Spatial distribution, electron microscopy analysis of titanium and its correlation to heavy metals: occurrence and sources of titanium nanomaterials in surface sediments from Xiamen Bay, China

Titanium nanomaterials are likely to sink into sediments in substantial quantities due to their wide use in a number of applications for decades. To assess the potential environmental consequences, a better understanding is required of the occurrence and sources of titanium (Ti) nanomaterials in sediments. In this research, we provide the first report of the Ti concentrations and the morphology and composition of Ti-based solids in surface sediments from Xiamen Bay, China. Results indicated that the anthropogenic Ti concentrations in the surface sediments from Xiamen Bay reached approximately 2.74 g kg(-1). Ti nanomaterials could be found in sediments with elevated Ti concentrations, which were often aggregated to a few hundred nanometers (<300 nm) and were composed of several spherical particles, less than 50 nm in size, that were made solely of TiO(x). However, Ti particles (approx. 300-700 nm) could be also found in sediments with lower Ti concentrations, which were presumably components of the natural clay mineral kaolinite. Ti nanomaterials could be easily distributed in sediments associated with elevated levels of organic matter and preferentially attach to those sediments with elevated fine fractions. As a sentinel, or tracer, for other nanomaterials, the field-scale investigation of Ti nanomaterials would contribute to increasing our knowledge on the behavior of engineered nanomaterials in an aquatic environment.     

Coal cleaning residues and Fe-minerals implications

In the present investigation, a study was undertaken to understand the origin of Fe-minerals presents in Brazilian coal mining and to understand the environmental implication and the chemical heterogeneity in the study area. Coal cleaning residue samples rich in clays, quartz, sulphides, carbonates, sulphates, etc. were sampled from Lauro Muller, Urussanga, Treviso, Siderópolis, and Criciúma cities in the Santa Catarina State and a total of 19 samples were collected and Mössbauer, XRD, SEM/EDX, and TEM analyses were conducted on the samples. The major Fe-minerals identified are represented by the major minerals chlorite, hematite, illite, and pyrite, while the minor minerals include, ankerite, chalcopyrite, goethite, hematite, jarosite, maghemite, magnetie, marcasite, melanterite, natrojarosite, oligonite, pyrrhotite, rozenite, schwertmannite, siderite, and sideronatrile. Pyrite is relatively abundant in some cases, making up to around 10% of the mineral matter in several samples. The sulphates minerals such as jarosite and others, probably represent oxidation products of pyrite, developed during exposure or storage.     

Challenges for physical characterization of silver nanoparticles under pristine and environmentally relevant conditions

The reported size distribution of silver nanoparticles (AgNPs) is strongly affected by the underlying measurement method, agglomeration state, and dispersion conditions. A selection of AgNP materials with vendor-reported diameters ranging from 1 nm to 100 nm, various size distributions, and biocompatible capping agents including citrate, starch and polyvinylpyrrolidone were studied. AgNPs were diluted with either deionized water, moderately hard reconstituted water, or moderately hard reconstituted water containing natural organic matter. Rigorous physico-chemical characterization by consensus methods and protocols where available enables an understanding of how the underlying measurement method impacts the reported size measurements, which in turn provides a more complete understanding of the state (size, size distribution, agglomeration, etc.) of the AgNPs with respect to the dispersion conditions. An approach to developing routine screening is also presented.     

Mapping Economic Returns to Agriculture for Informing Environmental Policy in the Murray–Darling Basin, Australia

We integrate information from several disparate data sources including agricultural statistics and remote sensing to quantify and map the distribution and dynamics of agricultural returns to land and water resources from 1996/1997 to 2000/2001 in the Murray–Darling Basin (MDB), Australia. Total profit to agriculture was estimated at AUD3.86B in 1996/1997 and AUD3.73B in 2000/2001. The mapping reveals a high spatial concentration of economic returns to land and water resources from agriculture. Dryland agriculture covers over 82% of the study area. Irrigated agriculture covers 1.7% of the land area (2000/2001) but returns one third of the total profit to agriculture. We found that around 80% of the profit to agriculture comes from just over 5% of the land area. The results from this regional scale economic mapping can inform regulatory policy and public investments in natural resource management through targeting industries and regions that provide low marginal returns to the natural resource base.     

Earthworm cytochrome P450 determination and application as a biomarker for diagnosing PAH exposure

We developed a new microsome purification method and used the Omura and Sato method to measure the total content of cytochrome (Cyt) P450 in earthworm (Eisenia fetida) microsomes. In method development, two different pretreatments, i.e. solubilization or manual separation were used to purify worm microsomes. Solubilization was more effective than manual separation and difference spectra showed a peak at 450 +/- 1 nm in microsomes received solubilization pretreatment. We conducted a 48 h contact test by exposing worms on pyrene (Py) and benzo[a]pyrene (BaP) spiked filter paper. A dose-response relationship was established between total P450 content and the concentration of Py or BaP ranging from 10(-6) mg mL(-1) to 10(-2) mg mL(-1). Results show that total Cyt P450 content in earthworms is a promising biomarker for diagnosing PAHs exposure at sublethal dose ranges.     

Aerosol size distributions in urban Jinan: Seasonal characteristics and variations between weekdays and weekends in a heavily polluted atmosphere

Aerosol size distributions, trace gas, and PM(2.5) concentrations have been measured in urban Jinan, China, over 6 months in 2007 and 2008, covering spring, summer, fall, and winter time periods. Number concentrations of particles (10-2,500 nm) were 16,200, 13,900, 11,200, and 21,600 cm(?-3) in spring, summer, fall, and winter, respectively. Compared with other urban studies, Jinan has higher number concentrations of accumulation-mode particles (100-500 nm) and particles (10-2,500 nm), but lower concentrations of ultrafine particles (10-100 nm). The number, surface and volume concentrations, and size distributions of particles showed obvious seasonal variation and are also influenced by traffic emissions. Through correlation analysis, traffic emissions are proposed to be a more important contributor to Atkien-mode and accumulation-mode particles than coal firing. Around midday, the presence of nanoparticles and new particle formation is limited to pre-existing particles from traffic emissions and the mass transport of particles from suburban and rural areas. Compared with other studies in urban areas of Europe and the USA, the variation of particle number concentration and related gas concentration in Jinan between weekdays and weekends is smaller and the reasons has been deduced.     

Characterisation of Airborne Particulate Pollution in The Cu Smelter and Former Mining Town of Karabash, South Ural Mountains of Russia

Airborne total suspended particulates (TSP), dusts from smelter blast furnace and converter stacks, and filtrates of snow melt waters have been characterised in the Cu smelter and former mining town of Karabash, Russia. TSP was collected at sites up- and downwind of the smelter and large waste and tailings dumps (Oct. 2000 and July 2001). Methods for particle size, mineralogical and elemental determinations have been tested and described, and a new PSD-MicroSOURCE XRD technique developed for the mineralogical analysis of microsamples on filter substrates. TSP in downwind samples has a mean equivalent spherical diameter of 0.5 microm (s.d. = 0.2) and was found to be 100% respirable. The main element of human health/environmental concern, above Russian maximum permitted levels (1 microg m(-3), average over any time period), was Pb which was measured at 16-30 microg m(-3) in downwind samples. Individual particulates mainly consisted of complex mixtures of anglesite (PbSO4), Zn2SnO4 and poorly ordered Zn sulphates. From experimental and theoretical considerations, a high proportion of contained Pb, Zn, Cd and As in this material is considered to be in a readily bioavailable form. Chemical and mineralogical differences between the TSP, stack dusts and snow samples are discussed, as well as the implications for human and regional environmental health.     

南疆棉田土壤中邻苯二甲酸酯(PAEs)的测定

采用超声萃取和柱分离技术,利用气相色谱法,对棉田环境激素类污染物质邻苯二甲酸酯进行了表层土壤(0～20 cm)分布测定.结果表明,棉田土壤中DMP、DEP、DIBP、DBP、DAP、DEHP 6种环境激素类污染物均被检出,土壤中PAEs的总含量为1 532.987 mg/kg,其中DEHP的含量最高,DIBP、DBP次...     

环境信息数据仓库建设及其相关的技术应用

阐述了环境信息数据仓库建设的需求和体系框架,介绍了环境信息数据仓库建设的关键技术和基于数据仓库的决策支持系统,列举了环境信息数据仓库在2000年2001年间对我国西部12个省、自治区和直辖市的大范围生态环境调查课题中的应用价值。     

A new nanosilver-based spectrophotometric method for monitoring Eriochrome black T in river water

In this paper, a new spectrophotometric method is reported for the determination of nanomolar levels of Eriochrome black T in environmental samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of Eriochrome black T by hexacyanoferrate (III) in acetate–acetic acid medium and at 25 °C. The absorbance is measured at 512 nm with the fixed-time method. It relies on the linear relationship between the absorbance difference (?A) and Eriochrome black T amounts in the range of 40–1,250 nM. Under optimum conditions, the sensitivity of the proposed method, i.e., the detection limit corresponding to 80 s, is about 25 nM. The method is featured with good accuracy and reproducibility for Eriochrome black T determination in river water samples without any pre-concentration and separation step.     

Characterization and environmental implications of nano- and larger TiO(2) particles in sewage sludge, and soils amended with sewage sludge

Titanium dioxide (TiO(2)) is the most extensively used engineered nanoparticle to date, yet its fate in the soil environment has been investigated only rarely and is poorly understood. In the present study, we conducted two field-scale investigations to better describe TiO(2) nano- and larger particles in their most likely route of entry into the environment, i.e., the application of biosolids to soils. We particularly concentrated on the particles in the nano-size regime due to their novel and commercially useful properties. First, we analyzed three sewage sludge products from the US EPA TNSSS sampling inventory for the occurrence, qualitative abundance, and nature of TiO(2) nano- and larger particles by using analytical scanning electron microscopy and analytical (scanning) transmission electron microscopy. Nano- and larger particles of TiO(2) were repeatedly identified across the sewage sludge types tested, providing strong evidence of their likely concentration in sewage sludge products. The TiO(2) particles identified were as small as 40 nm, and as large as 300 nm, having faceted shapes with the rutile crystal structure, and they typically formed small, loosely packed aggregates. Second, we examined surface soils in mesocosms that had been amended with Ag nanoparticle-spiked biosolids for the occurrence of TiO(2) particles. An aggregate of TiO(2) nanoparticles with the rutile structure was again identified, but this time TiO(2) nanoparticles were found to contain Ag on their surfaces. This suggests that TiO(2) nanoparticles from biosolids can interact with toxic trace metals that would then enter the environment as a soil amendment. Therefore, the long-term behavior of TiO(2) nano- and larger particles in sewage sludge materials as well as their impacts in the soil environment need to be carefully considered.     

Eco-friendly synthesis of silver nanoparticles using green algae (<Emphasis Type="Italic">Caulerpa serrulata</Emphasis>): reaction optimization,catalytic and antibacterial activities

Stable colloidal silver nanoparticles (AgNPs) were synthesized using Caulerpa serrulata (green marine algae) aqueous extract as an efficient reducing and stabilizing agent. This method is considered to be a sustainable alternate to the more complicated chemical procedures. To achieve the optimization synthesis of AgNPs, several effects such as extract concentration, contact time, pH values, and temperature were examined. The synthesized AgNPs were characterized by UV–Vis spectroscopy, FT-IR, XRD, and HR-TEM. The synthesized AgNPs showed an intense surface plasmon resonance band at 412 nm at the optimal conditions (20% (v/v) extract and 95 °C). TEM reveal that higher extract concentration and higher temperature leading to the formation of spherical AgNPs with an average particle size of 10 ± 2 nm. The synthesized AgNPs showed excellent catalytic reduction activity of Congo red (CR) dye from aqueous solutions. The degradation percentage of CR with AgNPs accelerated by increasing either NaBH₄ concentration or catalytic dosage. The AgNPs synthesized at higher temperature (e.g., 10Ag-95) exhibited the highest catalytic activity. The reaction kinetics was found to be pseudo first order with respect to the dye concentration. Moreover, the AgNPs displayed antibacterial activity at lower concentration against Staphylococcus aureus, Pseudomonas aeruginosa, Shigella sp., Salmonella typhi, and Escherichia coli and may be a good alternative therapeutic approach. The outcomes of the current study confirmed that the synthesized AgNPs had an awesome guarantee for application in catalysis and wastewater treatment.     

Observations of urban airborne particle number concentrations during rush-hour conditions: analysis of the number based size distributions and modal parameters

A summertime study of the number concentration and the size distribution of combustion derived nanometre sized particles (termed nanoparticles) from diesel and spark-ignition (SI) engine emissions were made under rush-hour and free-flow traffic conditions at an urban roadside location in Leeds, UK in July 2003. The measured total particle number concentrations (N(TOTAL)) were of the order 1.8 x 10(4) to 3.4 x 10(4) cm(-3), and tended to follow the diurnal traffic flow patterns. The N(TOTAL) was dominated by particles < or =100 nm in diameter which accounted for between 89-93% of the measured particle number. By use of a log-normal fitting procedure, the modal parameters of the number based particle size distribution of urban airborne particulates were derived from the roadside measurements. Four component modes were identified. Two nucleation modes were found, with a smaller, more minor, mode composed principally of sub-11 nm particles, believed to be derived from particles formed from the nucleation of gaseous species in the atmosphere. A second mode, much larger in terms of number, was composed of particles within the size range of 10-20 nm. This second mode was believed to be principally derived from the condensation of the unburned fuel and lube oil (the solvent organic fraction or SOF) as it cooled on leaving the engine exhaust. Third and fourth modes were noted within the size ranges of 28-65 nm and 100-160 nm, respectively. The third mode was believed to be representative of internally mixed Aitken mode particles composed of a soot/ash core with an adsorbed layer of readily volatilisable material. The fourth mode was believed to be composed of chemically aged, secondary particles. The larger nucleation and Aitken modes accounted for between 80-90% of the measured N(TOTAL), and the particles in these modes were believed to be derived from SI and diesel engine emissions. The overall size distribution, particularly in modes II-IV, was observed to be strongly related to the number of primary particle emissions, with larger count median diameters observed under conditions where low numbers of primary soot based particles were present.     

High-performance liquid chromatography method for determination of hydrogen peroxide in aqueous solution and application to simulated Martian soil and related materials

A new method for determination of hydrogen peroxide (H₂O₂) is described. H₂O₂ reacts with iodide in the presence of ammonium molybdate and vanillic acid resulting in the formation of iodovanillic acid which is quantified by reversed-phase high-performance liquid chromatography (HPLC) and detected by UV absorption at 280 nm. The method provides a detection limit of ～0.1 μM and is easy to implement. Iodovanillic acid is stable, allowing multiple measurements of the same sample, and the separation power of the HPLC yields high selectivity against potential interferences. This method will be useful for many environmental applications. The method has been applied to quantify the photochemical production of H₂O₂ by aqueous suspensions of various minerals and soils.     

基于7-羟基香豆素的F~-选择性识别

7-羟基香豆素(伞形花内酯,umbelliferone)认为是香豆素类成分的母核。具有调节昆虫、共生菌、病原菌与植物互作反应的信号分子[1]。棉铃虫抗性选育[2]中测定其含量,能碓定细胞色素P450氧化酶7-甲氧基香豆素0-脱甲基活性。本文以香豆素为发色团,羟基为氢键供体,研究了其对阴离子的识别能力。结果表明,加入F-光谱红移83 nm,吸光度值增大,而Cl-、I-、H2PO4-、NO3-等均不影响,有好的选择性。主客体形成了一定配合比的配合物,表明其为传感分子与F-间形成氢键,因而可以用作香豆素的灵敏测定以及F-化学传感器。     

Translocation of Sb and Ti in an undisturbed floodplain soil after application of Sb2O3 and TiO2 nanoparticles to the surface

The pore water transport of antimony and titanium, applied as nanoparticles (NPs), was studied by spiking stable suspensions of two different nanomaterials on the surface of an undisturbed floodplain soil. For preparation of stable dispersions, two different strategies were followed. (i) Comparable to those used in industrial applications: titanium dioxide nanoparticles, with an average diameter of 99 nm, were prepared by high-energy ball milling in water, whereas for (ii) antimony trioxide (Sb(2)O(3); average diameter 121 nm) a dispersing agent (sodium salt of poly[(naphthaleneformaldehyde)sulfonate] (pNFS) in water) was used. The upper 17 cm of a floodplain soil (river Rhine, Germany) was sampled using the minimally invasive sediment or fauna incubation experiment (SOFIE? two compartment cell; 3 l volume each), which preserved the pore system of the soil. The cells were equipped with 450 and 100 nm filter probes at different depths providing a non-invasive sampling of the pore water. The pore water was sampled at different times (T = 0, 24, 48, 96 and 196 h) and analysed by inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). Sb and Ti were transported via the pore water of the floodplain soil to a depth of 14 cm, corresponding to the maximum cell depth. The highest Sb concentration in the pore water was detected after 24 h at a depth of 5.5-8 cm. Although the spiked concentration was higher for Ti than for Sb, the total Ti concentration in the pore water of the spiked cell was lower. This indicates a stronger agglomeration of TiO(2) NPs or a more intensive interaction of Ti with the solid matrix and a faster transport of Sb towards deeper soil layers. The results show that metal(loid)s from metal oxide NPs are transported in the soil pore water and, hence, have the potential to act as the source of contamination of deeper soil layers after soil surface contamination.     

Black carbon in urban topsoils of Xuzhou (China): environmental implication and magnetic proxy

Combustion-derived black carbon has received attention as a form of refractory organic carbon that may be preferentially preserved in soils and sediments. However, little is understood about the environmental roles of black carbon in urban soils. This investigation represented the preliminary study to characterize black carbon (BC) concentrations and enrichment ratios in Xuzhou urban roadside topsoil. Data from 21 roadside topsoil samples showed that the median of BC concentrations is 21.8 mg/g, which is significantly higher than local background value that averages 3.8 mg/g. Hierarchical clustering analysis indicated that BC in Xuzhou urban roadside soils are mainly from the traffic emissions. The marked positive correlations between BC and the concentrations of heavy metals (Pb, Cu, Zn, Mo, and Sc; Pearson correlation coefficient, 0.623, 0.809, 0.846, 0.742 and 0.831, respectively) suggested that these heavy metals are likely to be strongly retained by BC present in roadside topsoil. The significant positive correlation between BC and specific magnetic susceptibility was also observed. Thus, the simple environmental magnetic method is potentially an efficient alternative technique for assessing BC concentration in roadside topsoil.     

TNT红水污染土壤中二硝基甲苯磺酸盐的分析方法

火炸药厂红水污染土壤中的主要污染物为二硝基甲苯磺酸盐[DNTS,包括2,4-二硝基甲苯-3-磺酸盐(2,4-DNT-3-SO_3~-)和2,4-二硝基甲苯-5-磺酸盐(2,4-DNT-5-SO_3~-)2种异构体]。研究建立了振荡提取-高效液相色谱法测定土壤中DNTS的方法。4种土壤(黄土、棕土、红壤和黑土)和5个浓度水平(50、100、250、500、1 000 mg/kg)时,DNTS的回收率为69.4%~111%,变异系数为0.28%~6.62%(n=3)。应用该方法测定甘肃某火炸药厂红水污染土壤样品,2,4-DNT-3-SO_3~-和2,4-DNT-5-SO_3~-浓度实测值(平均值分别为505、25.2 mg/kg)重复性好,变异系数为1.29%和1.53%(n=3)。     

Colloidal mercury (Hg) distribution in soil samples by sedimentation field-flow fractionation coupled to mercury cold vapour generation atomic absorption spectroscopy

Diverse analytical techniques are available to determine the particle size distribution of potentially toxic elements in matrices of environmental interest such as soil, sediments, freshwater and groundwater. However, a single technique is often not exhaustive enough to determine both particle size distribution and element concentration. In the present work, the investigation of mercury in soil samples collected from a polluted industrial site was performed by using a new analytical approach which makes use of sedimentation field-flow fractionation (SdFFF) coupled to cold vapour generation electrothermal atomic absorption spectroscopy (CV-ETAAS). The Hg concentration in the SdFFF fractions revealed a broad distribution from about 0.1 to 1 μm, roughly following the particle size distributions, presenting a maximum at about 400-700 nm in diameter. A correlation between the concentration of Hg in the colloidal fraction and organic matter (O.M.) content in the soil samples was also found. However, this correlation is less likely to be related to Hg sorption to soil O.M. but rather to the presence of colloidal mercuric sulfide particles whose size is probably controlled by the occurrence of dissolved O.M. The presence of O.M. could have prevented the aggregation of smaller particles, leading to an accumulation of mercuric sulfides in the colloidal fraction. In this respect, particle size distribution of soil samples can help to understand the role played by colloidal particles in mobilising mercury (also as insoluble compounds) and provide a significant contribution in determining the environmental impact of this toxic element.