Trace metal behaviour in an industrialised estuarine system and the toxicity of pulsed copper exposures

The concentrations of metal contaminants may fluctuate in estuarine waters due to the erratic nature of sources and various physico-chemical parameters that influence concentrations. Standard toxicity tests use continuous contaminant exposure to assess organism toxicity even though organisms may respond differently when exposed to fluctuating concentrations. An investigation was made of the spatial distribution and short-term temporal fluctuation trace metals in an industrialised estuarine system and the influence of short-term fluctuations in metal concentrations on the toxic effects elicited to aquatic organisms. Copper was determined to be the metal of greatest concern due to the elevation of this metal above concentrations representative of regional waters and because copper is known to be relatively toxic to aquatic organisms. The toxic effects and mechanisms of toxicity in a marine algae and amphipod elicited by pulsed copper exposures were thoroughly investigated in laboratory bioassays. Spatial and temporal sampling and analysis of trace metals in waters and sediments was undertaken in the highly industrialised central Queensland harbour of Port Curtis, Australia, and surrounding waters. The trace metals measured in Port Curtis were significantly higher (p