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31.
The main purpose of this paper was to carry out a source apportionment of suspended particulate matter (SPM) samples using
positive matrix factorization procedure. The central and local Government of Japan introduced strict emission regulations
in 2002/10 and 2003/10, respectively, in curbing SPM pollution from major metropolitans. This paper also highlighted the impact
of the measures taken by the central and local Government of Japan on the reduction of SPM and the contributions of sources.
SPM samples were collected for 6 years starting from 1999 to 2005 at two sites, i.e., site A (urban) and site B (suburban)
of Yokohama, Japan. Microwave digestion and inductively coupled plasma-mass spectroscopy (ICP-MS) were employed to measure
Mg, Al, Ca, V, Cr, Mn, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and Bi, while water soluble ions (Na + , NH4 +_{4}^{\ \,+}, K + , Ca2 + , Mg2 + , Cl − , NO3 -_{3}^{\ \,-} and SO4 2-)_{4}^{\ \,2-}) as well as carbonaceous mass (EC and OC) were analyzed using ion chromatograph and CHN analyzer, respectively. The sources
identified at two sites were automobile, soil dust, marine aerosol, mixed sources, and secondarily formed aerosol. Also, source
quantification was performed. Automobile and soil dust were striking contributors at site A. Automobile and soil dust of SPM
aerosol might be produced from local origin at current study areas. Besides, Asian dust had an impact on high concentrations
of SPM aerosol in some certain period of the year due to the outflows of East Asian emission. In contrast, secondary aerosol
in the form of sulfate and ammonium as well as mixed sources (coal, long-transported Cs, and other unknown sources) were remarkable
at site B. Stationary/industrial combustion has apparently more impact on the release of SPM components at site B than A.
Automobile regulations in 2002 and 2003, respectively, resulted in reduction of SPM by 28% for site A and 16% for site B.
There was also net reduction of automobile contribution at both sites due to the above measures being implemented. 相似文献
32.
Povinec PP Hirose K Honda T Ito T Scott EM Togawa O 《Journal of environmental radioactivity》2004,76(1-2):113-137
The data stored in the IAEA's Global Marine Radioactivity Database (GLOMARD) developed in the framework of the IAEA's project "Worldwide Marine Radioactivity Studies (WOMARS)" have been evaluated for Pacific and Indian Ocean surface waters. Four anthropogenic radionuclides-- 3H, 90Sr, 137Cs and (239,240)Pu --have been chosen as the most representative of anthropogenic radioactivity in the marine environment, comprising beta, gamma and alpha-emitters which are the most frequently analysed in the marine environment and which have (with the exception of tritium) the highest potential contribution to radiation doses to humans via seafood consumption. For the purposes of this study, the Pacific and Indian Oceans were divided into latitudinal boxes for which average radionuclide concentrations were estimated for the year 2000. The highest concentrations have been observed in the Japan Sea/East Sea and the North-West Pacific Ocean, the lowest in the Southern Ocean. 相似文献
33.
Sakuratani Y Noguchi Y Kobayashi K Yamada J Nishihara T 《Journal of environmental biology / Academy of Environmental Biology, India》2008,29(1):89-92
The relationships between the bioconcentration factor (BCF) of chemicals in fish and their size, as characterized by molecular weight (MW), effective cross sectional diameter (Deff), and maximum diameter (Dmax) have been investigated using an experimental data set of 737 new and 441 existing chemicals monitored by the Japanese Chemical Substances Control Law (CSCL). Substances with BCF > or = 5000 (very high bioconcentration potential) typically have MW < 550, Deff < 1.1 nm and Dmax < 2.0 nm, respectively and the substances with BCF > or = 1000 (high bioconcentration potential) have MW < 550, Deff < 1.4 nm and Dmax < 2.9 nm, respectively Therefore, the previously suggested threshold values for Deff (0.95 nm) and Dmax (1.5 nm) used for discriminating between bioconcentrative and non-bioconcentrative substances were found to be somewhat small. We found that many substances with BCF > or = 1000 and Dmax > or = 1.5 nm have Deff < 0.95 nm. 相似文献
34.
Angela F. McGaffin Stephen Nicol Patti Virtue Yasuo Hirano Tsuyoshi Matsuda Itaru Uchida Steven G. Candy So Kawaguchi 《Marine Biology》2011,158(8):1743-1755
Antarctic krill, Euphausia superba, hatched from eggs and maintained for four years, were sampled periodically for age-pigment analysis. Extractable pigments
from the eye and eyestalk ganglia were quantified using fluorescence intensity and standardised against protein. Three peak
fluorescence intensities were detected at wavelengths of excitation 280 nm, emission 625 nm (pigment 1); excitation 355 nm,
emission 510 nm (pigment 2); and excitation 463 nm, emission 620 nm (pigment 3). There was a positive correlation between
the quantity of pigments 1 and 3 and the age of Antarctic krill. A model was developed to predict age from pigment 3 and to
compare it with other age proxies (carapace length and eyeball diameter). The quantity of pigment 3 was the best predictor
of age. The pigment method can discriminate between similar sized krill aged 12 and 36 months. Age pigments provide an improved
tool for age estimation in Antarctic krill, particularly if used in conjunction with other demographic information. 相似文献
35.
Masahiko Tanahashi Kôhei Kubota Norihisa Matsushita Katsumi Togashi 《Die Naturwissenschaften》2010,97(3):311-317
Most wood-feeding insects need an association with microbes to utilize wood as food, and some have special organs to store
and convey the microbes. We report here the discovery of the microbe-storage organ (mycangium) in stag beetles (Coleoptera:
Lucanidae), which develop in decayed wood. The mycangium, which was discovered in the abdomen, is present in all adult females
of 22 lucanid species examined in this study, but absent in adult males. By contrast, adult insects of both sexes of selected
Passalidae, Geotrupidae, and Scarabaeidae, which are related to Lucanidae, lacked mycangia similar to those of the lucanid
species. Yeast-like microbes were isolated from the mycangium of five lucanid species. DNA sequence analyses indicate that
the microbes are closely related to the xylose-fermenting yeasts Pichia stipitis, Pichia segobiensis, or Pichia sp. known from the gut of a passalid species. 相似文献
36.
Burgerhout E Manabe R Brittijn SA Aoyama J Tsukamoto K van den Thillart GE 《Die Naturwissenschaften》2011,98(7):631-634
The journey of the European eel to the spawning area in the Sargasso Sea is still a mystery. Several trials have been carried
out to follow migrating eels with pop-up satellite tags (PSATs), without much success. As eels are very efficient swimmers,
tags likely interfere with their high swimming efficiency. Here we report a more than twofold increase in swimming cost caused
by a regular small satellite tag. The impact was determined at a range of swimming speeds with and without tag in a 2-m swimming
tunnel. These results help to explain why the previous use of PSATs to identify spawning sites in the Sargasso Sea was thus
far unsuccessful. 相似文献
37.
Anthropogenic radionuclides in seawater have been used as transient tracers of processes in the marine environment. Especially, plutonium in seawater is considered to be a valuable tracer of biogeochemical processes due to its particle-reactive properties. However, its behavior in the ocean is also affected by physical processes such as advection, mixing and diffusion. Here we introduce Pu/137Cs ratio as a proxy of biogeochemical processes and discuss its trends in the water column of the North Pacific Ocean. We observed that the 239,240Pu/137Cs ratio in seawater exponentially increased with increasing depth (depth range: 100–1000 m). This finding suggests that the profiles of the 239,240Pu/137Cs ratios in shallower waters directly reflect biogeochemical processes in the water column. A half-regeneration depth deduced from the curve fitting the observed data, showed latitudinal and longitudinal distributions, also related to biogeochemical processes in the water column. 相似文献
38.
Ramzaev V Yonehara H Hille R Barkovsky A Mishine A Sahoo SK Kurotaki K Uchiyama M 《Journal of environmental radioactivity》2006,85(2-3):205-227
In order to estimate current external gamma doses to the population of the Russian territories contaminated as a result of the Chernobyl accident, absorbed gamma-dose rates in air (DR) were determined at typical urban and suburban locations. The study was performed in the western districts of the Bryansk Region within the areas of 30 settlements (28 villages and 2 towns) with the initial levels of 137Cs deposition ranging from 13 to 4340 kBqm(-2). In the towns, the living areas considered were private one-story wooden and stone houses. DR values were derived from in situ measurements performed with the help of gamma-dosimeters and gamma-spectrometers as well as from the results of soil samples analysis. In the areas under study, the values of DR from terrestrial radionuclides were 25+/-6, 24+/-5, 50+/-10, 32+/-6, 54+/-11, 24+/-8, 20+/-6, 25+/-8, and 18+/-5 nGyh(-1) at locations of kitchen gardens, dirt surfaces, asphalt surfaces, wooden houses, stone houses, grasslands inside settlement, grasslands outside settlement, ploughed fields, and forests, respectively. In 1996-2001, mean normalized (per MBqm(-2) of 137Cs current inventory in soil) values of DR from (137)Cs were 0.41+/-0.07, 0.26+/-0.13, 0.15+/-0.07, 0.10+/-0.05, 0.05+/-0.04, 0.48+/-0.12, 1.04+/-0.22, 0.37+/-0.07, and 1.15+/-0.19 microGyh(-1) at the locations of kitchen gardens, dirt surfaces, asphalt surfaces, wooden houses, stone houses, grasslands inside settlement, grasslands outside settlement, ploughed fields, and forests, respectively. The radiometric data from this work and the values of occupancy factors determined for the Russian population by others were used for the assessments of annual effective doses to three selected groups of rural population. The normalized (per MBqm(-2) 137Cs current ground deposition) external effective doses to adults from 137Cs ranged from 0.66 to 2.27 mSvy(-1) in the years 1996-2001, in accordance with professional activities and structures of living areas. For the areas under study, the average external effective doses from 137Cs were estimated to be in the range of 0.39-1.34 mSvy(-1) in 2001. The average external effective doses from natural radionuclides appeared to be lower than those from the Chernobyl fallout ranging from 0.15 to 0.27 mSvy(-1). 相似文献
39.
Wen-Jun Ju Ritsu Dobashi Toshisuke Hirano 《Journal of Loss Prevention in the Process Industries》1998,11(6):423-430
Reaction zone structures and propagation mechanisms of two representative flames established in stearic acid (CH3(CH2)16CO2H) particle clouds have been investigated. The reacting zone structure was examined by using a micro-electrostatic probe and a high-speed schlieren system. A distinct difference was observed in the ion current fluctuations recorded across the two representative flames propagating through the clouds of the same total mass density of particles and different mass densities of the particles smaller than 60 μm in diameter. When the mass density of smaller particles was high, a single peak was recorded in the ion current fluctuation. On the other hand, when the mass density of smaller particles was low, multi-peaks of various heights and widths were recorded. In the former case, the single peak was considered to be attributable to a unitary and a relatively thin flame started burning in vapor generated by the evaporation of smaller particles in the preheat zone. The flame propagation mechanism in this case was inferred to be similar to that of a usual hydrocarbon–air premixed flame, although the reaction zone thickness is much larger than that of the premixed flame. In the latter case, the multi peaks of various shapes were considered to be attributable to strong combustion at blue spots far behind the schlieren front. The flame propagation in this case was inferred to be supported by the heat release due to combustion at the blue spots. 相似文献
40.
The oxidation of antimony (III) in soils was studied using X-ray absorption fine structure (XAFS) spectra. An andosol soil sample and artificial soil samples (SiO2 blended with iron (III) hydroxide and manganese (IV) oxide) were used herein. After adding antimony (III) oxide to all soil samples, the oxidation process was observed by recording the XAFS spectra of Sb K-edge, Fe K-edge, and Mn K-edge. The results indicated that manganese (IV) oxide played an important role in the oxidation of Sb(III); however iron (III) hydroxide was not directly related to the reaction. During a 2-hr continuous Sb K-edge X-ray absorption near edge structure (XANES) measurement with an interval of 1 min of one of the artificial soil samples (SiO2 + MnO2 + Sb2O3), a pseudo-first-order reaction was determined with an average estimated rate of 0.52 ± 0.04 hr? 1. Compared to the lower oxidation rate of andosol, it is suggested that because of the low concentration of Mn(IV) in natural soils, the oxidation process of Sb(III) might be relatively slow and require more time to convert Sb(III) to Sb(V). 相似文献