Caracterização geoquímica do Estuário do Rio Una, BA, Brasil

Abstract

With a vast estuarine area, southern Bahia (Brazil) has large natural resources. Estuaries aggregate various ecological dynamics that contribute significantly to ecosystem balance, bringing valuable sustainable resources to the community. These resources are now being drastically exploited in disarray, and local communities are the first to be harmed. Understanding and knowing the estuarine geochemical behavior allows us to identify environmental strategies for a balanced exploitation of these ecosystems. The present work aimed to geochemically characterize the low course of the Una River through the analysis of physical-chemical parameters in water (temperature, pH, dissolved oxygen, salinity, Eh, conductivity, turbidity and total dissolved solids) and metals (Ni, Cu, Cd, Pb and Cr) in water and suspended particulate matter. The samples were collected in the dry season in October 2012 and in the rainy season in May 2013. The highest values of metals were Ni, Cu and Pb in the suspended particulate matter. Cd was the only trace element present in the dissolved fraction, indicating a possibility of water contamination due to the surrounding anthropic activities. In general, the values of trace metals are considered high when compared with the established sediment indices.