Geochemical mapping in a subtropical estuarine system influenced by large grain-shipping terminals: insights using Metal/Metal ratios and multivariate analysis

In this study, we combine the use of Metal/Metal ratios of 134 sediment samples with multivariate analysis to provide the first geochemical mapping of a large subtropical estuary influenced by one of the largest grain-shipping terminals of South America. Together with grain-size data, the results allowed us to efficiently map the different sectors of the estuarine complex, defining its geochemical faciology. Also, potassium-related ratios appeared to be reliable proxies for the identification of point sources of terrigenous sediments. Since there was no evidence of widespread trace metal contamination, the results here presented can be used as a baseline for the area.