IOUSP

Apresentado pelo  Prof. Dr. Olivier Evrard do Laboratoire des Sciences du Climat et de l'Environnement (CEA-CNRS-UVSQ), Gif-sur-Yvette (France)

Soil erosion is a major process of land degradation worldwide. When an excess of fine sediment is supplied to the rivers, it may lead to problems such as reservoir siltation. Fine particle fractions also transport numerous contaminants, such as heavy metals, radionuclides and organic contaminants. At LSCE (Laboratório das Ciências Climáticas e Ambientais, Paris, (France), artificial and natural radionuclides are used to quantify sediment sources and improve our understanding of fine particle dynamics in rivers and catchments. Several case studies illustrating different environmental problems across the world will be presented:

• the investigation of persistence times of Polycyclic Aromatic Hydrocarbons in soils and rivers of the Seine River basin (Paris, France);
• the quantification of the proportions of recently eroded and resuspended sediment in cultivated catchments of Laos (Southeast Asia) using measurements of short-lived beryllium-7 in combination with caesium-137 and unsupported lead-210;
• the dispersion of artificial radionuclides in rivers draining the radioactive pollution plume of Fukushima Prefecture (Northeastern Japan) to the Pacific Ocean.