THE PAH AND ORGANIC CONTENT OF SEDIMENT PARTICLE-SIZE FRACTIONS

The relationship of nine Polycyclic Aromatic hydrocarbons (PAH) with organic matter present in various river sediment size fractions, from 63 μm to 1.0 to 2.0 mm, has been investigated. It is suggested that the PAH and organic matter content have bimodal distributions through the sediment size fractions which may be explained by the presence of two types of organic material in the sediment. Maxima in both factors are found in the two largest and the smallest size fractions. A positive linear relationship beween PAH concentration and organic matter has been demonstrated and the slope of this relationship has been used to identify sites where PAH pollution is generally high. The relative proportions of each PAH compound in the sediment remains relatively constant regardless of temporal and spatial differences in total PAH concentration and organic matter content and certain PAH compounds may be grouped together depending on their association with organic matter. Differing PAH compound availabilities, competition for adsorption sites and the reactivity of PAH compounds may all result in the unchanging sediment PAH profile seen in each size fraction. The organic material present in the sediment may have a similar affinity for all PAH's in a particular group. © 1990 Kluwer Academic Publishers.