Understanding Hg distribution in sediments from the Santos and São Vicente Estuarine System, southeastern Brazil

Abstract

The Santos and São Vicente Estuarine System (SSVES) is a region with significant economic importance in southeastern Brazil. It contains petrochemical and metallurgical industrial complexes and the largest commercial harbor in South America, which have made the area vulnerable to degradation by chemical pollutants, such as mercury (Hg). This study is the first to evaluate the environmental parameters that control the spatial distribution of Hg in the surface sediments of the SSVES which is influenced mainly by hydrodynamics and total organic carbon. The innermost part of the estuarine system, where weaker currents lead to an environment with more sediment deposition, has anomalous Hg concentrations, reaching values over 7.0 mg kg–1 and enrichment factors of 115, resulting from historical anthropogenic activities. Although there is a low probability of harmful effects of Hg in organisms, this element demonstrates greater mobility and bioavailability in the environment, indicating the need for monitoring Hg for the conservation of this region.

Keywords

• Baixada Santista
• Mercury
• Contamination
• Total organic carbon
• ICP-OES
• pollution