The Flame Research Project: Introduction and Methods

The FLAME (FLy-Ash and Metals in Europe: Implications for human and environmental health) research project funded by the EU COPERNICUS programme ran from 1994 to 1996. The main aims of the programme were to further develop an automated chemical characterisation to discriminate between fly-ash particles from the major fossil-fuels used throughout Europe (coal, oil, peat, brown coal and oil shale) and apply this to particles extracted from lake sediments taken from the four participating countries (Estonia, Czech Republic, Ireland and U.K.) in order to determine spatial distributions of deposited particulates from large combustion sources. In combination with trace metal analyses from lake surface sediments and catchment mosses, the fly-ash particle data were able to identify areas of elevated pollutant deposition and suggest potential sources for them. Given the transboundary nature of the pollutants, the techniques and results of FLAME are of relevance throughout Europe. Other papers in this volume describe results and interpretation. This paper describes the background and aims of the FLAME project, outlines the methods employed for sampling sediments and mosses and the analytical techniques for particle enumeration and trace metal analysis for sediments and mosses. Finally brief details of the particle characterisation are given showing how a hierarchical discriminant function was developed, based on energy dispersive spectroscopy (EDS) derived particle chemistry which correctly allocated particles from the five fuel-types with 80% accuracy.     

The FLAME Project: General Discussion and Conclusions

Detailed discussion of the FLAME data at individual country level is included in other papers in this volume but some aspects of the analyses and data interpretation are best discussed on a broader level and that is the aim of this paper. The spatial distribution of fly-ash particles in the participating countries shows good agreement with expected sources and this implies that the majority of particulates travel less than 100 km from their source although lower concentrations of particles were detected at all sample sites. Areas of elevated concentration mostly coincide with population centres and imply possible impacts on human health by fine particulates (e.g. PM₁₀) from fossil-fuel sources in these areas. Problems with the particle characterisation, developed within the FLAME project, include difficulties in allocation due to the overlap between coal-series fuels and the presence of a 'mineral coal' background at lake sites thought to be due to persistent sediment minerals surviving the chemical pre-treatment and becoming allocated to coal. This leads to implications for the inclusion of further fuels into the classification and the application of the technique to the same fuels beyond Europe. The combination of lake sediment SCP data and sediment and moss metals data can also provide an indication of the impact from anthropogenic contamination at a site and probable source types. Comparison with previous moss analyses from 1990 show that metal concentrations in central Europe may have decreased but levels in the UK have shown little change. Finally, comparisons of FLAME data with the EMEP model for pollutant budgets across Europe generally show good agreement for pathways, although further work is needed in receptor countries for additional confirmation.     

The Spatial Distribution of Characterized Fly-Ash Particles and Trace Metals in Lake Sediments and Catchment Mosses: Czech Republic

As a part of the FLAME research project funded by the EU COPERNICUS programme (1994-1996) samples of surface sediments were taken from 31 man-made lakes and one natural lake in the Czech Republic. The sites differ considerably in their altitude, area, catchment, depth, retention time, trophic status, and in parameters of local air pollution. The samples were analysed for concentration of spheroidal carbonaceous particles (SCP, numbers per gram dry mass of sediment), a characteristic component of industrial fly-ash. The extracted carbonaceous particles were allocated according to the fuel-types combusted throughout Europe (coal, oil, brown coal, peat, oil shale) using particle chemistries derived by energy dispersive spectroscopy (EDS). Trace metals were also analysed in the surface sediments as were mosses sampled at the study sites. The main objectives of the study were (i) to look for factors determining SCP concentrations in surface sediments of lakes, with special emphasis on the distribution of large fossil-fuel combustion sources (ii) to compare fuel-type allocation of carbonaceous particles with combustion of these fuels within the country, (iii) to look for trends in spatial distribution of trace metals and (iv) to characterize the impact of airborne particles from these sources on environmental and human health. The SCP concentrations show little or no relation to air-pollution parameters on a small scale, although some large-scale effects are evident. A good relationship was, however, found to site characteristics such as altitude and lake area : catchment area. The reason, why this relationship is more apparent from our dataset than from any other study published so far, is likely to be based on the high variation in the physical parameters (altitude, lake and catchment area) of the sites under study. The distribution of particles attributed to brown coal combustion are in good agreement with the distribution of major air pollution sources across the country but the fraction of particles attributed to coal seems to be overestimated by the present technique. The distribution of trace metals in surface sediments are also in agreement with expected sources. The usefulness of SCP concentrations as indicators of stress to human and environmental health is briefly discussed.