The distribution of microplastics in water, sediment, and fish of the Dafeng River, a remote river in China.

Although rivers are one of the dominant pathways by which microplastics reach the oceans, reports on remote rivers are rare. Dafeng River is located in Guangxi Province, China, is an important water source and a habitat of a coastal dolphin, Sousa chinensis, which is a first-class national protected animal in China. In this study, we determined the distribution and characteristics of microplastics in the surface water, sediment, and fish of the river. During the dry and rainy seasons, the microplastics content of the surface water ranged from 3 × 10-4-2.5 × 10-3 items/L (7 × 10-4-0.12 items/m2) and 4 × 10-5-9 × 10-4 items/L (2 × 10-3-2.8 × 10-2 items/m2), while those in the sediment samples ranged from 9.4 to 50.3 items/kg (dry weight) and 0.0-21.3 items/kg, respectively. The pollution level during the dry season was approximately two to three times higher than that during the rainy season (P   sediment > surface water in terms of items/kg. The level of microplastics pollution in the Dafeng River was relatively low; however, that in aquatic organisms was more severe. Our work highlights the requirement for concern towards microplastics pollution in the organisms of remote rivers.