Poster Presentation Australian Marine Sciences Association 2026 Conference

Stormwater Contributions to PFAS Contamination in Receiving Marine Environments: Evidence From Gamay (139694)

Thebny T. Moro 1 , Robert Cooley 2 , Rose Nguyen 1 , David P. Bishop 1 , Justin R. Seymour 1 , Martina A. Doblin 1 3
  1. University of Technology Sydney, Sydney, NSW, Australia
  2. Gamay Rangers, La Perouse Local Aboriginal Land Council, Sydney, NSW, Australia
  3. Sydney Institute of Marine Science, Sydney, NSW, Australia

Per- and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative chemicals that pose risks to ecosystems and human health, highlighting the need to understand their environmental distribution and impacts. They are commonly incorporated into industrial chemicals and household items, and can be discharged into coastal areas in industrial and residential wastewater, stormwater, and land runoff. This study monitored 49 PFAS in stormwater, receiving marine waters, and co-located sediments across Gamay/Botany Bay, Australia, spanning diverse land uses (airport, residential, port/agriculture, mixed-use, and conservation areas) in different seasons. A total of 33 PFAS were detected, with water samples exhibiting greater diversity than sediments (30 vs 19 compounds). Ultra-short and short-chain PFAS dominated both matrices, whereas long-chain PFAS were less prevalent. Regulated compounds, including PFOS, PFOA, and PFHxS, were detected, with PFOS reaching maximum concentrations of 0.529 µg L⁻¹ in water and 2.35 mg kg⁻¹ in sediments. While concentrations complied with recreational water guidelines, freshwater guideline values were exceeded at both 95% and 99% species protection levels. Stormwater and associated sediments generally exhibited higher PFAS concentrations than marine environments, except at airport sites. PFASs in Botany Bay create potential exposure pathways through seafood consumption, intersecting with both recreational fishing and cultural connections to Gamay.