Eighty-year sedimentary record of heavy metal inputs in the intertidal sediments from the Nanliu River estuary, Beibu Gulf of South China Sea

²¹⁰Pb analysis in the sediment core C11 was used to reconstruct the historical fluxes of Hg, Cu, Pb, Zn, Cd, Cr and As in the Nanliu River estuary during the last ∼81 year. The ²¹⁰Pb_xs-derived sedimentation rates, molar C/N ratios, enrichment factors and excess fluxes indicated that the natural inputs prevailed till the early 1990s. When the erosion related to land-use modifications enhanced, it promoted higher accumulation rates of the sedimentary material. In the recent sediments they were found a moderate enrichment of Cd and Hg (maximum 3.5- and 2.8-fold corresponding to the local background levels, respectively) and a slight enrichment of Cr, Zn, As and Pb (maximum 1.3-, 1.3-, 1.3- and 1.2-fold, respectively). The excess metal fluxes also showed a consistently increasing tread since the early 1990s, which could be associated with the intensive use of phosphate fertilizers and the combustion of fossil fuels derived from human activities.