HARMONIZATION OF MICROPOLLUTANT MONITORING IN LARGE INTERNATIONAL RIVER - DANUBE

Micropollutants (heavy metals, organic compounds) play an important ro le in the quality characterisation of surface waters. These pollutants are usually bioresistant persistent compounds or may undergo biotrans formation, photo-oxidation, sometimes resulting in more toxic breakdow n products than their parents, or can accelerate dispersion of hydroph obic compounds and mobilisation of heavy metals from the solid phase. Because of multiple introduction of these pollutants along a large, in ternational river, and due to the sedimentation and re-suspension of t he particulate matter by the river hydrodynamics, the deposition of th e polluting compounds into the bottom sediment may occur far downstrea m of the discharge. Appropriate micropollutant sampling and monitoring in both the water column and bottom sediment are discussed. It is con cluded that the higher the fine fraction in the sample, the more repre sentative the sediment-bound pollutant characterisation. In order to a chieve water and sediment quality guidelines and objectives for microp ollutants the guidelines and monitoring programmes must be harmonised, including the sampling, sample preparation, analytical and data inter pretation methods among the riparian countries along the Danube river.