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Complex patterns in fish - sediment mercury concentrations in a contaminated estuary: the influence of selenium co-contamination?

Citation

Jones, HJ and Swadling, KM and Butler, ECV and MacLeod, CK, Complex patterns in fish - sediment mercury concentrations in a contaminated estuary: the influence of selenium co-contamination?, Estuarine, Coastal and Shelf Science, 137 pp. 14-22. ISSN 0272-7714 (2014) [Refereed Article]

Copyright Statement

Copyright 2013 Elsevier

DOI: doi:10.1016/j.ecss.2013.11.024

Abstract

Environmental mercury (Hg) loads do not always correspond to Hg concentrations in resident fish and selenium (Se) presence has been reported to play a pivotal role in mitigating Hg bioaccumulation. Total mercury (THg), methylmercury (MeHg) and Se concentrations were measured in sediments and a benthic fish species (Platycephalus bassensis) from a contaminated estuary (Derwent Estuary, Tasmania). Elevated sediment concentrations of Se did not result in increased Se concentrations in fish, but low concentrations of Se were associated with increased MeHg bioavailability (% MeHg) from sediments to fish. Where MeHg (z99% of total Hg) concentration in fish was high Se uptake also increased, indicating that maintaining positive Se:Hg ratios may reduce the toxicity of MeHg. MeHg was detectable in sediments throughout the estuary, and a molar excess of THg over Se suggested that there was insufficient Se to prevent methylation from the sediments. Se:Hg ratios of less than 1.0 in sediments, coupled with high %MeHg fraction and high biotic sediment accumulation factors for MeHg (BSAFMeHg), indicated that the lower region of the Derwent Estuary could be a hotspot for Hg methylation, despite having significantly lower THg concentrations. In contrast, Hg bioavailability to fish from sediments close to the source may be reduced by both inorganic Hg species complexation and lower methylation rates. There was a strong association between THg and Se in estuarine sediments, suggesting that Se plays an important role in sediment Hg cycling and should be a key consideration in any future assessments of Hg methylation, bioavailability and bioaccumulation.

Item Details

Item Type:Refereed Article
Keywords:Derwent Estuary, biotic sediment accumulation factors, Se:Hg ratios, methylmercury, Platycephalus bassensis
Research Division:Agricultural and Veterinary Sciences
Research Group:Fisheries Sciences
Research Field:Aquatic Ecosystem Studies and Stock Assessment
Objective Division:Environment
Objective Group:Ecosystem Assessment and Management
Objective Field:Ecosystem Assessment and Management of Coastal and Estuarine Environments
Author:Jones, HJ (Mr Hugh Jones)
Author:Swadling, KM (Dr Kerrie Swadling)
Author:MacLeod, CK (Associate Professor Catriona MacLeod)
ID Code:88585
Year Published:2014
Web of Science® Times Cited:5
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2014-02-07
Last Modified:2017-11-04
Downloads:0

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