Monocyclic and monoaromatic naphthenic acids: synthesis and characterisation

Characterisation of the complex mixtures of carboxylic acids (naphthenic acids) occurring in crude oils and in degraded oil sands is environmentally important. Indeed some acids in waters from oil platforms are apparently hormonally active, and the oil sands acids are said to be toxic to a wide range of biota. Previous attempts to identify monocyclic and monoaromatic naphthenic acids have been hampered by the lack of authenticated synthetic reference compounds. Some studies have indicated that acids with ethanoic acid side chains are present in the naphthenic acids mixtures, so in the present study, we synthesised and characterised by mass spectrometry, a range (C_8–14) of monoaromatic and monocyclic ethanoic acids. Using 2-D comprehensive gas chromatography–mass spectrometry, we then compared the retention times and mass spectra of the synthetic acids with those of a commercial naphthenic acids mixture. Some alicyclic and numerous aromatic acids were successfully identified.     

Assessment of plant-driven uptake and translocation of clofibric acid by Scirpus validus

Pharmaceutical compounds are now considered as emerging contaminants of environmental concern. The overall objective of this study was to evaluate the uptake and translocation of clofibric acid (CA) by the macrophyte Scirpus validus growing hydroponically. A set of the three replicates was established for each exposure time and for each CA concentration. Plants were grown in 4 L vessels (four plants per vessel corresponding to the three exposure period studies, i.e., 7, 14, 18, and 21 days) which contained an aerated modified Hoagland nutrient solution that was spiked with CA at concentrations of 0.5, 1.0, and 2.0 mg?L^?1. At each exposure period, CA concentration was measured in the nutrient solutions. A sea sand disruption method was employed for the extraction of CA from plant tissues. The determination of the pharmaceutical concentration was carried out using solid phase extraction (SPE) followed by chromatographic analysis. The quantification of CA concentrations in both nutrient solutions (after SPE) and plant tissues (after extraction) was conducted by chromatographic analysis. CA concentrations of 5.4–26.8 μg?g^?1 (fresh weight) were detected in the roots and 7.2–34.6 μg?g^?1 (fresh weight) in the shoots after 21 days. Mass balance calculations showed that S. validus uptake alone accounted for a significant contribution (6–13 % for the roots and 22–49 % for the shoots) of the total loss of CA. The bioaccumulation factors (BAFs) based on fresh weight for the roots ranged from 6.6 to 23.2, while values for the shoots ranged from 9.5 to 32.1. All the BAFs for the shoots were greater than those in the roots, implying that CA has greater tendency to be translocated to the shoots, rather than the roots of S. validus. All the shoot-to-root concentration ratios were more than 1, denoting that the shoots of S. validus do preferentially accumulate CA. We demonstrated that CA can be actively taken up, subsequently translocated and accumulated by aboveground tissues of S. validus. Since S. validus could account for the removal of 28–62 % of the total mass loss of CA from the system, such phytoremediation technology has great potential for the removal of pharmaceuticals such as CA from inflowing waters.     

Source Apportionment of Particulate Matter (PM10) and Indoor Dust in a University Building

A study on source apportionment of indoor dust and particulate matter (PM₁₀) composition was conducted in a university building by using chemometrics. The objective of this study was to investigate the potential sources of selected heavy metals and ionic species in PM₁₀ and indoor dust. PM₁₀ samples were collected using a low-volume sampler (LVS) and indoor dust was collected using a soft brush. Inductively coupled plasma spectrometry (ICP-MS) was used to determine the concentration of heavy metals, while the concentration of cations and anions was determined by atomic absorption spectrometer (AAS) and ion chromatography (IC), respectively. The concentration of PM₁₀ recorded in the building throughout the sampling period ranged from 20 ± 10 μgm^?3 to 80 ± 33 μgm^?3. The composition of heavy metals in PM₁₀ and indoor dust were dominated by zinc (Zn), followed by lead (Pb), copper (Cu), and cadmium (Cd). Principle component analysis (PCA) and multiple linear regression (MLR) showed that the main sources of pollutants in PM₁₀ came from indoor renovations (73.83%), vehicle emissions (16.38%), earth crust sources (9.68%), and other outdoor sources (0.11%). For indoor dust, the pollutant source was mainly earth crust. This study suggests that chemometrics can be used for forensic investigation to determine the possible sources of indoor contaminants within a public building.     

宝鸡市PM_(2.5)中水溶性离子组分污染特征及来源分析

本文通过对2012年3月至2013年3月宝鸡市大气PM_(2.5)中各个水溶性无机离子组分的质量浓度进行研究,获得了水溶性离子的时间变化特征,并结合主成分分析方法讨论了不同离子的来源。结果显示,宝鸡市PM_(2.5)中水溶性离子主要由、和组成,分别占总水溶性离子质量浓度的40.47%、30.75%和15.07%;PM_(2.5)整体偏酸性。/比值随API指数的升高而增大,当空气质量较好时PM_(2.5)中硫酸盐居多,而随着空气污染发生硝酸盐逐渐增多并占优势。主成分分析结果表明PM_(2.5)中水溶性离子的主要来源有二次气溶胶、生物质燃烧和土壤尘。     

Evaluation of in situ catalysed hydrogen peroxide propagation (CHP) for phenanthrene and fluoranthene removals from soil and its associated impacts on soil functionality

Extensive contamination of soils by highly recalcitrant contaminants such as polycyclic aromatic hydrocarbons (PAHs) is an environmental problem arising from rapid industrialisation. This work focusses on the remediation of soil contaminated with 3- and 4-aromatic ring PAHs (phenanthrene (PHE) and fluoranthene (FLUT)) through catalysed hydrogen peroxide propagation (CHP). In the present work, the operating parameters of the CHP treatment in packed soil column was optimised with central composite design (H₂O₂/soil 0.081, Fe³⁺/soil 0.024, sodium pyrophosphate (SP)/soil 0.024, pH of SP solution 7.73). The effect of contaminant aging on PAH removals was also investigated. Remarkable oxidative PAH removals were observed for the short aging and extended aging period (up to 86.73 and 70.61 % for PHE and FLUT, respectively). The impacts of CHP on soil biological, chemical and physical properties were studied for both spiked and aged soils. Overall, the soil functionality analyses after the proposed operating condition demonstrated that the values for soil respiration, electrical conductivity, pH and iron precipitation fell within acceptable limits, indicating the compatibility of the CHP process with land restoration.     

Insights on the solubilization products after combined alkaline and ultrasonic pre-treatment of sewage sludge

This work provides insights on the solubilization products after a simultaneous combination of alkaline and ultrasonic(ALK + ULS) pre-treatment of sewage sludge.Soluble chemical oxygen demand(SCOD) increased from 1200 to 11,000 mg/L after such treatment. Organics with molecular weight around 5.6 k Da were solubilized because of the synergistic effect of ultrasound and alkali. Organics with molecular weight larger than300 k Da increased from 7.8% to 60%, 16% and 42.3% after ULS, ALK and ALK + ULS treatment, respectively. Excitation emission matrix fluorescence spectroscopy analysis identified soluble microbial product-like and humic acid-like matters as the main solubilization products. Sludge anaerobic biodegradability was significantly enhanced with the simultaneous application of ALK + ULS pre-treatment. ALK + ULS pre-treatment resulted in 37.8% biodegradability increase compared to the untreated sludge. This value was higher compared to the biodegradability increase induced by individual ALK pre-treatment(5.7%) or individual ULS pre-treatment(20.7%) under the same conditions applied.     

Interfacial-engineered CoTiO3-based composite for photocatalytic applications: a review

Environmental Chemistry Letters - Photocatalysis is a green chemical process that could partly solve energy and pollution issues. Catalysts such as cobalt titanate, CoTiO3, have intrigued...     

Age,work experience,and the psychological contract

The purpose of the current paper is to examine the ways in which age and work experience shape how individuals experience psychological contract breaches. We first introduce the concepts of contract malleability (the degree to which individuals can tolerate deviations from contract expectations) and contract replicability (the degree to which individuals believe that their psychological contracts can be replicated elsewhere). Next, we discuss the variety of reasons why contract malleability and replicability become greater with age and work experience and how contract malleability and replicability may temper negative reactions to psychological contract breaches. We also address the different ways contract malleability and replicability mediate the relationships between age and work experience, on one hand, and exit, voice, loyalty, and neglect behaviors on the other. We consider the moderating effects of age similarity and dissimilarity here as well. The paper concludes with a discussion of the implications for future research designs and for managing older and more experienced workers. Copyright © 2009 John Wiley & Sons, Ltd.