Influence of urban land uses on per- and polyfluoroalkyl substances contamination in urban runoff and the receiving marine environment

Overview

Understanding the influence of urban land uses on PFAS contamination in urban runoff and receiving marine environments is critical for effective urban coastal contaminant management. However, data on PFAS contamination in urban runoff and marine receiving environments under low-flow (dry weather) conditions, which represent baseline contamination, are scarce. This study assessed the influence of urban land uses on PFAS occurrence and fate in urban runoff and adjacent marine environments under low-flow conditions. Water and co-located sediment samples were collected from five sites representing distinct land uses, including airport, residential, mixed port/agriculture, and mixed national park/residential areas, and analysed for 49 PFAS. Twenty-six PFAS were detected in water (including runoff and seawater), and seven in sediment samples. The median total PFAS concentrations were 0.186 μg L−1 in low-flow urban runoff, 0.0062 μg L−1 in seawater, 0.69 μg kg−1 in runoff sediment, and 0.58 μg kg−1 in marine sediment. PFAS distribution varied by environmental matrix. Ultrashort and shorter-chain PFAS dominated in water, while longer-chain compounds were more prevalent in sediments. Apart from the commonly regulated PFAS (PFOS, PFHxS, and PFOA), several PFAS including novel compounds bisperfluoroalkane sulfonimides (bis-FASI) and ultrashort (≤3 carbons, C), short-chain (4-6C) perfluoroalkyl acids (PFAA), and perfluoroalkane sulfonamides (PFASA) were detected in at least 50% of water samples. In contrast, short- to long-chain (≥7C) PFAAs were detected in at least 50% of sediment samples. PFAS profiles in runoff were influenced by land use, with regulated PFAS dominant in runoff from airport and industrial zones, while shorter-chain alternative PFAS more prevalent in runoff from residential areas, reflecting shifts in PFAS usage following regulatory phase-outs. These findings highlight the importance of considering land use in PFAS monitoring and the need to include a broader suite of PFAS, including novel, ultrashort, and other alternative compounds, in urban runoff and coastal environmental assessments.

Highlights
• Twenty-six PFAS were detected in water (runoff and receiving seawater) and seven in sediment.
• Ultrashort and shorter-chain PFAS were detected in at least 50% of water samples.
• Longer chain PFASs were more prevalent in marine sediment samples.
• PFAS profiles vary by land use, reflecting shifts in usage patterns.

Article on the Environmental Research website.