Abstract: Microplastics are a kind of widespread environmental contaminants, with serious threat to aquatic environment. In this study, three benthic species (Corbicula fluminea, Unio douglasiaeand Cipangopaludina cahayensis) were sampled from the estuary of Raohe River to Poyang Lake and the estuary of the middle tributary in lower Ganjiang River to Poyang Lake. The samples were screened by tissue digestion, and then filtered through the filter membrane. The membranes were dried and observed under metallographic microscope to identify plastic fragments. The abundance and types of microplastics in the benthic animals were analyzed. Microplastic deposition was found in all the three benthic species, particularly in their digestive tracts, with their deposition abundance descending as follows: C. fluminea >C. cahayensis >U. douglasiae. The microplastics deposited in the three benthic species can mainly be divided into four types, including particles, chips, films, and fibers, with fibers being the dominant type. The dominant colors of the microplastics were transparent, blue, red, and purple. The abundance of microplastics with particle size less than 1 mm was the highest. The microplastic abundance in the benthic animals decreased with increasing particle size. Spatially, the microplastic abundance of benthic species from the estuary of Raohe River to Poyang Lake was higher than that from the estuary of the middle tributary in lower Ganjiang River. It is concluded that the microplastic pollution in Poyang Lake has resulted in microplastic deposition in benthic species. More attention therefore should be paid on controlling the intake of aquatic products from the lake. In comparison with other studies, the microplastic pollution of benthic animals in this study is at the medium level.

Key words: red soil dryland, multiple cropping pattern, grey relational analysis.