4.1. Heavy metal burden in environmental compartments
Many aquatic pollutants are strongly allied with the fine deposits that NMS-P715 are rich in organic matter, and the way of interaction with these deposits determines the bioavailability and toxicity of these metals (Chen and White, 2004). Besides the natural input of organic matter, sewage and urban discharges are released directly in the estuarine system especially in the Passagem canal. This area is at higher risk from human discharge (industrial and urban) leading to higher concentrations of heavy metal in the sediment, which could be increased by dredging and port activities. The sea side in Espírito Santo Bay is characterized by more course oceanic sediment with diverse physio-chemical characteristics because of the tidal perturbation and higher circulation.
4.1.2. Water and suspended matter
In the present study, we found higher concentrations of dissolved metals in water and suspended matter in the sites with low salinity such as river mouths, the upper Vitória Bay estuarine area, and sewage canals. Direct discharge from house hold, sewage disposal and effluents from the nearby industries into the riverine system or the enclosed bay might have contributed to a higher level of heavy metal load among freshwater and estuarine stations.