Abstract:

The pollution characteristics of microplastics in the hydro-fluctuation belt (HFB) of Danjiangkou Reservoir, especially under different land use types, remain inadequately understood. This study aimed to investigate the current contamination levels of microplastics in soil samples from various land use types—open space, forested land, and cropland—within the HFB of Danjiangkou Reservoir. Our findings revealed average microplastic abundances in open space, forested land, and cropland at 985±333 n/kg, 798±143 n/kg, and 625 ± 175 n/kg, respectively. The dominant polymer types identified were polyethylene (PE), polypropylene (PP), and polystyrene (PS), accounting for 44.0%, 27.2%, and 11.1% of the total microplastics, respectively. Over 75% of the microplastics were fibrous in form, and around 39.5% of the particles exhibited sizes ranging from 50 to 500 μm. Blue was the most frequently observed color among the microplastics. Moreover, there were significant variations in microplastic abundances across different land use types in the HFB, with the abundance in open space being the largest, followed by forested land and cropland in descending order. These results offer valuable insights into the occurrence characteristics of microplastics in the HFB under diverse land use scenarios and serve as a reference for future research in this area.

Key words: hydro-fluctuation belt, characteristics of microplastic occurrence, land use types, microplastic pollution control, water quality safety, Danjiangkou Reservoir