Das Projekt "RIACOL: Der Eintrag von Kolloiden und Partikeln in den Lago Ceresio (Lugano) durch Fluesse und die Atmosphaere (RIACOL)" wird vom Umweltbundesamt gefördert und von Eidgenössische Anstalt für Wasserversorgung, Abwasserreinigung und Gewässerschutz, Department of Biogeochemistry durchgeführt. Particulate inputs contribute significantly to the mass balances and to the cycling of various components in lakes. The goal of this project is to characterize particulate inputs of nutrients and trace elements into Lake Lugano, from riverine and atmospheric sources. Because of their significance for the eutrophic state of the lake, phosphorus inputs will be studied in detail, considering especially colloidal particles. The present research aims at developing sampling methods for particulate matter in rivers, especially under high flow conditions, and at characterizing riverine particulate matter in terms of size distribution, chemical and mineralogical composition, adsorption characteristics, and bioavailability of phosphorus in the various fractions. In a microbiological part, the role of bacterial adhesion and aggregation for the transport of particulate matter will be considered. Two river sampling sites (Cassarate and Vedeggio), representing different pollutant sources, and various hydrological conditions will be compared.