A reactor system combining reductive dechlorination with cometabolic oxidation for complete degradation of tetrachloroentylene

A laboratory sequential anaerobic-aerobic bioreactor system, which consisted of an anaerobic fixed film reactor and two aerobic chemostats, was set up to degrade tetrachloroethylene (PCE) without accumulating highly toxic degradation intermediates. A soil enrichment culture, which could reductively dechlorinate 900/zM ( ca. 150 mg/L) of PCE stoichiometrically into cis-l, 2-dichloroethylene ( cis-DCE), was attached to ceramic media in the anaerobic fixed film reactor. A phenol degrading strain, Alcaligenes sp. 115, which can efficiently degrade cis-DCE by co-metabolic oxidation, was used as inocuhim for the aerobic chemostats consisted of a transformation reactor and a growth reactor.The anaerobic fixed film bioreactor showed more than 99 % of PCE transformation into cis-DCE in the range of influent PCE concentration from 5μM to 35μM at hydraulic retention time of 48h. On the other hand, efficient degradation of the resultant cis-DCE by strain R5 in the following aerobic system could not be achieved due to oxygen limitation. However, 54% of the maximum cis-DCE degradation was obtained when 10μmol of hydrogen peroxide (H2O2 ) was supplemented to the transformation reactor as an additional oxygen source. Further studies are needed to achieve more efficient co-metabolic degradation of cis-DCE in the aerobic reactor.     

Decomposition and removal of ionic liquid in aqueous solution by hydrothermal and photocatalytic treatment

We demonstrated a complete decomposition method for ionic liquids (ILs; organic cation part: butyl-methyl or ethyl-methyl imidazolium, and inorganic anion part: PF₆ ⁻, BF₄ ⁻ or Br⁻) in aqueous media by combining a hydrothermal mineralization method with a photocatalytic decomposition (PD) method. As a result, the hydrothermal treatment with Ca(OH)₂ mineralizer could effectively remove the inorganic anion part, such as PF₆ ⁻ or BF₄ ⁻ and the PD could decompose the organic cation part effectively. Therefore, the detoxification of ILs in aqueous media was accomplished by the present method.     

日本职业卫生管理及对中国的启示

依据中日合作项目<加强中国国家安全生产科学技术能力计划>成果,系统介绍了日本职业卫生监管机构、法规、职业病确定、作业环境管理等.同时,结合中国职业卫生管理体制尚未完全理顺、法规较滞后、专业人才不足、企业基础资料不全和自主管理体制不健全等现状,提出了进一步明确职业卫生管理体制、完善职业卫生法规、建立职业卫生统计制度、强化企业自主管理能力等建立健全中国职业卫生管理的对策和建议.本文对完善中国职业卫生管理具有重要的参考意义.     

日本职业卫生管理及对中国的启示

依据中日合作项目《加强中国国家安全生产科学技术能力计划》成果,系统介绍了日本职业卫生监管机构、法规、职业病确定、作业环境管理等。同时,结合中国职业卫生管理体制尚未完全理顺、法规较滞后、专业人才不足、企业基础资料不全和自主管理体制不健全等现状,提出了进一步明确职业卫生管理体制、完善职业卫生法规、建立职业卫生统计制度、强化企业自主管理能力等建立健全中国职业卫生管理的对策和建议。本文对完善中国职业卫生管理具有重要的参考意义。     

Separate estimation of N export into baseline N leakage without disturbance and N loss due to insect defoliation in a pine forest watershed in central Japan

Pine wilt disease (PWD) is caused by a non-native pest that has spread extensively throughout Japan. Previous research has indicated that most infected trees have died and the litter deposited has resulted in changes to stream-water chemistry, particularly increased nitrate (NO ₃ ^? ) concentrations. In this study, we divided stream nitrogen (N) export into N loss due to PWD and baseline N leakage without disturbance based on long-term monitoring. The annual N export was 110.0 mol N ha^?1 year^?1 in 1990 and 749.8 mol N ha^?1 year^?1 in 1997, and had decreased to 37.0 mol N ha^?1 year^?1 in 2005. N export under PWD influence was estimated to be 3697 mol N ha^?1, and N loss due to PWD was 2810 mol N ha^?1. N loss due to PWD was three times larger than baseline N leakage for the disturbed period. These changes in plant–herbivore relationships could affect N status in a forest ecosystem. So-called “semi-natural” disturbances related to non-native species invasion and increases of atmospheric N deposition caused by human activity will increase. Long-term monitoring studies of various aspects are necessary to offer insight into this ecosystem.     

Pharyngeal aspiration of single-wall carbon nanotubes aggravates allergic reaction to inhaled ovalbumin in mice

Single-wall carbon nanotubes are a major type of nano-objects that have industrial applications such as fuel cells. In this study, four types of single-wall carbon nanotubes and their abilities to aggravate allergic reactions were examined: those containing Fe, those containing Ni, and the corresponding purified metal-free ones. These were administered to mice via pharyngeal aspiration. Subsequently, the mice inhaled ovalbumin a total of eight times over three weeks. After inhalation of ovalbumin, the concentrations of total immunoglobulin E and ovalbumin-specific immunoglobulin E in serum increased in mice treated with purified metal-free and Fe containing single-wall carbon nanotubes while those containing Ni did not affect total and ovalbumin-specific immunoglobulin E levels. Additionally, the purified metal-free and Fe containing nanotubes caused the gene expression of heme oxygenase-1, chemokine (C-X-C motif) ligand 2, and tumor necrosis factor-α, suggesting that some kinds of single-wall carbon nanotubes have the potential to aggravate allergic reactions via oxidative stress and inflammation. Incorporated metals do not seem to be involved in the aggravation of allergic reactions. Other physical properties, such as fiber length and aggregation state, may be involved in enhancing allergic reactions.     

Evaluation of material recycling for plastics: environmental aspects

“Zero emissions” is a concept envisaging the creation of a sustainable society with minimal disposal of resources. In order to realize zero emissions for plastics, it is important to establish a method for quantitatively evaluating candidate recycling processes. In this study, the principle of the substitution factor (SF) is introduced. A quantitative evaluation of the recycling process for plastics was then carried out. The production process for monofilament plastics was examined. The recycling of plastics discarded during the production process could be substituted in small amounts for virgin materials, giving reduced CO₂ emissions. Furthermore, production using recycled material mixed with virgin material was more effective in reducing CO₂ emissions than when recycled materials only were used. Received: November 19, 1999 / Accepted: November 28, 2000     

Concentrations and their ratio of (222)Rn decay products in rainwater measured by gamma-ray spectrometry using a low-background Ge detector

The concentrations and the concentration ratios of individual short-lived (222)Rn decay products ((214)Pb and (214)Bi) in rainwater were measured at Kumatori village (34.39 degrees N, 135.35 degrees E, approximately 70 m above sea level) in Osaka, Japan, by gamma-ray spectrometry using a low-background Ge detector. The dependence of the time variations of the concentrations and their ratios on rainfall rate was investigated. It was observed that the concentrations were negatively correlated with the rainfall rate in some rainfall events, and that there was no clear correlation in other rainfall events. The changes in the dependence of the concentration on the rainfall rate occurred after the passage of a cold front during a single rainfall event. The concentration ratios showed a weak negative correlation with the rainfall rate for most of the observed rainfall events. A scavenging model was designed in this study in order to explain the observation results. Based on the relationship between the concentrations of (214)Pb and (214)Bi in the rainwater and the rainfall rate for an individual rainfall event, the increase in the environmental gamma-ray dose rate from (214)Pb and (214)Bi deposited on the ground was calculated, and the calculated increase agreed well with that observed by the in situ measurement on flat ground.     

中日合作项目国内外危险化学品安全管理初步研究

按照中日合作项目《加强中国安全生产科学技术能力计划》,分析了日本、美国、加拿大、德国、欧盟和联合国等国际危险化学品安全管理现状,总结提出了实施风险评价、申报登记、风险控制、信息警示和员工培训等国际危险化学品安全管理方式及其特点。同时,结合中国危险化学品安全管理现状,提出了系统化建设危险化学品安全生产法规标准体系、制定作业场所危险化学品卫生要求、修订《危险化学品安全管理条例》等进一步建立健全中国危险化学品安全管理的对策和建议。这对完善中国危险化学品安全管理具有重要的参考意义。     

Damage to structures caused by the Japan Sea earthquake of 1983

A summary review of the Japan Sea (Nipponkai-chubu) earthquake of 1983 is presented. Damage to civil and building structures is explained in brief. Owing to the spread of earthquake-proof design, damage sustained was very slight for a M = 7.7 earthquake, except to those built on liquefied ground. Our next target in earthquake engineering may be to protect and maintain the functions of city-facilities against strong shaking so that citizens might not experience much disruption in their daily lives after big earthquakes.