Sampling and analysis of particulate and gaseous polycyclic aromatic hydrocarbons from coal tar sources in the working environment

A sampling method for polycyclic aromatic hydrocarbons (PAH) in workplace atmospheres using a standard glass fiber filter with a back-up section of Amberlite XAD-2 is described. Filters and XAD are solvent-desorbed and, without further clean-up, the solutions are submitted to high performance liquid chromatographic analysis using fluorimetric detection. Recovery of PAH from XAD-2 was studied, and was found to be in the range 80–100%. The sampling method was evaluated in a coke plant, an aluminium plant and in a creosote impregnating plant. The method described is rapid and sensitive for the determination of the most important workplace PAH, and accounts for both particulate and gaseous PAH.     

Coping with uncertainty: a call for a new science-policy forum

The scientific and policy worlds have different goals, which can lead to different standards for what constitutes "proof" of a change or phenomena, and different approaches for characterizing and conveying uncertainty and risk. These differences can compromise effective communication among scientists, policymakers, and the public, and constrain the types of socially compelling questions scientists are willing to address. In this paper, we review a set of approaches for dealing with uncertainty, and illustrate some of the errors that arise when science and policy fail to coordinate correctly. We offer a set of recommendations, including restructuring of science curricula and establishment of science-policy forums populated by leaders in both arenas, and specifically constituted to address problems of uncertainty.     

Sampling and analysis of polycyclic aromatic hydrocarbons (PAH) from two-stroke chain-saw engines

A sampling and analysis method for PAH from two-stroke engines is described. The method, which uses a standard glass fiber filter with a back-up section of Amberlite XAD-2 for sampling and GC or GC-MS for analysis, is suitable for both emission studies and occupational studies during logging. Filters and XAD-2 are desorbed with cyclohexane in an ultrasonic bath. After separation on a silica-gel micro column, the samples are submitted to analyses by capillary GC. The method is simple and covers both gaseous and particulate PAH. Naphthalene and alkyl substituted naphthalenes are also quantified.     

An alternative role for economic instruments: Sustainable finance for environmental management

Economic instruments, such as effluent fees and tradable discharge permits (TDP), have often been suggested by economists as efficient or cost-effective means to control pollution. In recent years such instruments have received increasing attention due to their growing political acceptability. Still, their use in practice has been tentative. The interest in possible application of such instruments has led to a set of studies regarding their practical potential. These studies indicate that economic instruments require substantial government involvement, entailing high administration cost; require restrictions so as to prevent significant deterioration in receptor areas; and have ambivalent effects on innovation adoption. Consequently, the efficiency gains from such instruments may be smaller than potential gains identified in earlier studies. In addition, the distributional impacts of such instruments and their possible adverse effect on market contestability reduce their attractiveness in some cases. These findings raise the question: what is the desired role of economic instruments in addressing environmental concerns? In recent years the demand for environmental services has increased dramatically. Current legislation and studies indicate that desired environmental expenditures are likely to increase. At the same time environmental programs face increasing competition from other programs for a declining pool of general revenues. One outcome of these processes has been the search for alternative sources of funds for environmental programs. Furthermore, as the competition for general revenue funds increases, the allocation of such funds for environmental programs becomes less predictable. This may endanger many long-term environmental programs that require stable funding. This article suggests that economic instruments may prove one source of dedicated funds for many environmental goals. Consequently, studies of environmental-program financing as well as studies of economic instruments may well explore the possible role of economic instruments as financing tools. Some examples of the potential of such tools for estuary cleanup programs are discussed.     

Passive sampling in combination with thermal desorption and gas chromatography as a tool for self-assessment of chemical exposure

Diffusive samplers for monitoring of air quality are user-friendly devices that can normally be operated by the user himself. Hence these samplers are suitable for self-assessment. Practical and work organisational aspects of self-assessment of chemical exposure were studied in different occupational settings. It was found that the diffusive sampler used in these studies, the Perkin-Elmer tube in combination with thermal desorption, worked well for the purpose and could be correctly handled by the individuals using it. The results from self-assessments agreed well with expert measurements carried out by an occupational hygienist. However, in order to obtain a sustainable system of self-assessment strong organizational support is needed.     

Hydrogen gas production in a microbial electrolysis cell by electrohydrogenesis

Electrohydrogenesis is a bio-electrochemical process where organic material is microbially oxidized to protons and electrons, which in turn are reduced to form hydrogen gas (H₂). The reactor in which these reactions occur is termed a microbial electrolysis cell (MEC). The microorganisms that colonize the anode are known as electricigens and behave as biological catalysts, significantly reducing the energy required to drive this process. Electricigens are capable of complete substrate degradation, leading to very high cathodic H₂ recovery efficiencies from sources previously considered organic waste. In this short review, the origination of the bio-electrochemical system (BES) is introduced, mechanisms for electron transfer between microbe and electrode are discussed, the challenges these electrochemical systems face are presented, and finally an overview of current MEC systems and their respective performance is evaluated. Electrohydrogenesis has established itself as a promising technology for sustainable H₂ production from renewable sources.