Hidetoshi Kumata

Source identification of Malaysian atmospheric polycyclic aromatic hydrocarbons nearby forest fires using molecular and isotopic compositions

We report measurements of molecular and carbon isotopic compositions of Malaysian atmospheric polycyclic aromatic hydrocarbons (PAHs) in smoke haze from the 1997 Indonesian forest fire. Comparison of the carbon isotopic compositions (δ13C) of individual PAHs from the smoke haze, with those from other PAHs sources (soot collected from gasoline and diesel vehicle muffler, woodburning smoke), enables us to discriminate among the diverse sources of atmospheric PAHs. Soot PAHs extracted from gasoline and diesel vehicles show heavy isotopic signatures with a large inter-species δ13C variation from −12.9‰ to −26.6‰, compared to soot PAHs extracted from woodburning smoke which are isotopically light, and have a small inter-species δ13C variation from −26.8‰ to −31.6‰. Values from −17.7‰ to −27.9‰ were obtained for the corresponding PAHs extracted from the smoke haze, indicating that they are derived mainly from automotive exhaust. Molecular and isotopic compositions of PAHs extracted from smoke haze were similar to those extracted from non-haze aerosol. Quantitative estimation shows that woodburning contribution to Malaysian atmospheric PAHs ranges from 25% to 35% with no relation to haze intensity, while automotive contribution ranges from 65% to 75%. These results suggest that the major contributor of PAHs in Malaysian air is automotive exhaust whether smoke haze is observed or not.

Vertical distributions and δ13C isotopic compositions of PAHs in Chidorigafuchi Moat sediment, Japan

Abstract Compound-specific carbon isotope analysis and molecular composition analysis were performed on polycyclic aromatic hydrocarbons (PAHs) extracted from a dated 50 cm sediment core from the Chidorigafuchi Moat, Japan. δ 13 C values ranged from −23.0 to −26.9‰ for individual PAHs, and ranged from −24.0 to −25.5‰ for the weighted average of PAHs at different core depths. Whilst total PAH concentrations showed a distinct maximum at around the year 1960, δ 13 C values did not show a statistically significant feature in the corresponding section of the core. Indeed, there was little correlation ( r 2 =0.12, P =0.19) between ΣPAH and δ 13 C throughout the core. PAHs in surface sediment (ca 0–8 cm) were characterised by a significantly higher benzo(ghi)perylene to indeno(1,2,3-cd)pyrene ratio ( t -test, P δ 13 C values ( P

Determination of 2-(4-Morpholinyl)benzothiazole in Environmental Samples by a Gas Chromatograph Equipped with a Flame Photometric Detector.

2-(4-Morpholinyl)benzothiazole (24MoBT) exists in automobile tire rubber as an impurity of a vulcanization accelerator and has been proposed as a potential molecular marker of street runoff (Spies, R. B.; Andresen, B. D.; Rice, D. W., Jr. Nature 1987, 327, 697-699). The present paper describes an analytical method for 24MoBT in environmental samples (e.g., street dusts and river sediments) by gas chromatography. The method relies upon extraction with a 6:4 (v/v) mixture of benzene and methanol, purification by acid extraction, and adsorption column chromatography, followed by determination using capillary GC equipped with a sulfur-selective detector (i.e., FPD). The recovery of 24MoBT for the entire procedure was 85%, and the relative standard deviation for four replicated analyses was 1.5%. The detection limit was 0.08 ng injected 24MoBT, corresponding to 0.20 ng/g of dry sample. The selectivity and sensitivity of the present method permit the determination of 24MoBT at the trace levels (e.g., ∼ng/g) encountered in environmental samples. 24MoBT concentrations in various environmental samples are also reported.

Chemical and optical properties of 2003 Siberian forest fire smoke observed at the summit of Mt. Fuji, Japan

Boreal forest fires are one of the major emission sources of trace atmospheric constituents in mid and high latitudes in the Northern Hemisphere. From late May through early June 2003, dense smoke aerosols that originated from large forest fires in Siberia were monitored on the summit of Mt. Fuji (3776 m msl.), Japan, a free-tropospheric height monitoring site where measurements of atmospheric chemistry were briefly intensified during a research project called Atmospheric Environmental Impact of Aerosols in East Asia (AIE). Inside a smoke layer, concentrations of black carbon (BC) measured by an Aethalometer exceeded 1900 ng m -3 with a concurrent increase of carbon monoxide mixing ratio. The slope of a BC/CO regression line was steeper than those obtained in other studies using measurements from lower-altitude ground monitoring stations, suggesting minimal wet removal processes. The smoke aerosols contained high levels of n-alkanes of high molecular weight and indicated high carbon preference indices. The time series of CO and O 3 mixing ratios indicated a double-layered vertical structure in which a high O 3 mixing ratio layer lay on top of a smoke layer. The wavelength dependence of the absorption coefficient of the smoke showed a slope much steeper than that measured in urban influenced measurements. The higher absorption in the shorter wavelengths was consistent with an abundance of organic species within the smoke.

Water-Particle Distribution of Hydrophobic Micro Pollutants in Storm Water Runoff

Abstract Sorptive behaviors of polycyclic aromatic hydrocarbons (PAHs) as well as other classes of hydrophobic pollutants (i.e., n-alkanes and linear alkylbenzenes: LABs) were investigated for street runoff and for particle-size segregated river water samples. PAHs, except for 3-ring aromatics, were mostly transported with particles >1.2μm. In all the environmental samples PAHs were more hydrophobic than expected from their Kow; whereas vigorous mixing of road dust with water for 24 hours resulted in more desorption of PAHs into the aqueous phase. It indicates that although strongly associated with particles, at least some part of the “particle bound” PAHs could be available for active exchange wirh their dissolved counterparts. As opposed to PAHs, n-alkanes and LABs revealed less hydrophobic nature than expected from Kow, although their majorities were in “particulate form”.

Evaluation of Hydrogenated Resin Acids as Molecular Markers for Tire-wear Debris in Urban Environments

To propose new molecular markers for tire-wear emissions, four dihydroresin acids, that is, 8-isopimaren-18-oic acid (I), 8-pimaren-18-oic acid (II), 13β(H)-abieten-18-oic acid (III), and 13α(H)-abiet-8-en-18-oic acid (IV), were identified and investigated for source specificities, distributions, and environmental stabilities. The absence of I-IV in natural sources and the linear correlations between dihydroresin acids with different skeletons in tires and in environmental samples demonstrated that I-IV are specific markers for synthetic rubbers. The ratio of III + IV to the sum of III + IV plus abietic acid showed the resin acids distribution between different environmental compartments receiving contributions from traffic and natural sources. The physicochemical properties and results of photolysis experiments suggested that I-IV can set lower limits for tire-wear contributions to environmental loads of particulate matter (PM) and polycyclic aromatic hydrocarbons with molecular weight ≥202. By comparing III + IV concentrations or (III+IV)/pyrene or (III+IV)/benzo[a]pyrene ratios in tires and those in environmental matrices, the contributions of tire-wear emissions to PM, pyrene, and benzo[a]pyrene were estimated to be 0.68 ± 0.54%, 6.9 ± 4.8%, and 0.37 ± 0.18% in roadside PM and 0.83 ± 0.21%, 0.88 ± 0.52%, and 0.08 ± 0.06% in rooftop PM.

Flow injection analysis to measure the production ability of superoxide with chemiluminescence detection in natural waters

In connection with the photo-chemical processes in the aquatic environment, the evaluation system for the production ability of superoxide anion was constructed. The technique was based on the flow-injection method with luminol chemiluminescence detection. The injected sample was first irradiated by a solar simulator in a vortex quartz cell (cell volume = 0.167 mL), whose vortex face was exposed to light after passing through two air-mass filters. The carrier was the aqueous solution at pH 11 adjusted by NaOH. After irradiation was finished, the carrier (with sample) flow was merged with 1.52 mM of the luminol solution and was introduced into a chemiluminescence detector. The results of the laboratory experiment show that the production of superoxide is linearly related to the concentration of humic acid up to 50 ppm, and also to that of dissolved oxygen. In addition, the chemiluminescence intensity (superoxide production) was proportionally related with the irradiation intensity of the solar simulator. By means of changing the flow rate of the carrier, the half-life of superoxide at pH 11 aqueous solution was estimated to be 15 s. ESR was measured for the sample containing 0.5% humic acid, 0.5% NaOH, and 20 μL DMPO (spin trap agent). ESR spectra were obtained after 5 min of irradiation of the solar simulator. In addition to the four sharp peaks due to OH radicals, a broad peak appeared at the middle of the OH signal. The obtained signal cannot conclusively be ascribed to superoxide, but the peak that appeared may be due to the radical produced in the humic acid molecule. The river water was collected at 18 points of the Tamagawa River located in Tokyo. Upstream, the production ability of superoxide was observed, but not downstream or in the estuarine district. Although the concentration of humic acid is much higher in the estuarine sample, some quenching mechanisms work for superoxide production.

Physiological and Photosynthetic ToxiCity of Thallium in Synechocystis sp. PCC6803

The physiological and photosynthetic toxiCity mechanism of monovalent thallium, Tl(I), in a cyanobacteria, Synechocystis sp. PCC6803, was examined based on a series of batch culture experiments, determination of the pigments content and measurements of photosynthetic activities under the metal exposure conditions. Results showed that micro-molar level of Tl(I) drastically inhibit its growth, then 50% inhibitory concentration (IC50) was approximately 1 μM. An acclimating incubation with 0.5 μM Tl(I) for 72 h bring no significant changes in IC50 of thallium for growth. Chlorophyll a and phycobiliproteins content per cell basis decreased by 71% and 94% during 72 h incubation with 2.5 μM Tl(I), respectively. Results from pigments determination suggested that metabolic defect was rose by thallium exposure in Synechocystis sp. PCC6803. Then, to investigate the effect of thallium on energy generation process, acute dose-response of Tl(I) on photosynthetic O2 evolution activities were measured. No effect on net photosynthetic O2 evolution activity per chlorophyll basis was observed in 1 mM and below Tl(I) exposure, while 20 mM Tl(I) decrease the activity by 60%. Furthermore, 20 mM thallium did not affect 1,4-benzoquinone dependent PSII activity. These photosynthetic 50% inhibitory doses of thallium were approximately 2,000-fold higher than IC50 of growth. Thus, photosynthetic energy metabolism did not constitute a limiting factor of growth under the thallium exposure. These results suggested that substance metabolic defect and/or NADP reducing processes could be the main process involved in thallium toxiCity in Synechocystis sp. PCC6803.

Correlations of asthma mortality with traffic-related factors: use of catalytic converters and radial tires.

Objective: The objective of this study was to test the hypotheses that the post-1970 rise in asthma mortality in industrialized nations was related to introduction of catalytic converters and/or radial tires. Methods: Annual asthma mortality data were plotted on linear coordinates for fraction of automobile fleet with converters or radial tires in Canada, Germany, Japan, and the United States. Results: Catalytic converter association could not account for asthma mortality that rose in Germany before general adoption of the technology there. Radial tire use was, however, linearly correlated with asthma mortality in all four countries. Conclusion: Rising exposure to materials related to radial tire use may account for a substantial fraction of increased asthma mortality risk since approximately 1970.

Thallium Induces Morphological Changes in the Photosynthetic Apparatus of Synechocystis sp. PCC6803

The aim of this study was to elucidate the mechanism of thallium (Tl) ion toxicity in photosynthetic organisms. The physiological and biochemical responses to Tl exposure were analyzed in the cyanobacterium Synechocystis sp. PCC6803, which is a widely used model to study photosynthesis. We examined the photosynthetic activities of Tl+-exposed cells, the extent of Tl accumulation, and the properties of membrane lipids. Exposure to Tl+ at 2.0 and 5.0 for 24 h decreased the net photosynthetic activities of cells to 92% and 34%, respectively. After exposure to 2.5 μM Tl+, cells concentrated the Tl to 20.8 μM on a packed cell volume basis. Exposure of Synechocystis to 0–2.5 μM Tl+ resulted in an approximately 9-fold concentration factor. Treatment with 2.0 μM Tl+ for 48 h decreased the total lipid content of the cells by 38%. Further, we observed the ultrastructure of cells treated with Tl+. The cells exposed to 5 μM Tl+ for 24 h showed thylakoid membrane fragmentation and generated less-dense particles following osmium staining. During this time, the net photosynthetic oxygen evolution of the cells was reduced to 34%. These results suggest that the accumulation of Tl in cells affects the integrity of the photosynthetic apparatus.