Vintage analysis on superficial sediments to predict future trends in metal contamination of Santos and São Vicente Estuarine System

Abstract

Due to its economic, social, and environmental importance, Santos and São Vicente Estuarine System is largely studied for almost two decades. Although many studies have been conducted, none of them tried to relate past activities to actual ones. This study provides an evaluation of the contamination on vintage superficial sediment samples investigating sediment contamination patterns over the years to help to understand future trends in metal contamination in this area. Thus, this study aims to assess levels of trace elements and rare earth elements (REEs) on samples collected in two seasonal periods of 2005 and 2006 (summer and winter). In each campaign, 16 surface samples were collected onboard R/V Veliger II, and trace elements and REEs were analyzed by neutron activation analysis. Results of metals presented similar levels over the years and it was not related to the port's activities since the levels did now increase following the total movement of containers. In addition, the enrichment of light REEs could indicate anthropogenic activities from steel plants, phosphate fertilizers, and the phosphogypsum piles. The system undergoes through many human pressures and constant monitoring over time it is important to avoid overloading the resilience capacity of the estuarine system because the expansion of port, industry, and urbanization is inevitable. From the results obtained, it was possible to conclude that SSVES undergoes more likely anthropogenic pressures from industrial activities and domestic effluents rather than port activity.