Hydrobiologia 274: 127-132, 1994. J. Fott (ed.), Limnology of Mountain Lakes. 127 © 1994 Kluwer Academic Publishers. Printed in Belgium. Characterization of carbonaceous particles from lake sediments Neil Rose Environmental Change Research Centre, Department of Geography, University College London, 26 Bedford Way, London WCIH OAP, UK Abstract Spheroidal carbonaceous particles produced by high temperature combustion of coal and oil are found in high concentrations in lake sediments from areas of high acid deposition. The sediment record of these particles showing the onset of industrialisation correlates well with the record of acidification as indi- cated by diatom analysis. To find sources of the atmospheric deposition affecting a lake and its catchment, characterisation of the carbonaceous particles is necessary. A reference data set of particle chemistries from coal and oil power stations was produced using EDS generated data of 17 elements. Using multivariate statistical techniques, the most important elements for the coal/oil separation were identified and incorporated into a linear discriminant function which allocated fuel type with > 97 % accuracy. Application of this technique to surface sediments in Scotland shows the influence of oil burning from outside the region, higher areas located on the east coast and in the south-west of the country. When applied to a full sediment core, the history of coal and oil combustion affecting the lake is seen and correlates well with known coal and oil consumption figures. Consequently this method could be used to add extra dating levels to sediment cores. The technique has been extended to include peat particles and could potentially be used on those from brown coal, lignite and oil shale combustion. Introduction Lake sediments provide a record of atmospheric contamination and so have been important in re- cent studies of surface water acidification. Car- bonaceous particles derived from fossil-fuel com- bustion are found in considerable numbers in upper levels of sediment cores taken from areas with high acid deposition (Griffin & Goldberg, 1981; Renberg & Wik, 1984). Sites in the United Kingdom show close correlation between the onset of atmospheric contamination as indicated by carbonaceous particles, heavy metals etc., and the acidification of lakes as indicated by diatom analysis (Battarbee et al., 1988). The particulate emissions from high tempera- ture fossil fuel combustion can be divided into two groups, spheroidal carbonaceous particles, which are composed mainly of elemental carbon (Goldberg, 1985), and inorganic ash spheres, which are formed by the fusing of inorganic min- erals within the fuel (Raask, 1984). Of the fossil fuels commonly used in Britain, only coal and oil produce spherical carbonaceous particles. Those produced from peat combustion have an amor- phous appearance, many still retaining some cel- lular structure. The inorganic ash spheres have not been char- acterised and this is because, being fused mineral inclusions their chemistry is independent of fuel type, and also, in Britain they are almost exclu- sively coal in origin.