Increase in the bioavailability of trace metals after sediment resuspension

摘要: This study evaluated the potential mobility of metallic contaminants (Cd, Cr, Cu, Ni, Pb and Zn) present in sediments at mouth Sao Francisco Channel (Sepetiba Bay, RJ), using resuspension tests. Fourteen surface sediment superficial water samples were collected along a salinity gradient from river into bay. The tests consisted mechanical agitation humid aliquots local unfiltered water, ratio 7.5 g:100 mL, during 1 h 24 h. determination metals bioavailable fraction was performed ICP-OES, after extraction 1 mol L−1 HCl. Significant differences observed between central external sectors for Cd (p = 0.009), Cr (p = 0.017), Ni (p = 0.047) Zn (p = 0.007) concentrations (Kruskal–Wallis). water’s temperature (p < 0.001), pH (p < 0.05) dissolved oxygen (p < 0.001) decreased both time intervals comparison to initial measures before resuspension. increased 222 316.2 mg kg−1 24 h (Kruskal–Wallis; p < 0.05) sector, possibly because this region has stronger oxidizing conditions. In general, significant increase metals’ resuspension, especially sector that showed more than 90% agitation. These increases could lead higher ecological risks biota, dredging activities.