Abstract
The geochemical composition of sediment pore water was investigated in comparison with the composition of sediment particles and surface water in an estuary within one of the most industrialized areas in Latin America (Santos-Cubatão estuarine system, SE Brazil). Pore and surface waters presented anomalously high levels of F(-), NH4(+), Fe, Mn and P due to two industrial point sources. In the summer, when SO(4)(2-)/Cl(-) ratios suggested an enhanced sulfate reduction, the higher dissolved levels observed in pore waters for some metals (e.g., Cu and Ni) were attributed to reductive dissolution of oxidized phases. Results evidenced that the risks of surface water concentration increase due to diffusion or advection from pore water are probably dependent on coupled influences of tidal pumping and groundwater inputs.
Highlights
The occupation of coastal areas by industrial and urban activities has been recognized as the main cause of sediment contamination by potentially toxic trace elements in many regions (e.g., Rebello et al 1986, Faria and Sanchez 2001, Molisani et al 2004, Pereira et al 2007, Fonseca et al 2011)
Methods that take into account this variability and consider the mechanisms affecting the chemical behavior in the sediment-water interface are important to predict trace element bioavailability to important groups of benthic organisms, such as filter-feeding mollusks
Previous studies have shown that Al, K and Mg are elements of geogenic origin in the Santos-Cubatão estuarine system sediments specially related to the clay minerals and feldspars (Luiz-Silva et al 2008, Machado et al 2008)
Summary
The occupation of coastal areas by industrial and urban activities has been recognized as the main cause of sediment contamination by potentially toxic trace elements in many regions (e.g., Rebello et al 1986, Faria and Sanchez 2001, Molisani et al 2004, Pereira et al 2007, Fonseca et al 2011). This relationship has been systematically observed in the Santos-Cubatão estuarine system (São Paulo State, SE Brazil). In Cananéia estuary (SE Brazil), Ferreira et al (2007) have observed lower concentrations of AVS and pyrite-Fe in the summer, which was related to increased crab bioturbation
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