Insights into the growth of newly formed particles in a subtropical urban environment

The role of different chemical compounds, particularly organics, involved in the new particle formation (NPF) and its consequent growth are not fully understood. Therefore, this study was conducted to investigate the chemical composition of aerosol particles during NPF events in an urban subtropical environment. Aerosol chemical composition was measured along with particle number size distribution (PNSD) and several other air quality parameters at five sites across an urban subtropical environment. An Aerodyne compact Time-of-Flight Aerosol Mass Spectrometer (c-TOF-AMS) and a TSI Scanning Mobility Particle Sizer (SMPS) measured aerosol chemical composition (particles above 50 nm in vacuum aerodynamic diameter) and PNSD (particles within 9-414 nm in mobility diameter), respectively. Five NPF events, with growth rates in the range 3.3-4.6 nm, were detected at two of the sites. The NPF events happened on relatively warmer days with lower condensation sink (CS). Temporal percent fractions of organics increased after the particles grew enough to have a significant contribution to particles volume, while the mass fraction of ammonium and sulphate decreased. This uncovered the important role of organics in the growth of newly formed particles. Three organic markers, factors f43, f44 and f57, were calculated and the f44 vs f43 trends were compared between nucleation and non-nucleation days. K-means cluster analysis was performed on f44 vs f43 data and it was found that they follow different patterns on nucleation days compared to non-nucleation days, whereby f43 decreased for vehicle emission generated particles, while both f44 and f43 decreased for NPF generated particles. It was found for the first time that vehicle generated and newly formed particles cluster in different locations on f44 vs f43 plot and this finding can be potentially used as a tool for source apportionment of measured particles.

Occupational release of engineered nanoparticles: A review

Characterising the release of different types of Engineered Nanoparticles (ENPs) from various processes is of critical importance for the assessment of human exposure, as well as understanding the possible health effects of these particles. Therefore, the main aim of this chapter is to present a comprehensive review of studies which report on the release of airborne ENPs in different nanotechnology workplaces. The chapter will cover topics of relevance to the occupational characterisation of ENP emissions, ranging from the identification of different particle release sources and scenarios, to measurement methods and working towards a more uniform approach to characterisation. Furthermore, a brief review of ENP exposure control strategies, together with the application of mathematical modelling as an effective tool for the characterisation of emissions at nanotechnology workplaces is included.

Biochemical, histopathological and ultrastructural changes in rat liver induced by r-( + )-pulegone, a monoterpene ketone

Biochemical, histopathological and ultrastructural changes occurring at different time points after intraperitoneal administration of a single dose of pulegone (300 mg/kg) were studied. Significant decreases in the level of liver microsomal cytochrome P-450 (67%), heme (37%), aminopyrine N-demethylase (60%) and glucose-6-phosphatase (58%), were noticed 24 hr after pulegone treatment. Alanine amino transferase (ALT) levels increased in a time dependent manner, following exposure of rats to pulegone. Light microscopic studies of liver tissues showed dilation of central veins and distention of sinusoidal spaces 6 hr after pulegone treatment. Initial centrilobular necrosis was noticed at 12 hr. Centrilobular necrosis became severe at 18 hr and nuclear changes included karyorrhexis and karyolysis. Midzonal and periportal degenerative changes in addition to centrilobular necrosis was observed 24 hr after pulegone administration. Electron microscopic changes showed severe degeneration of endoplasmic reticulum, swelling of mitochondria and nuclear changes, 24 hr after administration of pulegone. The time course profile of the hepatocytes after treatment with pulegone indicates that endoplasmic reticulum is the organelle most affected, following which other degenerative changes occur ultimately leading to cell death.

Retention characteristics of Cu2+, Pb2+, and Zn2+ from aqueous solutions by two types of low lime fly ashes

The technical feasibility of utilization of fly ash as a low-cost adsorbent for the removal of metals from water has been studied. For two types of fly ashes, the retention capacities of copper, lead, and zinc metal ions have been studied. Contact time, initial concentration, and pH have been varied and their effect on retention mechanism has been studied. The dominant mechanisms responsible for retention are found to be precipitation due to the presence of calcium hydroxide, and adsorption due to the presence of silica and alumina oxide surfaces in the fly ash. First-order kinetic plots have revealed that the rate constant increases with increase in the initial concentration and pH. Langmuir adsorption isotherms have been plotted to study the maximum adsorption capacities for metal ions considered under different conditions. X-ray diffraction studies revealed the formation of new peaks corresponding to respective metal ions precipitates under alkaline conditions.

Potential histopathological and molecular changes in rat vas deferens inhaled by Boswellia papyrifera and Boswellia carterii

Boswellia papyrifera and Boswellia carterii released from smoke contaminate indoor environment and consequently adversely affect humans as evidenced by respiratory disturbances. The aim of this study was to determine the effects of these plants on pathological and biochemical changes in vas deferens of albino rats. Animals were administered 4g/kg body weight B. papyrifera and B. carterii daily for 120days along with controls. Significant changes were observed in epithelial cell types and some cells showed signs of degeneration. The ultrastructural studies revealed marked changes in cytoplasmic organelles. Microvilli were missing and lysosomes were found in the cytoplasm. In addition, all treated groups plasma fructose and other biochemical parameters were decreased indicating reduced energy necessary for motility and contractility of spermatozoa. Many spermatozoa were disorganized and agglomerated. Data suggest that smoke from these plants adversely affects vas deferens.

Evaluation of developmental toxicity and apoptotic induction of the aqueous extract of Millettia pachycarpa using zebrafish as model organism

Extensive and indiscriminate use of synthetic compounds and natural compounds obtained from plant sources have resulted in serious threats to the aquatic ecosystem and human health. Aqueous extract of the root of the plant, Milletia pachycarpa Benth, is currently used for killing fish in the state of Manipur, India. Moreover, this plant is also used as traditional medicine in this region. Although it is widely used in traditional medicine, there is limited information available regarding the adverse effects and mechanism underlying its toxicity. This study examined the effects of exposure to aqueous extract of M. pachycarpa (AEMP) on early embryonic development of zebrafish embryos and mechanisms underlying toxicity. Zebrafish embryos treated with different concentrations of the AEMP produced embryonic lethality and developmental defects. The 96-hr-LC50 of AEMP was found to be 4.276 mu g/mL. Further, multiple developmental abnormalities such as pericardial edema, yolk sac edema, spinal curvature, swim bladder deflation, decreased heart rate, and delayed hatching were also observed in a dose-dependent manner. Zebrafish embryo showing moderate-to-severe developmental defects following AEMP exposure cannot swim properly. Further, this study examined oxidative stress and apoptosis in embryos exposed to AEMP. Enhanced production of ROS and apoptosis was found in brain, trunk, and tail of zebrafish embryos treated with AEMP. Data suggest that oxidative stress and apoptosis are associated with AEMP-induced embryonic lethality and developmental toxicity in zebrafish embryos.

Organic reactions in supercritical fluids: Continuous, selective and green

Supercritical fluids (SCFs) offer a wide range of opportunities as media for chemical reactions and supercritical CO2, ScCO2, is becoming increasingly important as a benign replacement for more toxic solvents.1 High pressure reactions, however, are more capital intensive than conventional low pressure processes. Therefore, supercritical fluids will only gain widespread acceptance in those areas where the fluids give real chemical advantages as well as environmental benefits. This lecture gives a brief account of the use of flow reactors for continuous reactions in supercritical fluids, particularly those of interest for the manufacture of fine chemicals.

包头稀土工业区土壤中钍的环境化学行为

本论文分为两部分：1. 综述部分（第一章和第二章），介绍了我国包头地区稀土工业区钍污染概况，对稀土工业生产造成的放射性生态环境污染进行了分析和归纳；评述了土壤和沉积物中放射性核素污染生态物理化学研究和进展；说明了本研究课题的背景、意义和技术路线。2. 实验部分（第三章至第六章），包括以下几方面内容：土壤样品和高铁矿渣样品中钍的分析方法的建立；对土壤和矿渣样品中钍的形态进行定量分析，考察了土壤性质对土壤中钍形态分布的影响；模拟自然环境，研究钍在土壤-植物系统之间的迁移积累和钍形态的植物可利用性；土壤样品对钍的吸附-解吸行为及其影响因素。 我国包头稀土工业在稀土矿浮选和稀土精矿湿法冶炼过程中产生了大量含放射性钍的废渣、废水和粉尘，对当地生态环境造成严重的破坏和放射性污染。 采用合适内标，ICP-MS法对样品中钍分析，考察了基体干扰、记忆效应和质谱干扰，比较了不同的样品消解方法对钍测定的影响，并用标准土壤样品和标准加入法对方法的准确性进行了评价。分别采用Tessier、BCR和Martínez-Aguirre形态萃取方法对土壤和样品中钍的形态进行分析，通过对总量的回收率和萃取剂选择性比较，选择了Martínez-Aguirre连续萃取法定量样品中钍的形态，并对其进行了优化和评价。考察了土壤性质影响着钍的形态分布。 通过盆栽实验，考察了小麦对根际土壤中钍形态分布以及的在不同生长期对钍的吸收影响。利用相应的材料人工模拟了土壤中钍的形态，对模拟的钍各形态的植物可利用性和植物吸收贡献指数进行评估分析。利用不同的磷酸盐对土壤进行培养处理，考察了磷酸盐的加入对土壤中钍的生物可利用性影响。 实验了土壤样品对钍的吸附-解吸过程，通过吸附容量、分配系数和吸附百分比等参数考察土壤对钍吸附能力，并考察了被土壤吸附钍的解吸行为。通过吸附机理的分析，土壤对钍的吸附作用主要是通过Th(IV)的表面水解吸附模式进行。根据实验结果，土壤样品对溶液中钍的吸附热力学可以用Freundlich方程式来描述，吸附的动力学过程可用Elovich方程描述，并对吸附方式和吸附过程进行论述。实验发现，吸附-解吸条件、土壤性质、外源稀土元素和施肥等对土壤吸附钍有一定影响。

Ion recognition: application of symmetric and asymmetric schiff bases and their complexes for the fabrication of cationic and anionic membrane sensors to determine ions in real samples

Schiff base compounds refer to the branch of supra-molecules and can be used as sensing material in the construction of potentiometric ion selective electrodes (ISEs). This relatively modern field has been subject to extensive research in the period of 1999-2007 when more than 100 ISEs employing Schiff bases were constructed. The quantitative high-throughput detection of 29 cations and 7 anions has been demonstrated in various scientific branches, such as biomedicine, pharmacy, biochemistry, pharmacology, environmental chemistry, food technology, and agriculture. This review discusses Schiff base compounds and their applications in the design and development of ion selective sensors and microsensors.

电厂燃煤中主要有害元素的种类、迁移及潜在环境影响

Distributions of elements especially hazard trace elements in coals and their wastes from a coal fired power plant have been studied in detail using knowledge of Geology, Mineralogy, Geochemistry and Environmental chemistry. The key work is on the small particle sizes of fly ashes which escaped from electric precipitator and discharged into atmosphere. By means of X-ray powder diffraction (XRD) and scanning electron microscopy with energy-dispersive spectrometer (SEM-EDS), the characteristics of minerals and morphologies were studied. Different types of fly ash were formed in different stages and processes. More than 50% of small fly ashes belonged to inhalable particles (PM10). The very fine fly ashes preferred to attach on surface of bigger fly ash or conglutinate with each other and this decreased the environmental impact of tiny fly ashes. The trace elements in coal, fly ashes, slags and small particle sizes of fly ashes had been analysed by means of Neutron Activation Analysis (INAA), inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES). As particle sizes decreasing, distributions of most elements increased, but in contrary to most studies, this increasing trend was not very obviously because of the tendency of attachment of tiny fly ashes. The occurrence of 30 elements including hazard trace elements of Cd, Cr, Ni, Co, Pb, Zn, As, Se, Cu, V was studied by means of sequential chemical extract. The annual discharge of hazard trace elements of slag, fly ash, small fly ash (PM10), tiny fly ash (PM2.5) and air was calculated by mass balance. S, V, Cu, Pb, Se, Mo, Cd from power plant had potential impacts on environment. Hazard trace elements from the power plant had little effect on soil and aerosol comparing to those from other industrial sources and the effects were mostly on downwind direction. Both the high performance electric precipitator and high chimney made the hazard trace elements from power plant being transported far away but little environmental impacts.

酸沉降环境化学与硫同位素示踪研究──以浙江中部地区为例

研究区域降水样品pH值的分布范围为3.64-7.20，pH年均值为4.45。SO4、NO3、NH4、Ca、H是降水中主要的阴、阳离子。降水中SO4对降水酸度的贡献逐渐降低，而NO3的贡献则显著增加。SO4、NH4、Ca、H、NO3的沉降通量相对较大，其它离子则相对较小，同时降水离子成分沉降通量的季节变化非常明显。SO4和NO3、Ca和Mg以及Na和Cl表现出较好的相关关系，另外Ca和SO4、Mg和SO4以及Mg和NO3等酸、碱性离子之间也存在较好的相关性，但H与其它离子间并没有表现出明显的相关关系。降水中SO4、NH4、NO3和F主要来自人为活动的影响，Ca、k和Mg主要来自土壤、沙尘等地壳来源，Na、Cl属于典型的海盐性成分。 浙江中部地区大气降水硫同位素δ34S值的变化范围为+0.53‰－+14.23‰，平均值+5.04‰，区域内各地大气降水硫同位素组成基本一致。大气SO2的δ34S值变化范围在+0.95‰－+7.50‰之间，年均值为+4.73‰，气溶胶δ34S值变化范围则在+6.39‰－+9.83‰之间，年均值为+8.09‰。降水和大气SO2的δ34S值存在冬季高夏季低的季节性变化特征，同位素平衡分馏引起的温度效应和夏季生物成因硫的大量释放是造成季节性变化的主要控制因素。降水中人为来源硫的相对贡献约为53%－91%，年平均为73%，生物成因硫的相对贡献约为8%－44%，年平均为26%。远距离传输硫是研究区域降水中另一个非常重要的硫源，其相对贡献约为27%－44%。大气SO2氧化反应中多相氧化处于相对重要的地位，均相氧化在氧化反应机制中也有其不可低估的作用。研究区域大气环境的相对湿度对大气SO2的氧化机制有着重要的影响。