Pesticides and Other Pollutants

IN BRIEF:

This presentation summarises key findings from Chapters 5 and 6 of the Great Barrier Reef Consensus Statement, focusing on pesticides and other pollutants. The main points are:

• Pesticides are ubiquitous across aquatic environments in the Great Barrier Reef catchments, frequently exceeding ecosystem protection guidelines, especially in freshwater systems during “first flush” rainfall events.
• The Pesticide Risk Metric shows the highest risks are in the Mackay-Whitsunday region and parts of the Burdekin, largely due to diuron, atrazine, and imidacloprid.
• Modelling of diuron transport and concentrations in marine waters indicates periodic spikes that can exceed guidelines, even if overall risks are lower offshore.
• Sugarcane is the main source of pesticides, with timing and rate of application as key drivers of pesticide export.
• Effective management practices to reduce pesticide risks include reducing total pesticide use, optimising application methods and timing, and adopting alternative pest control approaches.
• Much less is known about the distribution, concentrations, and impacts of other non-pesticide pollutants like metals and *PFAS, limiting the ability to assess their risks to the Great Barrier Reef.

            *PFAS are a large, complex group of synthetic chemicals that have been used in consumer products around the world since the 1950s.