Coupling fallout .sup.210Pb and stables isotopes for catchment urbanization reconstruction in southeastern coastal zone of Brazil

Eutrophication history was reconstructed by bulk organic and inorganic proxies (C, N, P) and isotope ([delta].sup.13C and [delta].sup.15N) analysis constrained by geochronological model derived from fallout .sup.210Pb in Brazilian coastal lagoon. The sedimentary record spanning the last four decades showed impact of urbanization starting from 1970s. These changes were marked by increase of TN, TP, IP fluxes that were significantly correlated with population growth. Significant covariation of C:N, MDP and [delta].sup.15N along age-depth profiles provided linkage with sedimentation rates, serving as an independent time marker for geochronology and validating use of .sup.210Pb dating model based on constant initial concentration.