Geochemical background indicators within a tropical estuarine system influenced by a port-industrial complex

This study aims to determine the background values for metals in the Suape estuarine system, Brazil, and to identify contamination caused by anthropogenic sources. Two cores were sampled. Sedimentation rates and metal content were analysed. The Al-normalized method was used to infer the background values, and to identify anthropic influences, the enrichment and contamination factors and the geoaccumulation index were employed. The results revealed an Mn, Ni, Zn, Ga, Pb, Sr, Ti, Mg, V and Fe content (mg kg−1) of 101.8, 5.7, 24.4, 8.3, 14.5, 41.9, 2744.6, 4581, 14.9 and ~ 1% respectively. After the installation of the Suape port, an increase in metal contents and in fluxes were recorded. Increases in Zn, Ga, V and Pb are supported by the indexes showing moderate contamination, enrichment and suggest an area moderately polluted. The other studied metals do not reflect an anthropogenic impact, with low values of contamination, enrichment factors and geoaccumulation indexes.