Yuko Soma

Effects of salinity, pH and temperature on aqueous solubility of four organotin compounds

Abstract The aqueous solubility of four organotin compounds, such as tributyltin chloride (TBTCl), bis(tributyltin) oxide (TBTO), triphenyltin chloride (TPTCl) and bis(triphenyltin) oxide (TPTO) was determined at various salinity, pH and temperature. The solubility of these compounds decreased with increasing the salinity. It also changed at different pH and was minimum in the pH range of 6–8. The solubility at 10°C was about half of that at 25°C. The minimal solubility of TBTs and TPTs in artificial seawater at 25°C was 1.0 mg Sn 1 −1 at pH 6–8 and 0.3 mg Sn 1 −1 at pH 7–8 and in distilled water at 25°C was 15 mg Sn 1 −1 at pH 7–8 and 0.8 mg Sn 1 −1 at pH 7–8, respectively.

Photosynthetic pigments and perylene in the sediments of southern basin of Lake Baikal

Depth profiles of carotenoids, chlorophylls and related pigments in the sediments of the southern basin of Lake Baikal were analyzed. The photosynthetic pigments were found to be preserved through the sediment cores which spanned several hundreds years. Pigments originating from green algae, diatoms, Cryptophyceae and cyanobacteria were abundant in the sediments and a major part of chlorophylls a and b were preserved as pheophytin. Biogenic perylene was detected throughout the core layers and its presence indicates that the sediment had been anoxic.

Behavioral effects of trichloroethylene and tetrachloroethylene in mice.

This study was performed to clarify the toxicological profiles of trichloroethylene (TRCE) and tetrachloroethylene (TECE) when they are administered intraperitoneally in mice. The ED50 for loss of righting reflex were 2596 mg/kg in TRCE and 4209 mg/kg in TECE. TRCE and TECE impaired bridge test performance at 500 and 2000 mg/kg, respectively. An operant behavior performance was also inhibited by TRCE at 1000 mg/kg and by TECE at 2000 mg/kg. Both TRCE and TECE exhibited anticonflict effects in a Vogel-type task at 500 mg/kg. This effect was confirmed by the finding that TRCE exhibited anticonflict action in a Geller-type paradigm at 250 mg/kg and more, as did TRCE did at 1000 mg/kg. These results show that TRCE and TECE affect various behaviors in mice and suggest that conflict behaviors are one of the most sensitive behavioral indicators of the effects of these substances. The toxicological profiles of TRCE and TECE with respect to behavioral effects were very similar, and they can be classified in a single category.

Resonance Raman spectra of benzene adsorbed on Cu2+-montmorillonite. Formation of poly(p-phenylene) cations in the interlayer of the clay mineral

Abstract Resonance Raman spectra of benzene adsorbed on Cu 2+ - and Ru 3+ -montmorillonites have demonstrated the formation of poly( p -phenylene) cations in the interlayer of the clay mineral. The interlayer cation is reduced in a humid atmosphere to yield poly( p -phenylene). Biphenyl or p -terphenyl gives consistently the same product.

The oxidative polymerization of aromatic molecules in the interlayer of montmorillonites studied by resonance Raman spectroscopy

Abstract The adsorption and reaction of aromatic molecules in the interlayer of transition-metal ion(Cu 2+ , Fe 3+ , Ru 3+ )-exchanged montmorillonites have been investigated by resonance Raman spectroscopy. Some mono-substituted benzenes are found to form cation radicals of 4,4′-substituted biphenyl together with those having the composition of the parent molecules. Benzene, biphenyl and p-terphenyl polymerize to form the poly-p-phenylene cation. Thus, the cation radicals or cations may remain stable when para-positions of the benzene ring are occupied by a stable substituent, or undergo polymerization when the para-position is open. Phenols behave differently in that the polymerization via the ortho-position also occurs and the reaction is faster in aerobic than in anearobic conditions.

Raman spectroscopic evidence of formation of p-dimethoxybenzene cation on Cu- and Ru-montmorillonites

Abstract It has been demonstrated through Raman spectroscopy that p -dimethoxybenzene (DMOB) is stably adsorbed on Cu- and Ru-montmorillonites as a cation. DMOB adsorbed is oxidized by Cu 2+ ion in a dry atmosphere and is reduced reversibly in the presence of water vapor, the process being represented by a reversible reaction: Cu 2+ (H 2 O) n + DMOB ⇌ Cu + (H 2 O) n-m + DMOB + + m H 2 O.

Application of an integrated PrepStation–GC-NPD system to automated continuous measurement of formaldehyde and acetaldehyde in the atmosphere

An integrated PrepStation-gas chromatography-nitrogen phosphorus detection (GC-NPD) system was used for the fully automated, continuous, low parts per billion analysis of lower aldehydes in the atmosphere. Analysis involved a solid phase extraction procedure based on the collection of aldehydes from air pumped through a silica gel cartridge impregnated with acidified 2,4-dinitrophenylhydrazine (DNPH). Automated continuous measurements were performed with a typical temporal resolution of 3 h, including 146 min for sampling of air at a constant air flow rate of 0.15 L min(-1) and 34 min for the preparation and extraction of several cartridges. Analysis of samples could be performed in parallel by using previously defined scheduler settings from separate, independent software to operate the PrepStation module. GC-NPD measurements were highly repeatable, and relative standard deviations were < 3.0%. Recoveries for all compounds were 88-101%. DNPH decomposition products did not adversely affect the quantitative determination of aldehyde DNPHs; therefore, it was not necessary to remove excess DNPH reagent. The limits of quantification (10sigma of the blank hydrazones) of formaldehyde and acetaldehyde were 2.2 and 1.2 ppb, respectively, for 21.9 L (0.15 L min(-1) for 146 min) of air sample volume. The integrated PrepStation GC-NPD system gave results comparable to those of the Sep-Pak DNPH silica cartridge method.

The influence of indoor air on personal exposure to volatile organic compounds and its risk estimation

This paper summarizes the results of personal exposure monitoring and estimates the risk from exposure to 18 volatile organic compounds compared with health criteria set by the US Environmental Protection Agency. In study 1, personal exposure levels and outdoor air concentrations were compared, and in study 2, personal exposure levels and the corresponding indoor air concentrations were compared. From these studies, it was concluded that personal exposure to volatile organic compounds depended markedly on indoor air quality and that handling of compounds increased personal exposure markedly. Risk estimations indicated that chloroform in tap water, benzene from cigarette smoke and p -dichlorobenzene from household insecticide needed caution.

The determination of carbonyl compounds inair using a robotic sampling preparation system integrated to a gas chromatographwith a nitrogen–phosphorus detector

A totally automated solid phase extraction gas chromatography procedure was developed for the sampling and analysis of carbonyl compounds in air. In this system, two PrepStation modules were used, one for the preparation and elution of 2,4-dinitrophenylhydrazine silica cartridges, and the other for air sampling. The sample collected by the sampling module was eluted to an autosampler vial in the PrepStation module and then transferred to the gas chromatograph for analysis via a robotic arm. The sampling module was modified to enable air sampling via an external pump. A typical run by this technique required 142 min, 100 min for air sampling and 42 min for the other operations, including a GC analysis time of 25 min. Recoveries of at least 85% were obtained for all compounds studied. The detection limits for formaldehyde, acetaldehyde and acetone were 2.2, 2.7 and 2.2 ppbv, respectively. All operations, including the conditioning of the cartridges, were performed without any intervention from the analyst.

Source and material balance of total organic halogen pollution in the Ayase River system, Japan

The total organic halogen (TOX) pollution in the highly polluted Ayase River system was investigated. Using the concentration of coexisting linear undecylbenzenesulfonate and the difference in the flowing water volume between summer and winter, the fractions of domestic and agricultural wastewaters in the whole water column were calculated and the variety of the TOX sources in the river was estimated. The river carried about 100 kgCl of TOX materials in one day; about 50 kgCl of the materials was from residential area in the basin. The contribution of agricultural drainage from paddy field was not negligible in summer. Highly contribution of industrial wastewater was observed in a tributary Furuayase River basin while the amount of TOX loaded in the area was widely varied; 0–105 kgCl of the materials was discharged as industrial wastewater.