Identification, impacts, and prioritisation of emerging contaminants present in the GBR and Torres Strait marine environments

Heavy/trace metals and metalloids are major anthropogenic contaminants in estuarine and coastal waters. Their concentrations in the GBR and TS marine environments are typically low, except in areas within ports and harbours and those adjacent to intense urban, industrial or agricultural activity. It is likely that heavy metal contamination in the GBR and TS will increase with increasing coastal and industrial development in these regions. This presents an ecological concern given the persistent nature of heavy metals and metalloids, known toxicity to marine organisms, and their estimated residence in the GBR lagoon ranging from years to decades. Metals and metalloids at some sites in the GBR and TS have concentrations that exceed water and sediment quality guidelines, indicating potential health risks to marine species. While point sources are often highly regulated to ensure that discharges and emissions of contaminants do not exceed levels of environmental concern, less is known about inputs from diffuse sources. For example, runoff from Papua New Guinean (PNG) catchments affects sediment quality in the northern and north-central TS. Similarly, our preliminary estimate of the dissolved aluminium load from the Calliope catchment near Gladstone suggests that diffuse source contribution could be considerable. This suggests that current management arrangements, which do not consider the risks of metals and metalloids from diffuse sources may need to be re-assessed and associated research recommendations are provided.