The importance of natural organic material for environmental processes in waters and soils

The role and function of natural organic material (NOM) for the terrestrial and aquatic environment is strongly related to nutrient availability for plants, relevant for crop production, as well as to be a source of energy for macro- and microorganisms, to influence physico-chemical conditions of soil and sediments and to buffering and exchange capacity, relevant for the immobilization and mobilization of environmental pollutants. This article will review the available information about the importance of natural organic material for environmentally processes in water and soil. After explaining general terms regarding natural organic material and its chemical structure and presenting the actual state of analytical methods, interactions between environmental variables and the natural organic material as regards its formation and behaviour, as well as interactions between natural organic material and the fate of pollutants in the terrestrial and aquatic environment are discussed emphasizi ng some relevant processes such as sorption, mobility and bioavailability. Finally some aspects on modeling such processes are presented.