Alexandre Barbosa Salaroli

Spatial distribution and enrichment assessment of heavy metals in surface sediments from Baixada Santista, Southeastern Brazil

The Baixada Santista, besides being an important estuarine system, is responsible for most of the international trade and economic development in the region because of the Santos Port and the Cubatão Industrial Complex. The aim of this study is to assess heavy metal contamination of the Santos São Vicente Estuary using enrichment factors (EFs) and sediment quality guidelines (SQGs). Thus, superficial sediment samples were subjected to acid digestion and analyzed (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sc, V, and Zn) by inductively coupled plasma optical emission spectrometry (ICP-OES). The results indicated an absence of contamination, with the EFs indicating moderate enrichment. As and Pb presented higher enrichment probably due to the natural processes of weathering and sedimentation, and the influence of human activity. This conjoint analysis showed that potentially polluting activities are of concern as the highest values converge near the Cubatão Industrial Complex, which correspond to intense urbanization and industrial activity.

Reconstruction of historical trends in potentially toxic elements from sediment cores collected in Bertioga channel, southeastern Brazil

Este estudo apresenta uma avaliacao da deposicao de elementos potencialmente toxicos no Canal de Bertioga (costa sudeste brasileira) ao longo de 150 anos, periodo principal de atividade antropogenica na area. O trabalho analisou cinco testemunhos sedimentares por meio de ICP-OES para determinar os niveis de metais (Cd, Cr, Cu, Ni, Pb e Zn) e As. O indice de carga de poluicao (PLI) e o fator de enriquecimento (EF) foram calculados para identificar a toxicidade relativa dos elementos dos sedimentos e a contribuicao antropogenica dos elementos investigados. Os indices indicaram a ausencia de contaminacao por metais pesados, mas houve uma entrada mais elevada de As nos testemunhos B2 e B5, amostrados em area com maiores taxas de sedimentacao. Atraves de analise estatistica de decomposicao de series temporais, verificou-se que o fluxo de metais para a area segue os ciclos de estacoes chuvosa (verao austral) e seca (inverno austral). Como conclusao pode ser verificado que o enriquecimento observado corresponde ao final do seculo XIX, quando o Porto de Santos foi inaugurado, e a decada de 1970, quando as atividades do porto foram expandidas. Ainda, a analise dos indices e da decomposicao temporal indica que a entrada de As no Canal de Bertioga da-se por processos naturais de intemperismo e sedimentacao.

Inorganic and organic geochemical fingerprinting of sediment sources and ocean circulation on a complex continental margin (São Paulo Bight, Brazil)

In this study, we use inorganic (metal) and organic (bulk and molecular) markers in sediment samples of the south-eastern Brazilian margin to investigate the response of geochemical fingerprints to the complex hydrodynamic processes present in the area. Results indicate the potential of export of terrigenous siliciclastic and organic constituents to the upper slope, even in an area with limited fluvial supply. Metal contents and especially the ln(Ti /Al) and ln(Fe /K) ratios make it possible to recognise the extension of shelf sediments toward the upper slope. Potassium, here expressed as ln(K /Sc) and ln(K /Al) ratios used as proxies of illite– kaolinite variations, proved to be an important parameter, especially because it allowed us to decipher the imprint of the northward flow of the Intermediate Western Boundary Current (IWBC) in comparison to the southward flows of the Brazil Current (BC) and Deep Western Boundary Current (DWBC). Using organic matter analyses, we were able to evaluate the extent of terrestrial contributions to the outer shelf and slope, even without the presence of significant fluvial input. In addition, molecular markers signify a slight increase in the input of C4-derived plants to the slope sediments, transported from distant areas by the main alongshore boundary currents, indicating that the terrestrial fraction of the organic matter deposited on the slope has a distinct origin when compared to shelf sediments.

Embryo toxicity assay in the fish species Rhamdia quelen (Teleostei, Heptaridae) to assess water quality in the Upper Iguaçu basin (Parana, Brazil)

The Iguaçu River is one of the largest and most important rivers in the Southern of Brazil. The Upper Iguaçu Basin is responsible for water supply (80%) of the Metropolitan Region of Curitiba (MRC). After crossing a large urban region, the river is polluted by domestic and industrial sewage, but despite of that few ecotoxicological studies have been performed in order to evaluate the water quality from Iguaçu River. The aim of the present study was to investigate the risk of exposure of Iguaçu water to biota and also human population. In this terms, was utilized the survival effect and the morphological deformities in larval embryos of Rhamdia quelen, a native South America species. The results showed a high level of pollution in all studied sites along the Upper Iguaçu River including PAHs and toxic metals such as lead. The lethal and non-lethal effects described in earlier stages of development suggest an elevated risk to biota. This data was corroborated by the theoretical model, showing that the pollutants present in water from Iguaçu River may further reduce the fish population density including risk of local extinction. The present study reflect the needs to conduct in-depth research to evaluate the real impact of human activities on the endemic fish biota of Iguaçu River including the risk for human populations.