Field Survey of Trans-boundary Air Pollution with High Time Resolution at Coastal Sites on the Sea of Japan during Winter in Japan}

An intensive field survey, with 6-h measurement intervals, of concentrations of chemical species in particulate matter and gaseous compounds was carried out at coastal sites on the Sea of Japan during winter. The concentration variation of SO₂(g) and HNO₃(g) were well correlated, whereas the NH₃(g) concentration variation had no correlation with those of SO₂(g) and HNO₃(g). The NH₄ ⁺ (p)/non-sea-salt- (nss-)SO₄ ^{2 −}(p) ratio in particulate matter was mainly affected by the location of the sampling site. One or more concentration peaks of nss-Ca^{2 +} for survey period were observed. Backward trajectories analyses for the highest nss-Ca^{2 +} concentration peaks showed some inconsistency in pathways. We consider that insufficient mixing of the atmosphere and/or insufficient time for the transported air pollutants to react with those discharged locally are the most likely explanations for the discrepancies between the measured products [HNO₃][NH₃] and the calculated values.     

Analysis of branched-chain fatty acids in humic substances as indices for compost maturity by pyrolysis–gas chromatography/mass spectrometry with tetramethylammonium hydroxide (TMAH-py–GC/MS)

Parameters that affect the degree of humification for humic substances (HSs) are deeply related to the maturity of the compost. In general, the matured composts contain HSs with a higher degree of humification. In addition, microbial activities during composting are also one of the indices for compost maturation. Branched-chain fatty acids are metabolites as the result of microbial activities in a soil environment. Such branched-chain fatty acids, regarded as humic precursors, are incorporated into HSs during the composting process. To determine whether branched-chain fatty acids in HSs can be used as biomarkers during composting processes or not, HSs were extracted from three types of composts with the different maturation, and the branched-chain fatty acids in the HSs were analyzed by pyrolysis–gas chromatography/mass spectrometry with tetramethylammonium hydroxide (TMAH-py–GC/MS). HSs with a higher degree of humification (higher aromaticity and lower molecular weight) contained higher levels of branched-chain fatty acids. These results show that branched-chain fatty acids in HSs from matured compost samples can be used as biomarkers, which indicate the history of microbial activities during overall composting process.     

Development of a testing method for asbestos fibers in treated materials of asbestos containing wastes by transmission electron microscopy

Appropriate treatment of asbestos-containing wastes is a significant problem. In Japan, the inertization of asbestos-containing wastes based on new treatment processes approved by the Minister of the Environment is promoted. A highly sensitive method for testing asbestos fibers in inertized materials is required so that these processes can be approved. We developed a method in which fibers from milled treated materials are extracted in water by shaking, and are counted and identified by transmission electron microscopy. Evaluation of this method by using asbestos standards and simulated slag samples confirmed that the quantitation limits are a few million fibers per gram and a few μg/g in a sample of 50 mg per filter. We used this method to assay asbestos fibers in slag samples produced by high-temperature melting of asbestos-containing wastes. Fiber concentrations were below the quantitation limit in all samples, and total fiber concentrations were determined as 47–170 × 10^?6 f/g. Because the evaluation of treated materials by TEM is difficult owing to the limited amount of sample observable, this testing method should be used in conjunction with bulk analytical methods for sure evaluation of treated materials.     

Reaction hazards of triethylaluminum under closed conditions

We evaluate the reaction hazards of triethylaluminum (TEA) under closed conditions for safe treatment of aluminum alkyls. The explosive reactions of TEA are difficult to be estimated using thermal analysis because the estimate reactions are too slow under these conditions. The results of our closed vessel tests and chemical equilibrium calculations show that the TEA and water system mixture in closed conditions decomposes into lower-molecular-weight compounds than the products by using well-known hydrolysis of TEA. The present work also demonstrates that large temperature and pressure increases could occur because of the existence of TEA and aluminum hydroxide. Since aluminum hydroxide contains water as alumina hydrates, aluminum hydroxide could have been the source of water at high temperatures and could have contributed to the mixed reaction between TEA and water.     

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solid electrode

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solidelectrode was studied. As solid electrodes, carbon cloth (CC), carbon felt (CF) and titanium mesh were used, and palladium was plated on solid electrodes by either electrolytic or electroless method. On each electrode with Pd, chlorophenols were qualitatively dechlorinated to phenol, while they were entirely intact on electrodes without Pd. Moreover, neither base electrode nor plating method significantly affected the activity of Pd as far as it was sufficiently loaded on the electrode. Based on the results in the experiments using one electrode repeatedly, Pd catalyst proved to possess a satisfactory duarability under the present condition. It was suggested that the reactive species responsinble for the dechlorination of chlorophenols could be formed during preliminary electrolysis. Thus, (Pd)_x-H resulting from the adsorption of electrogenerated hydrogen on metallic Pd might be assumed most probable.     

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solid electrode

Electroreductive dechlorination of chlorophenols with Pd catalyst supported on solidelectrode was studied. As solid electrodes, carbon cloth (CC), carbon felt (CF) and titanium mesh were used, and palladium was plated on solid electrodes by either electrolytic or electroless method. On each electrode with Pd, chlorophenols were qualitatively dechlorinated to phenol, while they were entirely intact on electrodes without Pd. Moreover, neither base electrode nor plating method significantly affected the activity of Pd as far as it was sufficiently loaded on the electrode. Based on the results in the experiments using one electrode repeatedly, Pd catalyst proved to possess a satisfactory duarability under the present condition. It was suggested that the reactive species responsinble for the dechlorination of chlorophenols could be formed during preliminary electrolysis. Thus, (Pd)_x-H resulting from the adsorption of electrogenerated hydrogen on metallic Pd might be assumed most probable.     

In situ measurement of isoprene in the marine air and surface seawater from the western North Pacific

Isoprene (2-methyl-1,3-butadiene) was measured on board of R/V Mirai for eight air samples and 14 seawater samples collected in the western North Pacific during ACE-Asia campaign (from 18 to 26 May 2001). The measurements were conducted in situ using a cryo-focus/gas chromatography/mass spectrometry (Cryo/GC/MS). Concentrations of isoprene ranged from 7.2 to 110 parts-per-trillion (pptv) in the marine air, and ranged from below 12 to 94 pmol l⁻¹ in the seawater. Based on these results, sea-to-air fluxes of isoprene were calculated to be 184 and 300 nmol m⁻² day⁻¹ for two samples, and the upper limits of the fluxes were also calculated to be from 32 to 300 nmol m⁻² day⁻¹. Atmospheric isoprene concentrations cannot be explained only by the flux from the seawater. Thus, the concentrations of isoprene in the marine air in western North Pacific should be significantly affected by terrestrial vegetational emission and subsequent long-range atmospheric transport of isoprene.     

Electrostatic hazards of charging of bedclothes and ignition in medical facilities

We investigated the charge generated on bedclothes (cotton and polyester) during bedding exchange with different humidities and the ignitability of an alcohol-based hand sanitizer (72.3 mass% ethanol) due to static spark with different temperatures to identify the hazards of electrostatic shocks and ignitions occurring previously in medical facilities. The results indicated that charging of the polyester bedclothes may induce a human body potential of over about 10?kV, resulting in shocks even at a relative humidity of 50%, and a human body potential of higher than about 8?kV can cause a risk for the ignition of the hand sanitizer. The grounding of human bodies via footwear and flooring, therefore, is essential to avoid such hazards (or to reduce such risks).     

Characteristics of cesium accumulation in the filamentous soil bacterium Streptomyces sp. K202

A filamentous soil bacterium, strain K202, was isolated from soil where an edible mushroom (Boletopsis leucomelas) was growing and identified as belonging to the genus Streptomyces on the basis of its morphological characteristics and the presence of LL-2, 6-diaminopimelic acid. We studied the existence states of Cs and its migration from extracellular to intracellular fluid in the mycelia of Streptomyces sp. K202. The results indicated that Cs accumulated in the cells through at least 2 steps: in the first step, Cs⁺ was immediately and non-specifically adsorbed on the negatively charged cell surface, and in the second step, this adsorbed Cs⁺ was taken up into the cytoplasm, and a part of the Cs entering the cytoplasm was taken up by an energy-dependent transport system(s). Further, we confirmed that a part of the Cs⁺ was taken up into the mycelia competitively with K⁺, because K⁺ uptake into the intact mycelia of the strain was significantly inhibited by the presence of Cs⁺ in the culture media. This suggested that part of the Cs is transported by the potassium transport system. Moreover, ¹³³Cs-NMR spectra and SEM-EDX spectra of the mycelia that accumulated Cs showed the presence of at least 2 intracellular Cs states: Cs⁺ trapped by intercellular materials such as polyphosphate and Cs⁺ present in a cytoplasmic pool.