Global NEST Journal, Vol 9, No 2, pp 137-143, 2007 Copyright© 2007 Global NEST Printed in Greece. All rights reserved TRACING DISPERSED COALY-DERIVED PARTICLES IN MODERN SEDIMENTS: AN ENVIRONMENTAL APPLICATION OF ORGANIC PETROGRAPHY S. KALAITZIDIS 1 1 Department of Geology, K. CHRISTANIS 1, * University of Patras, 26500 Rio-Patras, Greece G. CORNELISSEN 2,3 2 Department of Environmental Engineering, O. GUSTAFSSON 3 Norwegian Geotechnical Institute (NGI), P.O. Box 3930 Ullevål Stadion, 0806 Oslo, Norway 3 Department of Applied Environmental Science (ITM), Stockholm University, 10691 Stockholm, Sweden *to whom all correspondence should be addressed: Received: 06/06/06 Fax: +30-2610997560 Accepted: 12/09/06 e-mail: christan@upatras.gr ABSTRACT A crucial aspect in environmental sciences is related to the transportation, accumulation and fate of solid organic particles not native to the sediments. In this study we present the petrographical features of seven sediment samples obtained from aquatic environments in Sweden, Finland and The Netherlands. Most of the samples represent the uppermost layers, which accumulated during the recent past. Their total organic carbon content ranges between 1.5 and 20%. Density separations using heavy liquids were applied, in order to concentrate the organic matter and thus to facilitate the petrographical determinations. The microscopic approach revealed significant variations in the origin and hence, the type of the contained organic matter. Apart from modern plant debris and the algae indicating water-logged conditions, several particles of naturally and artificially derived solid-organic material were identified. The latter constitute organic contaminants, and include unburnt residues of high- rank coals and chars. The petrographic data show a significant comparability with the ‘black carbon’ data determined by chemo-thermal oxidation at 375°C, demonstrating the applicability of the microscopic analysis in environmental studies. KEYWORDS: black carbon, char, fly ash, maceral, environmental organic petrography, solid coal contamination INTRODUCTION A significant field of environmental research concerns the contamination of the natural environment from industrial activities and particularly from the power generation sector. The contamination occurs in the form of either solid particles or diluted pollutants (hazardous and/or toxic organic and inorganic compounds) and originates from mining activities, storage (e.g. coal/lignite particles), processing and combustion (i.e. combustion derivatives, e.g. fly ash, unburned residues). The knowledge of the lateral dissemination of these contaminants and their distribution in the catchments is essential for planning remediation measures. Moreover, in some areas coaly particles constitute a significant portion of the modern soils and thus it is necessary to evaluate the fate of these contaminants within the natural eco- system (e.g. Rumpel et al., 1998, Schmidt et al., 2000, Reyes et al., 2006). There is a variety of chemical methods to characterize the organic matter in sediments (e.g. 13 C-NMR). However, the heterogeneity of the organic constituents reduces the applicability of these methods. On the contrary, organic petrography techniques provide the optical characterization of the organic matter and can aid significantly to the determination of the kind