Mercury accumulation in sediments along an eutrophication gradient in Guanabara Bay, southeast Brazil

Abstract

A acumulação de Hg foi investigada em testemunhos sedimentares da Baía de Guanabara, Rio de Janeiro, Brasil, amostrados ao longo de um gradiente de eutrofização, que se refletiu na qualidade física dos sedimentos e na distribuição de carbono orgânico total (COT). Sedimentos da área oeste da baía foram fortemente afetados por aportes de efluentes domésticos e industriais, apresentando concentrações de Hg de até 7500 ng g -1 e inventários de Hg de até 786 mg m ). Uma mudança de uma relação negativa para uma positiva entre Hg e COT ocorreu no estuário mais eutrofizado, no qual um aumento nos níveis de Hg no sentido do topo foi observado. Este aumento pode ser atribuído a (i) um crescente aporte fluvial de Hg e (ii) um impacto da eutrofização sobre a qualidade dos sedimentos, que pode aumentar a sua capacidade de acumular Hg associado à matéria orgânica.The accumulation of Hg was investigated in sediment cores from Guanabara Bay, Rio de Janeiro, Brazil, sampled along an eutrophication gradient, which was reflected in the sediment physical quality and total organic carbon (TOC) distribution. Sediments from the western bay ). A shift from a negative to a positive relationship between Hg and TOC occurred in the most eutrophicated estuary, in which an upward increase in the recorded Hg levels was observed. This increase may be attributed to (i) an increasing riverine Hg input and (ii) an impact of eutrophication on the sediment quality, which may enhance the sediment capacity to accumulate organic matter-bound Hg.

Spatial distribution of intertidal sandy beach polychaeta along an estuarine and morphodynamic gradient in an eutrophic tropical bay

“…Guanabara Bay receives the discharge from a drainage basin impacted by over 7.8 million inhabitants, in which organic pollution and trace metal contamination of sediments have been evident in the last few decades (Carreira et al, 2002;Kjerfve et al, 1997;Machado et al, 2008). Concentrations of coprostanol in sediments as high as 40 lg g À1 indicate areas of severe sewage contamination (Carreira et al, 2004).…”

Urban Aquatic Sediments

“…2004 ). It preferentially binds to organic matter (Mason & Sullivan 1998 ;Machado et al . 2008 ) and sulfur (Marins et al .…”

Analytical chemistry in Brazil: healthy and growing

“…Guanabara Bay in Rio de Janeiro State (Brazil) was studied in relation to the accumulation of Hg in sediment cores and concentrations up to 7500 ng g -1 were observed. 126 Others investigated areas were Santos and Cubatão (São Paulo State) due to the high industrial activity. Luiz-Silva et al 127 determined 38 elements in sediments from the Santos-Cubatão estuarine system using ICP-MS and they observed that Cr, Mn, Ni, Zn, Ga, Ag, Cd, Sn, Sb, Pb and Bi were associated with steel plant-derived Fe concentrations.…”