Search Results (10)

Soil microbial communities are essential for the natural attenuation of organic pollutants, yet their ecological responses under long-term contamination remain insufficiently understood. This study examined the bacterial community structure and the abundance of dechlorinating bacteria at a decommissioned pharmaceutical-chemical site in northern Jiangsu Province, China, where the primary pollutants were dichloromethane, 1,2-dichloroethane, and toluene. Eighteen soil samples from the surface (0.2 m) and deep (2.2 m) layers were collected using a Geoprobe-7822DT system and analyzed for physicochemical properties and microbial composition via 16S rRNA gene amplicon sequencing. The results showed that the bacterial community composition was significantly shaped by the soil pH, moisture content, pollutant type, and depth. Dechlorinating bacteria were detected at all sites but exhibited low relative abundance, with higher concentrations in the surface soils. Desulfuromonas, Desulfitobacterium, and Desulfovibrio were the dominant dechlorinators, while Dehalococcoides appeared only in the deep soils. A network analysis revealed positive correlations between the dechlorinators and BTEX-degrading and fermentative taxa, indicating potential cooperative interactions in pollutant degradation. However, the low abundance of dechlorinators suggests that the intrinsic bioremediation capacity is limited. These findings provide new insights into microbial ecology under complex organic pollution, and support the need for integrated remediation strategies that enhance microbial functional potential in legacy-contaminated soils. Full article

The northern slope of the Tianshan Mountains city cluster (NSTM), as a key urban agglomeration for the development of western China, has experienced rapid regional economic development and high population concentration since the twenty-first century. Accompanied by the increase in human activities in the NSTM, it has significantly altered the land use structure, leading to varying levels of habitat disturbance and degradation. In this paper, based on the land use and land cover (LULC) of NSTM from 2000 to 2020. The InVEST model was employed to assess habitat quality, revealing notable spatial and temporal variations. A geoprobe was further employed to explore the key drivers of the spatially distributed pattern of habitat quality in the research region. The results show that (1) from 2000 to 2020, the NSTM was largely characterized by grassland, unused land, and cropland in terms of land use, with a notable expansion of cropland and construction land; (2) the overall habitat quality in the study area is poor, with a clear spatial distribution pattern of high in the south and low in the north, with a predominance of low grades, and a trend of decreasing and then increasing is shown in the temporal direction; (3) under the influence of rapid urbanization in the region, the degradation degree of habitat quality on the NSTM shows a distinct radial structure, with high degradation in the middle and low degradation at the edges, and shows the trend of “increase-decrease-increase” over time; and (4) the results of the geodetector show that altitude and land use type have the greatest influence on habitat quality on the NSTM, indicating that the habitat quality of the research region is primarily influenced by the type of land use. Full article

The present research examined the “production–living–ecological space” (“PLES”) by using land use data, the ecological and environmental quality index model, growth and reduction based on the spectrum, the center of gravity migration model, and the optimal parameter geoprobe model to further evaluate adjustments to ecological quality and the driving mechanisms. The findings indicate that (1) spanning the years 2000–2020, the production space and living area in Panjin increased to 2093 km² and 380 km² respectively, and the ecological area of forest land and water area showed a decreasing trend. (2) The center of gravity of the urban living space and the industrial and mining production space shifted significantly. (3) The negative effect of the contribution rate was of greater value than the positive effect. Thus, it can be concluded that the negative effect of “PLES” is greater than the positive one. (4) The results for this region showed that the mean annual temperature was the strongest explanation for the spatial variation in natural factors, and that social factors such as population density also had a strong effect, so an interaction analysis was carried out to analyze the interaction between the two factors, which showed that the relationship between mean annual temperature and density of population had the strongest explanatory power. Full article

Human activities and climate change have profound impacts on the ecological environment of oases in Xinjiang, and it is of great significance to explore the spatial and temporal evolution patterns of ecological environment quality in this region for the sustainable development of Xinjiang. The remote sensing ecological index (RSEI) was extracted from the Google Earth Engine (GEE) platform from 2000 to 2020, and the coefficient of variation and Hurst index were used to reveal the spatial and temporal characteristics and stability of the ecological environment quality of the artificial oasis and natural oasis in Xinjiang. The key factors affecting the ecological environment quality are explored through correlation analysis and geoprobes. The results show that the distribution of the ecological environment in Xinjiang oases is high in the north and low in the south, and the overall quality shows a fluctuating downward trend from 0.210 to 0.189. Artificial oases have higher RSEI values, stability, and sustainability than natural oases. The RSEI in the study area was mainly influenced by humidity, followed by greenness and heat, and dryness had the least influence on the RSEI model. Based on the geodetector, the top three highest contributors were found to be precipitation (PRE) (0.83) > relative humidity (RHU) (0.82) > evapotranspiration (ET) (0.57). Climate is the main factor affecting the ecological quality of oases, and the RSEI can be improved by increasing the proportion of artificial oases. The study aims to provide a scientific basis for the sustainable development of oases in arid zones. Full article

The design and performance of a shallow geothermal system is influenced by the geological and hydrogeological context, environmental conditions and thermal demand loads. In order to preserve the natural thermal resource, it is crucial to have a balance between the supply and the demand for the renewable energy. In this context, this article presents a case study where an innovative system is created for the storage of seasonal solar thermal energy underground, exploiting geotechnical micropiles technology. The new geoprobes system (energy micropile; EmP) consists of the installation of coaxial geothermal probes within existing micropiles realized for the seismic requalification of buildings. The underground geothermal system has been realized, starting from the basement of an existing holiday home Condominium, and was installed in dry subsoil, 20 m-deep below the parking floor. The building consists of 140 apartments, with a total area of 5553 m², and is located at an altitude of about 1490 m above sea level. Within the framework of a circular economy, energy saving and the use of renewable sources, the design of the geothermal system was based on geological, hydrogeological and thermophysical analytical studies, in situ measurements (e.g., Lefranc and Lugeon test during drilling; Rock Quality Designation index; thermal response tests; acquisition of temperature data along the borehole), numerical modelling and long-term simulations. Due to the strong energy imbalance of the demand from the building (heating only), and in order to optimize the underground annual balance, both solar thermal storage and geothermal heat extraction/injection to/from a field of 380 EmPs, with a relative distance varying from 1 to 2 m, were adopted. The integrated solution, resulting from this investigation, allowed us to overcome the standard barriers of similar geological settings, such as the lack of groundwater for shallow geothermal energy exploitation, the lack of space for borehole heat exchanger drilling, the waste of solar heat during the warm season, etc., and it can pave the way for similar renewable and low carbon emission hybrid applications as well as contribute to the creation of smart buildings/urban areas. Full article

The valuation of ecosystem services (ESs) is crucial for preserving ecosystems, assessing natural resources, and making decisions regarding compensation. In this study, we employed the InVEST model’s habitat quality (HQ) module to calculate the HQ and degradation levels in the study area using land use/land cover (LULC) data from 2000 to 2020. Our analysis utilized quantitative methods, including spatial correlation, hotspot analysis, and geo-probing, to determine the value of ESs and identify trends. Furthermore, we examined the spatial and temporal variation in the significance of ESs and their driving factors. The results show the following. (1) The primary LULC types in the Zhundong coalfield from 2000 to 2020 are grassland and barren areas. (2) The average value of the HQ index in the study area exhibited a generally decreasing trend. Between 2000 and 2010, HQ significantly declined, particularly in the region’s large barren industrial and mining zones. However, over time, the proportion of sites with minimal degradation improved steadily, resulting in better overall HQ in the study area by 2020. This pertains to the measures put in place by the local government to safeguard and rehabilitate the ecosystem. (3) The spatial distribution of the ecosystem service value (ESV) aligns with changes in HQ and LULC, with significant hotspots primarily observed in forest and grassland areas, nature reserves, and areas around water sources. (4) LULC, temperature, annual precipitation, and elevation are the main drivers of spatial variation in the ESV in the Zhundong area; the spatial variation in the ESV in the Zhundong coalfield is primarily influenced by the interaction between human factors and natural factors, in which LULC plays a dominant role. This study’s findings can guide the development of rational ecological planning, integrating resource conservation mining with effective zoning management. Full article

A prerequisite for the rational development and utilization of regional water resources is the measurement of water stress. In this study, from the perspective of water footprints, we took the proportion of the agricultural water footprint within the total water resource usage of Xinjiang (hereafter referred to as XJ) as an example to measure its water stress index and explore the state of water stress in the region and its corresponding driving factors. The ESDA method was applied to characterize the spatial patterns of and correlations with water stress. The effects of different factors on the spatial differentiation between the water footprint and water stress were quantified using the LMDI and geoprobes, respectively. The results showed that (1) both the agricultural water footprint and the water stress index in XJ showed an upward trend, the spatial distribution of water stress was uneven, and the regional pressure difference between the east and the west was greater than that between the north and the south; (2) the water stress index has an obvious negative spatial correlation, fluctuations in its discrete nature have been enhanced, and the number of spatially correlated prefectures is decreasing; (3) water consumption of CNY 10,000 GDP, GDP per capita, and total CO₂ emissions have the most significant impact on the evolution of the agricultural water footprint in XJ. Meanwhile, spatial variations in water stress are mainly determined by the area of cultivation, the area of natural oasis, and the proportion of water used in agriculture. Analysis of the characteristics of and factors influencing water stress in XJ from the perspective of its agricultural water footprint provides a new perspective for further analyzing the actual state of the water footprint and water stress in XJ and supplies a reference basis for the decision-makers of the XJ government. Full article

The Liangzi Lake Basin (LLB) is an important ecological buffer for Wuhan’s urban agglomeration. It involves the ecological security of the middle reaches of the Yangtze River. Historical land misuse has altered the topography and impacted the ecosystem services value (ESV). Amid urbanization, it is vital to highlight changing land use methods and their effects on ESV valuation, understanding the underlying drivers comprehensively. The research is centered on the LLB as its designated study region, and utilizes remote sensing satellite data spanning from 2000 to 2020. This data is combined with a value equivalence table to quantify ESV. The GeoDetector method is employed to investigate the driving factors behind ESV fluctuations. The findings indicate a substantial shift in land use patterns within the LLB between 2000 and 2020. Notably, arable land decreased by 6.28% and water bodies decreased by 0.92%, while built-up areas expanded by 5.14% and forest land expanded by 2.05%. During this period, the LLB’s ecosystem services value decreased by approximately 2.035 billion yuan. This drop was mainly due to reduced water areas resulting from urbanization, negatively impacting the ecological regulatory services provided by these water bodies. Based on the geoprobe model, possible drivers of changes in ESV in the LLB were identified, with human activity intensity and NDVI detection results being the most obvious. The research emphasized protecting and restoring key ecological areas, like water bodies and forests, to maintain a delicate balance between the environment and socio-economic development. Additionally, they exemplify the effectiveness of ecological policies, including initiatives such as “Returning Farmland to Forest or Pasture” (RFFP), and the prohibition of lake and field reclamation. Full article

It is very important to understand the distribution and sources of typical potentially toxic elements in industrial sites in order to provide essential information for risk assessment and the process of land reclamation selection. Here, around 29 soil column samples of 6 m depth were collected using a geoprobe drill rig from a typical electroplating site located in the Yangtze River Delta, which has been operating for more than 20 years. Analysis in the laboratory, including measurement of elemental concentrations using ICP-OES, was carried out. The distribution and sources of typical heavy metals were investigated, and correlated risks were assessed using positive matrix factorization. As, Pb, and Cr were the dominant heavy metal pollutants, with ranges of 3.20–154 mg/kg, 13.9–9271 mg/kg, and 27.2–2970 mg/kg, which were 1.28 times, 11.6 times, and 3.71 times higher than the Chinese national standard, respectively. Pb was found to be accumulated in the top 0–2 m and As in the top 0–3 m due to the presence of a typical clay and loamy soil. Additionally, Cr could be transferred into the groundwater, with a maximum concentration of 497 mg/kg, due to frequent interaction between the groundwater and soil. A PMF model showed that the dominant sources of pollution were the electroplating process section, the glass melting process section, the production process section, and the electroplating wastewater. Pb, As, and Cr were mainly generated from the industrial production process, glass melting process, and electroplating process. The pH and CEC appeared to influence the chemical speciation greatly, with higher content observed bound to carbonates as a result of exchange processes in the case of high CEC and low pH conditions. Both the Pb and As observed could contribute to non-carcinogenic and carcinogenic health risks, respectively, based on PMF-HRA analysis, which should receive greater attention in risk management strategies for polluted sites. Identification of the main sources of heavy metals in a site could provide a basis for potential land reclamation. Full article

The Tarim River Basin (TRB) is situated in the hinterland of northwest China, which is an extremely arid and fragile ecological zone. In recent years, the region’s ecological civilization construction has been facing huge challenges that are exacerbated by climate change and human activities. In order to verify the current ecological status of TRB, this paper explores the spatial and temporal variation in ecosystem service value (ESV) and the impact mechanism based on LUCC data from 2000 to 2020, using the adjusted unit area value equivalent method, the elasticity index method and the geo-probe analysis method. The results show that: (1) the ESV of the TRB has fluctuated since 2000, increasing by CNY 14.02 billion, especially in the Hotan River region. Among the individual ecosystem services, the increase in regulatory services is the largest, rising to CNY 8.842 billion. The growth of ESV mostly occurred in the mountains and oases. (2) The rise in ESV is mainly due to the conversion of barren land to water and grassland; ESV loss is mainly affected by the conversion of water to cropland and barren land and grassland to cropland and barren land. (3) Human activity impact or intensity (HAI) is the key driving factor for the spatial stratified heterogeneity of ESV, followed by elevation (DEM). In the interaction analysis, HAI∩DEM interaction is the primary reason for ESV’s spatial differentiation. The study’s findings show that the combined effects of human activities, DEM, and hydrothermal conditions underlie the spatial stratified heterogeneity of ESV in the TRB. This conclusion provides a scientific basis for future ecological civilization construction planning. Full article