Regional BDE-209 emission, environmental fate and risks: Methods establishment, data filling and feature analysis

BDE-209 is an emerging environmental contaminant that poses a significant threat to human health. Despite its inclusion in the Stockholm Convention, the current regional emission levels, environmental fate, and corresponding risks remain unclear, especially with the ongoing release of BDE-209 during the disposal of waste electrical and electronic equipment. The significant gaps in BDE-209 emission data highlight the need for a regional approach to better understand these issues. Therefore, we established a method to identify regional BDE-209 emissions, environmental fate, and risks in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) using a substance flow analysis framework, fugacity model, and risk model. Our results showed: (1) Despite the increasing pressure of electronic waste, emissions have decreased with gradual strengthening of restrictions. The stage with the highest contribution to emissions is flame-retardant plastic production, which accounts for 41 % of emissions, followed by informal treatment (36 %). (2) The largest BDE-209 emissions are into air and soil, at 7.23 t and 4.56 t, respectively, and the highest reserves are in soil and sediment. (3) Infants and young children have the highest levels of exposure and cancer risk. This research helps fill the multi-regional data gap for BDE-209 and clarify the complex regional emission situation in the GBA.