Terrigenous export and ocean currents' diffusion of organophosphorus flame retardants along China's adjacent seas

High demands for but strict regulatory measures on Organophosphorus Flame Retardants (OPFRs) have resulted in mainland China transitioning from the region that imports OPRFs to one that exports these substances. Simultaneously, large quantities of terrigenous OPFRs have been exported to adjacent seas by the major river systems, particularly the Yangtze River. This study examined the presence of ten OPFRs in China's adjacent seas. High levels of OPFRs were observed in seas south of mainland China, with Tris (2-chloroethyl) phosphate (TCEP) and Tris (1,3-dichloro-2-propyl) phosphate (TDCPP) dominant. The terrigenous OPFRs were redistributed by the ocean surface currents, with OPFRs tending to accumulate in regions with lower current speed. The producers of OPFRs are mainly distributed along the Haihe, Yellow, and Yangtze river systems. The application of OPFRs to electric vehicle charging stations, charging connectors, and 5G infrastructure in the Chinese mainland will likely drive rapid growth in OPFR related industry in the future. The diffusion trend map of OPFR indicated that the Bohai Sea and the central northern Yellow Sea are at high risk of ecological damage in the spring. The offshore region of the north of the South China Sea tended to aggregate more OPFRs in summer. Regions of the OPFR aggregation effect were at a higher risk of ecological damage.

Automated summary

Due to high demands and strict regulations, mainland China has transitioned from importing Organophosphorus Flame Retardants (OPFRs) to exporting them. Large quantities of terrigenous OPFRs have been exported to adjacent seas, particularly the Yangtze River. High levels of OPFRs, mainly Tris (2-chloroethyl) phosphate (TCEP) and Tris (1,3-dichloro-2-propyl) phosphate (TDCPP), were observed in seas south of mainland China. The ocean surface currents redistributed the terrigenous OPFRs, accumulating them in regions with lower current speed. OPFR producers are primarily located along the Haihe, Yellow, and Yangtze river systems. The application of OPFRs in electric vehicle charging stations, charging connectors, and 5G infrastructure in mainland China is expected to drive rapid growth in the OPFR related industry. The diffusion trend map of OPFRs indicated that the Bohai Sea and the central northern Yellow Sea are at high risk of ecological damage in spring, while the offshore region of the north of the South China Sea tends to aggregate more OPFRs in summer. Regions with the OPFR aggregation effect are at a higher risk of ecological damage.