Lithostratigraphy, mineralogy and the boron-bearing brine evolution of DaQaidam Salt Lake in Qaidam Basin since Holocene period, northern Qinghai-Tibet Plateau

Little attention has been paid to the study of sedimentary records from DaQaidam Salt Lake regarding brine evolution and hydro-climate change. Here we report the results of AMS 14C dating and mineralogical investigation on a sediment profile D4 from the south central of perennial saline water-body. The result revealed that pinnoite deposit in the lakebed was formed in early Holocene, the lake underwent three stages of lake-level and brine evolution in Holocene period, which were determined mainly by precipitation-controlled catchment inflow. The mineralogical records also depicted fluctuations in lake level and hydrochemistry on decadal and centennial scales

Distribution and health risks of aerosol black carbon in a representative city of the Qinghai-Tibet Plateau

Although aerosol black carbon (BC) exerts strong influences on human health, research on potential health risks of aerosol BC around the Qinghai-Tibet Plateau is very limited. This is the very first study to investigate the distribution of aerosol BC in a typical city of the Qinghai-Tibet Plateau and the resulting health risks. The results showed that the maximal real-time (5-min monitoring interval) concentration of aerosol BC was 22.34 pg/m 3 , much higher than day- and week-averaged concentrations which were in the range of 1.28-6.15 and 1.93-4.63 gg/m 3 , respectively. The health risks were evaluated using four different health endpoints including low birth weight (LBW), percentage lung function decrement of school-aged children (PLFD), cardiovascular mortality (CM), and lung cancer (LC). The highest risks of LBW, PLFD, CM, and LC had reached 69.5, 184.4, 67.4, and 31.8 numbers of equivalent passively smoked cigarettes (PSC), respectively. The concentrations and health risks of aerosol BC in the study area are at a middle level among the global cities/regions. In comparison, the cities of the Qinghai-Tibet Plateau are experiencing high potential health risks resulting from aerosol BC to need more effective prevention and control of air pollution

The dust storm events recorded in DaQaidam region of Qaidam Basin since Late Glacial period: evidence from the grain size of lake sediment

The paper focused on the study of detrital yellow layer from sediment profile D3 of DaQaidam Salt Lake, based on AMS 14C chronologic and mineralogical methods, aimed to discuss the dust storm events recorded by detrital yellow layer of DaQaidam region since Late Glacial period. The results showed that the grain-size distribution curve displayed double kurtosis, the main peak (10 µm in average) reflected the fine-grained fractions into lake by fluviation, and the secondary peak (> 32 µm) reflected the coarse silt fractions into lake by wind effect and fluviation. Finally, the coarse-grained fractions (> 64 µm) from sediment profile D3 probably recorded the dust storm events since Late Glacial period

Effect of freeze-thaw cycles on soil physicochemical properties and fractions of Pb and Cr in the northeastern Qinghai-Tibet Plateau

Simulation experiments were conducted using soils in the northeastern Qinghai-Tibet Plateau to explore the effects of freeze-thaw cycles on soil physicochemical properties, Pb and Cr distribution, and fraction transformation. Soils were incubated at -15 degrees C for 24 h and at 5 degrees C for 24 h to complete a freeze-thaw cycle. The soil physicochemical properties and fractions of Pb and Cr were analyzed after serial freeze-thaw treatments. The results showed that different freeze-thaw cycles and water content affected soil physicochemical properties and fractions of Pb and Cr to some extent. The cation exchange capacity increased significantly in agricultural and pastoral soils after five freeze-thaw cycles. The sand proportion of soil in an urban area decreased at 60 cycles. Freeze-thaw cycles did not change the functional groups and mineral constituents of the soils. The infrared peaks of soils with different freeze-thaw conditions were very similar. The freeze-thaw treatment influenced the mobility, chemical fractions of Pb and ecological risk in most of the soils. The exchangeable Pb in agricultural and pastoral areas increased from 0.19 to 1.52/0.90% after 5/10 freeze-thaw cycles with 60% water content. The ecological values of Pb in urban soil were 8.32/7.38% higher at 10/15 freeze-thaw cycles compared with the control treatment. Hence, these findings provide useful information on physicochemical properties and fraction transformation of Pb and Cr in soils undergoing freeze-thaw cycles, and offer an additional insight on Pb and Cr behaviors in cold and freezing environments. Thematic collection: This article is part of the Hydrochemistry related to exploration and environmental issues collection available at

Effects of Yak Dung Biomass Black Carbon on the Soil Physicochemical Properties of the Northeastern Qinghai-Tibet Plateau

The physicochemical properties of soils might be affected by the addition of biomass black carbon, a special black carbon produced by incomplete combustion of biomass. Therefore, this study performed experiments to explore the effects of yak dung biomass black carbon (YBC) on physicochemical properties of soils in the northeastern Qinghai-Tibet Plateau. Three YBCs (pyrolyzed at 300, 500, and 700 degrees C) were separately added into four typical soils with three addition amounts (1%, 5%, and 10%). Changes of soil texture, pH, electrical conductivity (EC), cation exchange capacity (CEC), CHN contents, morphologies, functional groups, and mineral constituents of soils were comparatively studied. The results showed that addition of YBCs affected physicochemical properties of soils. Soil pH, EC, CEC, and carbon/nitrogen content were positively related with addition amount of YBCs. YBC particles were unevenly distributed among soil particles and positively related with addition amount. Addition of YBCs did not change texture, functional groups, and mineral constituents of soils. These results indicated that addition of YBC would be beneficial to stability of the soil ecosystem and sustainability of the northeastern Qinghai-Tibet Plateau

Pollution, ecological-health risks, and sources of heavy metals in soil of the northeastern Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau, especially the northeastern region, is not a pure land any more due to recently increasing anthropogenic activities. This study collected soil samples from 70 sites of the northeastern Qinghai-Tibet Plateau to evaluate pollution, ecological-health risks, and possible pollution sources of heavy metals. The concentrations of heavy metals in soil were relatively high. Values of geo-accumulation index exhibited that Hg pollution was the most serious meanwhile Hg possessed the strongest enrichment feature based on enrichment factor values. The modified degrees of contamination showed that about 54.3% and 17.1% of sampling sites were at moderate and high contamination degree while pollution load indexes illustrated that 72.9% and 27.1% of sampling sites possessed moderate and high contamination level, respectively. Ecological risk indexes of heavy metals in soil ranged from 234.6 to 3759.0, suggesting that most of sites were under considerable/very high risks. Cancer risks for adults and children were determined as high and high-very high levels while non-cancer risks for children were high although those for adults were low. Industrial source contributed to the main fraction of ecological and health risks. Summarily speaking, heavy metals in soil of the study area has caused significantly serious pollution and exerted high potential ecological and health risks, especially for children who are more susceptible to hurt from pollutants. Therefore, more efficient and strict pollution control and management in study area should be put out as soon as possible. (C) 2018 Elsevier Ltd. All rights reserved