Distribution characteristics of microplastics in waterfront green space and the impact of land-use in high-density urban core area: a case study of jinjiang ecological belt in Chengdu

Microplastics, as a new type of pollutant, are widely present in urban aquatic environment, and the pollution problem of microplastics in waterfront green space within high-density urban core area is worth discussing. Ten urban waterfront parks in Jinjiang Ecological Belt in Chengdu were selected as the research objects. Through the systematic investigation of microplastics pollution in surface water and soil sediments, the study explored the distribution and characteristics of microplastics in the waterfront green space of Chengdu's high-density core area and analyzed the impact of different urban land-use types on microplastics pollution. It also assessed the risk of microplastics and proposed effective solutions to mitigate microplastics pollution. The results showed that the abundance of microplastics in surface water samples ranged from 10.73 items/L to 28.33 items/L, while in soil sediment samples, the abundance ranged from 587 items/kg dry weight to 958 items/kg dry weight. In both water and sediment samples, the main forms of microplastics were particles, fragments, fibers, and films, and the size was predominantly distributed in the range of 50~<500 μm. The main polymer types were polypropylene (PP), polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PET). Sites with large area of commercial and service-oriented facilities tended to have higher microplastics concentration. From the perspective of urban planning, limiting the distribution of land use type with high pollution potential (such as commercial service facilities) near waterfront green space will help alleviate the pollution problem of waterfront green space in microplastics, a high-density urban core area.