Authors: Gavin Birch Bibhash Nath Punarbasu Chaudhuri
Publish Date: 2014/11/18
Volume: 22, Issue: 8, Pages: 6185-6197
Abstract
Industrial activities and urbanization have had a major consequence for estuarine ecosystem health and water quality globally Likewise Sydney estuary has been significantly impacted by widespread poor industrial practices in the past and remediation of legacy contaminants have been undertaken in limited parts of this waterway The objective of the present investigation was to determine the effectiveness of remediation of a former Pbcontaminated industrial site in Homebush Bay on Sydney estuary Australia through sampling of intertidal sediments and mangrove Avicennia marina tissue fine nutritive roots pneumatophores and leaves Results indicate that since remediation 6 years previously Pb and other metals Cu Ni and Zn in surficial sediment have increased to concentrations that approach preremediation levels and that they were considerably higher than presettlement levels 3–30 times as well as at the reference site Most metals were compartmentalized in fine nutritive roots with bioconcentration factors greater than unity while tissues of pneumatophores and leaves contained low metal concentrations Lead concentrations in fine nutritive root pneumatophore and leaf tissue of mangroves from the remediated site were similar to trees in unremediated sites of the estuary and were substantially higher than plants at the reference site The situation for Zn in fine nutritive root tissue was similar The source of the metals was either surface/subsurface water from the catchment or more likely remobilized contaminated sediment from unremediated parts of Homebush Bay Results of this study demonstrate the problems facing management in attempting to reduce contamination in small parts of a large impacted area to concentrations below local base level
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