Microplastics (MPs) are among the most widespread anthropogenic pollutants of natural environments, while limited research has focused on the fate of MPs in soils along the Plateau rivers. In this study, we investigated MPs in soils along the source areas of the Yangtze River on the Qinghai-Tibet Plateau. The results showed mean MP abundance values of (89.4 ± 51.0) and (64.4 ± 24.5) items/kg of dry soils around the tributary and mainstream areas, respectively. Film, transparent colors, and polyethylene were common shape, color, and compositions, respectively. The correlation analysis and PCA revealed that MP abundance was related to soil heavy metals (Cr and Ni) and nutrients (TOC and TP) (p < 0.05). Structural equation modeling also revealed that population density was the dominant driving factor contributing to MPs, with a total effect coefficient of 0.45. In addition, the conditional fragmentation model further distinguished the differences in MP sources from upstream to downstream along the Jinsha River. The significant sources of MPs in the bare land and grasslands from the upper reaches of the Jinsha River included traffic, tourism, and atmospheric transport. In contrast, MP transport during farming activities mainly contributed to MPs in the agricultural soil in the lower reaches.
Microplastics (MPs) in the Yangtze River have been drawn increasing attention recently with most merely concentrating on the plain area. This research focuses on the source area of the Yangtze River on the Qinghai-Tibet Plateau (QTP), revealing the occurrence, drivers, sources, and exposure risks of riverine MPs in the Jinsha River (JSR) basin. The results showed that average MP abundances determined were higher in the tributaries than in the of mainstreams. According to the correlation analysis, MP abundance was consistently negatively related to pH and altitude both in water and sediment. However, MPs in two media showed a contrary relationship with river width, which could be explained by the special terrain of plateau rivers and hydrological conditions. After the tributary river flow into the mainstream, the concentration of MPs in the mainstream near the tributary side were significantly lower than that before confluence temporarily. Based on the conditional fragmentation-based model, the cumulative λ value of fibers in surface water along the river divided the JSR into three stages (upstream, midstream, and downstream). Under certain assumptions, the proportions of MPs sourced from three stages were eventually revealed, respectively. This is conducive to better understanding the plateau environmental impacts of MP distribution in the large river.
Aconitum carmichaeli Debx. is a traditional Chinese medicine that is cultivated in China and Japan. However, the monoculturing of this herb substantially decreases soil quality. Therefore, scientific planting management is crucial for resolving the current problems in the cultivation of A. carmichaeli. In this study, we conducted a comparative study on the soil environmental characteristics, herb growth and quality of A. carmichaeli intercropping with five local crops in two different areas. Herb growth and quality, including biomass and secondary metabolites, and rhizosphere soil environmental characteristics were measured. The results showed that the intercropping with the five local crops substantially improved the A. carmichaeli biomass and polysaccharide content, decreased the disease index, and altered three monoester diterpenoid alkaloids and three diester diterpenoid alkaloids accumulations. The intercrops also increased the soil pH, nitrogen-cycling-gene abundances, and potentially beneficial microorganism abundances, and it also changed the soil nutrient levels. Moreover, these intercropping patterns could alleviate the continuous cropping obstacles of A. carmichaeli. According to a comprehensive evaluation of the A. carmichaeli growth and quality, as well as the soil quality, the best intercropping systems were the A. carmichaeli intercropping with rice, maize, and peanut. In summary, the strip-intercropping systems could improve the A. carmichaeli growth and soil quality, and be beneficial to the sustainable ecological planting of A. carmichaeli.
Phosphorus imbalance for cropland can greatly influence environmental quality and productivity of agricultural systems. Resolving cropland phosphorus imbalance may be possible with more efficient multilateral crop trade within the involved trading countries; however, the driving mechanisms are unclear. This study calculates phosphorus budgets in China and five central Asian countries and proposes two optimal multilateral crop trade models to mitigate the phosphorus imbalance. Results show that the current trading pattern between China and Central Asia is causing a phosphorus imbalance intensification. Phosphorus surpluses in China and Uzbekistan are 41.7 and 8.9 kg/ha, while Kazakhstan, Kyrgyzstan, Tajikistan, and Turkmenistan exhibit phosphorus deficits with the negative value of -0.7, -1.2, -0.8, and -0.8 kg/ha, respectively. However, under the optimal multilateral crop trade patterns, phosphorus budget of China and Central Asia will become balanced. Phosphorus imbalance intensification for China is reduced to -2525 and -2472 kt under the single- and bilevel-objective-based crop trades. In Kyrgyzstan, it will drop 61.5 % and 50.0 % and change to 321 and 417 kt under the two optimal crop trades. Moreover, changes of phosphorus imbalance mitigations for other central Asian countries range from 11.9 % to 28.2 %. This provides a scientific basis when establishing policies for strengthening optimal multilateral crop trading across the world to promote global phosphorus management.
Schisandrae Sphenantherae Fructus (SSF), the dry ripe fruit of Schisandra sphenanthera Rehd. et Wils., is a traditional Chinese medicine with wide application potential. The quality of SSF indicated by the composition and contents of secondary metabolites is closely related to environmental factors, such as regional climate and soil conditions. The aims of this study were to predict the distribution patterns of potentially suitable areas for S. sphenanthera in China and pinpoint the major environmental factors influencing its accumulation of medicinal components. An optimized maximum entropy model was developed and applied under current and future climate scenarios (SSP1-RCP2.6, SSP3-RCP7, and SSP5-RCP8.5). Results show that the total suitable areas for S. sphenanthera (179.58×104 km2) cover 18.71% of China's territory under the current climatic conditions (1981-2010). Poorly, moderately, and highly suitable areas are 119.00×104 km2, 49.61×104 km2, and 10.98×104 km2, respectively. The potentially suitable areas for S. sphenanthera are predicted to shrink and shift westward under the future climatic conditions (2041-2070 and 2071-2100). The areas of low climate impact are located in southern Shaanxi, northwestern Guizhou, southeastern Chongqing, and western Hubei Provinces (or Municipality), which exhibit stable and high suitability under different climate scenarios. The contents of volatile oils, lignans, and polysaccharides in SSF are correlated with various environmental factors. The accumulation of major secondary metabolites is primarily influenced by temperature variation, seasonal precipitation, and annual precipitation. This study depicts the potential distribution of S. sphenanthera in China and its spatial change in the future. Our findings decipher the influence of habitat environment on the geographical distribution and medicinal quality of S. sphenanthera, which could have great implications for natural resource conservation and artificial cultivation.
This is the first attempt to simultaneously apply an improved three-dimensional ecological (EF3D) model and multivariate spatial-temporal collaborative relation model for evaluating the inter-regional ecological sustainability. Capital flow consumption and capital stock depletion can be tracked based on identification of variations in ecological footprint size (EFsize) and depth (EFdepth). Results display an unsustainable natural capital stock utilization in Chengyu urban agglomeration, especially in Neijiang, Chengdu, and Deyang with EFdepth higher than 35. There exists an obvious regional complementarity between EFsize and EFdepth, where cities with rich resources (or poor resources) are generally characterized as high EFsize and low EFdepth (or low EFsize and high EFdepth). The EF3D is slightly lower than traditional ecological footprint in value owing to its more concerns of intergenerational fairness and intrageneration fairness. Moreover, the spatial-temporal binary collaborative relation among EFsize, EFdepth, and GDP is generally higher than 0.6 with a medium level. Their temporal multivariate collaborative relation mostly lies in the intervals [0.30, 0.50] with an annual change rate of 10.22%, while slight variations exist in their spatial multivariate collaborative relation. GDP has a significant impact on the temporal collaborative relation of EFsize and EFdepth in Dazhou, Leshan, Luzhou, Mianyang, and Nanchong. There are slight impacts of EFdepth on the temporal collaborative relation of EFsize and GDP; meanwhile, GDP has a less effect on the spatial collaborative relation of EFsize and EFdepth. Findings can provide a reference for the coordinated development of social economy and ecological environment.
Conservation of Natural Resources , Economic Development , China , Cities
This study proposes water-carbon-ecological footprints to form footprint family indicators for identifying the ecological compensation and regional development equilibrium in the Triangle of Central China (TOCC). The occupation of natural capital stock and flow consumption can be illustrated using a three-dimensional ecological footprint model, and Gini coefficient is integrated into the evaluation framework for fairness measurement from various aspects. Quantificational ecological compensation standards can be given with considering indicators associated with ecological resource conversion efficiency and willingness to pay. Results reveal that ecological and carbon footprints in the TOCC demonstrate rising trends from 2000 to 2015, while its water footprint presents a fluctuating trend. The majority of average Gini coefficients exceed the threshold value of 0.4 under different footprints, thereby indicating poor overall fairness of regional development. Water footprint in Jingmen, Xiangtan, and Yichun show relatively higher compensation expenses, while Yichang, Zhuzhou, and Fuzhou exhibit higher received compensation values compared with other cities. Carbon footprint in Wuhan, Loudi, and Xinyu indicate high compensation expenses due to their overuse of biological resources. Maximum amounts of compensation expense appear in Nanchang and Wuhan from the perspective of ecological footprint. This study can provide a theoretical reference for sustainable development in the TOCC by performing a comparative analysis with Beijing-Tianjin-Hebei urban agglomeration and developed countries.
Carbon Footprint , Conservation of Natural Resources , Carbon , China , Water
