As a new product of rapid urbanization, the sprawl of urban construction land can objectively reflect urban land use efficiency, which is of great significance to China\'s new urban construction. This study aimed to summarize the expansion patterns and utilization efficiency of urban construction land in China from the perspectives of the status, speed and trends of expansion, and to uncover the key factors that lead to the differential distribution of the expansion of construction land. It can also provide land management experience for other countries with rapid expansion of construction land. The results show the following. (1) The expansion of China\'s construction land presents a \"point-line-plane\" pattern of evolution, forming changing stages of point-like aggregation, linear series and planar spread. (2) China\'s construction land shows the characteristics of disorderly spread, a low utilization rate and low output efficiency. The speed of expansion presents clear characteristics of being high in the east and low in the west, mostly concentrated in the Yangtze River Delta, Pearl River Delta and the Beijing-Tianjin-Hebei urban agglomeration. Shanghai, Beijing, Shenzhen and Guangzhou have the highest intensity of construction land use. In Shandong Peninsula and eastern coastal areas, the intensity of the construction land use is generally high. In Xinjiang and Xizang, the intensity of construction land use is relatively low. (3) The urban economic level, population size, industrial structure, foreign investment and land policies have significant effects on the spatial distribution of the expansion of construction land.

Objective: To investigate the spatial distribution pattern of local tumor progression (LTP) for hepatocellular carcinoma (HCC) ≤5 cm after microwave ablation. Methods: A retrospective analysis was performed on 169 HCCs with matched MRI before and after ablation from December 2009 to December 2019. A tumor MRI was reconstructed using three-dimensional visualization technology. LTP was classified as contact or non-contact, early or late stage, according to whether LTP was in contact with the edge of the ablation zone and the occurrence time (24 months). The tumor-surrounded area was divided into eight quadrants by using the eight-quadrant map method. An analysis was conducted on the spatial correlation between the quadrant where the ablative margin (AM) safety boundary was located and the quadrant where different types of LTP occurred. The t-test, or rank-sum test, was used for the measurement data. 2-test for count data was used to compare the difference between the two groups. Results: The AM quadrant had a distribution of 54.4% LTP, 64.2% early LTP stage, and 69.1% contact LTP, suggesting this quadrant was much more concentrated than the other quadrants (P < 0.001). Additionally, the AM quadrant had only 15.2% of non-contact type LTP and 17.1% of late LTP, which was not significantly different from the average distribution probability of 12.5% (100/8%) among the eight quadrants (P = 0.667, 0.743). 46.6% of early contact type LTP was located at the ablation needle tip, 25.2% at the body, and 28.1% at the caudal, while the location distribution probabilities of non-early contact LTP were 34.8%, 31.8%, and 33.3%, respectively. Conclusion: LTP mostly occurs in areas where the ablation safety boundary is the shortest. However, non-contact LTP and late LTP stages exhibit the feature of uniform distribution. Thus, this type of LPT may result from an inadequate non-ablation safety boundary.
目的： 探索≤5 cm肝细胞癌（HCC）微波消融后局部进展（LTP）的空间分布规律。 方法： 回顾性分析2009年12月至2019年12月169枚具有消融前后匹配MRI的HCC。运用三维可视化技术重建肿瘤MRI，根据LTP是否与消融区边缘接触及发生时间（24个月），将LTP分类为接触型或非接触型LTP，早期或晚期LTP，利用八象限地图法将肿瘤周围空间划分8个象限，分析消融最短安全边界（AM）所在象限与不同类型LTP发生象限空间关系。计量资料用t检验或者秩和检验；计数资料用χ(2)检验比较两组的差异。 结果： 54.4% LTP分布于AM所在象限，64.2%早期LTP及69.1%接触型LTP分布于AM所在象限，较其他象限显著集中（P<0.001)；仅15.2%非接触型LTP及17.1%晚期LTP分布于AM所在象限，与八象限平均分布概率12.5%差异无统计学意义（P = 0.667，0.743）。46.6%早期接触型LTP位于消融针尖端方位，25.2%位于体部方位，28.1%位于尾部方位,而非早期接触型LTP的位置分布概率分别为34.8%，31.8%和33.3%。 结论： LTP多数发生于消融最短安全边界所在区域，但非接触型LTP及晚期LTP呈均匀分布特点，这类LTP可能为非消融安全边界不足导致。.

The tailings ponds (TPS) stemming from mineral resource exploitation are becoming a global challenge due to their high hazards and pollution to the surrounding area. However, previous studies on China\'s tailings ponds have either focused on a single or few areas, or the number of tailings ponds varies greatly. A systematic assessment of the number, distribution characteristics, potential risks and management strategies of the tailings pond in China is lacking. This study obtained the latest list of tailings ponds in China up to the end of 2022 based on official information and assessed their spatial distribution characteristics, environmental risk and management strategies simultaneously. The results demonstrated that the distribution of TPS in China is relatively clustered and multiple factors affected the spatial distribution of TPS in China, which were concentrated in areas with low economic and population density, convenient transportation, and a developed water system. The risk assessment suggested that 1803 TPS had large or significant environmental risks, which were mainly distributed in Yunnan, Hunan, Shaanxi and Jiangxi provinces. To solve the problem of tailings ponds from the source, the key point of tailings pond management in China should be adjusted from the prevention of pollution or dam break accidents to the full resource utilization of tailings. In summary, this study will provide a scientific basis for the risk control of TPS and an innovative idea for the management of other solid waste.

Driven by industrialization and urbanization, urban air pollution can increase respiratory, heart, and cerebrovascular diseases, and thus mortality rates; as such, it is necessary to improve air quality through the consideration of individual pollutants and emission sources. In Republic of Korea, national and local governments have installed urban and roadside air quality monitoring systems. However, stations are lacking outside metropolitan regions, and roadside stations are sparsely distributed, limiting comparisons of pollutant concentrations with vehicle traffic and floating population levels. Local governments have begun using mobile laboratories (MLs) to supplement the fixed measurement network and investigate road pollution source characteristics based on their spatiotemporal distribution; however, the collected data cannot be used effectively if they are not visualized. Here, we propose a method to collect and visualize global information system (GIS)-based air quality data overlayed with environmental variables to support air quality management measures. Spatiotemporal analyses of ML-derived data from Bucheon, Korea, confirmed that particulate and gaseous pollutant concentrations were high during typical commuting hours, at intersections, and at a specially managed road. During commuting hours, the maximum PM10 concentration reached 200.7 µg/m3 in the Nae-dong, Gyeongin-ro, and Ojeong-dong ready-mix concrete complex areas, and the maximum PM2.5 concentration was 161.7 µg/m3. The maximum NOx, NO2, and NO levels of 1.34 ppm, 0.18 ppm, and 1.18 ppm, respectively, were also detected during commuting hours. These findings support the need for targeted management of air pollution in this region, and highlight the benefit of comprehensively comparing road levels, driving speed, and traffic levels when identifying hotspots of air pollution. Such analyses will contribute to the development of air quality management measures customized to regional characteristics.

This study aimed to investigate the distribution and migration characteristics of lead (Pb) and zinc (Zn) in paddy soils in Hunan Province, China. A total of 343 soil samples from 63 profiles were collected from typical regions. The concentration, spatial distribution, and migration behaviors of Pb and Zn in the paddy soils were examined. The results showed that (1) the concentration ranges of Pb and Zn in the surface layer were 17.62-114.07 mg/kg and 44.98-146.84 mg/kg, respectively. (2) The content was higher in the middle and lower reaches of the Xiangjiang River basin horizontally and exhibited shallow enrichment characteristics vertically. (3) Pb migration was weaker than Zn migration, and the parent material had the most significant influence on Pb and Zn content in the bottom soil layer. The research results will clarify the characteristics of Pb and Zn contents in paddy soils in Hunan Province, further understand the horizontal distribution and vertical migration and transformation characteristics of Pb and Zn contents in paddy soils, and provide basic data for scientific rice cultivation and safe food production.

Pharmaceutically active compounds(PhACs) have become a class of new pollutants in the environment after extensive production and use of PhACs in China. To investigate the pollution characteristics of PhACs in Guangdong Province, raw sewage was collected from 186 sewage treatment plants in 21 cities, including 178 townships and administrative districts in Guangdong Province. The pollution levels of ten typical PhACs in influent water of sewage treatment plants were analyzed using automatic solid phase extraction and high performance liquid chromatography-triple quadrupole mass spectrometry. The spatial distribution characteristics of PhACs in Guangdong Province were fully revealed, and the potential ecological risks of PhACs were evaluated. The results showed that PhACs were detected in all wastewater plants, and the mass concentration of PhACs ranged from 21.00 to 9558.25 ng·L-1. Metoprolo, acetaminophen, bezafibrate, and caffeine were the main pollutants. In terms of spatial distribution, the average mass concentration of ΣPhACs in various regions of Guangdong Province was in the following order:Pearl River Delta>North Guangdong>East Guangdong≈West Guangdong. When the mass concentration of ΣPhACs was over 2500 ng·L-1 in the influent water of sewage treatment plants, the concentration of PhACs in effluent was estimated according to the sewage disposal technology. The ecological risk of PhACs was carried out based on the effluent. The results revealed that the ecological risk of PhACs was low in Guangdong Province, and the risk of bezafibrate was moderate in the cities of Shaoguan, Jiangmen, and Shenzhen. The highest ecological risk of ΣPhACs was located in Shaoguan.

Dispersed karst water is an important water supply source, or even the only water supply source, for some districts and counties in Chongqing City. It is particularly necessary to understand the distribution characteristics of metal elements in karst water and the health risks exposed. In this study, the scattered karst water in the southeastern part of Chongqing was taken as the main research object, and the concentrations of Al, Cu, Pb, Zn, Cr, Cd, Ni, Mn, As, and Hg in 42 groups of karst spring water samples were determined. The spatial distribution of metal elements with a high detection rate was revealed using the ordinary kriging interpolation method, and the spatial distribution characteristics, sources, and health risks of metal elements were analyzed using multivariate statistical methods and health risk models. The results showed that the quality of dispersed karst water in southeastern Chongqing was generally good, and the spatial scale variability in the occurrence of metal elements in karst water was strong, especially for Ni and As. The sources of Cu, Pb, As, Zn, and Cr were mainly affected by the regional geological background; Al and Mn were mainly affected by human industrial, agricultural, and mining activities; and Ni was affected by both the natural background and human activities. The total health risk of exposure through the drinking route was higher than that of the skin infiltration route, which was the main exposure route of the human body. The total health risk of children exposed through the drinking route was higher than that of adults, and the total health risk of adults exposed through the skin infiltration route was higher than that of children. It is worth noting that Cr was the determinant of total health risk. From the perspective of drinking water safety, local residents need to pay certain attention to water quality when drinking distributed karst groundwater, in order to reduce the health risk of the population.

Solid-phase extraction and ultra-high performance liquid chromatography-mass spectrometry were used to detect and analyze the contamination of nine typical endocrine disrupting chemicals (EDCs) in drains flowing into the Yellow River of Ningxia. Sources of these EDCs were analyzed, and their risks were assessed. The results showed that EDCs were detected in drains at all 33 sampling sites, with total concentrations （ΣEDCs） of 82.28-1730.09 ng·L-1. Among phenolic compounds, bisphenol A (BPA) and nonylphenol (NP) were two that were more commonly detected EDCs, with the detection rates above 90%; estrone (E1) and estriol (E3) were more commonly detected estrogenic compounds, both with detection rates of 79%. On a spatial scale, the average concentrations of ΣEDCs in the drains in Shizuishan and Yinchuan were much higher than those in Wuzhong and Zhongwei. Concentrations of ΣEDCs at the sampling sites before flowing into Yellow River ranged from 82.28 to 979.82 ng·L-1. The source analysis showed that industrial wastewater and domestic sewage were two primary sources for BPA, whereas industrial wastewater was the primary source for OP. The primary sources of E1 and E3 were livestock and poultry breeding wastewater and domestic sewage, respectively. Risk assessment results showed that EDCs in drains flowing into the Yellow River posed low or moderate ecological risk but high risk for estrogenic activity at all sampling sites.

The construction of the world tourism destination on the Tibetan Plateau is inseparable from the traditional tourist attractions, which are significant landscape ecological units. Based on the data of high-grade tourist attractions on the Tibetan Plateau, the spatial heterogeneity and influence factors are studied employing the Standard Deviation Ellipse (SDE), Kernel Density Estimation (KDE), spatial autocorrelation (SA), and modified tourism gravity model methods. The results show that: (1) the overall spatial distribution characteristic of high-grade tourist attractions is in the direction of northeast-southwest, with solid centripetal force, and the center of gravity of the ellipse is in Yushu City. (2) The spatial heterogeneity of the kernel density distribution is remarkable, clustered in the southeastern half of the plateau, showing a double nucleus-driven and strip-connected pattern. The distribution among cities has a hierarchical heterogeneity, and the two capital cities of Xining and Lhasa play a crucial role. (3) The high-grade tourist attractions are spatially dependent, with evident characteristics of large dispersion and small clustering, and the spatial association type is mainly negative. (4) This paper verifies the significant single-factor mechanism affecting the spatial distribution from supportive and intrinsic dimensions with natural environmental base, tourism resource endowment, socio-economic development, transportation location constraints, and spatial tourism linkages. Finally, the article provides suggestions for the high-quality development of high-grade tourist attractions on the Tibetan Plateau.

As ammonia is the main component of PM2.5, long time series of ammonia emission characteristics are an important basis for studying the historical causes of PM2.5 pollution. In this study, the activity data of various anthropogenic ammonia emissions from 11 cities were collected in Zhejiang. The anthropogenic ammonia emissions inventory in Zhejiang was established using emission factors, and then a 1 km×1 km spatial grid distribution was carried out using ArcGIS software. The results showed that from 2008 to 2018, the ammonia emissions from anthropogenic sources in Zhejiang exhibited a downward trend, with an average annual decline rate of approximately 3.97%. The ammonia emissions were 108.52 kt in 2018, and the emission intensity was 1.03 t·km-2, in which there was 90.02 kt from agricultural sources and 18.50 kt from non-agricultural sources. The ammonia emissions of Hangzhou, Jiaxing, and Wenzhou were higher than those of the other cities, accounting for 14.72%, 11.86%, and 11.80% of the total ammonia emissions, respectively. The spatial distribution characteristics showed that ammonia emissions were mainly distributed in the northern part of Zhejiang, showing an emission trend of \"high in the north and low in the south.\" Uncertainty analysis showed that the simulated average value of ammonia emissions was 108.37 kt, and the uncertainty range in the 95% confidence interval was -5.40%-5.60%.