Zhicheng Shen

Heavy metals in livestock and poultry manure cause significant contamination; however, there is currently a lack of scenario analysis research on soil pollution risks under the influence of manure application. This study integrated multiple methods, including multi-source data fusion, heavy metal emission accounting, and ecological risk assessment, to investigate regional soil heavy metal pollution risks under baseline and improved scenarios of manure application, using Hunan Province, China, as a case study. The results indicate that pig manure (49.5%) and cattle manure (47.6%) are the primary sources of heavy metal emissions from livestock and poultry manure. The heavy metal loads on cropland (g/ha) were as follows: Cd (0.51), Hg (0.027), As (0.87), Pb (4.69), Cr (5.38), Cu (93.10), Zn (131.05), and Ni (5.07). Among the eight heavy metals, Cd poses the most prominent soil pollution risk. Under the baseline scenario (100% manure application), the study area exhibited an overall moderate ecological hazard level after 37 years of continuous application, with 71.93% of the cropland classified as Risk Level II and 7.04% as Risk Level III. After 184 years, a strong ecological hazard level was reached, with 54.93% of the cropland classified as Risk Level III and 19.64% as Risk Level IV. Under improved scenarios (75%, 50%, and 25% manure application), the overall moderate ecological hazard level was reached after 49, 74, and 147 years of continuous application, respectively. This study provides a theoretical and methodological basis for regional soil heavy metal pollution control and source analysis.

At present, there is a lack of in-depth knowledge of the effects of heavy metal-related industries (HMIs) in China on the environment. Hunan Province, as a representative gathering place of HMIs, is among the regions in China that are the most severely polluted with heavy metals. This paper selected Hunan Province as the study area to analyze the development trend, characteristics of pollution emissions, and environmental impacts of seven HMIs based on emission permit information data from Hunan Province. The results of this study show that (1) from 2000 to 2022, the number of heavy metal-related enterprises in Hunan Province increased overall. Among the seven industries, the chemical product manufacturing industry (CPMI) had the largest number of enterprises, whereas the nonferrous metal smelting and rolling industry (NSRI) had the highest gross industrial product (27.6%). (2) HMIs in Hunan Province had significant emissions of cadmium (Cd), arsenic (As), and hydargyrum (Hg) from exhaust gas and wastewater. Heavy metal-related exhaust gas and wastewater outlets from the NSRI constituted 43.9% and 35.3%, respectively, of all outlets of the corresponding type. The proportions of exhaust gas outlets involving Cd, Hg, and As from the NSRI to total exhaust gas outlets were 44.27%, 60.54%, and 34.23%, respectively. The proportions of wastewater outlets involving Cd, Hg, and As from the NSRI to total wastewater outlets were 61.13%, 57.89%, and 75.30%, respectively. (3) The average distances of heavy metal-related enterprises from arable land, rivers, and flooded areas in Hunan Province were 256 m, 1763 m, and 3352 m, respectively. Counties with high environmental risk (H-L type) were situated mainly in eastern Hunan. Among them, Chenzhou had the most heavy metal-related wastewater outlets (22.7%), and Hengyang had the most heavy metal-related exhaust gas outlets (23.1%). The results provide a scientific basis for the prevention and control of heavy metal pollution and an enhancement in environmental sustainability in typical Chinese areas where HMIs are concentrated.

Atmospheric deposition is an important source of heavy metal in soil and the use of dust collection cylinders is a traditional monitoring method. This method has limitations in agricultural areas because polluted soil particles may become resuspended and eventually deposited into these cylinders, leading to overestimates in the amount of atmospheric deposition in soil. To address this concern, we propose that frequent snowfall can help suppress local soil dust resuspension and that fresh snow can serve as an efficient surrogate surface when collecting atmospheric deposition samples. To investigate the rationality of this method, 52 snow samples were collected from sites surrounding smelting plants in Anyang, an industrial region of North China. The results revealed that the concentration of cadmium in the melted snow ranged between 0.03 and 41.09 μg/L, with mean values three times higher around the industrial sites (5.31 μg/L) than background farmlands (1.54 μg/L). In addition, the cadmium concentration in the snow from sites surrounding the factories was higher in the north than in the south because of prevailing winds blowing from the southwest. Moreover, snow samples from sites with high concentrations of cadmium and sulfate can be categorized into different groups via the clustering method, conforming to the spatial distribution of particulate matter emissions and sulfur dioxide satellite column concentrations. Finally, a positive correlation was found between the cadmium content in the snow and the production capacity (R² = 0.90, p < 0.05) and total permitted emissions (R² = 0.69, p > 0.05) of the nearby factories. These findings demonstrate that snow is a reliable medium for documenting atmospheric dry deposition associated with specific industrial emissions.

The main factor of the formation and deterioration in China’s urban thermal environment is human activity, which is difficult to describe and measure. A new perspective on the effect of human activity on the urban thermal environment can be obtained by examining the interaction between location-based service (LBS) data and the urban thermal environment in China. However, relevant research is still limited. In this study, we used Tencent LBS data, Terra/Aqua MODIS land surface temperature (LST) data, and land use data to investigate the relationship between LBS and the urban thermal environment, specifically the LST and surface urban heat island intensity (SUHII) across China and its provinces. Our results showed that (1) in summer, the heat island effect was an issue in 94% of the urban areas in China, which was worse during the day. The high- and low-value periods of LBS data on a given day coincided with the acquisition times of MODIS LST products during the day and at night, respectively. (2) During both the day and at night, there was a significant connection between LBS data and the urban thermal environment in China. The highest correlation coefficient (r) between LBS data and the LST could reach 0.55 (p < 0.01) at the provincial level, and the highest correlation coefficient (r) between LBS data and the SUHII could reach 0.78 (p < 0.01) at the provincial level. (3) The urban thermal environment diurnal difference and LBS data exhibited a significant relationship. The ΔLBS diurnal differences were significantly positively related to the SUHII diurnal differences in China. The overall study findings revealed that LBS data constitute an important parameter to represent the human activity intensity when investigating the formation of the urban thermal environment in China.

The accurate evaluation of shoreline movement is a crucial aspect for managing highly dynamic coasts. This study employed Landsat TM and OLI data through the Digital Shoreline Analysis System model to quantify changes in the spatiotemporal distribution of Tianjin’s coastline from 1985 to 2020. The results showed that the coastline length (CL) increased by 178 km and 151% over the past 36 years, with an average increase of 5.1 km/a. Accretion and erosion processes along the entire coast were observed at rates of 83.9% and 16.1%, respectively. Notably, the Tianjin Port Area and Nangang Industrial Zone showed remarkable changes in the shoreline in 2009. Night lights (NL) were used to display the intensity of human activity in this area, and the spatial heterogeneity of night light intensity was significant. Compared to the total night light (TNL) in 1985, it increased by 116% in 2020. The relationship between TNL and CL was then established and displayed a significant positive correlation (r = 0.91). With the increasing total night light, the growth of the CL presented changes with an initial slow increase, then rapid increase, and finally slow increase. In the second phase of TNL, the CL experienced a considerable increase due to anthropogenic activities such as land reclamation and port construction, fueled primarily by government policies during the period of 2005–2013. Subsequently, there was little change in the coastline. These findings provide valuable insights into spatiotemporal coastline monitoring programs and sustainable coastal management.

Major function-oriented zone (MFOZ) planning is an important blueprint for the spatial development and protection of the Chinese national territory. The “Three Zone Space” (TZS) perspective, including agricultural space, ecological space, and urban space, is an important principle and method for the transformation and diffusion of MFOZ planning to implement territory planning from the central government to local branches. More than ten years have passed since the release of the MFOZ plan in 2010 in China, but there is still a lack of comprehensive and systematic analysis of the dynamic characteristics of the TZS under the impact of MFOZ planning. Therefore, based on high-resolution remote sensing land use data from 2010 to 2020, this paper systematically analyzes the changing characteristics of the TZS on the national scale by reasonably determining TZS areas in China. The main results are as follows: in 2020, the proportions of ecological space, agricultural space, and urban space in China were 78.635%, 20.083%, and 1.282%, respectively. The TZS areas reflected the spatial pattern of MFOZs in China. From 2010 to 2020, the spatial heterogeneity of the TZS changes was significant. In China, agricultural space and ecological space as a whole showed a decreasing trend, with dynamic degrees of −0.05% and −0.04%, respectively, while urban space showed a significant expansion trend, with a dynamic degree of 4.69%. The temporal change processes of the TZS in the periods of 2010–2015 and 2015–2020 were noticeably different. The agricultural space first showed an increasing trend and then a decreasing trend. The ecological space showed a decreasing trend in the two periods, while the urban space showed a significant expansion trend in the two periods. From 2010 to 2020, the urban spatial structure of the optimized development zones tended to be stable, and the ecological space reduction in the key ecological function zones has gradually been curbed, but the agricultural space in the main agricultural production zones has shown a slight decline. On the whole, the dynamic changes in the TZS from 2010 to 2020 in China are basically in line with the governance objectives of territorial space. The reasonable allocation and development of the “three zone space” is of great significance for protecting the natural and ecological environment.

Currently, an urban agglomeration is a trend in global urbanization. With the continuous development of urban agglomerations, Chinese urban agglomerations have entered an era of high-quality development. Improving the economic efficiency of built-up land (EEBL) and maintaining a good ecological environment are important for promoting the high-quality development of urban agglomerations. Urban heat islands (UHIs) are one of the major ecological environmental problems affecting urban agglomerations. Therefore, it is meaningful to investigate the influence of the EEBL on UHIs in urban agglomerations. Based on the land-use data, MODIS land surface temperature (LST) data and gross domestic product (GDP) in the secondary and tertiary industries from 2000 to 2018, and electric power consumption data in 2018, this paper analyzed the influence of the EEBL on the surface urban heat island intensity (SUHII) in the Yangtze River Delta Urban Agglomeration (YRDUA). The results showed that most of cites in the YRDUA experienced rapid EEBL growth and a significant increase in heat island intensity from 2000 to 2018. There has been a significant positive correlation between the EEBL and the SUHII over the years, among which the EEBL had the strongest correlation (R = 0.76, p < 0.01) with the SUHII in 2000. Moreover, among the 27 cities in the YRDUA, 21 cities showed a significant uptrend of the SUHII with rising EEBL and the uptrend was significantly and negatively correlated with the electric power utilization efficiency (EPUE) of the secondary and tertiary industries (R = −0.6, p < 0.01). These results indicated that the EEBL of the secondary and tertiary industries had a significant influence on UHIs, which also reflected the significant influence of anthropogenic heat on UHIs to a certain extent. The findings of this paper can provide a scientific basis for mitigating the UHIs caused by the rapid economic development and promoting the high-quality development of urban agglomerations.

Maritime networks are one of the most important types of transportation networks in international logistics and it accounts for 90% of the global trade volume. However, the structure of maritime networks is severely impacted by tropical cyclones, especially the maritime network in the Northwest Pacific and the northern Indian Ocean. This paper investigates the vulnerability of the maritime network in the Northwest Pacific and the northern Indian Ocean to the influence of tropical cyclones through removing ports at high or very high tropical cyclones hazard levels and analyzing how the network structure characteristics change from a complex network point of view. From the results, we find that this maritime network is a small-world network and the degree distribution of ports follows a power law distribution. The ports in East Asia are impacted more severely by the tropical cyclones. Moreover, this maritime network exhibits some vulnerability to tropical cyclones. However, the interconnection of the survived ports is not severely impacted, when the network is attacked by tropical cyclones. The port system in the Philippines is most vulnerable to the influence of tropical cyclones, followed by the ports systems in Japan and China. The paper also shows that it is important for studies of maritime network vulnerability to identify the ports that are both important to the regional and cross-regional logistics and severely impacted by natural hazards. The findings provide a theoretical basis for optimizing the port layout and improving the ability of the network to resist damage caused by tropical cyclones.