NESP TWQ Round 5 - Project 5.14 – Identifying the water quality and ecosystem health threats to the Torres Strait from the Fly River runoff

Runoff from the Fly River in Papua New Guinea (PNG) influences water quality conditions in the Torres Strait region. Recent work (NESP Project 2.2.1 and 2.2.2) has clearly demonstrated that this influence is largely constrained to the northern Torres Strait, as far east as Bramble Cay and at least as far west as Boigu Island. The southern extent of influence is considered to be limited to within 40-50km of the PNG coast in the western areas, and around 80km in the eastern areas. The intensity of this influence, and the potential ecological impacts, are still not well understood. Trace metal concentrations are higher in the northern Torres Strait around Boigu and Saibai, however it is not clear whether this enrichment is natural or the result of mine derived inputs of trace metals. Further investigation is required to understand the prevalence and frequency of the extension of the Fly River plume into the northern Torres Strait, and further characterisation of plume constituents, particularly sediment and trace metals in comparison to previous results including the Torres Strait Baseline Study.