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Assessing the Effects of Bioturbation on Metal Bioavailability in Contaminated Sediments by Diffusive Gradients in Thin Films (DGT)
journal contribution
posted on 2016-02-05, 00:00 authored by Elvio D. Amato, Stuart L. Simpson, Timothy
M. Remaili, David A. Spadaro, Chad V. Jarolimek, Dianne F. JolleyThe
burrowing and feeding activities of benthic organisms can alter
metal speciation in sediments and affect an organisms’ exposure
to metals. Recently, the performance of the in situ technique of diffusive
gradients in thin films (DGT) for predicting metal bioavailability
has been investigated in response to the increasing demand of considering
contaminant bioavailability in sediment quality assessments. In this
study, we test the ability of the DGT technique for predicting the
metal bioavailability in clean and contaminated sediments that are
being subjected to varying degrees of sediments disturbance: low bioturbation
(bivalve Tellina deltoidalis alone)
and high bioturbation (bivalve and actively burrowing amphipod, Victoriopisa australiensis). Significant release
of DGT-labile Cd, Ni, Pb, and Zn, but lower Cu and Fe, occurred in
the pore and overlying waters of sediments exposed to high bioturbation
conditions, resulting in higher bioaccumulation of zinc in bivalves.
Strong relationships were found between bioaccumulation of Pb and
Zn and time-integrated DGT-metal fluxes, whereas poor relationships
were obtained using total or dilute-acid extractable metal concentrations.
This results demonstrate that DGT is a useful tool for assessing metal
bioavailability in sediments and can provide useful predictions of
metal bioavailable to benthic organisms in dynamic sediment environments.