Rangel Carlos M A, Neto José A Baptista, Fonseca Estefan M, McAlister John, Smith Bernard J
Departamento de Geologia, Universidade Federal Fluminense, Gragoatá, Niterói, RJ, Brasil.
An Acad Bras Cienc. 2011 Sep;83(3):801-15. doi: 10.1590/s0001-37652011005000020.
In this study, the geochemical analysis of ten sediment samples collected along the fluvial system of the Estrela River, which flows into the northern portion of Guanabara Bay, shows the presence of anthropogenic impacts in this area. Concentrations of Fe, Mn, Zn, Cu, Pb, Cr and Ni obtained were slightly higher, when compared with values found in natural environments. The particle size and organic matter content in most of the analyzed stations showed features not conducive to the accumulation of pollutants due to the low organic matter content and the strong presence of sand fraction. There was also the fractionation of heavy metals in sediments and it was found the prominence of residual and reducible phase, besides the significant occurrence of organic fractions in some analyzed stations. These factors, thus, highlight the potential risks of contamination, where the metals associated with the organic phase can become bioavailable in processes of dissolution, provided by physico-chemical changes that can occur in this aquatic environment.
在本研究中，对沿流入瓜纳巴拉湾北部的埃斯特雷拉河流水系采集的10个沉积物样本进行的地球化学分析表明，该地区存在人为影响。与自然环境中的值相比，所获得的铁、锰、锌、铜、铅、铬和镍的浓度略高。由于有机质含量低且砂质成分占主导，大多数分析站点的粒度和有机质含量显示出不利于污染物积累的特征。沉积物中还存在重金属分馏现象，除了在一些分析站点中大量出现有机组分外，还发现了残留相和可还原相的突出。因此，这些因素突出了污染的潜在风险，其中与有机相相关的金属在这种水生环境中可能发生的物理化学变化所导致的溶解过程中会变得具有生物可利用性。
