日本的塑料再循环

"清洁日本中心"是一个与再循环有关的非政府组织.本文综述了由各种类型塑料制成的产品的再循环方法.有一批这样的方法正在使用中或在研究中.重点介绍日本塑料再循环的现状.     

Behavioral and faunal implications of Early Cretaceous deinonychosaur trackways from China

Deinonychosaurian theropods, the dinosaurian sister group of birds, are characterized by a large raptorial claw borne on a highly modified second digit that was thought to be held in a retracted position during locomotion. In this study, we present new trackway evidence for two coeval deinonychosaurian taxa from the Early Cretaceous of Shandong, China that indicate a hitherto unrecognized body size diversity for this period and continent. These fossil tracks confirm diversity and locomotory patterns implied by phylogeny and biogeography, but not yet manifested in the body fossil record. Multiple parallel and closely spaced trackways generated by the larger track maker provide the best evidence yet discovered for gregarious behavior in deinonychosaurian theropods.     

Nematode community composition in hydrothermal vent and adjacent non-vent fields around Myojin Knoll,a seamount on the Izu-Ogasawara Arc in the western North Pacific Ocean

In contrast to specific large benthic invertebrates in chemosynthetic ecosystems such as hydrothermal vents, meiofaunal communities in such habitats have been reported to have strong taxonomic overlap with meiofauna in the adjacent “normal” environments. However, meiofauna have only recently been included in studies of those environments and detailed information on these communities is still rare. This is especially true in the Northwest Pacific Ocean, even though there are many seamounts with active vents in the calderas of the region. Nematode community composition at the genus level in sediments from a hydrothermal vent field in the caldera of Myojin Knoll (32°06′N, 139°52′E, depth 1,300 m), a seamount on the Izu-Ogasawara Arc, Japan, was investigated for the first time and was compared with adjacent non-vent areas inside and outside the caldera. Multivariate analyses showed that the composition of nematodes in the hydrothermal field was significantly different from that in the non-hydrothermal fields around the caldera. However, the common genera, such as Oxystomina, Pareudesmoscolex, Desmoscolex, and Microlaimus were found in two, or all three vent fields while their rank contributions differed among the three fields. When the data from Myojin Knoll were compared with those from other deep-sea vent environments in different regions (e.g., North Fiji Basin, East Pacific Rise, Mid-Atlantic Ridge), the nematode composition in the vent field of the Myojin caldera was more similar to that of the non-vent fields around the caldera than the composition in vent fields of other regions. These data from the Northwest Pacific Ocean also suggest the absence of long-range transport systems and local adaptations for meiofauna in hydrothermal vent fields.     

芦竹抑藻物质的初步分离及抑制铜绿微囊藻的效果

采用乙酸乙酯提取芦竹(Arundo donax Linn.)得到高效抑藻粗提物,其对产毒铜绿微囊藻的半效应抑制浓度(EC50.6d)为50mg·1-1.粗提物经溶剂萃取分离得到中/碱性物质及酸性物质.活性分析表明,酸性物质有显著抑制铜绿微囊藻的活性.通过酸性氧化铝柱层析进一步分离酸性物质,得到三组弱极性抑藻物质及一组强极性抑藻物质.培养3d后,四组抑藻物质在10mg·1-1时的抑藻率分别为82%,83%,100%以及70%.     

Control of Mercury Emissions from a Municipal Solid Waste Incinerator in Japan

Abstract

The control of Hg emissions from a municipal solid waste incinerator (MSWI) is very important, because more than 78% of municipal solid waste (MSW) is incinerated. The Hg content of coal used in utility boilers is relatively low in Japan. In this study, recent trends in the Hg content of MSW in Japan and activated carbon (AC) injection as a control technology of Hg emission from an MSWI are discussed. The effect of AC injection on Hg removal from flue gas in an MSWI was investigated by pilot-scale experiments using a bag filter (BF). The injection of AC increases the Hg reduction ratio by 20–30% compared with cases without AC injection. The Hg reduction ratio increases as the flue gas temperature decreases. The Hg reduction ratio is closely related to the inlet Hg concentration and was expressed with a Langmuir-type adsorption isotherm.     

Geographical distribution of non-PBDE-brominated flame retardants in mussels from Asian coastal waters

Hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), and decabromodiphenyl ethane (DBDPE) used as alternatives for polybrominated diphenyl ethers (PBDEs) are also persistent in the environment as PBDEs. Limited information on these non-PBDE brominated flame retardants (BFRs) is available; in particular, there are only few publications on environmental pollution by these contaminants in the coastal waters of Asia. In this regard, we investigated the contamination status of HBCDs, BTBPE, and DBDPE in the coastal waters of Asia using mussels as a bioindicator. Concentrations of HBCDs, BTBPE, and DBDPE were determined in green (Perna viridis) and blue mussels (Mytilus edulis) collected from the coastal areas in Cambodia, China (mainland), SAR China (Hong Kong), India, Indonesia, Japan, Malaysia, the Philippines, and Vietnam on 2003-2008. BTBPE and DBDPE were analyzed using GC-MS, whereas HBCDs were determined by LC-MS/MS. HBCDs, BTBPE, and DBDPE were found in mussels at levels ranging from <0.01 to 1,400, <0.1 to 13, and <0.3 to 22?ng/g lipid wt, respectively. Among the three HBCD diastereoisomers, α-HBCD was the dominant isomer followed by γ- and β-HBCDs. Concentrations of HBCDs and DBDPE in mussels from Japan and Korea were higher compared to those from the other Asian countries, indicating extensive usage of these non-PBDE BFRs in Japan and Korea. Higher levels of HBCDs and DBDPE than PBDEs were detected in some mussel samples from Japan. The results suggest that environmental pollution by non-PBDE BFRs, especially HBCDs in Japan, is ubiquitous. This study provides baseline information on the contamination status of these non-PBDE BFRs in the coastal waters of Asia.     

The possibility of sustainable pest management by introducing bio-diversity: simulations of pest mite outbreak and regulation

Since the late 1980s, spider mite pests have caused serious damage to many moso bamboo (Phyllostachys pubescens) forests in China’s Fujian province. The culms of this plant are an essential component of the building and handicraft industries, and the shoots are a prized food item in many Asian countries. Furthermore, bamboo forests play an important soil conservation role in mountainous areas. We examined pest mite outbreaks in several moso bamboo plantations in Fujian, and could show that a change in cultivation style from polyculture (a kind of mixed forest) to monoculture (all plants other than bamboo were removed) was primarily responsible for the local extinction of an important predaceous mite species. This phenomenon is due to the periodic shedding of leaves by the bamboo, which forces the predator mites occurring on bamboo to switch to prey mite species that occur on other plants. We then tried to elucidate the factors that resulted from such a cultivation change. Adopting a computer simulation approach, we could successfully show that at least two plants, moso bamboo and Chinese silvergrass, are necessary to maintain stable predator–prey interactions in moso forests. That is, systems consisting of one common predator and two host-specific pest mites on different host plant species frequently became stable when the pest mites were at low density. This finding indicates clearly that bio-diversity, even when it consists of only two plants and three mite species as in this study, is necessary for the sustainable regulation of large-scale forests, such as moso bamboo plantations.     

Current status of waste to power generation in Japan and resulting reduction of carbon dioxide emissions

We discuss the current status of waste to power generation (WPG) in Japan and various scenarios involving indirect reduction of carbon dioxide emissions by WPG. The number of WPG facilities domestically as of 2005 was 286. Power generation capacity attained 1,515 MW and power generation 7,050 GWh/year. This amount substitutes energy otherwise acquired from natural resources such as fossil fuels in thermal power plants. If the basic unit of carbon dioxide is 0.555 kg-CO₂/kWh, then the corresponding carbon dioxide emission reduction is calculated to be 3.9 million tons, equivalent to 26.7% of the 14.6 million tons emitted by municipal solid waste incinerators (MSWI) in 2005. Using various existing technological options, the power generation efficiency could reach more than 20% in MSWI facilities with capacity of 300 tons/day, although present efficiency is only 12.0%. If about 85% of MSW were incinerated in MSWI with power generation efficiency of 20% as a feasible assumption, the total power generation and the corresponding carbon dioxide reduction would be 16,540 GWh/year and 9.18 million tons, respectively, equivalent to 62.7% of the carbon dioxide emitted by MSWI. Also, the ratio of the additional reduction of carbon dioxide emissions by WPG to the total additional reduction (20,000 ktons/year) in Japan during the first commitment period would be 26.3%, suggesting that promotion of WPG in MSWI is an effective option for prevention of global warming.     

Time-series analysis of excess mercury in China

In October 2013, China signed the Minamata Convention on Mercury as the 30th signatory state, and its implementation will have a significant impact on the development, use, and management of mercury. Therefore, estimating excess mercury has become extremely important for providing fundamental information for strategic mercury management, such as planning the necessary storage capacity and the timeline for taking appropriate actions. In this study, quantitative information on past and current domestic supply and demand and on excess mercury over a 55-year period (1996–2050) in China was assessed through maximum and minimum scenario analyses. The total mercury supply increased markedly between 1996 and 2016, particularly during the 3 most recent years. The total demand for mercury during the same period increased gradually compared to the total supply. The amount of annual excess mercury has grown rapidly since 2014, from 636?–756 tons in 2013 to 2725–2845 tons in 2016. The minimum excess mercury scenario shows that cumulative excess mercury will continue to decline from 2017 on, and will reach one-third of 2016 levels in 2050. The cumulative amount in 2050 in the maximum scenario will be 3.5 times higher than that in the minimum scenario. The method applied would be useful for policymakers in other countries that are facing similar problems.     

Reactivity between PbSO4 and CaCO3 particles relevant to the modification of mineral particles and chemical forms of Pb in particles sampled at two remote sites during an Asian dust event

During the transboundary transport of anthropogenic heavy metals by mineral particles providing reaction sites, the divalent metal salt PbSO₄ can be converted to PbCO₃ in the presence of water. We carried out laboratory experiments to study the transformation process under various conditions by incorporating test particles comprising CaCO₃ of a particulate mineral component, PbSO₄, and NaCl. After the immersion of PbSO₄ particles in contact with CaCO₃ particles in a water droplet, the conversion of PbSO₄ into PbCO₃ was confirmed by the change in morphology of the original particles to stick or needle form; the percentages of the chemical forms relative to the total Pb were determined by X-ray absorption near edge structure (XANES) analysis. Approximately 60–80% of PbSO₄ was converted to PbCO₃ after 24 h. A small amount of stick particles was detected when NaCl particles attached to PbSO₄/CaCO₃ particles were exposed to air with a relative humidity (RH) of 80–90% for 24 h. XANES measurements of the samples revealed that the molar percentage of PbCO₃ relative to the total Pb content was 4%.Field experiments were also conducted to determine the chemical forms of the Pb particles during the Kosa (Asian dust storm) event. Samples were collected from two remote sites in Japan and Korea. The mass size distribution of Pb aerosols collected in Japan was bimodal with two peaks in the coarse mode; the enrichment factor of Pb suggested that its source was anthropogenic. Pb L3 edge XANES measurements of both samples indicated that they had similar shapes. These measurements also indicated that the major Pb components for the samples collected in Japan were PbO, PbSO₄ PbCl₂, and PbCO₃, with molar percentages of 44%, 30%, 21%, and 5%, respectively. No significant differences were found between the component ratios of the samples collected in Japan and Korea, suggesting that definite transformation did not occur during the transport of the Kosa particles from Korea to Japan. On the basis of these observations, we postulate that the transformation process either occurred mainly before the particles arrived at Korea or did not take place after the particles left continental Asia.