TEL :: [tel-00596847, version 1] Caractérisation et origine des métaux traces, hydrocarbures aromatiques polycycliques et pesticides transportés par les retombées atmosphériques et les eaux de ruissellement dans les bassins versants séparatifs péri-urbains

TEL :: [tel-00596847, version 1] Caractérisation et origine des métaux traces, hydrocarbures aromatiques polycycliques et pesticides transportés par les retombées atmosphériques et les eaux de ruissellement dans les bassins versants séparatifs péri-urbains

For the last 30 years, storm water runoff has been recognized as one of the major sources of pollution to receiving waters due to the high pollutant concentrations transported. Atmospheric fallout, erosion of impervious surfaces (roofs, streets, pavements, parking lots) are leaching of particles deposited on the soil or impervious surfaces generated by vehicular traffic, residential and collective heating and industries have been recognized as the principal sources of pollution. The objective of this thesis is to characterize and to determine the sources of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides transported by runoff from two suburban catchments equipped with separative sewer systems located in the East of Nantes city (Pin Sec and Gohards catchments). This study is carried out in the frame of Institut de Recherche en Sciences et Techniques de la Ville (IRSTV). The complete study of concentrations and flux of pollutants in total atmospheric depositions as well as in roof and street runoff was made in order to assess the contribution of the differents compartments to the total pollution transported by runoff at the outlet of separative sewer systems. This pollution monitoring establishes and in some cases confirm the origin and the main pathways of pollutant transfer to the storm water generated into suburban catchments with low population and low vehicular traffic. Total atmospheric deposition is the principal source of cadmium and chromium, roofs and their accessories are a large source of zinc and lead and street runoff provides nickel, copper and zinc. With regard to organic polltion, vehicular traffic has been identified as the main source of PHAs, while the treatment of surfaces with herbicides for the control of growing plants is the main source of pesticides in these catchments.