12th EuCheMS International Conference on Chemistry and the Environment

Environmental Science and Pollution Research -     

Bimodal orientation and the occurrence of temporary reverse bird migration during autumn in south Scandinavia

Extensive ringing data from a coastal site (Falsterbo Bird Observatory) in southwesternmost Sweden were used to investigate the occurrence of reverse autumn migration among 20 passerine bird species of widely different migration categories. The data demonstrate that reverse migration is a widespread and regular phenomenon among nocturnal as well as diurnal migrants and among irruptive migrants, temperate zone migrants, and long-distance migrants destined for tropical winter quarters. The reoriented movements were directed approximately opposite to the normal migration direction, i.e. between NNW and ENE from the coast and towards inland. Median distances of reverse movements varied between 9 and 65 km. Some individuals of irruptive and partial migrants settled to winter in the reverse direction. Bird species with relatively small fat reserves at capture were more likely to perform reverse migratory movements than species with larger fat deposits. In two species birds performing forward migration were significantly heavier within 10 days after capture than individuals performing reverse movements. The reoriented movements probably are of adaptive significance for birds confronted with the sea and pre-disposed to refuelling during migration. A bimodal orientation mechanism will bring the birds from an area with high competition for food and high predation risk to more suitable resting and feeding grounds before resuming migration in the forward direction and crossing the barrier. Received: 11 July 1995/Accepted after revision: 19 November 1995     

Farmers’ markets – linking food consumption and the ecology of food production?

Urban and industrialised societies usually involve little connection between consumers and the resource base upon which the production of goods depends. Changing this situation could potentially enhance social and ecological sustainability. This study explored ecological aspects of the educational role of local food supply, with the aim of identifying signs of enhanced consumer understanding or awareness of the ecology of food production resulting from producer–consumer interaction. A series of qualitative interviews were carried out with customers at a farmers’ market in Stockholm. The results showed that the interviewees were mainly concerned with quality, price and taste, and not production conditions. In addition, a number of interviewees experienced a sense of trust when shopping at the market. We found few examples of contributions to ecological knowledge among customers at the market, but there were some examples of learning opportunities. The local food supplied by the market reminded customers of the seasonality of production. Stallholders also provided information on how to store, prepare and cook vegetables, which may encourage a change in diet that is preferable from an environmental standpoint.     

Social sustainability – society at the intersection of development and maintenance

Since the late 1980s, much of the debate on sustainability has been dominated by ecological perspectives. However, the last decade has seen an increasing interest in the social aspects of sustainability. While, to some extent, general consensus has been reached regarding the definitions of ecological sustainability, the definition of social sustainability is still in the making. Therefore, there is a need for conceptual frameworks and theoretical constructs in order to develop the understanding of social sustainability further. This article addresses the lack of theorisation and is composed of three different sections. The first section is a literature overview covering some of the most influential texts on social sustainability. The second section introduces and relates a number of existing, polemically constructed theoretical frameworks. In the third section, Jacques Derrida's theory of différance is used to suggest a way of understanding the relationship between the oppositional positions identified in the frameworks.     

Simple elimination models: Theoretical estimates of the effect of variations in elimination rates

This paper analyses the effect of variations in the elimination rates of four elimination models. Three types of variations are studied: (1) a periodic change between two elimination rates; (2) changes between two elimination rates at random times; and (3), an elimination rate varying smoothly in time, generated by having the elimination rate vary exponentially with temperature and a sinusoidally varying temperature. The elimination process is described by four different models: (1) a single compartment; (2) two compartments in parallel; (3) two compartments in series; and (4) the Goldstein-Elwood model. It is shown that for all 12 cases, the solutions can be given the same form as with constant elimination rates through reinterpretation of the parameters. As a special case, the use of elimination methods to estimate respiration is discussed and a possible source of error is pointed out.     

Study on the conversion of waste plastics/petroleum resid mixtures to transportation fuels

Catalytic coprocessing of model and waste plastics with light Arabian crude oil residue was investigated using NiMo/Al₂O₃, ZSM-5, FCC, and hydrocracking catalysts. Reaction systems that were studied included low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene (PS), and polypropylene (PP). A series of single (plastic/catalyst) and binary (plastic/resid/catalyst) reactions were carried out in a 25-cm³ micro autoclave reactor under different conditions of weight and type of catalyst, duration, pressure, and temperature. The optimum conditions selected for our work were: 1% catalyst by weight of total feedstock weight, 60min reaction time, 8.3Mpa of H₂, and 430°C. The product distribution for the binary system using plastic and petroleum residue provided some encouraging results. High yields of liquid fuels in the boiling range of 100°–480°C and gases were obtained along with a small amount of heavy oils and insoluble material such as gums and coke. In general, this study helps to demonstrate the technical feasibility of upgrading both waste plastics and petroleum resid, as well as an alternative approach to feedstock recycling.     

Population respiration: A theoretical approach

It is shown that the error in an estimate of the population respiration should generally not exceed 10% if the mean body weight is used instead of the full weight distribution. A convenient mathematical formulation of the Krogh-curve is given such that the commonly used exponential temperature dependence (Q₁₀ law) of the respiration rate is only a special case. A formula is derived which expresses the effect of a cyclic temperature relative to a constant temperature on the respiration of an animal, the respiration rate of which follows a Krogh-curve. This formula is shown to provide good estimates of annual population respiration both for cases where the population biomass can be considered as constant over the year and when its variation can be approximated with a sinusfunction. Our methods of estimating population respiration are shown to compare favourably with earlier shortcut methods.     

Carbon Storage in Tagus Salt Marsh Sediments

Seasonal variation of above ground and belowground biomass of Spartina maritima and Halimione portulacoides, decomposition rates of belowground detritus in litterbags, and carbon partitioning in plant components and sediments were determined in two Tagus estuary marshes with different environmentalconditions. Total biomass was higher in the saltier marsh from 7,190 to 6,593 g m^-2 dw and belowground component contributed to more than 90%. Litterbag experiment showed that 30 to 50% of carbonis decomposed within a month (decomposition rate from 0.024 to 0.060 d^-1). Slower decomposition in subsequent periods agrees with accumulation of carbon concentration in sediment. Atmospheric carbon annually transferred to the plant belowground biomass is stored more efficiently in sediments of Corroios than Pancas.     

Options for Emission Allowance Allocation Under the Eu Emissions Trading Directive

The article investigates four alternative allocation schemes for emission allowances. The investigated schemes are emission-based allocation, production-based allocation with actor-specific emission factors, production-based allocation with benchmarking and production-based allocation based on data on best available technology (BAT). All the examined schemes apply free allocation based on historical activities. The allocation schemes are evaluated against the criteria for a National Allocation Plan, listed in the Annex III of the EU ETS Directive, and regarding their conformity with the criteria put forward by the Swedish Parliamentary Delegation on Flexible Mechanisms, The FlexMex 2 Commission. No allocation scheme unambiguously meets all criteria. Each has its advantages and disadvantages. Emission-based allocation schemes are most straightforward, transparent and are the easiest to implement. Production-based allocation schemes meet more of the criteria, but are more costly to implement and require more data. Data on BAT will not be available to the extent necessary in order to base an allocation scheme implemented for the trading starting 2005 on BAT. It is unlikely that any given allocation scheme will be perceived as fair by all concerned parties, no matter how sophisticated it is. The overall characteristics of the studied allocation schemes are summarised in the paper. Due to the lack of abatement cost curves, it is not possible to accurately model capital flows between the trading sectors. Data availability will most probably limit the options available to the authorities designing the allocation schemes. An erratum to this article is available at .