Accumulation characteristics and source analysis of microplastics derived traffic of soil in the Tibetan Plateau

The development of transportation infrastructure can stimulate economic growth. However, the environmental and human health risks associated with the release of traffic-derived microplastics (MPs) into the ecosystem must also be considered. This study examined four types of soil samples collected from the Qinghai-Tibetan Plateau along the Gemang Highway. The abundance, size, morphology, and types of MPs were analyzed using laser direct infrared (LDIR) spectroscopy to gain a better understanding of their distribution and characteristics. The average abundance of MPs in the study area was 2247.92 ± 2053.82 n/kg. It showed the characteristics of wasteland (4726.67 ± 2956.76 n/kg) > wolfberry plantation (3294.44 ± 2881.93 n/kg) > sandy land (1519.44 ± 282.65 n/kg) > soil along the highway (1144.44 ± 611.01 n/kg). 67.25 % of MPs had a particle size of less than 100 µm, posing greater environmental risks. The 6 factors identified by the PMF model suggested a variety of potential sources of MPs and highlighted their connections to the transportation sector. The ecological risk assessment of MPs demonstrated a significant degree of risk, with particular concern regarding more toxic plastics use. This study provides fundamental data for the source analysis and ecosystem risk assessment of MPs derived traffic.