Occurrence, migration and environmental effects of neglected BTEX in the coastal multiple environments.

Benzene, toluene, ethylbenzene, and o-, m-, p-xylene (BTEX) are toxic and hazardous pollutants with critical impacts on ecosystem health and air quality. Here, the spatial distributions, interfacial exchange fluxes and environmental effects of BTEX were investigated in multiple environmental mediums in the East China Sea. The average concentrations of ∑BTEX in the surface (bottom) seawater, atmosphere and sediment were 235 ± 168 (152 ± 98.3) ng L-1, 600 ± 408 pptv and 0.76 ± 0.29 μg kg-1, respectively, generally decreasing from inshore to offshore regions. Furthermore, BTEX in seawater served as sources for those in atmosphere and sediment, with interfacial exchange fluxes of ∑BTEX estimated at 734 ± 748 and 1.80 ± 1.56 g km-2 d-1, respectively. Ocean currents, air masses properties and accumulation of long-term terrestrial inputs were identified as key factors controlling BTEX distributions across the different mediums. Additionally, the ozone and secondary organic aerosol formations potentials of atmospheric ∑BTEX were 0.134 ± 0.093 and 14.3 ± 11.5 μg m-3, respectively. This study addresses a critical gap in data on BTEX contaminations in coastal environments, improves understanding of their interfacial exchange processes, underscores the necessity of continuous monitoring and provided a valuable basis for environmental impact assessments.