Neglected microplastics pollution in the nearshore surface waters derived from coastal fishery activities in Weihai, China

Plastic fishing gears have been widely used in marine fishing and mariculture, which could cause serious microplastics pollution but receive little attention. To further figure out the effect of fishery activities on microplastics, the occurrence and sources of microplastics contamination in the nearshore surface seawater of Weihai (a coastal fishery city of China) were studied. All the collected microplastics were sorted and counted based on their size, shape, and color. The distribution of microplastics pollution in this study areas was mapped. The results showed that the mean concentration of all sampling sites was 5.9±3.5 particles/m; the concentration in the mariculture areas was 11.49 particles/m, much higher than that in other areas without mariculture 1.57 particles/m. Fragment and fiber accounted for 45.4% and 28.2% of the total microplastics, respectively. Most fibers and fragments were identified as polyethylene (PE) and polypropylene (PP), mainly originated from the fishing nets/ropes. Polystyrene (PS) was also generally detected in the samples due to the foam floating balls used in the mariculture area. Our research strongly suggested that marine fishery activities, especially for mariculture, could be an underestimated sea-based microplastics source and more attentions should be given.