Aerosol Deposition and Origin in French Mountains Estimated with Soil Inventories of super(210)Pb and Artificial Radionuclides

Magnitude and extend of variations of atmospheric deposition using soil inventories of unsupported super(210)Pb in French mountains areas are examined. Soil inventories of radionuclides in French mountain areas provide indirect measurements of long-term total deposition of super(210)Pb bound to submicron aerosols. Deposition of super(210)Pb in high-altitude sites cannot only be explained by wet deposition as estimated by the meteorological model. Highest deposition of super(210)Pb and carrying submicron aerosols in high-altitude sites, compared to European lowland sites with the same annual precipitation rate, is explained by occult deposition and feeder-seeder mechanism as demonstrated by super(210)Pb/R sub(NWT) ratios. The super(210)/R sub(NWT) ratios in soils are increasing with altitude showing that within the boundary layer, deposition of aerosols is more intense in altitude sites.