Functional magnetic nanoshells integrated nanosensor for trace analysis of environmental uranium contamination

Transuranic radionuclides such as uranium tend to be a pervasive environmental contaminant. It is absorbed through the intestine or a lung, deposited in the tissues, predominantly kidney and bone, and is carcinogenic. A novel nanosensor system has been developed for voltammetric tracing of environmental uranium contamination.The sensor consists of an organophosphorous ligand, (t-butylphenyl)-N,N-di-(isobutyl) carbamoylmethylphosphineoxide (CMPO) functionalized superparamagnetic core-shell magnetic nanoparticles and magnet based electrodes. It exploits the natural affinity of uranium for phosphate molecules to fabricate a highly specific and reproducible sensor. The small dimension along with a dramatically increased contact surface has lead to a faster response and higher sensitivity. The system uses an external magnetic field gradient for preconcentration and removal of the analyte from the surrounding aqueous media. The redox properties of the analyte are exploited for enumeration of variables by electrochemical techniques such as square wave voltammetry. The detection limit of the system is observed to be in parts-per-billion (ppb) of the uranyl concentration.     

Influence of hydrogen contamination by mercury on the lifetime of the PEM-type fuel cell

The subject of this study is the influence of traces of mercury present in the hydrogen originating e.g. from the amalgam technology of brine electrolysis on the lifetime of PEM-type fuel cell. Accelerated tests were used in order to record deterioration of laboratory fuel cells’ performance. The power output decrease observed was only partly reversible. As was proven by XPS spectroscopy, the cell performance deterioration originates from the interaction between mercury and the platinum catalyst. The lifetime of the fuel cell was assessed on the basis of the experiments performed as 7000 h for an average mercury concentration in the hydrogen of 10 μg N m⁻³. This is a sufficient value to permit utilization of the hydrogen from this source as a fuel for the fuel cell. It should be kept in the mind, however, that this value was obtained on the basis of the accelerated durability tests.     

水中有机污染物的富集方法

本文介绍了水中有机污染物的富集方法,阐明了各种方法的使用原理、使用条件,为水中有机污染物的分析监测提供了基础资料。     

Updating of a DRASTIC-based Method for Specific Vulnerability Assessment in Carbonate Aquifers

Abstract

Some methodological modifications are suggested to improve a DRASTIC-based method as a reliable predictor of microbial contamination in extensively fractured and subordinately karstified carbonate aquifers. These modifications will allow a better assessment of vulnerability induced by the concentrated infiltration of surface runoff in two different scenarios: (a) when the karst system is entirely located within an unsaturated aquifer and (b) when the karst system is partially located within a saturated medium. The effectiveness of the updated method has been experimentally verified by comparing the vulnerability values with the results of a hydrogeological and microbiological study at a test site.     

“Integrated Water Resources Management: A Reassessment” by Asit K. Biswas

Abstract

A hydrogeological and microbiological study was carried out in Italy in order to verify the effectiveness of a DRASTIC-based method for groundwater vulnerability assessment in carbonate (fractured-karstified) aquifers. The research was developed: (a) by the monitoring of microbial contamination of two springs from January to July 2001 and from December 2002 to March 2003; and (b) by column tests in intact soil blocks, utilizing a collection strain of Enterococcus faecalis. The comparison of the vulnerability map with the results of the microbiological experiments demonstrated the effectiveness of the new DRASTIC-based method as a predictor of groundwater microbial contamination in carbonate aquifers. The effectiveness of the new proposed approach was verified and highlights the diversified role of the diffuse infiltration of precipitations through the fracture pattern and the more or less concentrated infiltration of surface water in karst areas.     

关于200 MW机组汽轮机油颗粒污染度标准的探讨

阐述了准确检测机械杂质的重要性和现行检测方法的局限性，并通过试验和现场考察，证明实行新方法的可行性并对如何实行新方法提出了建议。     

Effect of fluorine contamination on barrier metal oxidation

We clarified that interfacial barrier metal oxidation with inter layer dielectric (ILD) could be revealed by X-ray photoelectron spectroscopy (XPS) on the peeled-side of the barrier metal, and the barrier metal oxidation was promoted by fluorine contamination which adsorb to the ILD surface during etching. To consider the effect of fluorine contamination on barrier metal oxidation, hydrolysable property of fluorine contamination was evaluated by measuring the change of F 1s spectrum after dipping in boiling water. Moreover, fluoride ions and the acidity of water in which fluorine contamination was dipped were measured by Ion chromatography and pH measurement, respectively. According to our experiments, it was suggested that hydrofluoric acid (HF) acted as an oxidizing catalyst to promote barrier metal oxidation at the interface of barrier metal and ILD.     

某矿区石煤样品中放射性核素的测定及评价

介绍了某矿区石煤样品的采集、制样和选择适宜的室内分析方法,在实验室质保体系控制质量的条件下,准确测定了放射性核素含量;基于检测结果为该项目辐射环境影响作初步评价,提出了防治污染的措施。     

Identification and characterization of metabolic properties of bacterial populations recovered from arsenic contaminated ground water of North East India (Assam)

Diversity of culturable bacterial populations within the Arsenic (As) contaminated groundwater of North Eastern state (Assam) of India is studied. From nine As contaminated samples 89 bacterial strains are isolated. 16S rRNA gene sequence analysis reveals predominance of Brevundimonas (35%) and Acidovorax (23%) along with Acinetobacter (10%), Pseudomonas (9%) and relatively less abundant (<5%) Undibacterium, Herbaspirillum, Rhodococcus, Staphylococcus, Bosea, Bacillus, Ralstonia, Caulobacter and Rhizobiales members. High As(III) resistance (MTC 10–50 mM) is observed for the isolates obtained from As(III) enrichment, particularly for 3 isolates of genus Brevundimonas   (MTC 50 mM). In contrast, high resistance to As(V) (MTC as high as 550 mM) is present as a ubiquitous property, irrespective of isolates' enrichment condition. Bacterial genera affiliated to other groups showed relatively lower degree of As resistance [MTCs of 15–20 mM As(III) and 250–350 mM As(V)]. As(V) reductase activity is detected in strains with high As(V) as well as As(III) resistance. A strong correlation could be established among isolates capable of reductase activity and siderophore production as well as As(III) tolerance. A large number of isolates (nearly 50%) is capable of anaerobic respiration using alternate inorganic electron acceptors [As(V), Se(VI), Fe(III), ₃NO²⁻${{\text{NO}}_3}^{2\mathrm{-}}$, ₄SO²⁻${{\text{SO}}_4}^{2\mathrm{-}}$, S₂O₃²⁻${{\text{S}}_2{\text{O}}_3}^{2\mathrm{-}}$]. Ability to utilize different carbon sources ranging from C2–C6 compounds along with some complex sugars is also observed. Particularly, a number of strains is found to possess ability to grow chemolithotrophically using As(III) as the electron donor. The study reports for the first time the identity and metabolic abilities of bacteria in As contaminated ground water of North East India, useful to elucidate the microbial role in influencing mobilization of As in the region.     

关于太湖污染底泥生态疏浚工程的探讨

目前太湖面临着严峻的富营养化问题，太湖污染底泥生态疏浚工程已经开始启动，但是关于太湖清淤的问题，专家们仍存在不同的见解。针对目前存在的几种观点，认为首先要对太湖疏浚进行前期研究，然后开展太湖示范工程，对污染底泥的空间分布规律、水质影响程度和机制、疏浚和处置技术、环境和生态效应等关系的科学问题进行系统深入的研究，从而为污染底泥的疏浚和处置技术提供理论和实践依据。