Inorganic iodine incorporation into soil organic matter: evidence from iodine K-edge X-ray absorption near-edge structure

The transformation of inorganic iodine (I⁻ and IO₃⁻) incubated in soils with varying amounts of organic matter (Andosols from the surface layer of an upland field and forest, as well as Acrisols from surface and subsurface layers of an upland field) was investigated by using the iodine K-edge X-ray absorption near-edge structure (XANES). After 60 d of reaction, both I⁻ and IO₃⁻ were transformed into organoiodine in surface soils containing sufficient amounts of organic matter, whereas IO₃⁻ remained unchanged in the subsurface soil of Acrisols with low organic matter contents. Transformation of IO₃⁻ into organoiodine was not retarded when the microbial activity in soil was reduced by γ-ray irradiation, suggesting that microbial activity was not essential for the transformation of inorganic iodine into organoiodine. Soil organic matter has the ability to transform inorganic iodine into organoiodine.     

Rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar

The rapid hydropyrolysis of model compounds for epoxy resin oligomers and biomass tar was carried out in a hydrogen atmosphere at 1073 K and 973 K. The assumed oligomers were partially pyrolyzed epoxy resin with biomass tar as solvent for the resin. The product distributions obtained from rapid hydropyrolysis of phenol and bisphenol-A are shown. We also discuss the effects of reaction temperature and hydrogen partial pressure on the product yield. In particular, more phenol was produced from bisphenol-A at 973 K than at 1073 K. The yield of methane, which was the final hydropyrolysis product, increased with increasing hydrogen partial pressure, whereas benzene and phenol were believed to behave as intermediate products in the hydropyrolysis reaction. The results suggest that phenol could be obtained with high selectivity from tar by optimizing the reaction conditions.     

Genetic engineering of cyanobacteria to enhance biohydrogen production from sunlight and water

To mitigate global warming caused by burning fossil fuels, a renewable energy source available in large quantity is urgently required. We are proposing large-scale photobiological H(2) production by mariculture-raised cyanobacteria where the microbes capture part of the huge amount of solar energy received on earth's surface and use water as the source of electrons to reduce protons. The H(2) production system is based on photosynthetic and nitrogenase activities of cyanobacteria, using uptake hydrogenase mutants that can accumulate H(2) for extended periods even in the presence of evolved O(2). This review summarizes our efforts to improve the rate of photobiological H(2) production through genetic engineering. The challenges yet to be overcome to further increase the conversion efficiency of solar energy to H(2) also are discussed.     

Waste reduction through variable charging programs: its sustainability and contributing factors

 In this study, we analyzed the sustainability and determinant factors of waste reduction through variable charging schemes. We drew three main conclusions from the study. (1) Waste reduction was achieved by variable charging and was sustained over an average of at least 10 years. The results regarding the sustainability of the price effect were inconclusive. (2) The main factors contributing to the combustible waste reduction achieved through variable charging were two-tier pricing and the price of waste bags. The effect of two-tier pricing programs was positive. (3) Waste paper recycling and variable charging reinforce each other to promote waste reduction. Received: September 3, 2001 / Accepted: January 13, 2002     

A badge-type personal sampler for measurement of personal exposure to NO2 and NO in ambient air

A badge-type personal sampler was developed for measuring personal exposure to nitrogen dioxide (NO₂). An absorbent sheet containing triethanolamine (TEA) solution absorbed NO₂ which diffused through five layers of hydrophobic fiber filter. Wind effects on absorption rate were suppressed by these filter layers. NO₂ was measured by the sampler with a sensitivity of 124.8 μg h/m³ (66 ppb h) and an accuracy of within ± 20%. It could be used for measuring personal exposure to NO₂ without interfering with the wearer's daily activities. Nitric oxide (NO) could be measured after a small modification to the sampler provided oxidation ability to the layers of diffusion filter. Three layers of hydrophobic fiber filter were replaced by 12 layers of glass fiber filter containing chromium trioxide solution. NO was oxidized to NO₂ in the oxidation layers and absorbed by the absorbent sheet together with the coexisting NO₂. Sensitivity and accuracy of the sampler for NO were nearly equal to that for NO₂.     

Is a voluntary approach an effective environmental policy instrument?: A case for environmental management systems

Using Japanese facility-level data from an OECD survey, we estimate the effects of implementation of ISO14001 and publication of environmental reports on the facilities’ environmental performance. While most previous studies focused on an index of emissions toxicity, this study examines three areas of impacts, none of which have been explored in the literature: natural resource use, solid waste generation, and wastewater effluent. The study is also unique in that the effectiveness of ISO14001 is considered in relation to environmental regulations. Our findings are summarized as follows. First, both ISO14001 and report publication help reduce all three impacts; the former appears more effective in all areas except wastewater. Second, environmental regulations do not weaken the effect of ISO14001. Third, assistance programs offered by local governments—a voluntary approach—promote facilities’ adoption of ISO14001. These findings suggest that governments can use command-and-control and voluntary approaches concurrently.     

Characteristics of dioxin emissions at startup and shutdown of MSW incinerators

Dioxin concentrations from municipal waste incinerators in Japan and elsewhere often show low concentrations that comply with legal limits (in this paper, the term "dioxin" designates WHO-TEQ: PCDD/Fs+dioxin-like PCB). However, such data is usually generated under normal steady state operational conditions, and there has been little investigation of releases occurring during startup and shutdown. It is important, therefore, to ascertain quantitatively emissions in an unsteady state (startup and shutdown) in order to correctly evaluate the relationship between emissions from a facility and the surrounding environment. The present study aimed to examine dioxin emissions of a continuously operated incinerator at startup and shutdown, and estimating the time period of greatest emission, and the processes causing dioxin generation. The startup process was divided into five stages and the shutdown into two; at each stage, dioxins in the flue gas were measured at the boiler outlet and the stack. From the concentration of dioxins and the flue gas volume at each stage, the amount of dioxins at startup and shutdown were calculated, and these were compared with that under steady state conditions. Dioxin concentration at the stack under steady state conditions was a very low level, while those at startup and shutdown were higher. In the case where dioxin concentration under a steady state is a low level like in this study, it is indicated that the total annual dioxin emission from a facility could be attributed to the startup periods.     

Regional-specific emission inventory for NH3, N2O, and CH4 via animal farming in South, Southeast, and East Asia

Ammonia, nitrous oxide, and methane emission from animal farming of South, Southeast, and East Asia, in 2000, was estimated at about 4.7 Tg NH₃–N, 0.51 Tg N₂O–N, and 29.9 Tg CH₄, respectively, using the FAO database and countries’ statistic databases as activity data, and emission factors taking account of regional characteristics. Most of these atmospheric components, up to 60–80%, were produced in China and India. Pakistan, Bangladesh, and Indonesia, which were large source countries next to China and India, contributed more than a few percent of total emission of each atmospheric component. The largest emission livestock were cattle whose contribution was considerably high in South, Southeast, and East Asia; more than one-fourth of ammonia and nitrous oxide emissions: more than half of methane emission. The other major livestock for nitrous oxide and ammonia emissions were pigs. For methane emission, buffaloes were second source livestock. To provide spatial distributions of these gases, the emissions of county and district level were allocated into each 0.5° grid by means of the weighting by high-resolution land cover datasets. The regions with considerable high emissions of all components were able to be found at the Ganges delta and the Yellow River basin. The spatial distributions for ammonia and nitrous oxide emissions were similar but had a substantial difference from methane distribution.     

Comparison of polybrominated diphenyl ethers in fish, vegetables, and meats and levels in human milk of nursing women in Japan

At present, little is known about the occurrence of polybrominated diphenyl ethers (PBDEs) in fish and food products sold in Japan. To investigate whether human exposure to PBDEs through the diet is significant, the concentrations of PBDEs were determined in fish and in meat and vegetables sold in two food markets in the city of Hirakata, Osaka prefecture. The concentrations of PBDEs in the breast milk of 12 primiparae nursing women at one month after delivery also were determined to ascertain the relationship between the levels found in the diet and levels in humans. sigma PBDE concentrations ranged between 21 and 1650 pg/g fresh weight in the edible tissues of five species of fish and one shellfish species. The highest concentrations were measured in yellow-fin tuna, followed by short-necked clam, salmon, yellowtail, mackerel and young yellowtail. Interestingly, sigma PBDE concentrations were not statistically significantly different in two cultured mackerel samples from Japan and mackerel collected from northern European waters. sigma PBDE concentrations in beef, pork and chicken meat (ranging between 6.25 and 63.6 pg/g fresh weight) and in three different vegetables (ranging between 38.4 and 134 pg/g fresh weight) were significantly lower than the concentrations in fish. In human milk, sigma PBDE concentrations ranged between 668 and 2840 pg/g lipid basis, which is comparable to the levels in populations of nursing women reported in Sweden and elsewhere. There was a strong positive relationship between PBDE concentrations in human milk and dietary intake of fish and shellfish, which was established in the women from responses to a questionaire on food consumption habits. The results of this study of food products commonly consumed in Japan and the levels found in nursing women raise a concern about low level PBDE contamination of fish and other foods intended for human consumption.     

Effect of polyethylene addition to coal on hydrogasification enhancement

Hydrogasification of a coal/polyethylene mixture was carried out using a low concentration of polyethylene in the samples with the aim of industrial application. Coal/polyethylene mixtures in the ratio of 90:10 and 75:25 were used in this study. A hydrogasification experiment was conducted using a unique batch reactor at 1073 K under a 7.1 MPa hydrogen atmosphere. The reaction time varied from 1 to 80 s. The results revealed a methane yield from the mixtures that was noticeably greater than the values calculated from experimental results obtained from coal and polyethylene respectively, assuming no mutual influences. A significant synergistic effect was observed even when the polyethylene content was as low as 10 %. It is suggested that there might be an advantage in hydrogasification processes if waste plastics are mixed with coal, such content being practically assumed.