There are growing concerns on microplastic pollution worldwide. Due to their slow degradation time, plastics can exist in the environment for hundreds of years. Also, microplastics are proved to cause negative effects on marine organisms. The occurrence of microplastics has been well documented in marine environments. However, information on plastic pollution from the freshwater environment is limited compared to that from marine environments. Freshwater systems have many important functions and can be one of the biggest sources of microplastic pollution. The Three Gorges Reservoir (TGR) is the largest reservoir in China. The impoundment of the Yangtze river has drastically changed the hydrologic conditions. To investigate the microplastic pollution in Xiangxi River, which is one of the longest tributaries of the TGR, related surveys were conducted at seven sampling sites along the river during April 2015 to January 2016. A total of 28 samples were collected with a net of 112 μm mesh, trawled at the surface water of the river. The abundance of microplastics in the Xiangxi River ranged from 7.8 × 104 to 3.4 × 107particles/km2, which was 1-3 orders of magnitude higher than those in marine environments in the remote areas. Yet, it was comparable to those in urban areas under heavy human influences. The detected microplastics mainly consisted of polyethylene, polypropylene, and polystyrene. Generally, the abundance of microplastics was higher in the downstream compared to that in the upstream of the Xiangxi River, and such an abundance was the highest in July when the water level of the river is the lowest. Intensive anthropogenic activities and high precipitation in summer may contribute to a significant amount of microplastics in the river due to sewage discharge and run-off. It can be concluded that the Xiangxi River has been seriously polluted by microplastics.

Distribution of microplastic pollution in a tributary of the Three Gorges Reservoir: A case study in Xiangxi River

253rd National Meeting (2017)

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