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Ecotoxicology of contaminated marine sediments in Tasmanian estuaries

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Mondon, JA (2000) Ecotoxicology of contaminated marine sediments in Tasmanian estuaries. PhD thesis, University of Tasmania.

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Abstract

Sediments are components of marine and estuarine ecosystems. Toxicants most often
become sorbed to suspended particulate matter, then fall to the bottom to become
incorporated into bed sediments. The bioavailability of the toxicants is difficult to measure
chemically and the interpretation of biological significance is unclear. Toxicants stored in
sediments can be released due to physical and chemical changes in the environment. The
extent of the effects of these changes is also not well established and there is little
knowledge of what levels of contaminants may be mobilised, and the ecological effect of
that mobilisation.
Although recently, pore water toxicity and chemistry has been included in sediment testing,
there is a lack ofresearch characterising pore water from Australian marine sediments.
Further, there is a paucity of multidisciplinary research of the quality of marine sediments
in Australia to provide information on factors affecting quality and remediation of marine
sediments that will contribute to improved environmental management of marine sites and
allow for successful remediation practices.
The primary aim of this study was to apply a multidisciplinary approach to form a weight of
evidence assessment of sediment quality in northern Tasmanian estuaries. The technical
objectives associate with this aim were to:
• determine whether shallow subtidal sediments adjacent to a heavy metals industrial estate
was chemically contaminated relative to other northern Tasmanian locations, and relative to
numerical, effects-based guidelines
• determine ifbenthic communities exposed to chemical contamination differed relative to
benthic communities exposed to non-contaminated sediments
• establish whether the contaminated sediments were toxic relative to non-contaminated
sediments
• determine the relationships between toxicity, chemical composition and benthic
communities of the subtidal sediments at contaminated and non-contaminated sites
• generate background data for future assessment of sediment remediation.
The relationship between the toxicity, chemical composition and benthic communities was
investigated through a field program. Over two years, samples were collected at four
locations. One of these, Deceitful Cove in the Tamar River estuary, has been heavily
contaminated by past industrial effluents from aluminium refining and ferro-manganese
smelting industrial plants, another (East Ann in the Tamar River estuary) has intermediate
contamination, while the other two (Squeaking Point and North East Arm in the Port Sorell
estuary) are effectively free of pollution. A Sediment Quality Triad (SQT) assessment of
shallow subtidal marine sediments within the two adjacent northern Tasmanian estuaries
was conducted to assess sediment quality in terns of potential to elicit adverse biological
effects. The SQT provides a weight-of-evidence approach integrating toxicological and
chemical analysis with benthic community structure to determine likely impacts of
contaminants. Generic effects-based sediment quality guideline (SQG) values were also
used to facilitate evaluation of sediment quality by identification of potential contaminants
or mixtures of contaminants, likely to cause adverse biological effects. Chemical analysis
involved assessment of total trace metals and organics concentrations within sediments.
Assessment of toxicity involved the adaptation of a suite of first tier screening bioassays,
currently used for testing toxicity of marine water: Micro lox®, sea urchin larval
development inhibition and algal growth inhibition tests. Benthic macroinvertebrate
community structure was evaluated using univariate, distributional and multivariate
analysis of assemblages: species diversity indices, hierachical cluster analysis and nonmetric
multi-dimensional scaling ordination.
Differential SQT analysis indicated strong evidence of contaminant-induced stress, and
possible environmental degradation in the Tamar River estuary at Deceitful Cove.
Additionally, contaminant-induced stress was not restricted to a geographically isolated
area adjacent to the industrial estate. Multi-dimensional scaling ordination and univariate
analyses identified significant differences between the patterns of distribution and
abundance of benthic fauna from contaminated and non-contaminated estuaries. There was
a significant correlation between patterns of assemblages and concentrations of trace
metals.
The overall findings from the SQT and multivariate analyses strongly suggest that a
combination of metal contaminants are directly related to elevated pore water toxicity and
alteration in macroinvertebrate community structure. The liquid phase Microtox® and algal
growth bioassays are suitable for testing pore water toxicity of Tasmanian coastal marine
sediments. However, difficulty in interpreting Microtox® solid phase test results limits the
use of this assay for routine testing. Additionally, research on extending the spawning
period of the sea urchin Heliocidaris tuberculata is necessary before this species can be
used for routine bioassay work.

Item Type: Thesis (PhD)
Keywords: Water, Marine pollution
Copyright Holders: The Author
Copyright Information:

Copyright 2000 the Author - The University is continuing to endeavour to trace the copyright
owner(s) and in the meantime this item has been reproduced here in good faith. We
would be pleased to hear from the copyright owner(s).

Additional Information:

Chapter 4 is the equivalent of a post-print of an article published as: Mondon JA, Duda S, Nowak BF, 2001, Histological, growth and 7-ethoxyresorufin O-deethylase (EROD) activity responses of greenback flounder Rhombosolea tapirina to contaminated marine sediment and diet, Aquatic toxicology, 54(3-4):231-247 and has the DOI 10.1016/S0166-445X(01)00146-1

Chapter 5 is the equivalent of a post-print of an article published as: Mondon JA, Duda S, Nowak BF, 2000, Immune response of greenback flounder Rhombosolea tapirina after exposure to contaminated marine sediment and diet, Marine environmental research, 50(1-5), 443-450 and has the DOI 10.1016/S0141-1136(00)00253-1

Appendix 5 is the equivalent of a post-print of an article published as: Mondon JA, Nowak BF, Sodergren, A, 2001, Persistent organic pollutants in oysters Crassostrea gigas and sand flathead Platycephalus bassensis from Tasmanian estuarine and coastal waters, Marine pollution bulletin, 42(2), 157-161 and has the DOI 10.1016/S0025-326X(00)00211-3

Date Deposited: 03 Feb 2015 03:04
Last Modified: 11 Mar 2016 05:54
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