TRANSIENT PB ISOTOPIC SIGNATURES IN THE WESTERN-EUROPEAN ATMOSPHERE

The progressive phasing-out of lead from gasoline has resulted in a si gnificant decrease in the global atmospheric lead burden over the last 20 years. Here we show that in Europe this change in lead concentrati on-determined by the analysis of aerosols-is accompanied by a systemat ic change in lead isotopic compositions and that there was a significa nt reversal in this trend during the 1970s. Such changes in isotopic s ignatures over time have been accurately documented in North America. We observe that European and North American records display opposite t rends in isotopic composition, thus providing a powerful tool for asse ssing the response time of the North Atlantic environment and its surr ounding continents to transient lead inputs. This database could help to better constrain the time scale of coastal and upper ocean mixing p rocesses and of particle transport to marine sediments.