Assessment of toxicity of metals in river sediments for human supply: Distribution, evaluation of pollution and sources identification.

Autor: Almeida LC; Postgraduate Program in Chemistry, Chemistry Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-270 Salvador, BA, Brazil., da Silva Júnior JB; Postgraduate Program in Geochemistry: Petroleum and Environment (POSPETRO), Geoscience Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-290 Salvador, BA, Brazil. Electronic address: jucejr@ufba.br., Dos Santos IF; Universidade Estadual de Feira de Santana (UEFS), 44036-900 Feira de Santana, Bahia, Brazil., de Carvalho VS; Postgraduate Program in Chemistry, Chemistry Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-270 Salvador, BA, Brazil., de Santana Santos A; Postgraduate Program in Chemistry, Chemistry Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-270 Salvador, BA, Brazil., Hadlich GM; Postgraduate Program in Geochemistry: Petroleum and Environment (POSPETRO), Geoscience Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-290 Salvador, BA, Brazil., Ferreira SLC; Postgraduate Program in Chemistry, Chemistry Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-270 Salvador, BA, Brazil.
Jazyk: angličtina
Zdroj: Marine pollution bulletin [Mar Pollut Bull] 2020 Sep; Vol. 158, pp. 111423. Date of Electronic Publication: 2020 Jul 08.
DOI: 10.1016/j.marpolbul.2020.111423
Abstrakt: Ten surface sediments collected from Joanes River, Bahia, Brazil in rainy and drought periods in 2019 were evaluated according to the enrichment factor (EF), potential ecological risk index (RI), potential contamination index (PCI), pollution load index (PLI), and index of geoaccumulation (I geo ). Initially the dry sediment was subjected to granulometric analysis and determination of the concentration of organic matter. Then, the samples were digested in HNO 3 and analyzed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) to determine the metals cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb) and zinc (Zn). Zn and Cu were classified in that order as the most contaminated elements in most sediment. Comparison of the total metal concentrations with the threshold (TELs) and probable (PELs) effect levels in sediment quality guidelines suggested a more worrisome situation for Zn (648.83-1415.90 μg g -1 ; PEL Zn  = 315 μg g -1 ), of which concentrations were occasionally associated with adverse biological effects in four sediments, followed by Cu in five sediments during dry and rainy periods; while adverse effects were rarely associated with Cd, Cr, Ni, and Pb. In another evaluation, Cd, Cu, Cr, and Zn could be considered the most dangerous in the entire river, as they were classified in the high levels of contamination by the PCI, associated with serious adverse effects in most samples. In an assessment regarding the ecological risks in the study environment, the sediment samples remained below the limit established by the risk index (IR). The Zn presented moderately severe enrichment (6.78-11.83) in all the collection stations in the dry and rainy periods, followed by the Cd that presented moderate enrichment (2.23-4.17), whose values exceeded almost 1000 times the background at one site. Through the PCA it was possible to evidence the existing correlation between metals, organic matter, and silt and clay fraction. The results obtained in the PCA represented more than 80% of the variance between the data. The environmental risk assessment revealed a significant increase in the risk associated with metals during the rainy season. This is probably due to the greater supply of organic matter from the leaching of the margins.
(Copyright © 2020. Published by Elsevier Ltd.)
Databáze: MEDLINE
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