Spatial characteristics of microplastics in the high-altitude area on the Tibetan Plateau.

Microplastics (MPs) have been widely detected in the environments, yet the sources of MPs in freshwater of remote areas at high altitude were not well understood. This study investigated the abundance and distribution of MPs in water bodies and sediments at the Qinghai-Tibet Plateau (QTP). MPs were detected in all samples (47 water and 33 sediment samples) with the mean abundance of 624.70 ± 411.39 items/m3 in water and 41.52 ± 22.31 items/kg in sediment. In descending order, the highest MP oncentrations were found in turbid rivers＞agricultural channel water＞lakes＞ordinary rivers. The results showed that MP abundance was associated with the water quality (especially COD) on the QTP, and it was negatively correlated with altitude due to less human activities (especially agricultural activities) at high altitude areas. In addition, more abundant MPs with small sized was found in the higher altitudes than low ones. Determining the effects of different environments on the distribution and degradation of MPs in the high altitude area of the QTP, this study emphasized the attention to be given to this emerging pollutant in the high altitude remote areas.