Selenium Enrichment in Pore Water of Estuarine Sediments Subject to Salt Marsh Vegetation Bioirrigation (Patos Estuary, Southern Brazil)

• Published in: Bulletin of environmental contamination and toxicology Vol. 105; no. 3; pp. 468 - 473
• Main Authors: Costa, Larissa, Mirlean, Nicolai
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2020; Springer Nature B.V
• Subjects: Aquatic plants; Aquatic Pollution; Brackish water; Brazil; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Estuaries; Iron; Lagoons; littoral zone; metalloids; oxygen; pH effects; Pollution; Pore water; Redox potential; Salt marshes; Sediments; Selenium; Soil Science & Conservation; Spartina alterniflora; Sulfides; toxicology; vegetation; Volatilization; Waste Water Technology; Water Management; Water Pollution Control; Brazil; Salt marsh; Pore water; Free sulfides; Selenium; Environmental criteria
• ISSN: 0007-4861; 1432-0800; 1432-0800
• DOI: 10.1007/s00128-020-02978-8

Selenium (Se), iron (Fe), and free sulfides contents in pore waters were measured to study the liberation of soluble Se in suboxic conditions. The sediment core was collected in a salt marsh in Patos Lagoon estuary (southern Brazil), and it was obtained during a brackish water period, in a low intertidal stand vegetated by Spartina alterniflora . The redox potential (Eh), pH, andacid volatile sulfides (AVS) content were also investigated. Pore water results sustained the idea that S . alterniflora roots promote oxygen penetration to depths of ca. 10 cm below the salt marsh surface, increasing Eh and lowering the pH in this interval. High Se concentrations (e.g., 16.9 µg L −1 ), that are above US. EPA environmental criteria, were observed in the pore water to depths between 10 and 20 cm and are associated to low AVS contents and high concentrations of free sulfides. In the first 10 cm the lowering of Se contents probably happens due the low pH and biological volatilization of the metalloid.