Evaluation of trace metal levels in surface sediments of the Sergipe River Hydrographic Basin, Northeast Brazil

Abstract

As distribuições de Co, Cr, Cu, Mn, Ni, Pb, Fe e Al foram investigadas em sedimentos superficiais coletados em 19 sítios da Bacia Hidrográfica do Rio Sergipe, Nordeste do Brasil. Foi definida uma base geoquímica para a região (RGB) usando o ferro como elemento de referência. Fatores de enriquecimento (EF) e índice de geoacumulação (I geo ) foram empregados para determinar a contribuição por origem antropogênica. Valores de EF mostraram que os sedimentos dos sítios 1, 5 e 13 podem ser considerados contaminados por Pb, Cr e Cu, respectivamente. Valores de I geo mostraram que o sítio 13 pode ser considerado contaminado. Há uma grande predominância nos sedimentos de metais de origem natural. A possível toxicidade foi avaliada comparando com os valores PEC-TEC dos guias de qualidade de sedimentos (SQG). Análise de componentes principais (PCA) separou claramente os pontos em dois grupos e a análise de agrupamento hierárquico (HCA) confirmou as interpretações feitas pela PCA.The distributions of Co, Cr, Cu, Mn, Ni, Pb, Fe and Al were investigated in surface sediments collected at 19 sites in the Sergipe River Hydrographic Basin of Northeast Brazil. A regional geochemical baseline (RGB) was defined using iron as a reference element. Enrichment factors (EF) and geoaccumulation indices (I geo ) were used to determine the extent of anthropogenic metal pollution. EF values showed that sediments from sites 1, 5 and 13 could be considered contaminated by Pb, Cr and Cu, respectively. I geo values showed that only site 13 could be considered contaminated. For other sites, results indicated that naturally occurring metals predominated in the sediments. Possible toxicity related to these metals was examined using the comparing sediment chemical data with sediment quality guidelines (SQG) PEC-TEC values. Principal component analysis (PCA) clearly separated the sites into two groups and hierarchical cluster analysis (HCA) confirmed the interpretations made from the PCA results.

The contribution of physical and chemical sediment characteristics to environmental risk from an irrigation scheme in South Africa

“…The various geochemical processes within an ecosystem are major determinants of metal toxicity irrespective of the metal loads present; i.e. high metal loads do not necessarily constitute toxicity but rather the bioavailability of the metals (Passos et al 2011;Silva et al 2012). Sequential extraction techniques have long been used to determine the availability of metals within sediments (Li et al 1995;Canuto et al 2013).…”

<b>Diffuse sources of pollution and their influence on the nature of the sediments in Água Preta Lake

“…Nickel concentrations reported from the sediments of Billings Reservoir (HORTELLANI et al, 2013), and the superficial sediments of the Rio Sergipe Hydrographic Basin (SILVA et al, 2012) were also above the PEL. As in the case of copper and cadmium, zinc and lead also were at low concentrations at point 5.…”

“…Copper concentrations found in our study are similar to those found in the stretch of the Mogi River that passes through São Paulo. Amounts of both metals observed in the surface sediments of the Uberabinha river, in Uberlândia (SILVA et al, 2011), sediments of the Sergipe River Hydrographic Basin (SILVA et al, 2012), and sediments of the Billings Reservoir, in the state of São Paulo (HORTELLANI et al, 2013) were also below the PEL benchmark.…”

Evaluation of sediment contamination with heavy metals: the importance of determining appropriate background content and suitable element for normalization

“…Metal pollutants have received considerable attention due to their persistence, biogeochemical recycling, and environmental risk (Silva et al 2012;Gao et al 2013). However, high metal concentrations in sediment do not automatically imply that contamination has occurred, but may simply reflect the natural mineralogical composition of the parent geological material and the grain size and organic matter content of the host sediment (Silva et al 2012).…”

“…However, high metal concentrations in sediment do not automatically imply that contamination has occurred, but may simply reflect the natural mineralogical composition of the parent geological material and the grain size and organic matter content of the host sediment (Silva et al 2012).…”