Das Projekt "OPUS - Transport organischer Verunreinigungen in ungesaettigten Boeden - Ein integrierter Ansatz (Bodenphysikalischer Teil)" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule Zürich, Institut für Terrestrische Ökologie, Arbeitsgruppe Bodenphysik durchgeführt. In controlled laboratory experiments, the dominant physical, chemical, and biological characteristics of transport of organic pollutants through well defined, but partly heterogeneous porous media are investigated. Joint experiments with eight other groups from ETHZ, EAWAG and EPFL are carried out predominantly under unsaturated flow conditions in columns to examine simultaneously occurring physical, chemical, and biological processes. These columns are equipped with pressure transducers, time domain reflectometry probes, solution and gas sampling ports to ensure a high spatial and temporal resolution of measurements. Unsaturated gravity flow is used to simulate the unsaturated zone above the capillary fringe. In contrast, a fluctuating water table in the columns is used to mimic conditions found in natural aquifers. This experimental design allows to examine phase distribution as affected by the presence of soluble organic compounds and hydrophobic surfaces. Also changing redox conditions due to varying degrees of saturation is evaluated. The impact of sorption on the transport of nitro aromatic compounds is analyzed. In this research programme we emphasize interactions across disciplinary boundaries.