Soil microplastic pollution in an e-waste dismantling zone of China

Microplastic pollution is ubiquitous and has emerged as a severe global environmental issue. Recent research on microplastic pollution has mainly focused on aquatic ecosystems, while knowledge gaps still exist regarding microplastic in terrestrial environments. In this study, we established a new method for characterizing microplastic in complex soil substrate using FTIR spectroscopy. Microplastic was separated by density without removing soil organic matter to protect microplastic from damage. The Wizards feature was adopted to automatic, direct and continuous characterize micron-size plastic. Furthermore, 33 soil samples were taken from Guiyu, a notorious e-waste dismantling area in Guangdong Province, China, under different land-use. The results showed that microplastic was involved in 30 samples, and the abundance of microplastic varied considerably among different soils, ranged from 0 to 34,100n kg, implying that the e-waste dismantling sites have become the microplastic hotspots. There were 60 kinds of microplastic detected with 6 different shapes and 10 colors, most of which were secondary microplastic. They mainly consisted of engineering-plastic and modified plastic, 88.61% had a size range <1 mm, indicating that the majority of microplastics at Guiyu were derived from e-wastes. The surface morphology of microplastic showed signs of aging and degradation, possibly due to primitive dismantling methods and long-term exposure to the soil. The mean Pb, Cd, Cr, Ba, Cu, Co, As concentrations of microplastic were 20.94, 0.67, 11.82, 308.78, 4.11, 1.26, 3.06 μg·g, respectively. Our findings providescientific basis for monitoring and controlling microplastic pollution in terrestrial environments.