Tracking Hg historical inputs by Pb-210 geochronology for the Itapessoca Estuarine Complex, Pernambuco, Brazil

The application of geochronology for tracking mercury contamination was remarkably demonstrated in the Itamaraca Estuarine Ecosystem, Pernambuco State, Brazil. Here, two sediment cores were sampled, layered and analyzed by the Gas Flow Proportional Counter technique for determining 210Pb, radionuclide applied to geochronology. Mercury was quantified in sediment samples by Cold Vapor Atomic Absorption Spectrometry, varying from 0.17 to 1.29 mg kg−1 in deep sediments. From 210Pb results, the sedimentation rates of 0.84 (0.07) cm year−1 and 1.03 (0.22) cm year−1 confirmed Hg contamination in Itamaraca since mid-1965. Events of extreme precipitation and drought have been also related to the distribution pattern for Hg concentrations in deep sediments.