This study aims to assess the impact of recent bushfire and flood on the potential mobilisation of PFAS from contaminated sites to natural water-bodies and the resulting impact on biodiversity.
Water quality and biodiversity during bushfires
Bushfires have the potential to degrade water quality and alter the dynamics of stream ecosystems in many complex ways. Most critical effects occur if there is heavy rain after fires, as loss of vegetation and altered soil structure can make fire-affected soils more erodible. Runoff can carry sediments and pollutants that affect coastal aquatic and marine environments, water quality and biodiversity. The problem can be even more critical if the land and water in the bushfire-affected area had already contained toxic chemicals from previous pollution.
In the past, Polyfluoroalkyl substances (PFAS) have been extensively used for stain-resistant coatings, water-resistant fabrics, metal plating paints, pesticides, and aqueous film-forming foams used in firefighting. Although their use is being gradually phased out in Australia, the historical use of PFAS in fire-fighting foams has resulted in increased levels being detected at sites where fire-fighting training has been conducted, or where fire suppression systems are installed for extinguishing liquid-fuel fires. PFAS of greatest concern are highly mobile in water, which means they travel long distances from their source-point; they do not fully break down naturally in the environment; and they are toxic to a range of animals, particularly freshwater species.
The team will assess amphibian abundance, distribution, and species richness in relation to sediment PFAS content and water chemistry in wetlands located along two sites which are known to be historically contaminated with PFAS, with one affected by recent bushfire, while the other was not.
This project is working towards the UN Sustainable Development Goals: