Atmospheric deposition of metallic pollutants over the Ligurian Sea: labile and residual inputs

Atmospheric fluxes of six trace metals (Cd, Cr, Cu, Ni, Pb and Zn) with Al as a crustal reference were measured at Cap Ferrat (French Riviera) between February 1997 and July 1998. An original sampling protocol enabled the separation of labile (seawater at pH 2) and residual fractions in the total atmospheric input. Median acid-labile fractions were 91%, 69%, 83%, 84%, 97% and 98% of the total for Cd, Cr, Cu, Ni, Pb and Zn, respectively. Under the conditions used, lability of individual metals is related to the anthropogenic component of the samples. Enrichment factors and anthropogenic fraction are estimated for each metal. Some interannual changes are investigated (Pb, Zn). The observed increase of Zn inputs may be linked to local input from the Nice district waste plant (commissioned in 1988), 6.5 km away.