Metal contamination and fractionation in sediments from the lower basin of the Vale do Ribeira (SE, Brazil)

Abstract

The sediment quality of Ribeira de Iguape River is affected by former Pb extraction mining. Some studies affirm the restoration status of the basin, however, mobility of metals and its associated risk is still questioned. This study integrates the metal concentrations in the lower part of the basin with different contamination source to determine the existence of risks associated with the mobile fractions of the geochemical matrix. Despite concentrations of metals were low and the environmental risk factor values were negative, our results indicated that As, Mn, Pb, and V were present in the most labile forms. The multivariate analysis conducted using metal concentrations, environmental risk factor values and speciation suggested that any risk would be associated with the labile fractions of the analyzed elements, especially for Pb. The station from Registro was stressed by Co, Pb and Zn; with Pb under the reactive fraction that could be associated with high mobility and potential bioavailability.

Integrative assessment of sediment quality in lower basin affected by former mining in Brazil

“…Downstream in the RIR, in R, the positive values for both factors indicate bioaccumulation of all metal without effect. This is supporting the idea that contaminants ''rest'' in the lower part of the basin under mobile forms (Bonnail et al 2017) to be dumped into the ocean with flooding; this effect agrees with Abessa et al (2015) study. Finally, the station located in the Natural Park (P) displayed negative scores for both factors; toxic responses are attributed to other contamination sources.…”

“…A preliminary evaluation of sediment potential toxicity risk was made by contrasting obtained metal(loid) concentrations with the international freshwater sediment guidelines proposed by the USEPA (2007). Initially, the studies sites appear to not present any risk to biota due to the low concentrations of the different metals, except for Co (Bonnail et al, 2017). This element overpasses the thresholds Table 1 Results of the sediment characterization: organic matter (OM); total organic content (TOC); nitrogen (N); Sulfur (S) and total metal concentration in mg/kg in sediments from the stations: Sete Barras (SB) and Registro (R) in the RIR; and the Natural Park Perequê (P) in São Paulo state Results of metal concentration in soft tissue of Corbicula fluminea in the controls (C 24h and C 10d ) and after the sediment bioassay in organisms exposed to sediments from stations SB, R and P are also shown as mg/Kg wet weight (or dry weight) bdl below detection limit, nm not measured established by the USEPA in the three stations (Table 1).…”

“…For the analysis of elements in the sediments, the pseudototal digestion described by the International Organization for Standardization was carried out based on the standard procedure ISO 11466 (1995). Detailed sediment proceed is described in Bonnail et al (2017).…”

Avaliação ambiental da qualidade limnologica e de sedimentos em córrego do Centro Oeste do Brasil

“…Pontos Fe Zn Cu Seco 1 1,185±0,007* 0,064±0,007 0,004±0,000 2 1,210±0,014* 0,065±0,001 0,004±0,000 3 1,235±0,007* 0,066±0,000 0,005±0,000 4 1,235±0,007* 0,066±0,000 0,004±0,000 Chuvoso 1 1,210±0,010* 0,062±0,000 0,000±0,000 2 1,236±0,005* 0,065±0,001 0,004±0,000 3 1,230±0,000* 0,065±0,000 0,005±0,000 4 1,206±0,005* 0,065±0,000 0,004±0,000 (Bonnail et al, 2017). E mesmo considerando que o Fe é um elemento essencial no metabolismo celular, em níveis elevados esse elemento pode causar toxicidade, persistência e a bioacumulação na biota aquática, podendo ser transferida para a cadeia trófica (Driessnack et al, 2017;Gárriz et al, 2018).…”

“…Neste contexto, o monitoramento em ambientes aquáticos com a avaliação da estrutura da paisagem circundante de corpos hídricos é fundamental para a compreensão da integridade ambiental, e também possibilita subsidiar projetos relacionados ao planejamento voltados para a recuperação de áreas degradadas (Teresa;Casatti 2017). E a investigação em conjunto de fatores abióticos de rios e córregoságua e sedimentosé essencial para fornecer informações das condições ambientais atuais que a biota aquática está submetida, além de avaliar o risco de consumo de água e peixes contaminados para a saúde humana (Silva et al, 2017;Bonnail et al, 2017).…”