Document Detail

Considerations for capping metal-contaminated sediments in dynamic estuarine environments.
MedLine Citation:
PMID:  12322750     Owner:  NLM     Status:  MEDLINE    
The effects of tides, bioturbating organisms, and periods of anoxia on metal fluxes from contaminated harbor sediments in a shallow tidal estuarine bay were studied, together with capping technology options for the containment of metal contaminants. Zinc fluxes from the sediments were high, ranging from 10 to 89 mg of Zn m(-2) day(-1). In the absence of capping, experiments in corer-reactors showed that simulated tidal processes increased zinc fluxes 5-fold. Fluxes were also greater in the presence of sediment-dwelling organisms. If organisms were removed, and recolonizing organisms later added, their bioturbation activities initially lowered zinc fluxes, but fluxes gradually reached steady state at the higher levels seen previously. Capping materials physically isolate contaminated sediments, provide a binding substrate for metals released from the sediment and importantly create an anoxic environment below the cap, which stimulates the formation of insoluble metal sulfides. Clean sediment (5 mm) was the most effective capping material in reducing zinc fluxes. Zeolite/sand mixtures (10 mm) also greatly reduced these fluxes, but significant breakthrough of zinc occurred after 2 weeks. Sand (20 mm) was not effective. The presence of organisms disturbed capping materials and increased zinc fluxes. Installed capping materials should have depths of >30 cm to minimize organisms burrowing to contaminated sediments beneath.
Stuart L Simpson; Ian D Pryor; Ben R Mewburn; Graeme E Batley; Dianne Jolley
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Environmental science & technology     Volume:  36     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2002 Sep 
Date Detail:
Created Date:  2002-09-26     Completed Date:  2003-02-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3772-8     Citation Subset:  IM    
Centre for Advanced Analytical Chemistry, CSIRO Energy Technology, Bangor, New South Wales, Australia.
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MeSH Terms
Environmental Pollution / prevention & control*
Geologic Sediments / chemistry*
Metals / analysis*
New South Wales
Silicon Dioxide / chemistry
Water Movements
Water Pollutants, Chemical / analysis*
Zeolites / chemistry
Zinc / analysis
Reg. No./Substance:
0/Metals; 0/Water Pollutants, Chemical; 1318-02-1/Zeolites; 7440-66-6/Zinc; 7631-86-9/Silicon Dioxide

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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