Pollutant and organic matter content in sediment particle size fractions

In a partly urbanized catchment to the south of Trier, Germany, selected sediment samples were separated into different size fractions ranging from <2 urn to 200 urn. Each sample fraction was analysed for heavy metals, poly chlorinated biphenyls (PCB), poly cyclic aromatic hydrocarbons (PAH) and organic carbon. The results show a linear correlation between heavy metal content and particle size. The organic content of the samples does not play an important role in heavy metal adsorption. In contrast, the organic micropollutants (PAHs and PCBs) do not correlate with the particle size distributions but with the content of the organic material. The maximum concentrations of organic micropollutants and organic carbon are not associated with the clay fraction but are bimodally distributed. The bimodal distribution can be explained by the presence of two types of organic material in the sediment.