Environmental assessment concerning trace metals and ecological risks at Guanabara Bay, RJ, Brazil

Abstract

Three-stage sequential extraction BCR was applied to surface sediments from the west part of Guanabara Bay to assess the mobility of Zn, Cu, Pb, Ni, Cr, and Mn. Results were satisfactory for the analysis of certificate standard material (BCR 701), with recoveries between 71 (Cu) and 123% (Cr). Evaluation of organic matter composition classified the area as eutrophic (CHO:PRT > 1), with aged organic detritus at some stations. Zn exhibited by far the greatest bioavailability, with 43.49% of its concentrations associated with the exchangeable fraction. Cu and Cr showed stronger affinity for organic matter, with 51.18 and 48.73% of their concentrations, respectively, bounded to the oxidizable fraction. Pb presented higher concentrations in the reducible fraction (45.41%). The strongest lithogenic contribution was shown by Ni (31.91%) and Mn (35.44%). PCA clearly showed the determinant role of organic matter and fine sediments in the distribution of metals in the study area and also a common source for these elements, with the exception of Cu. Risk Assessment Code (RAC) established Zn as the most concerning element in the study area. The decreasing mobility order, based on the sum of the three extractable fractions of BCR, was Pb > Cu > Cr > Zn > Ni > Mn. The comparison of the results with sediments quality guidelines (SQG) proved fractionation to be mandatory in the evaluation of effective ecological risk concerning trace elements in sediments.

Chemical and Biological Indicators of Environmental Pollution in the Canal do Cunha (Guanabara Bay, Rio de Janeiro, Brazil): Analysis and Determination of Toxins

“…(2014) highlighted that several trace elements, such as Pb, Ni, Cu, Cd, and Zn, were found at high levels in the Canal do Cunha basin. These trace elements were observed in the surface sediments from other parts of Guanabara Bay (Aguiar et al ., 2018; Baptista Neto et al ., 2000) and showed a strong correlation with some dinocysts (Freitas, Aguiar, and Baptista Neto, 2021). The majority of samples analysed in the present study showed extremely high values when compared to background values for Guanabara Bay (Baptista Neto et al ., 2000; Monteiro et al ., 2012).…”

Trace elements: critical insights from 15 years of monitoring in the Venice Lagoon catchment basin (Italy)

“…Therefore, the assessment of actual pollution levels and the identification of appropriate management policies may be difficult (Masiol et al 2014). Many studies dealt with assessment of metals pollution in coastal areas or river catchments worldwide, focusing especially on trace elements in sediments in Europe (Alharbi and El-Sorogy 2017) (Charizopoulos et al 2016;Couto et al 2018;Nagy et al 2016;Rodriguez et al 2018) and worldwide (Batbayar et al 2017;De Carvalho Aguiar et al 2018;Vystavna et al 2018).…”