Theoretical studies of the conformations and 19F NMR spectra of linear and a branched perfluorooctanesulfonamide (PFOSAmide)

Technical perfluorooctanesulfonate (PFOS) and its derivatives, such as perfluorooctanesulfonamide (PFOSA), are not clean compounds but, instead, complex mixtures of linear and branched isomers, and other compounds including sulfonate homologues. Questions have been raised as to whether the linear and the branched isomers behave differently in the environment. However, little is known about the physical properties or the finer details of the structures of the individual branched isomers. This study sought an effective computational method to model the preferred conformations of PFOS derivatives, and the energy differences between them and to determine if these results can be used to explain the temperature dependence of their NMR spectra. Good predictions of the 19F chemical shifts were obtained for some PFOSA-type molecules with a computational approach [B3LYP-GIAO/6-31++G(d,p)//B3LYP/6-31G(d,p)] that is relatively inexpensive. Large 5JFF couplings found in one of the branched isomers could be rationalized on the basis of the relevant F-F distances in the optimized structure. At low temperatures, the splitting observed in the NMR spectrum at C-1 for these sulfonamides can be explained by the existence of the two conformers predicted by the computations.     

Socioeconomic consequences of mercury use and pollution

In the past, human activities often resulted in mercury releases to the biosphere with little consideration of undesirable consequences for the health of humans and wildlife. This paper outlines the pathways through which humans and wildlife are exposed to mercury. Fish consumption is the major route of exposure to methylmercury. Humans can also receive toxic doses of mercury through inhalation of elevated concentrations of gaseous elemental mercury. We propose that any effective strategy for reducing mercury exposures requires an examination of the complete life cycle of mercury. This paper examines the life cycle of mercury from a global perspective and then identifies several approaches to measuring the benefits of reducing mercury exposure, policy options for reducing Hg emissions, possible exposure reduction mechanisms, and issues associated with mercury risk assessment and communication for different populations.     

Nuclear magnetic resonance spectral characterization and semi-empirical calculations of conformations of alpha- and gamma-1,2,5,6,9,10-hexabromocyclododecane

The full 1H and 13C NMR spectral characterization of alpha- and gamma-1,2,5,6,9,10-hexabromocyclododecane (HBCD) is reported in this paper. The use of various NMR experiments, an analysis of the magnitude of the NMR chemical shifts and coupling constants, and computer modeling has enabled the visualization of the three-dimensional structures for both the alpha- and gamma-diastereomers. This information may provide insight into the different behavior of the alpha- and gamma-HBCD diastereomers in the environment.     

Firm incentives to promote technological change in pollution control: Comment

Following on from an analysis by Milliman and Prince, this article considers further the relative incentives for technical change provided by different pollution control instruments. The comments involve the recognition that emission targets are typically chosen fairly arbitrarily because of regulators' lack of knowledge of abatement cost schedules. There is also a more detailed discussion of the practicability of auctioning emissions permits, as these have been less thoroughly covered in the literature than the other instruments.     

Questioning the Waste Hierarchy: The Case of a Region with a Low Population Density

Discussions of municipal solid waste (MSW) management are influenced increasingly by the concept of the waste hierarchy which, broadly speaking, places landfill as the least acceptable option for dealing with MSW, followed by incineration, recycling, re-use and reduction at source. In this paper, we want to question the wisdom of applying the waste hierarchy in a region with a low population density. The hierarchy was first developed with reference to the high population density areas such as the core of the EU. However, in low population density areas the economics of the various approaches to MSW is likely to be quite different. As a result, the application of the hierarchy could place an undue economic burden on a region relative to the environmental benefits that might arise. We estimate the costs, both internal and external, of the various methods of dealing with MSW in an area with the appropriate population density, drawing on information from a wide variety of sources. We find that landfill is significantly cheaper than in high population density areas, even when account is taken of the associated externalities. In addition, it is generally cheaper than the alternative methods. As such, we conclude that landfill should not be shunned as a disposal method in low population density areas.     

CDM Projects under the Kyoto Protocol: A Methodology for Sustainability Assessment – Experiences from South Africa and Uruguay

Under the Clean Development Mechanism (CDM) of the Kyoto Protocol, industrialised countries may finance greenhouse gases mitigation projects in developing countries. The Kyoto Protocol explicitly requires that the CDM shall assist developing countries to achieve sustainable development. However, a clear definition of sustainability for CDM projects is still debatable. MATA-CDM (Multi-Attributive Assessment of CDM Projects) is an approach that facilitates a quantitative assessment of potential projects regarding their contribution to sustainable development. This paper presents applications of MATA-CDM in two different countries. In South Africa, the application was done mainly for academic and demonstrative purposes, whereas in Uruguay it was implemented together with the responsible Designated National Authority (DNA). The work in both countries included the selection of sustainability criteria and measurable indicators. Experts weighted the criteria using personal interviews and a multi-stakeholder workshop. This method was applied to three potential CDM projects in South Africa and one in Uruguay. Results show that under the conditions of this study, the MATA-CDM approach yet fails to yield a perfect quantitative overall sustainability assessment of CDM projects but that several findings could be useful to further develop the approach with the aim to translate the vague term sustainable development to a mainstream project level. Valuable experience was in particular collected with different stakeholder processes to perform criteria weighting.     

Improving food security in Swaziland: The transition from subsistence to communally managed cash cropping

The Komati Downstream Development Project (KDDP), based upon the Maguga Dam has enabled 6,000 hectares of semi‐arid lowveld, in a region with low and highly variable rainfall to be converted from subsistence to irrigated commercial farming, mainly of sugar cane. This has transformed the Swazi sugar industry from one dominated by a small number of large‐scale commercial estates to one where more than 1,500 previously impoverished small‐scale Swazi farmers have been able to enter the industry by joining farmers’ associations and creating communally managed farms. Recent changes to the EU's Sugar Protocol have undermined the financial viability of the KDDP farms and undermined food security, especially for the poorest, due to the cut in sugar prices. However, some farmers’ associations have opted to keep some of their land as irrigated home gardens, rather than convert all their land to sugar cane. This model has improved food security at a time of low sugar prices and points to a more sustainable way of using water from large scale dams than the conventional model. It is argued that the EU should target support to members of the KDDP who have taken out large‐scale loans to pay for the in‐field infrastructure and encourage all farmers’ associations to adopt the food garden model. This would enable them to continue to benefit from the irrigation through improved production of subsistence crops, whilst they diversify their commercial production into novel markets.     

Does planning deregulation threaten the environment? The effect of ‘permitted development’ on the natural heritage of Scotland

This paper reports research into the effect on the UK environment of the deregulation of land development controls. One form of deregulation is granting advance approval to specified classes of small-scale development because they are considered inconsequential. Previous research has indicated that such ‘permitted development’ may adversely affect the natural heritage. This study systematically investigated its impact on the natural heritage of Scotland. The study canvassed the opinions of agents best placed to comment: natural heritage authority field staff, local government planners and representatives of non-governmental organizations. The results revealed concern about permitted development as a whole, and about specified classes. Despite professed concerns about sustainable development, UK planning modernization has failed to grasp the opportunity for a radical and fundamental reform of the scope of UK planning control in the context of contemporary environmental issues. Accordingly, there remains an unresolved tension between the desire to remove unnecessary state regulation of land development and the protection of the natural heritage.