PH08 Metals in the Environment: Aquatic Biological Perspectives
Exhibit Hall
8:00 AM - Thursday

(PH107) Otolith Microchemistry to Determine Past Environmental Exposure of Fish to Trace Metals.

RANALDI, M1, GAGNON, M1, WATLING, J2, 1 Department of Environmental Biology, Curtin University, Perth, Western Australia, Australia2 Department of Applied Chemistry, Curtin University, Perth, Western Australia, Australia

ABSTRACT- In fish, environmental bioavailable trace metals derived from both natural and anthropogenic sources may be deposited on the growing edge of the otolith and be incorporated in the otolith matrix. These incorporated trace metals may permanently record environmental conditions experienced by fishes. Pink snapper (Pagrus auratus), a long-lived fish, important both commercially and recreationally were collected from the chronically contaminated site of Cockburn Sound, Perth, Western Australia. Industries releasing contaminants in Cockburn Sound include refineries, fertilizer plant, ship building facility and a naval base. The otoliths were analysed for trace metals with the use of continuous laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS). This method ablates the otolith from the nucleus to the outer edge and provides a continuous reading of the fish′s environmental history encapsulated in its otolith. The composition of otoliths of fish from contaminated Cockburn Sound were compared with those from Shark Bay (reference site) where heavy metal contamination is virtually non-existent. The metal deposition in otoliths may give new insights on the bioavailability of various metal contaminants present in contaminated waters, which may potentially allow us to relate contaminant bioavailability to historical trends in environmental contamination. The method provides information which may be useful for long-term environmental management, fish stock discrimination and assessment of population structure.

Key words: trace metals, otolith microchemistry, fish, LA–ICP–MS

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