14C and 125I Labelling of Humic Material for Use in Environmental Studies

Humic and fulvic acids are present in nearly all natural waters. These acids are known to affect the transport of environmental contaminants such as metals and hydrophobic organics through the terrestrial environment. an understanding of their role in the transport of contaminants is therefore essential and is facilitated if the acid is labelled with a suitable radioactive label. This paper reports the use of ¹⁴C-methylamine and ¹²⁵I to label humic acid with either ¹⁴C or ¹²⁵I and investigates factors which affect the yield of these reactions. the stability and mobility of the labelled humic material through sand is also reported.     

纳米Fe掺杂MIL-101(Cr)及其吸附放射性碘研究

目的改进并提高MIL-101(Cr)吸附气态碘单质的性能,以期用于核事故放射性碘富集吸收。方法通过水热法制备MIL-101(Cr)材料,并利用纳米Fe掺杂改性,运用SEM、XRD等对掺杂前后的材料进行表征。将材料在75℃条件下对气态碘单质进行吸附,并比较不同Fe掺杂量下材料对气态碘吸附性能的差异。结果纳米Fe成功掺杂于基体材料MIL-101中,并对基体材料晶体结构无破坏作用。吸附性能研究表明,掺杂纳米Fe质量分数为1%的Fe@MIL-101吸附性能最优,对气态碘的饱和吸附量可达3.42 g(I2)/g(MIL-101)。结论纳米Fe掺杂改性的MIL-101材料在高温条件下对气态碘单质具有良好的吸附效果,有望应用于核反应堆事故中对放射性碘的富集或捕集。     

放射性污染的危害及防护措施

环境巾的各种放射性污染都能影响人类健康。介绍了放射性污染性质、来源和特点,重点介绍了各种影响人类生活的放射性污染。和环境中的其他污染小同,它不易察觉,但容易在人体中积累,人们要关注放射性污染,对它有一个科学的认识,才能保护自身的健康。     

施灰田土壤及所产蔬菜铀、钍和钾、钼、镁、锌含量变化及影响评价

U和Th是放射性元素,K、Fe、Mo、Mg和Zn是植物生长需要的必要营养元素。粉煤灰中U、Th、Fe和Mo的含量略高于空白土壤中Fe和Mo的含量,K、Mg和Zn的含量低于空白土壤中K、Mg和Zn的含量。掺施粉煤灰并没有引起施灰土壤及所产蔬菜中各元素含量的明显变化。与国家土壤环境质量标准及食品、卫生标准的限值相比,施灰土壤及所产蔬菜的U、Th、K、Fe、Mo、Mg和Zn的含量均在正常范围内波动。     

辐射污染防治地方立法评析

由于国家立法的缺失,近年来中国的辐射污染防治地方立法十分活跃。将放射性污染防治和电磁辐射污染防治合并,制定综合性的辐射污染防治法已成为地方立法的趋势。两种辐射污染同中有异,在污染特性、危害原理和危害程度上有明显的区别,综合性立法既有必要又具可行性。但现有立法未能反映两种辐射污染防治的根本不同,特别是回避和混淆两种辐射污染的防治原则,确立电磁辐射污染防治适用风险预防原则是当务之亟。     

Fate and transport of the β-adrenergic agonist ractopamine hydrochloride in soil–water systems

The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter(OM).Sampling of the liquid layer for 14 days demonstrated that ractopamine rapidly dissipated from the liquid layer. Less than 20% of the fortified dose remained in the liquid layer after 4 hr,and recoveries of dosed ractopamine ranged from 8 to 18% in the liquid layer at 336 hr. Sorption to soil was the major fate for ractopamine in soil:water systems, i.e., 42%–51% of the dose at14 days. The major portion of the sorbed fraction was comprised of non-extractables; a smaller fraction of the sorbed dose was extracted into water and acetone, portions which would be potentially mobile in the environment. Partitioning coefficients for all soils suggested strong sorption of ractopamine to soil which is governed by hydrophobic interactions and cation exchange complexes within the soil OM. Ractopamine degradation was observed, but to mostly non-polar compounds which had a higher potential than ractopamine to sorb to soil. The formation of volatiles was also suggested. Therefore, despite rapid and extensive soil sorption,these studies indicated a portion of ractopamine, present in manures used to fertilize soils,may be mobile in the environment via water-borne events.     

柠檬酸对核电站低放废液中110mAg吸附去除性能的影响

具有γ放射性的~(110m)Ag是核电站放射性废液中的主要核素之一,半衰期长,并且可以通过食物链在海洋生物中富集,研究其高效去除技术具有重要的意义.核电站化学去污过程加入的络合剂(如柠檬酸)对~(110m)Ag的化学形态和吸附性能有重要的影响.因此,本文首先模拟核电站水化学环境,研究了柠檬酸对~(110m)Ag化学形态的影响规律,其次研究了不同形态的~(110m)Ag物种在几种优选材料上的吸附性能.结果表明,由于核电站放射性废液的来源不同,柠檬酸与~(110m)Ag同时形成离子态络合物和~(110m)Ag0/柠檬酸纳米金属复合物;采用过氧化氢与紫外线联合高级氧化的方法能够破坏柠檬酸络合离子及~(110m)Ag0/柠檬酸复合物结构,形成单独的离子态~(110m)Ag+,从而有效地提高了~(110m)Ag物种的吸附去除性能.     

Determination of natural and artificial radionuclide materials in the Ma’assel used in hubbly-bubbly (Shisha) in Jordan

In the last decade the habit of smoking the hubbly-bubbly has increased sharply in many regions, including Europe, North America and Australia. Jordan is considered as having one of the highest consumptions of hubbly-bubbly in the world with respect to the general population. Our investigation was initiated due to the increasing trend of cancer cases in the last 10 years. The aim of this study was to determine the radioactive content in tobacco products available in the Jordanian market together with the related supplies. This study showed that all 13 samples investigated contained one or more radionuclides, from ²¹⁰Pb, ⁴⁰K, ¹³⁷Cs, ²³⁸U, and ²²⁶Ra. Most of the samples contained natural potassium ⁴⁰K and uranium ²³⁸U, lead ²¹⁰Pb was found in three samples, while radium ²²⁶Ra was present only in one sample. Five samples contained the anthropogenic ¹³⁷Cs. The estimated daily intake of U was found in the range between 4.4 and 115.8?µg per day (0.05–1.43 Becquerel (Bq) per day ²³⁸U), with geometric mean of 17.3?µg per day (0.2?Bq per day ²³⁸U). The geometric mean of U daily intake found represents 25% of the reference dose (RfD) value, where the highest determined U content represents 165% of the RfD value. This study demonstrated that a water vessel of hubbly-bubbly trapped less than 1.5% of the total U in Ma’assel samples. It is misleading to the public to indicate that a water vessel serves as an active filter for toxic and radiotoxic elements.     

238U、239Pu在板岩和土壤中迁移速度的实验模拟

以西南某低放废物处置库地质环境中板岩和土壤介质为研究对象,开展了238U和239Pu核素在这两种地质介质中的动态迁移实验研究,通过氚穿透实验(地下水流速=1 mL.min-1、实验柱连续淋洗时间=180 d)得到氚在板岩中的弥散系数DL为0.027 cm2.min-1,弥散度αL为0.324 cm,在土壤中的弥散系数DL为0.064 cm.2min-1,弥散度αL为0.895 cm.通过淋滤实验(地下水流速=0.1 mL.h-1、实验柱连续淋洗时间=350 min),得到了238U在板岩和土壤介质中的迁移速度分别为6.1—8.1 cm.a-1和7.3—8.5 cm.a-1,239Pu在板岩和土壤介质中的迁移速度分别为4.1—6.1 cm.a-1和3.7—4.9 cm.a-1.     

卡源故障下悬挂链式辐照室火灾危险性研究

为了分析悬挂链式辐照室的火灾危险性,采用实验测定得出室内典型辐照物品的点着温度,通过设置3组火灾场景模拟得到卡源故障下各火灾场景辐照室内温度变化曲线。结果表明:各火灾场景卡源初期1 h,温度上升速度较快。随着时间的增长,室内温度不断上升,但上升速率逐渐放缓。在火灾场景A,B,C等3组条件下卡源故障分别发生9,4,2.4 d后,室内局部温度能达到210℃,室内辐照物品有可能被引燃。