Influence of eco-friendly float replacement on microplastic pollution and their metal adsorption behavior in Sanggou Bay, China.

Mariculture regions represent significant hotspots for microplastic (MP) pollution. While eco-friendly floats are increasingly replacing conventional counterparts, the efficacy of this intervention in mitigating MP pollution and its implications for metal adsorption behavior in the marine environment remain poorly characterized. This study investigated the influence of eco-friendly float replacement on MP pollution and their metal adsorption behavior in Sanggou Bay, China. The results showed that the average abundance of MPs was 4.50 ± 0.57 items/L in surface seawater and 1872.86 ± 138.68 items/kg in sediments, respectively. MPs smaller than 0.5 mm and fibers in shape were dominated in both surface seawater and sediments. Transparent MPs were most prevalent, with polyethylene (PE), polypropylene (PP), and polystyrene (PS) as the dominant polymers. Following the replacement of conventional floats with eco-friendly floats, MP abundance in surface seawater decreased by 77.57 %. Notably, MP toxicity equivalent values in both seawater and sediment were significantly declined, indicating that eco-friendly floats effectively alleviate MP pollution. Analysis of metal adsorption onto MPs in surface seawater indicated that Mn, Cr, and Cu accounted for >84 % of total adsorption. Adsorption behavior was influenced by MP size, polymer type, and ambient metal concentrations. These findings highlight eco-friendly floats as an effective mitigation strategy to reduce MP pollution and advance understanding of the fate and risk of MPs in mariculture ecosystem.