Metals and acid volatile sulfide in sediment cores from the Sergipe River Estuary, Northeast, Brazil

Abstract

Foram estudados o sulfeto volatilizado em meio ácido (AVS), os metais simultaneamente extraídos (SEM) e os metais em sítios de sedimentos do Estuário do Rio Sergipe, Brasil. As concentrações de AVS e SEM foram, em geral, maiores nos sedimentos dos sítios situados nas áreas que recebem maior aporte antrópico devido à poluição urbana. Nesses sítios, o sulfeto parece ser a principal fase de ligação para os metais. No sítio do sedimento situado na área de maior influência marinha, as fases mais importantes de ligação para os metais parecem estar associadas à matéria orgânica e aos carbonatos. Os perfis de AVS permitiram identificar dois tipos de processos de sedimentação no estuário. Em todos os sítios, as relações SEM/AVS foram muito menores do que 1. Acid volatile sulfide (AVS), simultaneously extracted metals (SEM) and metals were studied in sediment cores from the Sergipe River Estuary, Brazil. AVS and SEM concentrations were, in general, higher in the core sediments from areas which receive a higher anthropic contribution due to urban pollution. In these cores, the sulfide seemed to be the main connection for the metals. In the core obtained from the area of major marine influence, the most important binding phases for the metals seemed to be associated with organic matter and carbonates. The AVS profiles allow identification of two types of sedimentation processes in the estuary. In all cores SEM/AVS ratios were much lower than 1.

Metal fractionation in sediments of the Sergipe River, northeast, Brazil

“…It flows about 210 km from its source, before reaching the Atlantic Ocean at the city of Aracaju, the State capital. 24 The study area extended over 6 km, covering the lower part of the Sergipe River Estuary, between latitudes 10°52'S and 10°56'S, and longitudes 37°02'W and 37°03'W ( Figure S1). Water salinity values varied from 27 to 33, very close to the value of the salinity of sea water (35).…”

“…Step 3 residue was digested using a mixture of the acids HNO 3 (4 mL), HCl (2 mL), and HF (4 mL), to determine the metal content, as described by Alves et al 24 …”

Regional geochemical baselines and controlling factors for trace metals in sediments from the Poxim River, Northeast Brazil

“…The reference element must be of lithogenic origin, be structurally linked to at least one of the main carriers of metals to the sediment, and its concentration must not be significantly influenced by anthropogenic inputs. 3,8 Aluminium has been most frequently used for normalization, since it is the main component of fine-grained aluminosilicates. However, in the case of sediments composed mainly of immature, physically abraded material, such as feldspars, aluminium has not shown good correlations with metals, since in such sediments it is present in similar proportions in both fine and coarse fractions.…”

Assessing the carrying capacity of Perinereis aibuhitensis in a Chinese estuarine wetland using a GIS-based habitat suitability index model

“…Petroleum hydrocarbon was extracted from the soil with n-hexane and determined using an ultraviolet spectrophotometer (Shimadzu, UV-3600) (Yang et al 2015). Sulfide was determined through methylene blue spectrophotometry according to the method of Alves et al (2007). Quality assurance and control were assessed using duplicates, method blanks, and standard reference materials (GBW07401 and GBW080913) from the National Research Center for Standards in China with each batch of samples.…”