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21.
Shin-ichi Sakai Yasuhiro Hirai Hirofumi Aizawa Shizuko Ota Yasuhiro Muroishi 《Journal of Material Cycles and Waste Management》2006,8(1):56-62
Atmospheric emissions of deca-brominated diphenyl ether (DBDE) in Japan were estimated based on the material flow of DBDE
products and their emission factors. In 2002, the demand for DBDE in Japan was 2200 ton/year and the stock level was about
60 000 ton. The DBDE flow into the waste stream was estimated to be about 6000 ton/year and the flow out through second-hand
product exports was more than 700 ton/year. Home appliance recycling facilities dismantle and crush domestic wastes containing
about 600 ton of DBDE annually. Material recycling of crushed plastics is not commonly practiced as yet. Emission factors
from plastics processing (2 × 10−9–1 × 10−7), textile processing (9 × 10−7), home appliance recycling (8 × 10−9–5 × 10−6), and waste incineration (1 × 10−7–2 × 10−6) were estimated using field measurement data. The DBDE emission rate through house dust during the service life of final
products (2 × 10−7–9 × 10−7 per year) was estimated using the DBDE concentration in dust and the amount of dust in used televisions. Emission factors
from previous studies were also used. The estimated total DBDE emission was 170–1800 kg/year. These results suggest the necessity
of characterizing emissions during the service life of products, which is essential information for formulating an appropriate
e-waste recycling strategy. 相似文献
22.
Masanori Terasaki Yoshiharu Takemura Masakazu Makino 《Environmental Chemistry Letters》2012,10(4):401-406
This article reports the first identification of paraben-chlorinated derivatives in river water. Parabens are widely used as preservatives in pharmaceuticals and personal care products. Parabens can be easily chlorinated by chlorinated tap water. The resulting chlorinated derivatives might pose a higher potential risk to humans and ecosystems than the corresponding parent parabens. However, the occurrence of such derivatives in rivers remains unknown so far. We studied 23 parabens and their chlorinated derivatives from rivers receiving effluents from sewage treatment plants in Shizuoka city, in the central Pacific region of Japan. The compounds were extracted by solid-phase extraction with a styrene polymer sorbent, trimethylsilyl-derivatized, and then identified by gas chromatography–mass spectrometry. Six chlorinated parabens and their primary degradation products, two chlorinated hydroxybenzoic acids, were found for the first time in river water. Moreover, in river water, chlorinated derivatives preferentially partition into the suspended-solid phase. 相似文献
23.
Yuzo Ota Osamu Hoshino Mamiko Hirose Katsuhiko Tanaka Euichi Hirose 《Marine Biology》2012,159(10):2333-2347
The life cycle of the fish ectoparasitic isopod Gnathia trimaculata is described based on both field samplings and laboratory observations. Species identification of the larvae was based on morphological observation and supported by molecular analysis. As the results of field samplings in several sites of southwestern and central Japan (24–34°N, 124–139°E) from 2005–2011, approximately 900 third-stage larvae of G. trimaculata were found on 25 elasmobranch species, and 220 first- and second-stage larvae were found on three teleost species. No third-stage larvae were found on the teleosts, and the larvae of younger stages never infested elasmobranchs. Therefore, G. trimaculata is supposed to shift its host from teleosts to elasmobranchs as it develops. We discuss the developmental periods, life span, distribution, and predation risk of the present species compared with other gnathiid species. 相似文献
24.
Measurements of oxidation rate of hydrogen isotopic gases by soil were made to model HT oxidation rate by soil. Soil was sampled at a cultivated farmland and laboratory measurements of the oxidation rate of H(2) and D(2) gases simulating HT gas were carried out under controlled conditions of soil. The oxidation rate increased with increase of H(2) or D(2) concentration in air and nearly saturated at high concentration. The oxidation rate was low under extremely dry and wet soil conditions and was the highest at soil water content of 8-14 w/w%. The oxidation rate increased exponentially with increasing soil temperature and was the highest at 46 degrees C. Michaelis constant K(m) increased exponentially with increasing soil temperature. Oxidation rate of H(2) was generally higher than that of D(2), while K(m) of H(2) was generally lower than that of D(2). From these results, oxidation rate of HT was modeled as a product of the functions that represent dependency on each soil factor. 相似文献
25.
Terasaki M Fukazawa H Tani Y Makino M 《Environmental pollution (Barking, Essex : 1987)》2008,151(1):53-59
In this study, eight compounds have been identified and quantified from the samples collected from paper-recycling process water discharge areas. In particular, five aryl hydrocarbons, including a novel chlorinated aryl ether, were identified for the first time as environmental pollutants. In the effluent stream, concentration levels of up to 1600 microg L(-1) and 190 microg g(-1) were detected in the surface water and surface sediment, respectively. The results of this study have raised concerns regarding the organic chemicals used in thermal paper and the environmental consequences of their release. 相似文献
26.
Masahiro Miura Atsushi Shimahata Toshio Nishikawa Masakazu Aoyama Kiyoshi Tada Junichi Horiuchi Masahiro Nakahara Chikara Sakai 《Journal of Material Cycles and Waste Management》2011,13(1):80-83
To prepare a substrate for microbial conversion of xylose into xylitol, the culm of Sasa senanensis was hydrolyzed with dilute sulfuric acid. When the reaction temperature was fixed at 121°C, an optimum yield of xylose was
obtained by treatment with 2% sulfuric acid for 1 h. An increase in the sulfuric acid concentration or a prolonged reaction
time resulted in a decrease in the xylose yield. A fermentable substrate with a relatively high xylose concentration (36.7
g l−1) was obtained by hydrolysis with 2% sulfuric acid with a liquid-to-solid ratio of 5 g g−1. During hydrolysis at elevated temperatures, certain undesired byproducts were also generated, such as degradation products
of solubilized sugars and lignin, which are potential inhibitors of microbial metabolism. These compounds were, however, successfully
removed from the hydrolysate by treatment with activated char. 相似文献
27.
Masakazu Ota Hiromi Yamazawa 《Atmospheric environment (Oxford, England : 1994)》2010,44(36):4529-4535
Having a quantitative understanding of the carbon cycle in forests is of great importance for predicting global warming issues. Carbon dioxide production in soil is the largest CO2 source in forests, and exhibits large temporal and spatial variations. Continuous observation of soil CO2 flux at many sites over a forest is therefore necessary to obtain representative soil CO2 fluxes for the forest. In this study, a gradient method to measure soil CO2 flux indirectly from soil radon and CO2 measurements was theoretically modified to conveniently measure the soil CO2 flux from soil radon and CO2 concentrations measured at one soil depth. To experimentally test the modified method, a field observation was conducted continuously in a forest over a 31-day period.Since changes in the soil water content near the soil surface were small throughout the observation, a constant effective diffusivity for CO2 was assumed for the soil CO2 flux estimation. The soil CO2 flux was then calculated as the product of the effective diffusivity and the gradient of the soil CO2 concentration, each calculated from soil radon and CO2 concentrations. The estimated flux ranged from 1.9 to 5.8 μmol m?2 s?1, and, correlating well with the reference value, measured with a conventional ventilated-chamber method. We therefore conclude that the modified gradient method based on the measurement of soil CO2 and radon concentration at one depth is reliable, at least under conditions where the change in the soil water content is small. 相似文献
28.
29.
江西九连山区常绿阔叶林林冠截留量的估算 总被引:5,自引:1,他引:5
为了研究常绿阔叶林小流域的水分平衡,我们在江西九连山区进行了3a林外雨量、林内雨量和树干流量的观测,并据此进行了年林冠截留量的估算。观测结果表明,林冠截留率由一次降雨量为0.4~1mm的78.1%逐步降低到一次降雨量为60mm的3.4%~3.6%。一次降雨量大于60mm时,林冠截留率基本稳定在这一百分数。1988、1989和1990年3a的年降水量在1718.5~2116.5mm之间。估算结果表明,年林冠截留量在300~340mm之间,约为年降水量的16%~17.5%。 相似文献
30.
Katsunori Tanaka Natsuko Yoshifuji Nobuaki Tanaka Katsushige Shiraki Chatchai Tantasirin Masakazu Suzuki 《Ecological modelling》2009
A soil–plant–air continuum multilayer model was used to numerically simulate canopy net assimilation (An), evapotranspiration (ET), and soil moisture in a deciduous teak plantation in a dry tropical climate of northern Thailand to examine the influence of soil drought on An. The timings of leaf flush and the end of the canopy duration period (CDP) were also investigated from the perspective of the temporal positive carbon gain. Two numerical experiments with different seasonal patterns of leaf area index (LAI) were carried out using above-canopy hydrometeorological data as input data. The first experiment involved seasonally varying LAI estimated based on time-series of radiative transmittance through the canopy, and the second experiment applied an annually constant LAI. The first simulation captured the measured seasonal changes in soil surface moisture; the simulated transpiration agreed with seasonal changes in heat pulse velocity, corresponding to the water use of individual trees, and the simulated An became slightly negative. However, in the second simulation, An became negative in the dry season because the decline in stomatal conductance due to severe soil drought limited the assimilation, and the simultaneous increase in leaf temperature increased dark respiration. Thus, these experiments revealed that the leaflessness in the dry season is reasonable for carbon gain and emphasized the unfavorable soil water status for carbon gain in the dry season. Examining the duration of positive An (DPA) in the second simulation showed that the start of the longest DPA (LDPA) in a year approached the timing of leaf flush in the teak plantation after the spring equinox. On the other hand, the end appeared earlier than that of all CDPs. This result is consistent with the sap flow stopping earlier than the complete leaf fall, implying that the carbon assimilation period ends before the completion of defoliation. The model sensitivity analysis in the second simulation suggests that a smaller LAI and slower maximum rate of carboxylation likely extend the LDPA because soil water from the surface to rooting depth is maintained longer at levels adequate for carbon gain by decreased canopy transpiration. The experiments also suggest that lower soil hydraulic conductivity and deeper rooting depth can postpone the end of the LDPA by increasing soil water retention and the soil water capacity, respectively. 相似文献