Occurrence of microplastics in natural and farmland soil in the Qilian Mountains of the Northern Tibetan Plateau

Microplastics(MPs)become ubiquitous in soil and are an environmental and public health concern worldwide.However,the status of MPs in natural and farmland soils in remote areas remains poorly understood.In this study,we investigated the characteristics of MPs in natural and farmland soils along two transects in the Qilian Mountains of the northern Tibetan Plateau.The average abundance of MPs in natural and farmland soils was 29,778 and 56,123 items kg^(-1),respectively,with a detection size range of 10-1000μm.MPs in the size range of 10-100μm accounted for 84.1%of particles detected.Among the 21 polymers detected,polyethylene dominated in both farmland and natural soils.The shape of MPs was dominated by fragments(95.8%),followed by fibers(3.8%)and beads(0.4%).The abundance of MPs was positively correlated with increasing altitude in natural soils.There was no significant correlation between the abundance of MPs and soil physicochemical properties due to the narrow range of values of soil physicochemical properties.With the growing concern regarding MPs pollution,research on the status of MPs in high altitude and remote areas is critical to understanding their global cycle.

Effects of Volcanic Activity on Organic Matter Sources and the Paleoenvironment:Geochemical Evidence from Upper Carboniferous Source Rocks(Batamayineishan Formation)in Eastern Junggar,NW China

The mudstone,gray tuffite and carbonaceous shale in the Upper Carboniferous Batamayineishan Formation(Bashan Formation)are essential source rocks for the volcanic reservoir in eastern Junggar,northwestern China.The kerogen components,vitrinite reflectance,Rock-Eval pyrolysis,lipid biomarkers and isotope compositions were measured to understand the provenance and depositional environment of Bashan Formation under the background of volcanic activities.There were 10 and 4 periods of volcanic eruptions identified in the wells CS and DZ,respectively.The source rocks developed in the late or intermittent phase of volcanic activity.The original island arcs of the Early Carboniferous evolved into the Wucaiwan sag and the Dishuiquan sag in the Bashan Formation.The Wucaiwan sag inherited the restricted,closed residual sea,which had a slightly anoxic and hypersaline environment.The Dishuiquan sag was generally an oxidizing lacustrine environment,influenced by a marine transgression that may have occurred at the end of the DZ_(Ⅲ)period during the Late Carboniferous.Although the total organic matter decreased due to the volcanic eruption,ash could cause an increase of aquatic organisms,coinciding with increases in salinity and reducibility in the Dishuiquan sag.