Distribution and characteristics of microplastics in urban waters of seven cities in the Tuojiang River basin, China

Microplastics pollution presents an increasing concern worldwide due to the large amount and potential risks. However, data on microplastics in the freshwater environment are still limited, especially in southwest China. This study investigated the microplastics distribution, characteristics and risks in urban water of different cities in the Tuojiang River basin in southwest China. Microplastics were found in all seven cities of the Tuojiang River basin and the concentrations varied from 911.57 ± 199.73 to 3395.27 ± 707.22 items/m3, among which Ziyang urban water had the highest microplastics concentration. Fiber (34.88–65.85%) was a typical and abundant microplastic type. The small size (0.5–1 mm) (27.27–66.67%) was predominant, and white (23.30–54.29%) was the dominant color among all samples. Polypropylene was identified as the main polymer type by Fourier transform infrared spectroscopy. The morphological analysis by scanning electron microscopy indicated that the surfaces of the microplastics had many cracks and a multitude of particles were adsorbed onto it. According to correlation analysis, there was a significant positive correlation between gross domestic product(P=0.015