Interplay between flow and bioturbation enhances metal efflux from low-permeability sediments

Minwei Xie*, Ning Wang, Jean François Gaillard, Aaron I. Packman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Understanding the interplay effects between processes such as hydrodynamic forcing, sediment resuspension, and bioturbation is key to assessment of contaminated sediments. In the current study, effects of hydrodynamic forcing, sediment resuspension, and bioturbation by the marine polychaete Nereis virens were evaluated both independently and together in a six-month flume experiment. The results show that hydrodynamic forcing without resuspension or worm action slightly enhanced efflux of dissolved Cu to the water column, sediment resuspension released considerable amounts of dissolved Cu, and interactions between hydrodynamics and worm burrowing further enhanced Cu efflux. In non-bioturbated sediments, fine particles were only resuspended to the overlying water under the highest imposed shear stress, 0.58 Pa. However, bioturbated sediments were resuspended under all shear stresses tested (0.11–0.58 Pa), indicating that bioturbation destabilized the sediment bed. Further, increases in fluid shear following bioturbation caused rapid releases of dissolved Cu to the overlying water within a few hours. Cu efflux under fluid shears of 0.47 Pa and 0.58 Pa were 360× and 15× greater after the introduction of worms compared with the same flow conditions without their presence. Overall, our results indicate that the release of metals from low-permeability sediments is greatly enhanced by interactions between flow and bioturbation.

Original languageEnglish (US)
Pages (from-to)304-312
Number of pages9
JournalJournal of Hazardous Materials
Volume341
DOIs
StatePublished - 2018

Keywords

  • Bioturbation
  • Contaminated sediments
  • Hydrodynamics
  • Metal efflux
  • Nereis virens

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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