Quantifying Footprints of Perfluorinated Compounds in China: From Production to Discharge into the Seas

Understanding the emission sources and environmental footprints of perfluorinated compounds (PFASs) is essential for tracing their pervasive presence in the environment. This study aims to comprehensively assess the emissions and footprints of 10 commonly reported PFASs in China from production to their final release into the sea. In 2022, China produced 120 t target PFASs, with 104 t utilized in secondary industrial production. One-third of those applied PFASs emit into the environment primarily from industrial processes. Domestic use resulted in the emission of 4.21 t of PFASs, half of which was sourced from wastewater treatment plants. River water received 57.6% of the total PFAS emissions, with 11.4% eventually flowing into China's surrounding seas. During 2015-2022, China experienced a cumulative PFAS emission of 467 t, with 40.3 t emitted into neighboring seas, predominantly into the Bohai and East China Seas. The spatial distributions of PFAS emissions and pollution levels were consistent with China's topographical three-tiered stepped lines. Economic and topographical factors strongly influenced the footprint processes and transport patterns of PFASs into the ocean. This study traces and quantifies the major PFAS pathways from production to discharge into the sea, highlighting the need for targeted interventions to reduce PFAS emissions and protect ecosystems.