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2007-4-17 EST最新文章和摘要
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Elimination of Selected Acidic Pharmaceuticals from Municipal Wastewater by an Activated Sludge System and Membrane Bioreactors Katsuki Kimura,* Hiroe Hara, and Yoshimasa Watanabe Department of Environmental Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo 060-8628, Japan Received for review July 14, 2006 Revised manuscript received March 8, 2007 Accepted March 19, 2007 Abstract: The elimination of six acidic pharmaceuticals (clofibric acid, diclofenac, ibuprofen, ketoprofen, mefenamic acid, and naproxen) in a real wastewater treatment plant (WWTP) using an activated sludge system and membrane bioreactors (MBRs) was investigated by using a gas chromatography/mass spectrometry (GC/MS) system for measurement of the compounds. Limited information is available for some of the tested pharmaceuticals at present. Solid retention times (SRTs) of the WWTP and the two MBRs were 7, 15, and 65 days, respectively. The elimination rates varied from compound to compound. The MBRs exhibited greater elimination rates for the examined pharmaceuticals than did the real plant. Dependency of the elimination rates of the pharmaceuticals on SRTs was obvious; the MBR operated with a longer SRT of 65 days clearly showed better performance than did the MBR with a shorter SRT of 15 days. The difference between the two MBRs was particularly significant in terms of elimination of ketoprofen and diclofenac. Measurements of the amounts of adsorbed pharmaceuticals on the sludge and aerobic batch elimination experiments were carried out to investigate the elimination pathways of the pharmaceuticals. Results of the batch elimination tests revealed that the sludges in the MBRs had large specific sorption capacities mainly due to their large specific surface areas. Despite the sorption capacities of sludges, the main mechanism of elimination of the pharmaceuticals in the investigated processes was found to be biodegradation. Biodegradation of diclofenac, which has been believed to be refractory to biodegradation, seemed to occur very slowly. -------------------------------------------------------------------------------- Modeling the Transport of Metals with Rate-Limited EDTA-Promoted Extraction and Dissolution during EDTA-Flushing of Copper-Contaminated Soils Daniel C. W. Tsang, Irene M. C. Lo,* and K. L. Chan Department of Civil Engineering, The Hong Kong University of Science and Technology, Hong Kong, China, and Department of Mathematics, The Hong Kong University of Science and Technology, Hong Kong, China Received for review July 24, 2006 Revised manuscript received January 2, 2007 Accepted March 19, 2007 Abstract: EDTA-flushing of artificially contaminated soils enhanced Cu extraction but also induced mineral dissolution simultaneously. The mobilization and transport of these metal-EDTA complexes was investigated with column experiments. A quantitative transport model was proposed for simulating the experimental breakthrough curves of Cu, Fe, Al, and Ca. The rate-limited EDTA-promoted extraction and dissolution could be described by respective second-order kinetic terms, which were necessary for explaining the time-dependent depletion of extractable metals (sorbed and indigenous) in soils with continuous EDTA-flushing. Simultaneous simulation of extraction of sorbed Cu and dissolution of soil Fe, Al, and Ca is more conceptually accurate than individual modeling of each metal because the latter approach tends to overestimate the concentration of free EDTA during transport and thus underestimate the rate coefficients of EDTA-promoted dissolution. The fitted rate coefficients of Cu were about an order of magnitude larger than those of Fe and Al; these values probably reflect Cu extraction from weakly sorbed fractions and Fe and Al dissolution from amorphous oxides. The apparent retardation of Fe, Al, and Ca transport had to be taken into account by empirical determination, which was attributed to the metal lability in soils and thermodynamics of surface complexation. -------------------------------------------------------------------------------- Different Catalytic Effects by Copper and Chromium on the Formation and Degradation of Chlorinated Aromatic Compounds in Fly Ash Tomas Öberg,* Bo Bergbäck, and Erik Öberg Department of Biology and Environmental Science, University of Kalmar, SE-391 82 Kalmar, Sweden Received for review October 18, 2006 Revised manuscript received March 12, 2007 Accepted March 19, 2007 Abstract: Fly ash from municipal solid waste incineration may catalytically enhance the formation and degradation of chlorinated aromatic compounds. The activities of three Deacon catalysts in this process were investigated in a statistically designed experiment. Chlorides of copper, chromium, and nickel were added to fly ash samples and the resulting samples heated at 300 C for 2 h in an air atmosphere. The addition of copper increases the formation of all chlorinated aromatic compounds except the low chlorinated congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans. The addition of chromium decreased the formation of most chlorinated aromatic compounds except the highest chlorinated species, where it was without effect. The addition of nickel did not show any significant effect. The outcome of the experiment can be interpreted as two competing processes: the chlorination of aromatic rings and the oxidation of carbon-carbon and carbon-oxygen bonds. The delicate balance between chlorination and oxidation could probably be further exploited to minimize both the emissions and the net production of chlorinated aromatic compounds from combustion. -------------------------------------------------------------------------------- n-Alkane Profiles of Engine Lubricating Oil and Particulate Matter by Molecular Sieve Extraction Gianni A. Caravaggio, Jean-Pierre Charland,* Penny Macdonald, and Lisa Graham CANMET Energy Technology Center-Ottawa, Natural Resources Canada, Ottawa, Ontario, Canada, Emissions Research and Measurement Division, Environment Canada, Ottawa, Ontario, Canada Received for review September 19, 2006 Revised manuscript received March 7, 2007 Accepted March 8, 2007 Abstract: As part of the Canadian Atmospheric Fine Particle Research Program to obtain reliable primary source emission profiles, a molecular sieve method was developed to reliably determine n-alkanes in lubricating oils, vehicle emissions, and mobile source dominated ambient particulate matter (PM). This work was also initiated to better calculate carbon preference index values (CPI: the ratio of the sums of odd over even n-alkanes), a parameter for estimating anthropogenic versus biogenic contributions in PM. n-Alkanes in lubricating oil and mobile source dominated PM are difficult to identify and quantify by gas chromatography due to the presence of similar components that cannot be fully resolved. This results in a hump, the unresolved complex mixture (UCM) that leads to incorrect n-alkane concentrations and CPI values. The sieve method yielded better chromatography, unambiguous identification of n-alkanes and allowed examination of differences between n-alkane profiles in light (LDV) and heavy duty vehicle (HDV) lubricating oils that would have been otherwise difficult. These profile differences made it possible to relate the LDV profile to that of the PM samples collected during a tunnel study in August 2001 near Vancouver (British Columbia, Canada). The n-alkane PM data revealed that longer sampling times result in a negative artifact, i.e., the desorption of the more volatile n-alkanes from the filters. Furthermore, the sieve procedure yielded n-alkane data that allowed calculation of accurate CPI values for lubricating oils and PM samples. Finally, this method may prove helpful in estimating the respective diesel and gasoline contributions to ambient PM. -------------------------------------------------------------------------------- Classification of Heavy-Metal Toxicity by Human DNA Microarray Analysis Koji Kawata, Hiroyuki Yokoo, Ryuhei Shimazaki, and Satoshi Okabe* Department of Urban and Environmental Engineering, Graduate School of Engineering, Hokkaido University, North-13, West-8, Kita-ku, Sapporo 060-8628, Japan Received for review November 14, 2006 Revised manuscript received February 21, 2007 Accepted February 27, 2007 Abstract: Microarray technology is proving to be a useful tool to classify undefined environmental toxicants, to investigate underlying mechanisms of toxicity, and to identify candidate toxicant-specific genetic markers by examining global effects of putative toxicants on gene expression profiles. The aim of this study was to evaluate the toxicities of six heavy metals through the comparison with gene expression patterns induced by well-known chemicals. For this purpose, we first identified the genes altered specifically in HepG2 under the exposure of 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), phenol, and N-nitrosodimethylamine (DMN), which were selected as the model chemicals, using DNA microarray. On the basis of the expression profiles of these genes, toxicities of six heavy metals, arsenic, cadmium, nickel, antimony, mercury, and chromium, were evaluated. The specific gene alteration and hierarchical clustering revealed that biological action of six heavy metals was clearly related to that of DMNQ which has been reported to be a reactive oxygen species (ROS) generating chemical and which induced the genes associated with cell proliferative responses. These results suggest that cell proliferative responses which are probably caused by ROS are a major apparent biological action of high-dose heavy metals, supporting the previous reports. Overall, a mechanism-based classification by DNA microarray would be an efficient method for evaluation of toxicities of environmental samples. -------------------------------------------------------------------------------- Aryl Hydrocarbon Receptor Plays a Significant Role in Mediating Airborne Particulate-Induced Carcinogenesis in Mice Yutaka Matsumoto,* Fumio Ide, Reiko Kishi, Tomoko Akutagawa, Shigekatsu Sakai, Masafumi Nakamura, Toshitaka Ishikawa, Yoshiaki Fujii-Kuriyama,# and Yoko Nakatsuru Department of Public Health, Graduate School of Medicine, Hokkaido University, Sapporo, Japan, Department of Oral Pathology, Meikai University School of Dentistry, Saitama, Japan, Department of Environmental Protection, Hokkaido Research Institute of Environmental Sciences, Sapporo, Japan, Hiyoshi Corporation, Shiga, Japan, Department of Pathology, Faculty of Medicine, University of Tokyo, Tokyo, Japan, and TARA Center, University of Tsukuba, Tsukuba, Japan Received for review November 24, 2006 Revised manuscript received February 21, 2007 Accepted February 26, 2007 Abstract: Urban particulate air pollution is associated with an increased incidence of cancers, and especially lung cancer. Organic extracts of airborne particulate matter (APM) cause cancer in mice, and PAHs adsorbed to APM are associated with particle-induced carcinogenesis. PAHs are agonists for AhR and are predominantly responsible for lung cancer through induction of highly carcinogenic metabolites. PAH metabolization requires CYP1A1 induction through activation of AhR, and therefore we hypothesized that carcinogenesis due to PAHs in APM would be reduced in AhR-/- mice. To examine this hypothesis, we performed a long-term continuous-application study of carcinogenesis in AhR-/- mice using airborne particulate extract (APE) of APM collected in Sapporo. Tumor development (squamous cell carcinoma) occurred in 8 of 17 AhR+/+ mice (47%), but no tumors were found in AhR-/- mice, and CYP1A1 was induced in AhR+/+ mice but not in AhR-/- mice. These results demonstrate that AhR plays a significant role in APE-induced carcinogenesis in AhR+/+ mice and CYP1A1 activation of carcinogenic PAHs is also of importance. Therefore, measurement of CYP1A1 induction in vitro may be useful for assessment of APM-induced carcinogenesis in humans. We also show that PAH-like compounds are major contributors to AhR-mediated carcinogenesis, whereas TCDD and related compounds make a smaller contribution. -------------------------------------------------------------------------------- |
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