Pollutant lead transport and input to the Caribbean during the 20thcentury

Abstract

We evidence significant shifts in the sources of Pb input to the Caribbean based on lead isotope records from massive corals collected near Puerto Rico. While mean Pb/Ca ratios in these corals generally mimic alkyl Pb consumption in the US, we observe a 5 to 8 years delay in the maximum Pb peak in the 1970s. Pollutant Pb decay in corals is not as rapid as expected from the phasing out of leaded gasoline related to European and regional sources. Furthermore, 206 Pb/ 207 Pb imprints often display significant interannual variations with no clear temporal evolution. This seems to be partly connected to specific meteorological events and seasonal atmospheric shifts with mixed input from the southern US, Europe and Latin America/Caribbean. New corals from the Western Caribbean (Martinique, Guadeloupe) are presently analysed in order to investigate these isotopic shifts it relation to atmospheric input sources and oceanic recirculation.