On-site measurement of methanethiol (CH3SH) was performed for three years on ships and cars near a pulp and paper plant standing on the shore of Lake Baikal in Siberia, Russia, to investigate the behavior and impact of atmospheric CH3SH emitted from a point source. Despite its strong odor, there are few reports on atmospheric CH3SH, while many investigations have been carried out on dimethyl sulfide (DMS). In this work, CH3SH and DMS were measured every 15 min by a recently developed automated instrument based on single column trapping/separation and chemiluminescence measurement. Hydrogen sulfide, sulfur dioxide and ozone were also measured simultaneously by individual instruments. Of these sulfur compounds, CH3SH was dominant and its concentration sometimes reached several tens of ppbv. The concentration of CH3SH was high at night, because of the lack of photodecomposition and local winds from the mountain to the lake. Such time variation was marked in the summer. The CH3SH level decreased significantly downwind, while decreases in concentrations of other compounds such as DMS and SO2 were relatively small. From these temporal and spatial variations, the behavior of CH3SH is described in this paper. The impact of CH3SH near the Siberian big sources is discussed with the presented data. 相似文献
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. 相似文献
The three-spined stickleback, a small teleost species with habitats that range from full marine to fresh water bodies across the whole Northern hemisphere, has a number of advantages for endocrine disruption research. It is the only teleost species with an unambiguous biomarker for androgens, the presence of the glue protein spiggin in the male kidney, which can be measured by enzyme-linked immunosorbent assay (ELISA). The androgen assay has been adopted to detect antiandrogens in two different ways and an homologous ELISA for stickleback vitellogenin is also available. DNA markers for molecular sex determination are available; thus, sex ratios can also be used for in situ biomonitoring. In addition, the critical period of sexual differentiation has been determined and the occurrence of intersex fish has been reported several times. The species full genome sequence is almost complete. All aspects of stickleback biology (ecology, evolution, behavior, physiology, endocrinology) are well documented. In European waters, the stickleback is the only fish that can bring laboratory and field studies together and allow the true impact of endocrine disruptors on fish populations to be evaluated. 相似文献
The catalytic decomposition of mixed plastics consisting of polypropylene (PP) and polyethylene terephthalate (PET) has been
investigated over titania/silica catalysts at 698 K. The yield of oil produced was about 70%, and the large amounts of C18+ hydrocarbons this contained was from the aromatics in PET. Gas was also produced, including C3–C5 hydrocarbons. The carbon-number fractions in the oil was influenced by the PET/(PP + PET) ratios and the catalyst weight.
The titania/silica catalysts could be used repeatedly, and after they had been fouled, could be regenerated. From the Fourier
Transform Infrared (FT–IR) spectroscopic data of adsorbed pyridine on the catalyst surface, most of the acid sites of the
titania/silica catalysts were found to be Lewis sites where the hydride abstracted from PP pyrolysates react with PET pyrolysates
to form oil and gas.
Received: July 19, 2000 / Accepted: October 20, 2000 相似文献
In this study, polychlorinated biphenyls (PCBs) were decomposed by low‐temperature heat treatment with metallic catalyst, and with metallic catalyst and a hydrogen source. Of the catalysts used, iron (Fe) was the most active catalyst for the decomposition of PCBs, and the decomposition was due to dechlorination. The addition of hydrogen sources accelerated the decomposition of PCBs in the presence of catalyst. Surface analysis of the catalyst using X‐ray photoelectron spectroscopy (XPS) suggested that the emitted chlorine was presumed to form metal chloride. The reactions of each homolog can be expressed by a successive first‐order reaction model. This means that a substituted chlorine is successively detached during this reaction. The overall decomposition rate in this reaction system was controlled by that of the lower chlorinated homologs. The decomposition rates with Fe and NaBH4 for the lower chlorinated homologs were about 10 times as fast as the rates with only Fe. 相似文献
Fossil footprints are important in understanding Cretaceous avian diversity because they constitute evidence of paleodiversity
and paleoecology that is not always apparent from skeletal remains. Early Cretaceous bird tracks have demonstrated the existence
of wading birds in East Asia, but some pedal morphotypes, such as zygodactyly, common in modern and earlier Cenozoic birds
(Neornithes) were unknown in the Cretaceous. We, herein, discuss the implications of a recently reported, Early Cretaceous
(120–110 million years old) trackway of a large, zygodactyl bird from China that predates skeletal evidence of this foot morphology
by at least 50 million years and includes the only known fossil zygodactyl footprints. The tracks demonstrate the existence
of a Cretaceous bird not currently represented in the body fossil record that occupied a roadrunner (Geococcyx)-like niche, indicating a previously unknown degree of Cretaceous avian morphological and behavioral diversity that presaged
later Cenozoic patterns.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Mercury enters into the environment or waste streams because it is present as an impurity in natural minerals. Mercury must be appropriately managed as an hazardous waste. In this study, a waste layer of artificial mercury sulfide mixed with incinerator ash and sewage sludge compost in a simulated landfill experiment for 5 years was analyzed using microscopic synchrotron X-ray to obtain basic knowledge of mercury behavior in a landfill. Mapping by synchrotron X-ray revealed the distribution of mercury-containing particles in the waste layer. In most cases, the movement of mercury sulfide was not considered significant even within a microscopic range; however, water flows could enhance the movement of mercury sulfide particles. When disposing of mercury sulfide, “concentrated placement” or solidification, rather than mixing with other wastes, was more effective at preventing mercury leaching in lysimeters. The chemical form of mercury sulfide in each lysimeter was confirmed by X-ray absorption fine structure (XAFS) analysis, which showed that most of the mercury was present as metacinnabar and had not undergone any changes, indicating that it was extremely stable. The microscopic synchrotron X-ray analysis proved very useful for studying the behavior of mercury waste in a simulated landfill experiment.
Journal of Material Cycles and Waste Management - Appropriate management of waste containing mercury is important. However, reducing greenhouse gases (GHGs) associated with this process is equally... 相似文献
Journal of Material Cycles and Waste Management - We focused on incineration of solid waste and resource recycling, when clarifying how to achieve carbon neutrality (CN) by 2050; we describe how... 相似文献
Journal of Material Cycles and Waste Management - Mercury, a highly toxic environmental pollutant with a global circulation, must be controlled worldwide. Taking the Wuda underground coal fires,... 相似文献