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

JOURNAL OF HAZARDOUS MATERIALS

卷:341

Article

Xie, Minwei^1,2  Wang, Ning^1,3  Gaillard, Jean-Francois¹  Packman, Aaron I.¹ 

[1] Northwestern Univ, Dept Civil & Environm Engn, 2145 Sheridan Rd, Evanston, IL 60208 USA

[2] HKUST Shenzhen Res Inst, Marine Envrionm Lab, Shenzhen 518000, Peoples R China

[3] Southwest Jiaotong Univ, Fac Geosci & Environm Engn, Chengdu 610031, Sichuan, Peoples R China

关键词: Contaminated sediments;    Hydrodynamics;    Bioturbation;    Nereis virens;    Metal efflux;   

DOI  :  10.1016/j.jhazmat.2017.08.002

来源: Elsevier

【 摘 要 】

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 360x and 15x 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. (C) 2017 Elsevier B.V. All rights reserved.

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