Title: Effect of bioturbation on contaminated sediment deposited over remediated sediment

Abstract

A challenge to all sediment remediation technologies is the continued influx of contaminants from uncontrolled sources following remediation. However, contaminants deposited on sediments remediated with chemically active sequestering agents may be affected by the sequestering agents resulting in reduced impacts. We deposited sediment contaminated with As, Cd, Cu, Ni, Pb, and Zn over clean sediment capped with the sequestering agent, apatite, and clean uncapped sediment in laboratory mesocosms to simulate the recontamination of remediated sediment by influxes of particle-bound contaminants. Cap effectiveness was assessed in the presence and absence of the bioturbating organism Corbicula fluminea based on metal fluxes to sediment pore water and surface water, the distribution of mobile contaminants in sediment and surface water measured by Diffusive Gradients in Thin Films, and contaminant bioaccumulation by Lumbriculus variegatus. The metal sequestration capacity of apatite caps was unaffected or improved by bioturbation for all elements except As. Effects with uncapped sediment were metal specific including reductions in the bioavailable pool for Ni, Cd, and to a lesser extent, Pb, increases in the bioavailable pool for As and Cu, and little effect for Zn. It is likely that the reductions observed for some metals in uncapped, clean sediment were the resultmore » of burial and dilution of contaminated sediment combined with chemical processes such as sequestration by minerals and other compounds. These results indicate that apatite caps can control recontamination by metals regardless of bioturbation but point to the complexity of sediment recontamination and the need for further study of this problem.« less

Authors:

Knox, Anna Sophia ^[1]; Paller, Michael H. ^[1]

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+ Show Author Affiliations

1. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

Publication Date:

Thu Jan 09 00:00:00 EST 2020

Research Org.:

Savannah River Site (SRS), Aiken, SC (United States); Savannah River National Laboratory (SRNL), Aiken, SC (United States)

Sponsoring Org.:

USDOE Office of Environmental Management (EM)

OSTI Identifier:

1648298

Alternate Identifier(s):

OSTI ID: 1682460

Report Number(s):

SRNL-L3230-2020-00002
Journal ID: ISSN 0048-9697; TRN: US2202462

Grant/Contract Number:  

AC09-08SR22470; AC09-798861048; DEFC09-07SR22506

Resource Type:

Accepted Manuscript

Journal Name:

Science of the Total Environment

Additional Journal Information:

Journal Volume: 713; Journal ID: ISSN 0048-9697

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES