Aggregated Estimation of Basic Parameters of Biological Production and Carbon Budget of Russian Terrestrial Ecosystems: 3. Biogeochemical Carbon Fluxes

The biogeochemical cycle of organic carbon in Russian terrestrial ecosystems in 1990 is considered. Its components have been estimated as follows: net primary production, 4354 million metric tons of carbon (Mt C); annual amount of plant detritus, 3223 Mt C; heterotrophic soil respiration, 3214 Mt C; biomass utilization, 680 Mt C; damage to vegetation caused by fire and pests, 140 Mt C; and removal by surface and ground waters, 79 Mt C. Anthropogenically regulated fluxes of organic carbon (820 Mt C) are comparable to its amount involved in the natural cycle.     

A method for measuring the potential dermal exposure to methyl methacrylate during two different dental technical work tasks

Dental technicians are exposed on a daily basis to undiluted methyl methacrylate (MMA) when performing various routine tasks. Although the clinical effects of this chemical have been known for decades, no previous studies have been performed to estimate the potential dermal exposure to it. In this study we describe a patch-sampling technique to intercept the MMA that would otherwise have contaminated the skin on different parts of the hand and lower arm. Two different work tasks, making an orthodontic splint and denture preparation, were both performed under simulated workplace conditions twice by two recent graduated dental technicians. Air measurements were collected simultaneously. The results indicate that the exposure patterns associated with producing an orthodontic splint and denture preparation differed. We found work task-dependent differences in the amounts of MMA collected at the different parts of each hand, and differences between the right and left hands. There was also an interaction between hand and work task, especially for the right hand. The air measurements were positively correlated with the dermal exposure. This study highlights the importance of using a measurement strategy that takes the variability within the hand/arm body parts into account when measuring potential exposure during these kinds of work tasks. In order to establish future dermal exposure limits, more workplace and experimental studies are required.     

A chemosorptive cylindrical denuder designed for personal exposure measurements of isocyanates-evaluation on generated aerosols of 4,4'-methylenediphenyl diisocyanate

A denuder/filter system constructed for solvent-free personal exposure measurements was evaluated for separation of vapour and particulate 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) generated from heated PUR-foam. The two different phases were collected in the denuder and on the filter, respectively, by chemosorption on a polydimethylsiloxane (SE-30)-dibutylamine (DBA) stationary phase. Both repeatability and the total mass concentration of 4,4'-MDI were similar to that obtained from the reference method, in this case an impinger/filter system. The penetration of particles through the denuder at 300 ml min(-1) was nearly 100% in the particle size range 25 to 700 nm, which fits well with the Gormley-Kennedy equation. Denuder/filter sampling of the 4,4'-MDI aerosol at 500 ml min(-1) yielded a phase distribution that was in accordance with the results from the reference method. The method limit of detection was 6 ng m(-3) and 4 ng m(-3) for the denuder and filter, respectively, when using an air sampling flow rate of 300 ml min(-1) and a sampling period of 15 min. This is well below the Swedish occupational exposure limit (OEL) of 50 and 100 microg m(-3) for an 8-hour working day and a 5-min period, respectively.     

Solid chemosorbent for sampling sub-ppm levels of acrolein and glutaraldehyde in air

A personal air sampling method using Amberlite XAD-2 coated with 2,4-dinitrophenylhydrazine has been developed for acrolein and glutaral dehyde. Acrolein in the 0.01 to 1.2 mg/m³ range or glutaraldehyde in the 0.03 to 3.5 mg/m³ range is easily analysed in a 5 1 air sample. Recoveries are high (80–100%), and samples stable at least for two weeks if stored in the dark until analysed.     

Synthesis of halogenated diphenyl ethers and dibenzofurans - A discussion of specific isomers available

Synthetic routes for the preparation of halogenated diphenyl ethers and dibenzofurans are reviewed, and isomers reported in the literature are listed. In addition, the routes preferred for the synthesis of specific chlorinated isomers - especially from the point of view of an unambiguous structural assignment - are discussed in detail. The route recommended for chlorinated diphenyl ethers is the coupling of biaryliodonium salts with phenols, and for chlorinated dibenzofurans the palladium acetate-promoted cyclization of diphenyl ethers. Chlorinated isomers of diphenyl ethers and dibenzofurans which are available via these routes are listed. Furthermore, the synthesis of a new octachlorodiphenyliodonium salt and its coupling with three different chlorophenols are described, and the cyclization of an octachlorodiphenyl ether to octachlorodibenzofuran is shown.     

Sampling of epichlorohydrin and ethylene chlorohydrin in workroom air using Amberlite XAD-7 resin

Activated charcoal, Amberlite XAD-2 and Amberlite XAD-7 were evaluated for the adsorption of epichlorohydrin and ethylene chlorohydrin from air followed by desorption with solvent. Ethylene chlorohydrin was found to be unstable on activated charcoal in the presence of carbon disulfide. Recoveries from XAD-2 were low, and XAD-7 was found to be the best adsorbent for the sampling of these compounds from air.     

Greening of a campus restaurant at Stockholm University: sustainable development audits by means of the SDR methodology

The aim of this paper is to show how the environmental practices of a restaurant may be evaluated in a quantitative way. For this, a new methodology, sustainable development records (SDR), was used. This allows financial, environmental and social aspects of an operation to be handled in a systematic way. The results of the two sustainable development audits show that the restaurant washes more dishes per unit of chemicals used in 1994 than in 1991. However, there is a negative trend regarding the number of meals served per unit of water used and waste generated, which suggests that the restaurant in 1994 is more wasteful with these resources than in 1991. On the other hand, this might be explained by the fact that the restaurant has increased its use of primary products. The environmental ratios are increasing for both chemicals and energy, which means that more and more of the resources used are environmentally acceptable. The lowest environmental ratios are those for provisions (<2%) and transportation (<5%), which means that not more than 2% of the provisions and 5% of the transportation are environmentally acceptable in the long run. The restaurant's ratio of satisfied customers as well as its environmental image is improving, while the profitability has not changed. The results of this paper point to a general problem of environmental auditing in regard to the evaluation of perceived positive or negative developments of an individual enterprise, since there might be an opposite implication for the larger system. It is therefore crucial to look at several hierarchical levels in order to be able to assess the effects of environmental measures.