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21.
Given the amounts of end-of-life electrical and electronic equipment (EoL-EEE) being generated and their contents of both harmful and valuable materials, the EoL-EEE issue should be regarded not only as an emerging environmental problem but also as a resource management strategy in China. At present, in order to provide the basis for managing EoL-EEE at both product and substance levels in China, it is necessary to carry out a quantitative analysis on EoL-EEE and to determine how much of it will be generated and how much materials and substances it contains. In this study, the possession and obsolescence amounts of five types of household appliance (HA) including television (TV) sets and the amounts of substances contained in EoL TV sets were estimated using time-series product flow analysis (PFA) and substance flow analysis (SFA). The results of PFA indicated that the total possession amounts of those five types of HAs will exceed 3.1 billion units in 2030, which will be two times higher than those in 2010. In addition, it was estimated that cumulatively over 4.8–5.1 billion units of these five types of EoL HA would be obsoleted between 2010–2030. The results of SFA on TV sets indicated that the generated amounts of most of the less common metals and a part of common metals such as copper (Cu) would tend to decrease, whereas those of other common metals such as iron (Fe) as well as precious metals would tend to increase in EoL TV sets in 2015–2030. The results of this study provide a quantitative basis for helping decision makers develop strategic policies for the management of EoL-EEE considering both environmental and resource aspects. Moreover, a calculation scheme of obsolete HAs presented in this study can be applied to estimate other types of EoL durable good. Meanwhile, the frameworks of this study will help not only the policy decision makers in the Chinese government but also those in developing countries that are facing similar problems. 相似文献
22.
Shigefumi Okumura Tomohiro Tasaki Yuichi Moriguchi Wassana Jangprajak 《Journal of Material Cycles and Waste Management》2017,19(2):718-730
A reasonable selection of waste treatment options is indispensable to address challenges in waste management. Introduction of incineration plants for municipal waste in Bangkok had been considered in the past, but each time it was dismissed. In 2013, however, the Bangkok Metropolitan Administration (BMA) decided to introduce an incinerator facility with electricity generation. This study examined how changes in socio-economic factors resulting from economic growth affected the BMA’s decision. First, we conducted interviews of key relevant stakeholders (policymakers and other experts) to determine what kinds of changes in socio-economic factors affected their decision. Then, for interpretation and confirmation of the results from interview, we quantitatively estimated changes in environmental factors (e.g., greenhouse gas emissions), financial factors (e.g., construction and operating costs), and social factors (e.g., employment) in 1990, 2000, and 2012. Based on the result of interview and quantitative analysis, we illustrated the complicated structure of the mechanism of how economic growth affected the selection of waste treatment options in Bangkok, particularly those that led to the selection of the incineration. In addition to local conditions, global economic also affected the waste treatment policy in Bangkok even though waste management is usually thought of as a local issue. 相似文献
23.
Here, we examined the incineration of extruded polystyrene containing hexabromocyclododecane(HBCD) in a pilot-scale incinerator under various combustion temperatures(800–950℃) and flue gas residence times(2–8 sec). Rates of HBCD decomposition ranged from 99.996%(800℃, 2 sec) to 99.9999%(950℃, 8 sec); the decomposition of HBCD, except during the initial stage of combustion(flue gas residence time 2 sec), followed a pseudo-first-order kinetics model. An Arrhenius plot revealed that the activation energy and frequency factor of the decomposition of HBCD by combustion were 14.2 kJ/mol and 1.69 sec~(-1),respectively. During combustion, 11 brominated polycyclic aromatic hydrocarbons(BrPAHs)were detected as unintentional by-products. Of the 11 BrPAHs detected, 2-bromoanthracene and 1-bromopyrene were detected at the highest concentrations. The mutagenic and carcinogenic BrPAHs 1,5-dibromoanthracene and 1-bromopyrene were most frequently detected in the flue gases analyzed. The total concentration of BrPAHs exponentially increased(range,87.8–2,040,000 ng/m~3) with increasing flue gas residence time. Results from a qualitative analysis using gas chromatography/high-resolution mass spectrometry suggest that bromofluorene and bromopyrene(or fluoranthene) congeners were also produced during the combustion. 相似文献
24.
Yuichi Yamaura David Lindenmayer Yusuke Yamada Hao Gong Toshiya Matsuura Yasushi Mitsuda Takashi Masaki 《Conservation biology》2020,34(1):194-206
Stand structure develops with stand age. Old-growth forests with well-developed stand structure support many species. However, development rates of stand structure likely vary with climate and topography. We modeled structural development of 4 key stand variables and a composite old-growth index as functions of climatic and topographic covariates. We used a hierarchical Bayesian method for analysis of extensive snap-shot National Forest Inventory (NFI) data in Japan (n = 9244) to account for differences in stand age. Development rates of structural variables and the old-growth index exhibited curvilinear responses to environmental covariates. Flat sites were characterized by high rates of structural development. Approximately 150 years were generally required to attain high values (approximately 0.8) of the old-growth index. However, the predicted age to achieve specific values varied depending on environmental conditions. Spatial predictions highlighted regional variation in potential structural development rates. For example, sometimes there were differences of >100 years among sites, even in the same catchment, in attainment of a medium index value (0.5) after timber harvesting. The NFI data suggested that natural forests, especially old natural forests (>150 years), remain generally on unproductive ridges, steep slopes, or areas with low temperature and deep snow, where many structural variables show slow development rates. We suggest that maintenance and restoration of old natural forests on flat sites should be prioritized for conservation due to the likely rapid development of stand structure, although remaining natural forests on low-productivity sites are still important and should be protected. 相似文献
25.
Takeda A Tsukada H Takaku Y Akata N Hisamatsu S 《Journal of environmental radioactivity》2008,99(6):900-911
For a better understanding of the soil-to-plant transfer of radionuclides, their behavior in the soil solution should be elucidated, especially at the interface between plant roots and soil particles, where conditions differ greatly from the bulk soil because of plant activity. This study determined the concentration of stable Cs and Sr, and U in the soil solution, under plant growing conditions. The leafy vegetable komatsuna (Brassica rapa L.) was cultivated for 26 days in pots, where the rhizosphere soil was separated from the non-rhizosphere soil by a nylon net screen. The concentrations of Cs and Sr in the rhizosphere soil solution decreased with time, and were controlled by K+NH(4)(+) and Ca, respectively. On the other hand, the concentration of U in the rhizosphere soil solution increased with time, and was related to the changes of DOC; however, this relationship was different between the rhizosphere and non-rhizosphere soil. 相似文献
26.
Heon-Sook Kim Yuichi Nagata Kenji Kai 《Atmospheric environment (Oxford, England : 1994)》2009,43(3):557-567
LIDAR observations were conducted in the northern Taklimakan Desert to investigate the vertical distribution of dust in April 2002. During the observation period, a dust outbreak occurred on 13 April, remaining over the desert for several days. Despite only slight variations being observed in dust layer height before the dust event, marked diurnal variation in dust layer height was observed after the dust event. In this study, we conducted two numerical simulations to investigate differences in the variation exhibited by the dust layer heights before and after the dust event, and assessed the influence of meteorological conditions on this variation. The simulated results show that the clearly diurnal variation in dust layer height is strongly influenced by local circulation which is affected by the characteristic topography and synoptic conditions of the Tarim Basin. 相似文献
27.
Amin Yousefi-Sahzabi Kyuro Sasaki Hossein Yousefi Saied Pirasteh Yuichi Sugai 《Journal of Cleaner Production》2011,19(17-18):1982-1993
CO2 is the dominant constituent of non-condensable gases in the steam phase of most geothermal fluids. This paper attempts to present the results of a study conducted to develop prediction modeling of CO2 dispersion in the surrounding atmosphere from a planned 50 MWe geothermal power plant prior to its production. Dispersion models are widely used for predicting future concentrations of environmental emissions on a range of geographic scales. The dispersion type for gases and their average removal rate depends on the meteorological conditions such as wind direction, wind speed, precipitation, atmospheric stability, and surface roughness and topography. Geographic Information System (GIS) capabilities were used for quality visualization of the model outputs and presenting an accurate numerical copy of the study area. The results by the prediction model show that the natural transfer of CO2 will be from the power plant toward east and northeast and CO2 concentration trends after the power plant utilization will be similar to the background conditions with minor changes. This dispersion test was carried out to validate and field test the GIS aided dispersion modeling approach described in the paper and the procedure may be applicable for other studies assessing the emission dispersion of pollutants from a point source. 相似文献
28.
Wyrzykowska B Bochentin I Hanari N Orlikowska A Falandysz J Yuichi H Yamashita N 《Environmental pollution (Barking, Essex : 1987)》2006,143(1):46-59
The isomer specific composition of 13 technical PCB formulations of different origin and of pine needles was analyzed using GC/MS and HRGC/HRMS. Nonachlorinated biphenyls were identified in 11 among 13 formulations analyzed, with the highest abundance found for highly chlorinated ones (Aroclors 1268 and 1260, Chlorofen, Sovol, Kanechlors 600 and 500, Delor 106, Clophen A60). Decachlorobiphenyl was identified only in Aroclor 1268, Clophen A60, Aroclor 1260 and Chlorofen, comprising, respectively, 8.9, 2.8, 1.3 and 0.82% of the total bulk of nona- and decaCBs detected. Nona- and decaCB were detected in pine needles in Poland with the highest concentrations found at the sites neighboring to a former production sites of the Polish PCB formulations, while in pine needles collected around the Tokyo Bay nona- and decacCB were detected only in four of 10 sites and the concentrations corresponded to those found at the rural areas of Poland. 相似文献
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30.
Mifuyu Ogawa Yuichi Yamaura Shin Abe Daisuke Hoshino Kazuhiko Hoshizaki Shigeo Iida Toshio Katsuki Takashi Masaki Kaoru Niiyama Satoshi Saito Takeshi Sakai Hisashi Sugita Hiroyuki Tanouchi Tatsuya Amano Hisatomo Taki Kimiko Okabe 《Environmental monitoring and assessment》2011,177(1-4):85-94
An alkaline comet assay and a micronucleus test were carried out on erythrocytes of the European chub, Squalius cephalus L., collected in spring and autumn in 2005 and 2006 at three sampling sites in River Sava, near Zagreb, Croatia. The results of comet assay showed the lowest genotoxic influence at the least polluted site, while higher DNA damage was observed at the polluted sites. Although the basal levels of DNA damage were elevated, a clear gradation of DNA damage was found due to pollution intensity in all sampling periods. The lowest cytogenetic damage as revealed by the micronucleus test (MNT) was observed as well at the least polluted site. High variations in MN frequency were observed between sampling periods, although the number of micronucleated erythrocytes was consistently the highest one at the polluted site. The comet assay as a biomarker of genotoxic effect exhibited higher sensitivity in discriminating the genotoxic capacity of studied polluted sites while the MNT was less sensitive. However, both tests should be used together in biomonitoring studies because they can reveal different aspects of DNA damage; comet assay, the early event of genotoxic exposure, and MNT, its final result as a mutagenic potential. 相似文献