Bias from two analytical laboratories involved in a long-term air monitoring program measuring organic pollutants in the Arctic: a quality assurance/quality control assessment

Initiated in 1992, air monitoring of organic pollutants in the Canadian Arctic provided spatial and temporal trends in support of Canada's participation in the Stockholm Convention of Persistent Organic Pollutants. The specific analytical laboratory charged with this task was changed in 2002 while field sampling protocols remained unchanged. Three rounds of intensive comparison studies were conducted in 2004, 2005, and 2008 to assess data comparability between the two laboratories. Analysis was compared for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in standards, blind samples of mixed standards and extracts of real air samples. Good measurement accuracy was achieved for both laboratories when standards were analyzed. Variation of measurement accuracy over time was found for some OCPs and PCBs in standards on a random and non-systematic manner. Relatively low accuracy in analyzing blind samples was likely related to the process of sample purification. Inter-laboratory measurement differences for standards (<30%) and samples (<70%) were generally less than or comparable to those reported in a previous inter-laboratory study with 21 participating laboratories. Regression analysis showed inconsistent data comparability between the two laboratories during the initial stages of the study. These inter-laboratory differences can complicate abilities to discern long-term trends of pollutants in a given sampling site. It is advisable to maintain long-term measurements with minimal changes in sample analysis.     

A novel wet-scrubbing process using Fe(VI) for simultaneous removal of SO2 and NO

The objective of this work was to develop a novel wet-scrubbing process using Fe(VI) for the simultaneous removal of gaseous NO and SO(2). The oxidation of SO(2) and NO with Fe(VI) was studied in aqueous solution at alkaline pH (9.0-11.0). A stoichiometric molar ratio for NO and SO(2) oxidation with Fe(VI) was determined to be nearly 3.0. Sulfate and nitrate was identified as final products by ion chromatography from the reaction at pH 9.0-11.0. The feasibility of simultaneous removal of multiple gas pollutants with the continuous feeding of ferrate in lab-scale was investigated from the view of industrial application. It was found that the removal efficiency of NO and SO(2) was enhanced with the increase of Fe(VI) concentration, more than 90% NO removal efficiency and 100% SO(2) removal efficiency were achieved by wet-scrubbing process using Fe(VI) at room temperature and ambient atmosphere. The results demonstrate that Fe(VI) could be an effective wet-scrubbing agent for the simultaneous removal of NO and SO(2).     

CREAM-based communication error analysis method (CEAM) for nuclear power plant operators’ communication

Communication error has been considered a primary cause of many incidents and accidents in the nuclear industry. In order to prevent these accidents, a method for the analysis of such communication errors is proposed here. This paper presents a qualitative and a quantitative method to analyze communication errors. The qualitative method focuses on finding a root cause of the communication error and predicting the type of communication error which could happen in nuclear power plants. We develop context conditions and antecedent-consequent links of influential factors related to communication errors. The quantitative analysis method focuses on estimating the probability of communication errors. To accomplish the quantification of communication errors, the Cognitive Speaking Process (CSP) is defined and a method to estimate the weighting factors and the probability is suggested. Finally, case studies conducted to validate the applicability of the proposed methods are detailed. From the results, we can foresee the effects of given plant conditions on communication errors and reduce the error occurrences.     

人工强化生态滤床滤料性能研究

为了给人工强化生态滤床在工程应用选择滤料提供参考,利用室内模拟试验装置,考察了沸石、砾石、火山岩、陶环、碳环5种滤料在孔隙率、挂膜速度、机械强度、不同进水流量条件下COD、氨氮去除效果等方面的性能.结果表明,陶环和碳环孔隙率远大于其他3种滤料,陶环、碳环.火山岩.沸石和砾石的孔隙率分别为77％,75％,47％,38％和35％.当水力负荷为8mL/min时,在第11d,砾石滤料和火山岩滤料的COD去除率稳定,分别达到40.8％和41.6％,而其他3种滤料去除率仍处于上升阶段.这说明砾石与火山岩挂膜速度大于其他3种滤料.当系统稳定运行后,在水力负荷为3.75 mL/min时,碳环和火山岩滤料的COD去除率高于其他3种滤科.当水力负荷保持3.75mL/min时,进水COD升高,火山岩滤料COD去除率降低,小于其他3种滤料.这说明火山岩滤料与其他滤料相比具有更好的抗COD负荷冲击能力.沸石抗氨氮负荷冲击能力高于其他滤料.陶环和碳环强度差于其他3种滤料.研究表明,5种滤料各具特点,在实际工程滤料选择过程中应充分考虑施工和造价等因素.对于大型工程,如果工程当地不具备火出岩和沸石矿资源,应优先选择砾石滤料.     

GB 19083-2010《医用防护口罩技术要求》标准解读

本文主要介绍新标准GB19083-2010的修订背景、新旧标准的差异对比,重点介绍影响口罩防护效果的重要指标—过滤效率和口罩密合性项目,并对生产厂家在应用标准时需要注意的事项加以说明。     

Association between noise exposure and atrial fibrillation: a meta-analysis of cohort studies

Environmental Science and Pollution Research - Noise has become an important environmental risk factor. Some studies have shown that exposure to noise can cause coronary artery disease, high blood...     

Sorption isotherm studies of Cd(II) ions using living cells of the marine microalga Tetraselmis suecica (Kylin) Butch

The present work reports the use of living cells of the marine microalga Tetraselmis suecica for the biosorption of cadmium ions. For a better understanding of the biosorption characteristics, three fractions of removed cadmium (total, bioadsorbed and intracellular) were measured in the cells after 24 and 72 h of exposure to different initial cadmium concentrations (0.6–45 mg L^?1). Both the Langmuir and Freundlich models were suitable for describing the sorption of cadmium ions by this microalga. The maximum sorption capacity was estimated to be 40.22 mg Cd g^?1 after 72 h using the Langmuir sorption model. In the lower cadmium concentrations, metal removed intracellularly was higher than that removed on the microalgal cell surface. Therefore, the intracellular fraction contributed more to the total removed cadmium than the fraction bioadsorbed to the cellular surface. The results showed that the cadmium removal capacity using living biomass could be much more effective than with non-living biomass due to the intracellular bioaccumulation. According to the microorganism selected and its tolerance to the toxic effect of the metal, the cadmium content in the intracellular fraction can become very significant, just like it happened with Tetraselmis.     

小型砂滤池在废水处理中的应用

本文通过湿式除尘后的废水治理及工程实例,探讨了小型砂滤池在废水处 理中应用的可行性。     

民国初年北洋政府救灾举措述评

学界有一种观点认为,民初北洋政府漠视救灾,事实并非如此。本文例举了当时内务部等政府部门在救灾方面的措施,其大致可分为消极式的治标举措和积极式的治本举措。其中治标举措包括赈济、调粟、养恤、除害、资遣、蠲缓、放贷类灾后补救办法,积极式的治本举措包括重农、仓储、水利和林垦等。各重治标措施和治本措施的同时并举,显现了民初北洋政府对救灾的重视,学界那种认为政府漠视救灾的观点,值得商榷。