Abstract:To understand the storage characteristics of microplastics in estuaries of Wanquan river, Hainan. The distribution and composition of microplastics were explored through the research methodology involved a combination of on-site investigation and laboratory analysis, its potential sources were also analyzed, and evaluated its ecological risk by combining the polymer risk index, pollution load index, and potential ecological risk index. Results showed that microplastics abundance in Wanquan river estuaries were ranged from 0.32 to 0.74 ind/m3 and the mean was 0.53±0.13 ind/m3; the components of microplastics were polypropylene (34.8%), polyester (23.7%) and polyethylene (20.0%); Microplastics shapes were mostly in the form of fragments (58.4%), followed by fibers (32.3%). While colors were display a wide variety, with a predominance of translucent (41.6%) and white (36.8%) colors. Size of microplastics were ranged from 1.0 to 4.0 mm, which accounted for 42.2%. The characteristic analysis indicated that microplastics primarily originated from tourism activities, fisheries production, and domestic sewage from residents. Furthermore, microplastics abundance exhibited a regional distribution unevenly, which influenced by wind power, ocean currents, runoff, and seawater dilution. When compared with the results from domestic and abroad studies, the surface seawater microplastics in the estuary of Wanquan river were at a relatively low pollution level. The risk assessment results also showed that the overall pollution level of microplastics in this region were low, but control measures should be taken for plastic products with high chemical toxicity.