Kinetics and pathways for the debromination of polybrominated diphenyl ethers by bimetallic and nanoscale zerovalent iron: effects of particle properties and catalyst

Polybrominated diphenyl ethers (PBDEs) are recognized as a new class of widely-distributed and persistent contaminants for which effective treatment and remediation technologies are needed. In this study, two kinds of commercially available nanoscale Fe⁰ slurries (Nanofer N25 and N25S), a freeze-dried laboratory-synthesized Fe⁰ nanoparticle (nZVI), and their palladized forms were used to investigate the effect of particle properties and catalyst on PBDE debromination kinetics and pathways. Nanofers and their palladized forms were found to debrominate PBDEs effectively. The laboratory-synthesized Fe⁰ nanoparticles also debrominated PBDEs, but were slower due to deactivation by the freeze-drying and stabilization processes in the laboratory synthesis. An organic modifier, polyacrylic acid (PAA), bound on N25S slowed PBDE debromination by a factor of three to four compared to N25. The activity of palladized nZVI (nZVI/Pd) was optimized at 0.3 Pd/Fe wt% in our system. N25 could debrominate selected environmentally-abundant PBDEs, including BDE 209, 183, 153, 99, and 47, to end products di-BDEs, mono-BDEs and diphenyl ether (DE) in one week, while nZVI/Pd (0.3 Pd/Fe wt%) mainly resulted in DE as a final product. Step-wise major PBDE debromination pathways by unamended and palladized Fe⁰ are described and compared. Surface precursor complex formation is an important limiting factor for palladized Fe⁰ reduction as demonstrated by PBDE pathways where steric hindrance and rapid sequential debromination of adjacent bromines play an important role.     

异波折板水解酸化-A~2O一体化反应器实验研究

设计了异波折板水解酸化-A2O一体化反应器,进行生活污水处理的实验研究。10个月的实验结果表明,系统的最佳水力停留时间(HRT)为8 h时,最适COD进水浓度为240~600 mg/L,最佳混合液回流比(r)-污泥回流比(R)为250%~100%。控制反应器于以上运行参数下,25±2℃所对应的COD、TN和TP去除率分别为96.84%、67.55%和81.92%。当温度降至7℃时,其COD、TP和TN分别降至86.35%、50.25%和65.68%。基于实验分析结果,阐明了一体化反应器高效性的机理在于异波折板水解酸化段具有高效传质特性和A2O段具有复合式活性污泥-接触氧化好氧池的特点。     

巩固和建立企业集团安全生产宣教体系

1997年10月20日,国务院办公厅转发的劳动部<关于认真落实安全生产责任制的意见>中,把加强安全生产的宣传教育和培训工作,努力提高人民群众遵章守纪的自觉性和安全意识,掌握必要的安全生产知识,熟练掌握岗位安全操作技能,提高自我保护和处理突发事件的能力,作为敦促各级领导认真落实安全生产责任制,强化安全生产管理的一项重要要求.安全生产宣传教育是强化安全生产管理的"先导工程".在当前大力发展企业集团,进行战咯生重组过程中,巩固和建立企业集团安全生产宣教体系刻不容缓.收槁日期:1998年12月2日     

Analysis of microcystins in cyanobacteria blooms and surface water samples from Meiliang Bay,Taihu Lake,China

Taihu Lake is the third largest freshwater lake in China. In recent years, the water pollution of cyanobacteria blooms has become a severe problem in this area. Microcystins (MCs) are an important group of toxic compounds mainly produced by some cyanobacteria species and have both acute and chronic hepatotoxic effects on animals and humans. This paper presents the first data on the identification and detection of MCs in both natural occurring cyanobacteria blooms and surface water samples (0-0.5 m), collected from Meiliang Bay, Taihu Lake, China. A conventional method for extraction and isolation of MCs from cyanobacteria blooms was applied. High-performance liquid chromatography (HPLC) analysis showed that the main toxic component in the cyanobacteria materials was MC-LR. The monoclonal antibody (mAb) against MC-LR produced by hybridoma technique was employed for direct competitive ELISA to detect the concentrations of MCs in bloom and water samples collected in 2001. The results not only revealed the presence of MCs but also temporal variations of MCs levels of three sampling stations in Meiliang Bay in 1 year. It is obvious that the MC contents were relatively higher during warm months and related with the status of eutrophication. Our study indicates the threat associated with MCs in water body of Taihu Lake. To prevent the MCs potential hazard on public health in this area, some necessary measures of monitoring and control of growth of cyanobacteria are urgently needed.     

某飞机维修公司个人听力防护用品使用情况调查分析

为了解听力防护用品使用过程中的问题,提高我国噪声暴露工人听力防护用品的使用率和有效率,选择噪声危害较大的某飞机维修公司的员工,进行听力防护用品使用情况的问卷调查。结果显示:该公司为员工提供耳塞和耳罩两种听力防护用品;员工的听力保护意识、使用情况较好,使用率达95%,但对听力防护用品相关知识的了解不够全面;能够在工作中一直坚持使用的工人较少,仅占11%,影响工人工作时间使用听力防护用品时间长短的因素主要是其舒适性。调查分析提示:在未来听力防护用品的生产过程中,需要进一步加强和改善舒适性的技术;政府、企业和个人3方面共同参与,降低职业性噪声暴露对工人听力的损伤。     

The fungicide difenoconazole alters mRNA expression levels of human CYP3A4 in HepG2 cells

The fungicide difenoconazole has been frequently detected in agricultural products, soils and surface waters, causing increasingly public concern due to toxicological properties. Although systemic triazole fungicides can inhibit the enzymatic activity of many CYP450 isozymes, how difenoconazole affects the human CYP3A4 still remains largely unknown. We thus investigated the effect of difenoconazole on normal mRNA expression and protein expression of human CYP3A4 by real-time quantitative PCR and western blot, respectively. Results show that the exposure to difenoconazole from 0.01 to 0.5 μM for 24 h down-regulates mRNA expression levels of human CYP3A4 in HepG2 cells. We also found that difenoconazole could inhibit the enzymatic activity of human CYP3A4 in a concentration-dependent mode. The IC₅₀ of difenoconazole for inhibition of CYP3A4 activity is 0.41 µM, showing a stronger inhibitor in comparison with ketoconazole. Overall, our findings indicate the potential risk of difenoconazole for the disruption of human CYP3A4.     

絮凝剂PAN-DCD与甲基橙相互作用中的热力学研究

用平衡渗析法研究了有机高分子絮凝剂ＰＡＮ－ＤＣＤ与甲基橙（ＭＯ）在２０，２５，３０，３５℃下相互作用的热力学，求得结合常数Ｋ和热力学参数△Ｇ，△Ｈ，△Ｓ，在对不同絮凝剂结构进行表征的基础上，探讨了不同ＰＡＮ，ＤＣＤ配比对合成的絮凝剂与ＭＯ相互作用的影响，结果表明：ＰＡＮ－ＤＣＤ与ＭＯ的相互作用中能量作用是主要的：随ＰＡＮ与ＤＣＤ的比值增大，合成的絮凝剂ＰＤ１，ＰＤ２，ＰＤ３在常温下与ＭＯ的结合程试     

再生水厂原水水质在线预警系统研究与应用

再生水原水水质在线预警系统能够为再生水工艺安全、稳定的运行提供保障.以中国北方T市某再生水厂为例,分析再生水厂进水主要污染指标的变化规律,根据再生水厂的MBR处理工艺特征及要求,确定6项预警指标为pH、COD、TN、NH3-N、TP和SS.在原水水质在线监测系统的基础上,建立了基于神经网络的水质预测方法.结合实际运行情...     

基于模糊综合评价的流域社会经济活动对太湖生态影响评价研究

太湖是我国的五大淡水湖之一。太湖流域是我国经济最发达、水污染最严重的地区之一，正面临着严重的环境问题。随着太湖流域社会经济的发展，太湖流域生态环境将承受更大的压力。因此，分析人类社会经济活动对太湖流域生态的影响，对研究太湖生态环境具有重要意义。采用系统分析的方法，围绕流域人类社会经济活动对湖泊生态安全的影响，建立湖泊生态安全的评价指标体系，利用层次分析法计算各指标因子的权重。在此基础上，以太湖流域2005年和2006年相关数据为依据，以MATLAB为工具，根据模糊数学的原理，利用多级模糊综合评价的方法对太湖进行生态综合评价，确定流域社会经济活动对整个湖泊生态系统的影响。研究结果表明，3个重要指数得分高低顺序依次为：水体环境状态指数＞水体污染负荷指数＞社会经济压力指数;除了点源污染以外，面源污染也是太湖流域生态环境问题的重要根源。     

我国石油炼化企业主要水污染物排放量核算方法研究

从企业工艺和产品特点出发,分析了石油炼制企业主要水污染物的排放量与企业加工量、加工工艺、加工装置、末端治理设施之间的简单逻辑关系,提出了一种基于企业规模、生产装置特征和污染治理技术的石油炼化企业水污染物排放量复杂系数核算方法。通过与实际监测数据的对比,该方法的误差满足总量核算中石油炼化企业排放量核算的要求,为行业总量减排核算提供了一种新的方法。