DISSOLVED AND PARTICULATE MATTER IN A MEDITERRANEAN RIVER (VENE, HERAULT, FRANCE) - CONTRIBUTION OF MAJOR AND TRACE-ELEMENTS AND PB AND SR ISOTOPES TO DEFINING THE SOURCE AND TRANSPORT OF MATTER AND WATERS

Major and trace elements and lead and strontium isotopic compositions have been measured in the dissolved and particulate phases of a Medite rranean river (Vene), and for comparison at Issanka spring. A hi-month ly sampling, from September 1993 to June 1994, has been carried out to better constrain the origins, movements and fluxes of waters and load s in the Vene watershed during high and low flows. Sr isotopic composi tions led to distinction between water from the karstic spring (Sr-87/ Sr-86 similar to 0.7083) and water from the river (0.7087 < Sr-87/Sr-8 6 < 0.709). Systematic leaching on the different Jurassic limestone st ages identify the natural lead endmember as having highly radiogenic v alues (Pb-206/Pb-204 similar to 20) as compared to the local anthropic lead endmember from gasoline (Pb-206/Pb-204 similar to 17.5). In a si mple two component mixing model, calculation shows that about 70 to 80 % of particulate lead comes from gasoline.