Investigation of the complexation of metal-ions by strong ligands in fresh and marine water

SCOPE: The detection and investigation of metal ions bound in strong complexes in natural waters is a difficult task, due to low concentration of the metal ions themselves, and also of the strong ligands, which, moreover, are often not of a well-defined composition. Here, a method is proposed for the investigation of the speciation of metal ions in natural waters. OBJECTIVE AND METHOD: It is based on the sorption of metal ions on strongly sorbing ion exchange resins, i.e. complexing resins. For this reason the method is called Resin Titration. It has been shown in previous investigations that the concentration of metal ion totally sorbed by a particular resin, and its reaction coefficient in the solution phase in the presence of the resin, can be determined from the sorption data using a simple relationship. Here, a data treatment (the Ruzic linearization method) is proposed for also determining the concentration of the ligands responsible for the complex in equilibrium with the resin. RESULTS: The method was applied to data obtained by Resin Titration of a freshwater and a seawater. Copper(II) and aluminium(III) were considered, using Chelex 100 as a titrant, due to its strong sorbing properties towards these metal ions. The results were: the total metal concentration in equilibrium with the resin, the side reaction coefficients, and the concentration of ligands. In all these cases the ligands forming very strong complexes were found to be at concentration lower than that of the metals. CONCLUSION: The Ruzic linearization method allows the determination of the concentration of the ligands forming very strong complexes in equilibrium with Chelex 100. The reaction coefficient was better determined by the calculation method previously proposed for RT. The ligands responsible for the strong complexes were found to be at low concentration, often lower than that of the metal ions considered. The metal in the original sample is partly bound to these ligands, since the complexes are very strong. Only a part of the metal is linked to weaker ligands, or free.     

生物膜填料塔净化低浓度苯乙烯废气的实验研究

研究了进口气体中苯乙烯浓度、气体流量和液体流量等3个因素对生物膜填料塔净化苯乙烯废气的影响。研究结果表明，当进口气体中苯乙烯浓度为1000mg／m^3以下、气体流量为200L／h、循环液流量为10L／h的操作条件下，废气中苯乙烯的去除率可达90％以上。     

新装饰装修房屋室内空气中的苯系物调查

对新装饰装修房屋室内的一类主要有机苯系污染物进行了调查,调查采用吸附柱采集、GC/MS 和GC-FID测定,检测了321家居室内的苯系物.检出的苯系物有12种,苯平均浓度为0.068 mg/m^3,有86.9%的居室符合《室内空气质量标准》（GB/T18883-2002）规定的限量值,甲苯、二甲苯平均浓度分别为0.14 mg/m^3和0.41 mg/m^3,符合《室内空气质量标准》规定限值的居室分别达85.4%和73.3%.苯系物约占室内空气中TVOC的62%,浓度由低到高分别是苯、甲苯、乙苯和二甲苯,其中二甲苯中的间二甲苯占二甲苯总量的55% .     

杭州交通噪声投诉点污染现状调查与防治

近年来杭州交通噪声投诉点主要分布在高架道路、立交桥和绕城高速附近的高层住户。对其中9个交通噪声投诉点的监测表明,昼间超4 a类标准的有4个,超标范围为0.1~7.6 dB;夜间9个点全部超4 a标准,超标范围为5.4~17.4 dB,夜间噪声超标特别严重。采用低噪声路面,设置隔声屏障,对敏感点安装通风隔声窗以及加强交通噪声管理等对策,可减轻交通噪声对敏感点的影响,从而减少交通噪声的投诉。     

The effect of contextual information on professional judgment: Reliability and biasability of expert workplace safety inspectors

Introduction: A critical aspect of occupational safety is workplace inspections by experts, in which hazards are identified. Scientific research demonstrates that expectation generated by context (i.e., prior knowledge and experience) can bias the judgments of professionals and that individuals are largely unaware when their judgments are affected by bias. Method: The current research tested the reliability and biasability of expert safety inspectors’ judgments. We used a two-study design (Study 1, N = 83; Study 2, N = 70) to explore the potential of contextual, task-irrelevant, information to bias professionals’ judgments. We examined three main issues: (1) the effect that biasing background information (safe and unsafe company history) had on professional regulatory safety inspectors’ judgments of a worksite; (2) the reliability of those judgments amongst safety inspectors and (3) inspectors’ awareness of bias in their judgments and confidence in their performance. Results: Our findings establish that: (i) inspectors’ judgments were biased by historical contextual information, (ii) they were not only biased, but the impact was implicit: they reported being unaware that it affected their judgments, and (iii) independent of our manipulations, inspectors were inconsistent with one another and the variations were not a product of experience. Conclusion: Our results are a replication of findings from a host of other professional domains, where honest, hardworking professionals underappreciate the biasing effect of context on their decision making. The current paper situates these findings within the relevant research on safety inspection, cognitive bias and decision making, as well as provides suggestions for bias mitigation in workplace safety inspection. Practical Application: Our results have implications for occupational health and safety given that inspection is an integral aspect of an effective safety system. In addition to our findings, this study contributes to the literature by providing recommendations regarding how to mitigate the effect of bias in inspection.     

Investigative consequence analysis: A case study research of beirut explosion accident

Around 15:00 GMT on August 4th, an explosion occurred in the warehouse facility storing Ammonium Nitrate (AN) at Beirut port, Lebanon. The explosion resulted in more than 178 fatalities and injured more than 6500 people, and also left an estimated 300,000 people homeless and registered as an equivalent to a 3.3 magnitude earth quake. The accident was considered to be the largest of its kind and the most severe anthropological disaster of the decade, the financial loss the nation was subjected to post the explosion was estimated to be around $ 15 billion as informed by the governor. The storage conditions of ammonium nitrate at Beirut port is not definitively known to anyone, and there is no documentation provided so far from the authorities regarding the same. This work focuses on the investigation & consequence analysis of the explosion using TNT equivalent approach. The overpressure and the impulse obtained from TNT calculations are used in probit models to assess the damages caused on human beings and structures. The results obtained in this investigative approach are then utilized to provide an analytical inference relative to the damage proxy map reported by the advance rapid imaging analysis team from NASA. Also, this work examines the existing standards, fire safety measures and legal regulations for ammonium nitrate facilities in the region. AN explosion during storage like other fire and explosion accidents are definitely preventable owing to the technological advancements and developments to prevent or extinguish controllable fires. The significance of this work relates to the methods for calculation of consequences of explosion that are happening due to the storage of highly hazardous explosive materials in excessive quantities and insists the necessity of incorporating adequate safety measures while storing such reactive and hazardous materials.     

行为实验视角下煤矿员工不安全行为路径分析

面对煤矿事故频发现状,立足矿井安全实际生产困难,深入探索矿工不安全行为影响因素。研究表明,煤矿安全事故中,员工不安全行为是导致事故发生的主要原因。通过建立实验平台模拟煤矿员工工作现场,比较不同文化程度的矿工不安全行为发生率以及安全文化教育后矿工不安全行为发生率趋势。对比发现,文化程度越高的员工的不安全行为发生次数不一定越低,且安全文化教育的刺激作用具有保质期。     

氯气泄漏扩散过程及后果评价的研究现状分析

综述了氯气泄漏扩散过程及后果评价的研究成果。从现场试验、实验室模拟和数学模拟三方面分析了氯气泄漏扩散各研究方法的优势和局限性。强调了氯气泄漏扩散后果评价的必要性。指出:必须针对中国特有的一些重气扩散建立专属知识产权的数学模型;不同层次数学模型的精度皆有待于进一步提高;需加强基于特定数学模型的全过程统一界面模拟程序的开发。     

上海浦东某氯代烃场地地下水污染现状调查

氯代烃曾经广泛用作工业清洗剂,由于过度使用和储存不当,造成严重的土壤和地下水污染.本研究选取上海浦东某1,1,1-三氯乙烷(1,1,1-TCA)污染场地作为研究对象,连续5年观测了75个监测井的地下水样品氯代烃分布.采用吹扫捕集和气相色谱联用法检测了地下水样品中氯代烃的种类和浓度,运用GMS软件构建了污染场地水文地质模型和氯代烃污染羽分布图.结果表明,氯代烃污染羽主要分布在5个区域,面积达5000 m2左右,深度主要在地下4~8 m的粘土层中,污染土壤和地下水总量为50000 m3左右;2号区域的污染情况最为严重,氯代烃浓度范围为10~1700 mg·L~(-1),发现50 m3左右的自由相(DNAPL).研究结果将为揭示该场地污染物迁移转化规律,为后续的人体健康风险评估和制定修复方案提供数据支撑.     

东北严寒地区村镇环境现状调查研究

在城乡一体化发展背景下,农村内部现代化进程不断加快,而与之配套的社会公共服务设施与管理体制尚不健全,使得农村环境污染不断加剧.经问卷调研,东北严寒地区村镇环境突出的问题是水体和空气污染严重,垃圾围村现象普遍,工业企业生产及道路交通使得噪声污染加剧,工业企业污染较重.探究环境污染形成机制包括:农村粗放的经济发展模式、农民生活形式现代化和模式传统化的矛盾、农民环保意识薄弱以及城乡二元化体制结构使得东北严寒地区村镇环境不断恶化.文章最后提出了针对性的对策建议.