The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

226 / 2024-09-11 23:16:05

Fate and mass budget of microplastic in the Beibu Gulf, the Northern South China Sea

microplastic,Inventory,Mass budget,Beibu Gulf

Beibu Gulf is an essential region of the microplastic fluxes in the northwest part of the South China Sea and, therefore in the Indo-China peninsula due to different coastal activities such as industry, tourism, urban development, intensive fishing, and loads of riverine discharge. Multiple samples from surface water, bottom water, and surface sediment were taken for this investigation. The results showed that in surface and bottom seawater, MP concentrations were 0.25 ± 0.25 items/m³ and 0.29 ± 0.29 items/m³, respectively, while 74.99 ± 37.53 items/kg in surface sediment. Statistical analysis and the abundance of MP between surface water and sediment showed vise-versa phenomena. Both had similar features, in contrast, statistical analysis showed a negative relationship between these two. The mass balance of the box model showed that riverine discharge account for a substantial portion of MPs (42 %), whereas the South China Sea (SCS) receives 49 % of MPs discharged from Beibu Gulf. Just 1 % is deposited in sediment annually, which could explain the vise-versa phenomena between statistical analysis and the geographical distribution of microplastics. Nonetheless, it is revealed that human activities and coastal influence have more influence on microplastic abundance and distribution in the Beibu Gulf.