Title: Biocatalysed acidification and metal leaching processes in sediments of polluted urban streams

Authors: Natalia Florencia Porzionato; Roberto Candal; Gustavo Curutchet

Addresses: Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, Campus Miguelete, 25 de mayo y Francia, 1650 San Martín, Provincia de Buenos Aires, Argentina ' Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, Campus Miguelete, 25 de mayo y Francia, 1650 San Martín, Provincia de Buenos Aires, Argentina ' Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, Campus Miguelete, 25 de mayo y Francia, 1650 San Martín, Provincia de Buenos Aires, Argentina

Abstract: Sediments of fluvial streams are a sink for pollutants such as heavy metals and organic recalcitrant compounds. In anoxic conditions, sulphide generation and alkalinisation cause precipitation of heavy metals. The redox potential of the system could change to higher values, mainly owing to oxygen exposition generated by anthropogenic disturbances of the sediment such as dredging operations. Knowledge about the mechanisms involved is fundamental to assess the risk of acid generation and rise in heavy metals bioavailability. In this paper, the characterisation and assessment of acidification risk of sediments of a contaminated stream near Buenos Aires was carried out by static and kinetic assays. Speciation of heavy metals was determined after metal sequential extraction procedure. Also, re-suspension of sediments assay in batch mode, with and without Acidithiobacillus ferrooxidans inoculum, was carried out to assess the chemical changes that occur at oxygen exposure, verifying the acidification and heavy metal release processes.

Keywords: sediment acidification; acid generation risk; metal leaching; biocatalysed leaching processes; polluted urban streams; water pollution; stream sediments; heavy metals; oxygen exposure.

DOI: 10.1504/IJENVH.2014.060125

International Journal of Environment and Health, 2014 Vol.7 No.1, pp.3 - 14

Received: 08 May 2021
Accepted: 12 May 2021

Published online: 26 Mar 2014 *

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