Abstract

Literature research is done on the composition of organic material along soil profiles in relation to sorption capacity for non-ionic hydrophobic organic compounds. Organic matter of deeper soil layers is mostly better humified and therefore less polar than the organic matter of superficial soil layers. Several studies illustrate that sorption of non-ionic hydrophobic organic compounds decreases with increasing polarity of the soil organic matter. Other factors that affect sorption are the aromaticity and the 'open' structure of the material. Sorption coefficients will improve when qualitative differences of soil organic matter are taken into account. This is feasible by relating sorption coefficients to both organic oxygen and organic carbon content. Another suggestion in order to eliminate qualitative differences is normalization of sorption coefficients on a reference compound.