The effect of various cations and pH on the adsorption of U(VI) on Amberlite IR-118H resin

The effects of various metal cations and pH on the adsorption of uranium(VI) on strongly acidic cation exchanger Amberlite IR-118H (AIR-118H) were studied. The metal cations suppress U(VI) adsorption differently depending on their ionic radii. Adsorption of U(VI) on AIR-118H peaks at pH 3.4, which was attributed to the occurrence of different forms of U(VI) at different pH values. The adsorption data were then processed using the Frumkin–Fowler–Guggenheim equation, and the standard free energy of adsorption was calculated.     

铀作业人员的微循环改变

对铀作业者１９９例及无毒物接触史的正常人１０１例行甲襞微循环检测。结果，铀作业人员甲襞微循环有改变，其加权积分值大于对照组。主要表现在管袢数减少（Ｐ＜０．０１）、管径增粗（Ｐ＜０．０１）、毛细血管运动增加（Ｐ＜０．０１）、乳丛增多（Ｐ＜０．０１）。通过对铀致微循环改变的机理试以分析，提出这种微循环改变是铀中毒的病理表现，亦是铀中毒的重要发病环节；提示铀中毒治疗中应注重改善微循环。     

新疆某铀矿山周边食品放射性核素监测与分析

目的 了解新疆某铀矿山周边食品的放射性水平,补充新疆食品放射性核素基线数据库,分析放射性核素含量,估算居民由膳食摄入所致内照射剂量。方法 2018—2020年采集食品样品6类71份,用高纯锗γ能谱仪对感兴趣核素²³⁸U、²³²Th、²²⁶Ra、⁴⁰K和¹³⁷Cs的比活度进行测量、统计、分析,并对其所致居民年有效剂量进行估算。结果 2018—2020年食品样品中均未检出核素²³⁸U,其余放射性核素的平均活度浓度和检出率分别为²³²Th：0.428 ±0.038 Bq/kg（18.3%）、²²⁶Ra：0.477 ±0.063 Bq/kg（38%）、⁴⁰K：162 ±7 Bq/kg（100%）、¹³⁷Cs：0.071 ±0.011 Bq/kg（29.6%）,居民因食品放射性核素所致年有效剂量约为0.198 mSv。结论 新疆某含铀矿山周边食品的放射性水平在国家标准限值以内,居民因膳食所致年平均有效剂量与(UNSCEAR)2000年报告相符合,食品样品中检出的人工放射性核素¹³⁷Cs的含量不会对居民健康造成危害。     

Evaluation of three electrodeposition procedures for uranium,plutonium and americium

While both mass spectrometry and alpha-particle spectrometry have been widely used for measuring alpha activities, the former is preferred since many laboratories are not equipped with ICP-MS and MC-ICP-MS systems. In this study, three electrodeposition techniques using ammonium chloride, ammonium oxalate and ammonium sulphate as electrolyte solutions were applied and evaluated for the preparation of uranium, plutonium and americium sources for alpha-particle spectrometry. Changes in pH and temperature throughout the electrodeposition process were measured every 15 min, together with percentage deposition every 30 min. The percentage deposition in each method was checked at 300, 400 and 500 mA, and the optimised time and current were determined.     

What are the health costs of uranium mining? A case study of miners in Grants,New Mexico

Background:

Uranium mining is associated with lung cancer and other health problems among miners. Health impacts are related with miner exposure to radon gas progeny.

Objectives:

This study estimates the health costs of excess lung cancer mortality among uranium miners in the largest uranium-producing district in the USA, centered in Grants, New Mexico.

Methods:

Lung cancer mortality rates on miners were used to estimate excess mortality and years of life lost (YLL) among the miner population in Grants from 1955 to 2005. A cost analysis was performed to estimate direct (medical) and indirect (premature mortality) health costs.

Results:

Total health costs ranged from $2.2 million to $7.7 million per excess death. This amounts to between $22.4 million and $165.8 million in annual health costs over the 1955–1990 mining period. Annual exposure-related lung cancer mortality was estimated at 2185.4 miners per 100 000, with a range of 1419.8–2974.3 per 100 000.

Conclusions:

Given renewed interest in uranium worldwide, results suggest a re-evaluation of radon exposure standards and inclusion of miner long-term health into mining planning decisions.     

Ex vivo decrease in uranium diffusion through intact and excoriated pig ear skin by a calixarene nanoemulsion

Cutaneous contamination by radionuclides is a major concern in the nuclear industry. In case of skin exposure to uranium, no efficient emergency treatment is available to remove the actinide from the skin. For this purpose, we developed a nanoemulsion containing calixarene molecules displaying good chelating properties towards uranium. In this paper, we describe the ability of this formulation to trap uranium and limit its transfer from the cutaneous contaminated site into the blood. Uranium percutaneous diffusion kinetics was assessed with Franz cells over 24 h through intact and excoriated pig ear skin biopsies, after or without application of the nanoemulsion. Uranium distribution in the skin layers was analysed by SIMS microscopy. The results showed that prompt application of the calixarene nanoemulsion allows a 94% and 98% reduction of the amount of uranium diffused respectively through intact and excoriated skin. The formulation is still efficient in case of delayed application up to 30 minutes since the 24 h-uranium transfer through excoriated skin is reduced by 71%. Besides, no accumulation of uranium or uranium-calixarene chelate was observed in the different skin layers. In conclusion, this study demonstrated the efficiency of the calixarene nanoemulsion, which can be regarded as a promising treatment for uranium cutaneous contamination.     

Uranium content in porcelain denture teeth and in porcelain powders for ceramic crowns

Some porcelain denture teeth and porcelain powders marketed in Sweden have been analyzed for the content of uranium. The fission track method and the delayed neutron technique were the methods used.

Compared to results published previously the content of uranium was generally found to be lower in the brands analyzed. The denture teeth contained 23–186 ppm for Anatoform. 35–137 ppm for Myerson. 15—15 ppm for Candu-lor G and 20–53 ppm for Vivopearl. The baked and fired porcelain powders showed values of about 2.8 ppm at most, those in the form of powder about 25 ppm at most.

The radiation dose to the mucosa of the upper lip was calculated and is discussed.     

Evolution of the percutaneous penetration and distribution of uranyl nitrate as a function of skin-barrier integrity: an in vitro assessment

As recommended by OECD Guidelines, percutaneous penetration studies consider intact skin, but rarely injured skin. Recent years have witnessed a growing concern for these two types of dermal exposure in the industry, particularly in the nuclear industry. The aim of this study was to show that a method based on an in vitro device can be used to realistically assess how skin-barrier alterations caused by occupational accidents can modify the percutaneous penetration and distribution of radionuclides, particularly uranium. Wounds encountered in the nuclear industry (i.e., nitric acid burns and abrasion) were simulated on hairless rat skin. Skin-barrier alterations were characterized by means of a histological study and by measuring transepidermal water loss (TEWL) and skin thickness. The percutaneous penetration of uranyl nitrate through intact or injured skin biopsies was then measured in vitro. The maximum uranium flux values obtained for intact skin, skin abrasion with stratum corneum removal, and skin exposed to 2 N HNO₃, 5 N HNO₃, and 14 N HNO₃ were, respectively, 0.6?±?0.02, 1.2?±?0.03, 1.2?±?0.04, 42.0?±?1.0, and 174.0?±?8.7?ng.cm^?2.h^?1. These results demonstrated that the percutaneous absorption of uranium increased with the increased impairment of the stratum corneum. TEWL, combined with maximum uranium flux values measured in vitro, yielded a good prediction of the percutaneous penetration of uranium through injured skin, previously observed in vivo. To conclude, this in vitro assay provides a conservative estimate of the percutaneous diffusion of uranium through intact or injured skin, making it a good alternative method for toxicological studies and risk assessments.     

铀促排药物研究Ⅱ:邻苯二酚类胺羧酰胺螯合剂的合成

In searching for drugs against uranium intoxication a series of 2,3-dihydroxy-N, N′-dicarboxymethyl-N, N′-di (substituted phenylcarbamoylmethyl)-1, 4-benzenedimethanamine (Ⅵ) was synthesized starting with 2,3-dihydroxy-1, 4-benzenedimethanamine tetraacetic acid Their ability to enhance the elimination of uranyl nitrate from animal bodies was tested and three of them (Ⅵc, Ⅵe and Ⅵf) were found to be more effective than the reported uranium chelating agents, Tiron and phosphicine.