RIVERINE AND ATMOSPHERIC INPUTS OF HEAVY-METALS TO THE LIGURIAN SEA

The aim of this paper is to provide an estimation of the riverine and atmospheric contributions of Pb, Cd, Cu and Zn supply to the Ligurian Sea. Riverine data come from Arno, Var and Roya rivers and atmospheric data come from total deposition-sampling on the southeastern coast of France. Taking into account the behaviour of each metal in estuarine conditions (i.e. the net dissolved metal inputs from rivers to the sea ), the atmospheric inputs are always higher, with the following ratios : 195-1055, 3.3-11.5, 16.3-32.6 and 7.4-160 for Pb, Cd, Cu and Zn, res pectively. Here an interpretation of the preponderence of the atmosphe ric factor, is proposed. Considering that riverine metal fluxes are fa r lower than atmospheric metal fluxes over the associated watershed su rface area, it is suggested that atmospheric deposition over the water shed is the major contribution of riverine pollutant fluxes and most o f this atmospheric deposition is lost into soils and riverine sediment s. This assumption could be extended to the whole western Mediterranea n basin whose surface area is larger than that of its associated water shed.