Occurrence and Driving Mechanism of Microplastics in River-connected Lake of the Mid-lower Yangtze River Basin

Abstract

Microplastics (MPs) in river-connected lake of the mid-lower Yangtze River Basin (YRB) are emerging pollutants. There is limited understanding of how human activities influence their presence and the associated risks remain uncertain. This study analyzed data from 19 peer-reviewed experimental research articles, from 262 and 210 samples for water and sediment, respectively. The results found an average MP abundance of 11,853.52 items/m³ in water and 649 items/kg.dw in lake sediment, with varied shapes, colors, and polymer types of different proportions. The GeoDetector model and Redundancy analysis explained the geography location and sampling method, depth, and time were influence factors drivers affect and interact with the results distribution of MPs in water and sediment. The accuracy of detection results requires reliable and standardized methods for MP extraction and identification in the laboratory. The Mantel test indicated the significant factors influenced by factors of human activities such as social factors, economic factors, and the effluence of wastewater factors on MP morphology. Ecological risk assessments indicate the classified levels of hazard as low, moderate, high, and very high, according to the Pollution Load Index, Polymer Risk Index, and Potential Ecological Assessment Index which extend to extremely high. Monte Carlo simulation indicated that polyvinyl chloride (PVC) and polycarbonate (PC) as the most contribution to the ecological risk should be considered. This study examines MP abundance, driving factors, and ecological risk in river-connected lakes of the mid-lower YRB, which will improve control and monitoring strategies for MP pollution.