We have discovered that HNO3 and related species are released from the TiO2 surface into air in the TiO2 photocatalytic oxidation of NO2 (1 ppm) under continuous UV light illumination (1 mW cm−2) by dehumidifying the outlet gas of the reaction and analyzing the recovered condensate liquid by ion chromatography. The
origin of the HNO3 recovered in the dehumidifier could not be explained by a simple desorption of HNO3 overproduced on the TiO2 surface. The produced HNO3 must be activated on the TiO2 surface and causing the unidentified reaction. 相似文献
For the purpose of a field diagnosis of Mn toxicity, we showed the possibility of using visible foliar symptoms of Japanese white birch (Betula platyphylla var. japonica Hara) as indicator. To examine the relationship between the expression of visible symptoms and leaf Mn concentrations, white birch seedlings were grown under four different Mn levels: 1 mg Mn l-1 as control, 10, 50 and 100 mg Mn l-1. Foliar symptoms of Mn toxicity for white birch were: (1) chlorosis at entire young leaves in the 50 and 100 mg Mn l-1 treatments; and (2) brown speckles at the leaf marginal and interveinal area for old leaves in the treatments greater than 1 mg Mn l-1. Mn preferably accumulated into the leaf marginal and interveinal area, where the brown speckles were observed. The mechanism determining the expression of symptoms seems to be associated with the physiological state related to leaf age as well as Mn distribution and concentration within a leaf. 相似文献
Forest conversion is one of the greatest global threats to biodiversity, and land-use change and subsequent biodiversity declines sometimes occur over a variety of underlying geologies. However, how forest conversion and underlying geology interact to alter biodiversity is underappreciated, although spatial variability in geology is considered an integral part of sustaining ecosystems. We aimed to examine the effects of forest conversion to farmland, the underlying geology, and their interaction on the stream fishes’ diversity, evenness, and abundance in northeastern Japan. We disentangled complex pathways between abiotic and biotic factors with structural equation modeling. Species diversity of stream fishes was indirectly shaped by the interaction of land use and underlying geology. Diversity declined due to nutrient enrichment associated with farmlands, which was mainly the result of changes in evenness rather than by changes in species richness. This impact was strongest in streams with volcanic geology with coarse substrates probably because of the differential responses of abundant stream fishes to nutrient enrichment (i.e., dominance) and the high dependency of these fishes on large streambed materials during their life cycles. Our findings suggest that remediation of deforested or degraded forest landscapes would be more efficient if the interaction between land use and underlying geology was considered. For example, the negative impacts of farmland on evenness were larger in streams with volcanic geology than in other stream types, suggesting that riparian forest restoration along such streams would efficiently provide restoration benefits to stream fishes. Our results also suggest that land clearing around such streams should be avoided to conserve species evenness of stream fishes. 相似文献
Home medical care (HMC) is advancing not only in Japan but also throughout the world. In Japan, HMC waste is legally classified as municipal waste. Nevertheless, some municipalities do not collect some or all the HMC waste because of fear of infection. Therefore, this study was conducted to clarify the following two issues: First, have the municipalities made progress in collecting and appropriate disposal of HMC waste in the past 13 years? Second, is there a difference between a large city and a small city in terms of appropriate disposal progress? A total of 687 municipalities published the treatment of HMC waste. Currently, 42 municipalities collected all HMC waste. 236 municipalities were collecting HMC waste except for self-injection needle. 117 municipalities were collecting HMC waste except for self-injection needle and Syringe. The collection status of HMC waste was better in cities with high population than in cities with low population. HMC waste collection status was progressed over 13 years. However, more than 60% of the municipality staff stated that they could not avoid being anxious about infection caused by HMC waste. We suggest that providing HMC waste education to the municipalities wherein these efforts have not yet progressed is important.
The effect of the bivalveCorbicula japonica on the nitrogen cycle in Lake Shinji, a mesohaline brackish lagoon in Japan, was examined quantitatively based on field surveys and laboratory experiments carried out in the summer of 1982 and 1983. The biomass of the flesh ofC. japonica comprised 97% of the total biomass of the macrozoobenthos in summer. Total biomass ofC. japonica in the lake was estimated 30 986 t fresh wt. The concentration of suspended solids immediately above the lake bottom, whereC. japonica filters the water, was 1.5 to 4 times higher than that in the surface water. In laboratory experiments, the filtration rate was 5.0 litres g dry flesh wt-1 h-1, the excretion rates of ammonia and of feces and pseudofeces ofC. japonica were 200×10-6 g N g dry flesh wt-1 h-1 and 33.4 mg dry wt g dry flesh wt-1 h-1, respectively at 27°C, the average summer water temperature in the lake. From our study, we estimated thatC. japonica filters almost the same amounts of particulate organic nitrogen produced in the lake by phytoplankton and that supplied from rivers, and that it excretes 30% of filtered nitrogen as feces or pseudofeces and 18% as ammonia. 相似文献
An ecotoxicological study of river water discharged from the agricultural area around Lake Biwa was performed by using algal bioassays to guide chemical analysis. Water samples were collected once a week, at least, for 1 year starting in April 1997 and continuing until April 1998. The toxicities of the dissolved and particulate-adsorbed extracts of water samples were evaluated by the algal growth inhibition test and concentrations of individual pesticides were determined. Most of the river water that was collected during the periods when pesticides were applied to the paddy fields caused algal growth inhibition. Some extracts were found to contain herbicides (molinate, mefenacet, simetryn, or esprocarb) as major compounds. According to chemical assay and bioassay, simetryn was identified as the most toxic compound that caused algal growth inhibition. 相似文献
We tried to decolorize mixtures of four reactive textile dyes, including azo and anthraquinone dyes, by a white-rot basidiomycete Phanerochaete sordida. P. sordida decolorized dye mixtures (200 mg l-1 each) by 90% within 48 h in nitrogen-limited glucose-ammonium media. Decolorization of dye mixtures needed Mn2+ and Tween 80 in the media. Manganese peroxidase (MnP) played a major role in dye decolorization by P. sordida. Decolorization of dye mixtures by P. sordida was partially inhibited by polyvinyl alcohol (PVA) that wastewaters from textile industries often contain. This was caused by an inhibitory effect of PVA on the decolorization of Reactive Red 120 (RR120) with MnP reaction system. Second addition of Tween 80 to the reaction mixtures in the presence of PVA improved the decolorization of RR120. These results suggest that PVA could interfere with lipid peroxidation or subsequent attack to the dye. 相似文献
It is desirable when drawing up a maritime traffic environmental project or a project for consolidating port and harbour facilities, that the safety of the maritime environment for shipping-traffic is assessed quantitatively, and that the rationale of a given project and the proposed safety measures are evaluated in an objective manner.In this report, the system flow and procedures to integrally assess the safety of the maritime traffic environment by systematically combining various simulation techniques are discussed first.Subsequently, the quantitative risk evaluation procedure for collisions of ships in waters with a high traffic density, among the assessment procedures above, and an outline of the shipping traffic flow simulation capable of reproducing ships′ movements, are described. In evaluating the results of simulations, a method introducing Subjective Judgement values (SJ-values) as indexes manifesting the subjective degree of danger felt by shiphandlers, is shown. The SJ-values were experimentally determined from simulator experiments using parameters representing the relation ship with other ships proceeding in the vicinity.Finally, some of the results of studies conducted for the recent construction of new LNG berths in Tokyo Bay are introduced as an example of practical safety assessment in this field. 相似文献