Within the framework of the Geneva Convention on long range transboundary pollution, the aim of this work is to propose heavy metal deposition map in the French Alps. To achieve that, ail the snowy precipitation from two consecutive winters (97-98 and 98-99) have been collected in 15 medium altitude sites (-2000m) located in remote areas of the Alps. We've then transposed the snow heavy metal concentrations into metal fluxes deposited for the time period concerned. Beyond this map-making work, this study is devoted to identify the metal sources, trying in particular to discriminate regional and long rang transport sources. To do so, we've used lead isotopic systematic, together with air masses back trajectories leading to the snow events. Two particular cases were developed. In the first one, snow and aerosols samples were collected at the same place to characterize the air/snow transfer. The second one shows the metals spatial distribution, as a function of altitude, and identify the valleys' emissions influence on metal deposition. The principals results of this work show that heavy metal deposition in the Alps is mainly influenced by its massive relief, which is the first real barrier to air masses coming from Atlantic. It turns out that pollutants are not coming from long range atmospheric transport but rather from regional sources (Rhone-Alpes region and Italy). This study also brings out that lead from automobile emissions is now negligible compared to industrial emissions, due to the increasing use of unleaded petro!.
