salt miners and phlegm in older salt miners was elevated compared to nonmining workers. Mean predicted pulmonary function was reduced 2–4% for FEV₁ and FVC, 7–13% for FEF₅₀, and 18–22% for FEF₇₅ below all comparison populations.     

Determination of natural radioactivity in rock salt and radiation doses due to its ingestion.

The Khewera Mines located in Pakistan contain the world's second largest reserves of rock salt. Rock salt is used in Pakistan in food recipes. It was decided to investigate the concentrations of naturally occurring radionuclides in rock salt from the Khewera Mines. Samples of rock salt were collected from 10 different locations and analysed by gamma spectrometry. The mean activity concentrations of 226Ra, 232Th and 40K were 790 +/- 262, 640 +/- 162 and 23 000 +/- 6000 mBq kg(-1), respectively. The mean annual effective dose due to the intake of natural radionuclides from rock salt for adults was estimated to be 0.0638 +/- 0.015 mSv, which is lower than the average annual effective dose of 0.29 mSv received per caput worldwide due to the ingestion of natural radionuclides, as reported by the United Nations Scientific Committee on the Effects of Atomic Radiation in 2000.     

75例有色矿山职业伤害危险因素的病例-交叉研究

目的探索有色金属矿山职业伤害的危险因素及其作用强度。方法采用病例-交叉设计的研究方法。以某有色金属矿山2006年发生的75例非致死性职业伤害工人为对象，每个对象以相同的方式分别收集受伤前10min、上一工作日同一时段和受伤前1w内有关短暂暴露因素的信息，用配对时间段和一般频数法进行分析，评估各种短暂暴露因素的危险度。结果配对时间段分析的结果显示，工作条件、劳动管理和个人行为等11项危险因素OR值大于1；一般频数法分析：除“衣着不安全”、“未使用防护用品”的RR小于1，其他危险因素的RR值大于1。两种分析结果相比，一般频数法所得的95％CI的范围小。结论有多种可能诱发有色矿山职业伤害的危险因素。病例-交叉设计能有效地识别职业伤害的危险因素，揭示其作用强度。     

Distribution of natural radioactivity in rocks from Ikogosi-Ekiti, Southwestern Nigeria and its radiological implications

The natural radioactivity in some rock samples in Ikogosi-Ekiti, Southwestern Nigeria, has been measured using a very sensitive gamma spectroscopic system consisting of a 76 mm x 76 mm NaI(TI) scintillation detector system coupled to a versatile Canberra Series 10 plus multichannel analyzer. The average concentrations of natural radioisotopes 238U, 232Th, and 40K are 57.9 +/- 28.1 Bq kg-1, 81.6 +/- 23.8 Bq kg(-1) and 1203.1 +/- 687.2 Bq kg(-1), respectively. These average values give rise to a mean absorbed dose rate of 0.128 +/- 0.051, microGy h(-1) at a height of 1.0 m and an effective dose equivalent of 156.90 microSv (y-1). The results indicate no radiological anomaly. The data presented here will serve as a baseline survey for primordial radionuclide concentrations in rocks of the area.     

广东地区儿童白血病与天然放射性的关系

目的 了解广东省儿童青少年白血病发病的生态学病因.方法 采用疾病监测结合文献查阅,用SPSS 13.0软件进行Spearman等级相关分析.结果 广东省儿童(0～18岁)白血病发病率具有明显的地区差异,茂名地区最低为0.42/10万,江门地区最高为3.13/10万,危险性相差7.45倍,与自然地理环境中的天然放射性核素226Ra以及232Th有等级相关,相关系数(rs)分别为0.70(P=0.011)、0.66(P=0.020),其中急性淋巴细胞性白血病与226Ra、232Th的rs分别为0.66(P=0.019)和0.64(P=0.025).分析室内γ辐射剂量率与儿童白血病发病率存在相关性,rs为0.59(P=0.042),同时对人均总有效剂量当量与儿童白血病关系进行分析,上述相关性仍然存在rs=0.59(P=0.042).结论 广东省儿童青少年白血病发病可能与该地区土壤天然放射性核素以及天然放射性有关.     

Assessment of natural radioactivity and radon exhalation rate in Sannur cave, eastern desert of Egypt.

Activity concentrations of 238U, 232Th and 40K in rocks and soil samples collected from Sannur cave, Beni Suef governorate, eastern desert of Egypt, were determined using the high-resolution gamma spectrometry technique. The results show that the concentrations of the naturally occurring radionuclides are the following: 238U ranged from 8.51 +/- 1.23 to 20.66 +/- 2.12 Bq kg(-1), 232Th ranged from 7.69 +/- 1.02 to 22.73 +/- 1.60 Bq kg(-1) and 40K ranged from 185.74 +/- 0.42 to 2084.70 +/- 23.30 Bq kg(-1). The radium equivalent activity (Raeq), the absorbed dose rate (D), and the external hazard index (Hex) were also calculated and compared to the international recommended values. The radon concentration and radon exhalation rate from the rock and soil samples were measured using the Can technique. The average value of annual effective dose for cave workers is 1.98 mSv y(-1), while for visitors it is 2.4 microSv per visit. The radon exhalation rate varies from 0.21 +/- 0.03 to 1.28 +/- 0.02 Bq m(-2) h(-1). A positive correlation has been observed between uranium content and radon exhalation rate.     

National survey on the natural radioactivity and 222Rn exhalation rate of building materials in The Netherlands

The present study reports on results of a nation-wide survey on the natural radioactivity concentrations and Rn exhalation rates of the prevailing building materials in the Netherlands. In total 100 samples were taken and analyzed for the activity concentrations of Ra, Ra, Th, and K and for their Rn exhalation rate. The sampled materials consisted of gypsum products, aerated concrete, sand-lime and clay bricks, mortars and concrete, representing about 95% of the stony building materials used in the construction of Dutch homes. The laboratory analyses were performed according to two well-documented standard procedures, the interlaboratory reproducibility of which is found to be within 5% on average. The highest radionuclide concentrations were found in a porous inner wall brick to which fly ash was added. The second highest were clay bricks with average Ra and Ra levels around 40 Bq kg. Concrete and mortar show the highest exhalation rates with a fairly broad range of 1 to 13 microBq (kg s). Low natural radioactivity levels are associated with either natural gypsum (products) or gypsum from flue gas desulphurization units, and low exhalation rates with clay bricks. To evaluate the radiological impact the radioactivity concentrations in each sample were combined into a so-called dose factor, representing the absorbed dose rate in a room with a floor, walls and ceiling of 20 cm of the material in question. For that purpose, calculations with the computer codes MCNP, Marmer and MicroShield on the specific absorbed dose rates were incorporated in the paper. The results of these codes corresponded within 6% and average values were calculated at 0.90, 1.10, and 0.080 nGy h per Bq kg for the U series, the Th series, and K, respectively. Model calculations on the external dose rate, based on the incidence of the various building materials in 1,336 living rooms, are in accordance with measured data.     

Assessment of the natural radioactivity and its radiological hazards in Shewa-Shahbaz Garhi igneous complex, Peshawar Plain, NW Pakistan.

Forty-two representative rock samples used for construction purpose were collected from the quarries and outcrops of the rock units forming the Shewa-Shahbaz Garhi igneous complex, North-West Pakistan. Radioactivity of terrestrial radionuclides (238U, 232Th, and 40K) was measured in these samples using gamma ray spectrometry system with an HPGe detector. The samples showed fairly high mean concentrations of 51 +/- 16 Bq kg(-1) of 238U, 70 +/- 20 Bq kg(-1) of 232Th and 1,272 +/- 367 Bq kg(-1) of 40K. Mean absorbed gamma dose rate in air of 119 +/- 29 nGy h(-1) was found. Assessment of radiological hazards was made by calculating radium equivalent activities with external and internal hazard indices. The calculations showed radium equivalent activity ranging from 52 to 346 Bq kg(-1). External and internal hazard indices ranging from 0.14 to 0.94 and 0.17 to 1.1, respectively, were found.     

北京市房山区儿童水痘自然免疫现状横断面调查

目的 掌握北京市房山区儿童水痘自然免疫现状,为今后有效开展水痘预防与控制提供流行病学依据.方法 采用横断面调查的方法,选取有代表性的1～14岁健康儿童作为研究对象,进行问卷调查和血样采集,采用酶联免疫吸附法检测血清水痘IgG抗体.结果 648名儿童水痘抗体阳性率为44.1%;抗体阳性率在不同性别、户籍间差别无统计学意义(P＞0.05),在不同年龄和地区间儿童水痘抗体阳性率差别有统计学意义(P＜0.01),3～5岁年龄组、山区儿童水痘抗体阳性率最低,分别为30.6%和34.4%.结论 该地区儿童水痘抗体阳性率偏低,尚不能形成有效的免疫屏障,山区和3～5岁儿童是重点保护地区和人群,需采取有效措施加强这一薄弱环节的水痘预防管理与控制工作.     

Natural radioactivity of potassium 40K in curative and natural mineral waters and dose estimation

Natural mineral and curative waters often characterize elevated level of mineral components. If the mineralization grows, the concentration natural radionuclides, which are one population's exposure sources on ionizing radiation, also grows. The main purposes work were: (1) determine the concentration isotope potassium 40K in samples of water, (2) calculate effective doses caused by intake of water with potassium 40K, (3)- explore correlation between potassium 40K concentration and total dissolved solids (TDS). The concentration radioisotope 40K in analysed samples determined by means of gamma spectrometry. Received concentrations have values from the interval 0.65 to 28.42 Bq/dm3. Measured values compared to values calculated from physico-chemical analyses composition of water, which amounted from 0.07 to 22.87 Bq/dm3. The calculated effective dose resulting from intake water with potassium 40K, concentration 2.26 Bq/dm3 equaled 294 nSv by treatment and caused by inhalation water with concentration 40K 1.45 Bq/dm3 reached value 9 nSv by treatment.     

Measurement of the natural radioactivity in building materials used in Ankara and assessment of external doses

A total of 183 samples of 20 different commonly used structural and covering building materials were collected from housing and other building construction sites and from suppliers in Ankara to measure the natural radioactivity due to the presence of (226)Ra, (232)Th and (40)K. The measurements were carried out using gamma-ray spectrometry with two HPGe detectors. The specific activities of the different building materials studied varied from 0.5 +/- 0.1 to 144.9 +/- 4.9 Bq kg(-1), 0.6 +/- 0.2 to 169.9 +/- 6.6 Bq kg(-1) and 2.0 +/- 0.1 to 1792.3 +/- 60.8 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The results show that the lowest mean values of the specific activity of (226)Ra, (232)Th and (40)K are 0.8 +/- 0.5, 0.9 +/- 0.4 and 4.1 +/- 1.4 Bq kg(-1), respectively, measured in travertine tile while the highest mean values of the specific activity of the same radionuclides are 78.5 +/- 18.1 (ceramic wall tile), 77.4 +/- 53.0 (granite tile) and 923.4 +/- 161.0 (white brick), respectively. The radium equivalent activity (Ra(eq)), the gamma-index, the indoor absorbed dose rate and the corresponding annual effective dose were evaluated to assess the potential radiological hazard associated with these building materials. The mean values of the gamma-index and the estimated annual effective dose due to external gamma radiation inside the room for structural building materials ranged from 0.15 to 0.89 and 0.2 to 1.1 mSv, respectively. Applying criteria recently recommended for building materials in the literature, four materials meet the exemption annual dose criterion of 0.3 mSv, five materials meet the annual dose limit of 1 mSv and only one material slightly exceeds this limit. The mean values of the gamma-index for all building materials were lower than the upper limit of 1.