A Review of Microplastics in China Marine Waters

Microplastics (<5 mm) are ubiquitous in the environment and can pose potential danger to the ecosystem and even human health. As the sink of microplastics, the ocean, especially the densely populated coastal area, has become a hotspot for research on microplastic pollution. In the last decade, the research of marine microplastics has been rapidly increasing in China. This review summarized the microplastic research conducted in China marine waters so far, and introduced the trends and progress of microplastic research in the four seas along the coast of China. We reviewed and compared the current sampling, extraction, and identification methodologies of China's microplastic research. According to the sampling method, the 30 reviewed studies were separated into two categories, trawl sampling and bulk sampling, to summarize relevant data, including abundance, sizes, shapes, colors and polymer types of microplastics. The main results showed that the distribution of microplastics in China's marine environment varied significantly, with offshore mariculture zones and the South China Sea being the most contaminated areas. Transparent, granules (or pellets) and fibers were the most dominant microplastic colors and shapes, and the size of microplastics was influenced significantly by the sampling method. Polyethylene (PE), polypropylene (PP) and polystyrene (PS) were the most common polymer types found in the China Sea, accounting for 49.96%, 29.97%, and 12.38% of the total studies, respectively. Compared with other global data, China's coastal microplastic pollution is at an intermediate level and does not seem to be a major microplastic pollution source.