Assessment of metal concentration in the Billings Reservoir sediments, São Paulo State, Southeastern Brazil

Marcos A Hortellani,Priscila F G Garcia,Paula M Gênova De Castro,Luciana C B Menezes,Jorge E S Sarkis,Renata Bazante-Yamaguishi,Alder S A Pereira,Lídia S Maruyama

doi:10.1590/s0103-50532013000100009

Marcos A Hortellani, Priscila F G Garcia + Show 6 more

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https://doi.org/10.1590/s0103-50532013000100009

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Abstract

Four approaches were applied to evaluate the metal contamination in 47 sediment samples (< 63 µm fraction) collected at 13 fishing points of the Billings Reservoir: sediment quality guidelines (SQGs), geoaccumulation index (I Geo), metal pollution index (MPI) and statistical analyses. Only Fe and Co concentrations seemed to be associated with crustal material or natural weathering processes, while Al, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn showed increases in their concentrations, which seemed to be associated with anthropogenic sources. MPI identified the most critical sites in relation to the total metal accumulation while I Geo identified the specific metal accumulation for each site. Analysis of variance (ANOVA) and box plot method were performed to evaluate seasonal effects on the metal levels. Only box plot suggested a slight increase in Hg and Pb contamination during heavy rainy periods and also indicated high concentrations of Cu and Zn in one of the analyzed point, with incidence of outliers and extreme values. Thus, an environmental policy in order to reduce these metal contaminations must be adopted.

Highlights

The Billings Reservoir is extremely important as it is the largest water reservoir for the Metropolitan Region of São Paulo, Brazil
The metal recovery was > 80%, an indicative of a satisfactory method, except for elements Cr ((1)-56.7%, (2)-48.9%) and Al ((1)-38.4%, (2)-51.1%). These results are in agreement with other studies[24,25] and compliant with validation data presented by the method 3051A for Buffalo River sediment.[16]
The measured levels of metals were above Threshold effect level (TEL) limits, indicating contamination according to the Canadian Sediment Quality Guidelines[6] and CONAMA criteria,[7] whereas below that no adverse effect in the biological community is observed

Summary

Introduction

The Billings Reservoir is extremely important as it is the largest water reservoir for the Metropolitan Region of São Paulo, Brazil. The Billings Reservoir produces 12 m3 s-1 of water and supplies the ABC region, part of São Paulo City and the Baixada Santista region. The. ABC region refers to three smaller cities bordering São Paulo City (Santo André, São Bernardo do Campo and São Caetano do Sul). The ABC area is well‐known in Brazil because of the numerous automotive manufacturers located in the vicinity. The Baixada Santista Metropolitan region is a densely urbanized region in São Paulo State.[1] This reservoir is impacted by urban invasion, industrial and sewage waste, seriously affecting its ecosystems and quality of life of population in this region.[2,3]

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