Baseline assessment of anthropogenic change and ecological risk of an estuary bordered by an urbanized catchment and a pristine national park (Port Hacking estuary, Australia)

Highlights: • Port Hacking estuary separates intense urbanization from pristine bushland. • First baseline evaluation of anthropogenic change and ecological risk posed by sedimentary metals • Estuary separates metal-enriched sediment with moderate ecological risk from sediments with no ecological risk. • Full set of baseline data is provided in support of new monitoring of future anthropogenic impacts. Port Hacking is a tide-dominated, drowned river valley at the southern edge of the Sydney conurbation (Australia) and is bordered by intense urbanization to the north and native bushland in the south. The current work provides a first-time, baseline evaluation of the magnitude of human-induced change and risk posed by sedimentary metals in Port Hacking and catchment. The estuary separates fluvial and estuarine sediment enriched in metals exhibiting moderate ecological risk from sediments with minimal anthropogenic change and no biological risk. A full set of baseline data is provided in support of new monitoring of recent and future anthropogenic impacts on the system.