Geochemistry of selenium, barium, and iodine in representative soils of the Brazilian Amazon rainforest.

Autor: da Silva Junior EC; Department of Soil Science, Federal University of Lavras, Lavras, MG CEP 37200-900, Brazil., de Oliveira Wadt LH; Embrapa Rondônia, Porto Velho, RO CEP 76815-800, Brazil., da Silva KE; Embrapa Amazônia Ocidental, Manaus, AM CEP 69010-970, Brazil., de Lima RMB; Embrapa Amazônia Ocidental, Manaus, AM CEP 69010-970, Brazil., Batista KD; Embrapa Roraima, Boa Vista, RR CEP 69301-970, Brazil., Guedes MC; Embrapa Amapá, Macapá, AP, CEP 68903-419, Brazil., de Oliveira Junior RC; Embrapa Amazônia Oriental, Belém, PA, CEP 66095-903, Brazil., Dos Reis AR; São Paulo State University (UNESP), School of Sciences and Engineering, Tupã, SP, CEP 17602-496, Brazil., Lopes G; Department of Soil Science, Federal University of Lavras, Lavras, MG CEP 37200-900, Brazil., Broadley MR; School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE125RD, UK., Young SD; School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE125RD, UK., Guilherme LRG; Department of Soil Science, Federal University of Lavras, Lavras, MG CEP 37200-900, Brazil. Electronic address: guilherm@ufla.br.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2022 Jul 01; Vol. 828, pp. 154426. Date of Electronic Publication: 2022 Mar 09.
DOI: 10.1016/j.scitotenv.2022.154426
Abstrakt: The Amazon rainforest is a heterogeneous ecosystem and its soils exhibit geographically variable concentrations of trace elements. In this region, anthropic activities - e.g., agriculture and mining - are numerous and varied, and even natural areas are at risk of contamination by trace elements, either of geogenic or anthropogenic origin. A reliable dataset of benchmark values for selenium (Se), barium (Ba), and iodine (I) concentrations in soils is needed for use as a reference in research and public policies in the region. In this study, 9 selected sites in the Brazilian Amazon rainforest within areas represented by Oxisols and Ultisols were assessed for relevant soil physicochemical characteristics, along with the concentrations of total Se (Se Tot ), total Ba (Ba Tot ), and sequentially-extracted soluble Se (Se Sol ) and adsorbed Se (Se Ad ) in 3 different soil layers (0-20, 20-40, and 40-60 cm). In addition, organically bound-Se (Se Org ) and total I (I Tot ) concentrations in the surface layer (0-20 cm) were measured. Soil Se concentrations (Se Tot ) were considered safe and are likely a result of contributions of sedimentary deposits from the Andes. Available Se (Se Sol + Se Ad ) accounted for 4.5% of Se Tot , on average, while Se Org in the topsoil accounted for more than 50% of Se Tot . Barium in the western Amazon (state of Acre) and central Amazon (Anori, state of Amazonas) exceeded national prevention levels (PVs). Furthermore, the average I Tot in the studied topsoils (5.4 mg kg -1 ) surpassed the worldwide mean. Notwithstanding, the close relationship found between the total content of the elements (Se, Ba, and I) and soil texture (clay, silt, and sand) suggests their geogenic source. Finally, our data regarding Se Tot , Ba Tot , and I Tot can be used to derive regional quality reference values for Amazon soils and also for updating prevention (PV) and investigation (IV) values established for selected elements by the Brazilian legislation.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022. Published by Elsevier B.V.)
Databáze: MEDLINE
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