In recent years, the development and utilization of water resources have imposed great impacts on hydrological characteristics and ecological environment. In this paper, methods based on stable isotopes were used to analyze the cumulative effect of water projects and urbanization on the hydrological cycle in Qingbaijiang River Basin. Isotope evidence shows that the hydrological processes affected by water regulation and urbanized runoff generation differentiate greatly from the natural state. The annual mean isotopic values follow an order of groundwater > rainwater > river water. Consistent isotopic composition and variation trend between the near-bank groundwater and river water were only observed from May to late June 2018 and from February to April 2019 in the upper zone, indicating the dominant recharge of river to the groundwater. However, the isotopic variations between the two waters in the middle and lower zones suggested that the hydraulic exchange was limited, demonstrating the significant changes in river water level caused by the reservoir impoundment. The isotopic enrichment rate along the flow path is highest in January (0.0265‰/km), followed by October (0.0160‰/km), indicating the significant evaporation, while slight spatial changes in July (0.0027‰/km) reflected masked evaporation effect. This variability can be mainly attributed to the flow rate change and increase of water salinity in anthropic zones. Periodic regression analysis was employed to evaluate the difference in rainfall-runoff responses between hydrographic zones and estimate the mean residence time (MRT). Periodicity of isotopes in river water increased from upper to lower reaches with increasing R² values from 0.04 in SW1 to 0.46 in SW8. The MRT grew shorter along the flow path from 870 days in SW1 to 293 days in SW8, reflecting accelerated rainfall-runoff process due to the increasing impervious surface area and drainage system. These results identify the sensitivity of stable isotopes to the land use changes, runoff generation, and topography, and have implication for the potential water and environmental risks. Based on these understandings, suggestions for sustainable water-environment management in urban and rural areas were proposed.

Urbanization has led to the rapid and large-scale changes in land use and land cover and has affected the spatial distribution of land surface temperature (LST) in urban areas. Studying the LST pattern and their spatial heterogeneity characteristics at different scales can help understand the dynamic mechanism of the thermal landscape and provide insights into urban ecological planning. We utilized transfer matrixes, landscape metrics, and spatial autocorrelation analyses to study the transfer of LST classes, changes in the LST pattern, and changes in LST clusters with varying grain sizes by taking the central urban districts of Hangzhou City in China as a case study. Results indicate that (1) the transfer proportion of the LST classes increased, except for high-temperature class, and each LST class shifted to the adjacent dominant LST class with the increase in grain size. (2) The landscape metrics remarkably changed as the grain size increased, indicating that the LST pattern was scale-dependent. As the grain size increased, the small patches gradually merged into large patches; the fragmentation, complexity, and ductility of the urban thermal landscapes decreased; and the shape of the patches became simple and regular. (3) The LST pattern exhibited a positive spatial autocorrelation. The area of low–low cluster decreased, whereas that of non-significant clusters substantially increased with the grain size. The area of high–high cluster remained steady when the grain size exceeded 90 m. (4) Patch density, mean patch fractal dimension, clumpiness index, and contagion index exhibited predictable responses to changing grain size, whereas Shannon’s diversity and Shannon’s evenness indexes showed erratic responses, indicating that the diversity and evenness of the LST pattern were not scale-dependent. (5) The suitable domain of scale for the analysis of LST pattern was (60, 120), and the optimal grain size was 120 m. The selection of domains of scale and optimal grain size need to be determined according to the changes in thermal landscape patterns at different grain sizes and regional environments.

Vapour-liquid equilibrium (VLE) of CO₂ in aqueous dipropylenetriamine (DPTA) is investigated experimentally using a stirred equilibrium cell setup. Equilibrium solubility of CO₂ is measured in the temperature and pressure range of (313–333) K and (1–100) kPa respectively. Composition of aqueous DPTA solvent used for the absorption study is in the range of (5–15) mass%. Experimental data shows higher CO₂ loading capacity of this solvent compared to conventional solvents like monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP), and N-methyldiethanolamine (MDEA) as well as recently developed polyamine solvents like aminoethylethanolamine (AEEA), piperazine (PZ), and hexamethylenediamine (HMDA). Experimental VLE data is then correlated using the electrolyte non-random two-liquid (e-NRTL) theory which is an activity coefficient–based model for the electrolyte system. Data regression system (DRS) in Aspen Plus® (V8.8) is employed to fit the e-NRTL model equation with the experimental data by regressing the model parameters. Model-predicted data is found to be in good agreement with the experimental VLE data with an average absolute deviation of 22.3%. Performance of aqueous DPTA solvent is also analysed by predicting solvent capacity, equilibrium liquid-phase speciation, and heat of CO₂ absorption using the newly developed e-NRTL model for the investigated system.

Mangrove sediment acts as a natural accumulator of potentially toxic metals (PTMs). Here, we have investigated the efficiency of mangrove species, e.g., Sonneratia caseolaris and Avicennia officinalis phytoremediation potential in a globally significant vulnerable river. The lower pH and anoxic conditions facilitate the elevated accumulation of PTMs in river Hooghly. The presence of PTMs in fine sediment fraction in greater proportion indicates a larger role of fine-grained silt and clay particles in the accumulation process. The estimated sediment quality indices indicate no significant change in the last 30 years. However, the ecotoxicological indices suggest a low level of ecological risks but can turn toxic because of the gradual accumulation of metals. The accumulations of PTMs in mangroves are regulated by the metal bio-availability. The result emphasizes mangrove pneumatophores, as a greater accumulator of PTMs than mangrove leaves. Higher translocation factors also indicate the applicability of mangroves as a phytoremediator of contaminated sediment.

International investment is needed in every economy, and every economy is expected to grow and attract investment. Despite the need of the above in every country, the dilemma is whether it has something to do with the environment. Hence the study into the impact of FDI on environment takes into consideration twenty African countries from 1995 to 2016. The study utilized Pesaran (2015) LM test, Pesaran (2007) CD, and Breusch and Pagan (1980) LM test as well as Pesaran (2007) and Im et al. (2003) panel root unit test, Westerlund (2007) test, Driscoll-Kraay OLS, average mean group (AMG), fully modified least square (FM-OLS), and the quantile regression (QR). The study indicated that foreign direct investment favorably impact ecological sustainability in the long run. The study found bi-directional link between income and CO₂ pollution. Clean energy and urbanization were found to have negative impact on the economy, while fossil fuel had positive impact on the economy. Both clean energy and urbanization were found to have bi-directional relationship with CO₂ pollution, but fossil fuel has uni-directional relationship with pollution. The study prompted a lot of policy recommendation such as in the interest of reducing ecological harm; these countries’ authorities could enforce the laws in the form of protecting ecology policies when dealing with international investment.

More and more scholars have paid attention to the importance of coordinated development between ecological environmental protection and economy. Eco-city construction has been implemented in many countries in recent years; however, quantitative research on its economic impact has only started. This study establishes a theoretical model of the impact of eco-city construction on a firm’s research and development (R&D) investment. The numerical simulation results show that eco-city construction promotes a firm’s R&D investment and long-term earnings from two aspects: (1) macro policies increase a firm’s exogenous uncertainty and (2) ecological capital enhances a firm’s business conditions. The empirical study matches the microscopic data of 115 cities and 2612 listed firms in China from 2008 to 2017, and results show that eco-city construction has a significant positive impact on firm innovation input and output. Further research shows that this positive impact mainly comes from ecological environment and ecological economy, and there is regional heterogeneity. For the first time, this study affirms the positive role of eco-city construction from the perspective of firm innovation activities at the micro level. It provides strong evidence for the government to realise the sustainable development of firms by accelerating eco-city construction.

Chlorophenols are used in many industries for their importance in preservation and herbicide preparation even though they possess high-risk factors. The prolonged usage of these compounds makes it very complicated to remove them from water and soil by conventional treatment methods. Biosurfactant are the promising structures with the ability to remove contaminants effectively. In this work, an attempt has been made to eliminate 2,4-dichlorophenol from soil and water using amino acid–enhanced cationic biosurfactant obtained from Bacillus axarquiensis. The produced BS has the ability to reduce the surface tension to 30.0 mN m⁻¹. From RSM, the optimum conditions for the maximum production of BS were obtained at time 95 h; pH 7; temperature 35 °C, and concentration of substrate 5%. The BS was immobilized using a solid support matrix for the stability. The environmental factors such as temperature and pH have no effect on the matrix used and found to be viable even under extreme conditions. The removal efficiency was achieved in the range of 93–96% from water and 80–85% from soil. Additionally, the recyclability and reusability of the matrix were also analyzed, and it withstands up to 8 cycles. As a result, the significance of biosurfactant by enhancing the amino acid content was explored in remediation technology.

To investigate the effect of chiral pesticide fenvalerate (FV) on the micro-ecological environment of aquaculture pond sediment, we used an indoor static experiment to observe the effects of FV added at different concentrations with different chiral isomers on the changes in the sediment bacterial community. The 16S rDNA high-throughput sequencing technique was used to conduct sequencing and analysis of the bacterial community structure as well as changes in aquaculture pond sediments after 4 weeks of cultivation. The results showed that the microbial alpha diversity indices (Sobs and Shannon indices) of the treated groups were significantly lower than those of the control group after 4 weeks (P < 0.05), and the values in the high-concentration group were significantly lower than those of the low-concentration group (P < 0.05). In terms of bacterial group composition, the proportion of abundance of Proteobacteria and Acidobacteria in the treated groups were greater than in the control group after 4 weeks, while the proportion of abundance of Bacteroidetes and Verrucomicrobia were lower. In the high-concentration FV treatment group, the proportion of abundance of Bacteroidetes, Acidobacteria, Chloroflexi, Nitrospinae, unclassified_k_norank, Ignavibacteriae, and Nitrospirae were significantly different from those of the other groups (P < 0.05). Principal coordinate analysis (PCoA) and ANONISIM/Adonis analysis showed that the cis-enantiomer had a stronger effect on the bacterial community as the concentration of FV increased. In addition, the linear discriminant analysis effect size (LEfSe) and linear discriminant analysis (LDA) results revealed differences in the level of enrichment of bacterial groups caused by FV at different concentrations and isomer levels. Collectively, this study showed that FV residue has a pronounced effect on bacterial communities in sediment, which becomes more significant with increasing exposure concentration. The effects of the cis- and trans-enantiomers of FV on the sediment environment are different; the cis-enantiomer has a stronger effect on the bacterial community.

Colletotrichum gloeosporioides is one of the most common and serious fungal diseases of the tree Mangifera persiciforma. Yet we lack an effective method to evaluate this ecological interaction accurately. Here, we measured the functional traits and leaf reflectance spectrum of the host plants under different disease degrees. The findings provide a fast and efficient method for large-scale and high-precision monitoring of C. gloeosporioides in M. persiciforma stands. Using the collected leaf reflection data, we set up a prediction model of the optimal disease degree. Firstly, we found that leaf functional traits of M. persiciforma generally consisted of low leaf thickness, low relative chlorophyll content, small specific leaf area, high leaf tissue density, high dry matter content, low stomatal density, and large stomatal area. Secondly, leaf reflectivity increases with damage of C. gloeosporioides, which corresponds to five main reflection peaks and five absorption valleys in the spectral reflectance curve of leaves at the same positions (350–1800 nm). Thirdly, with the increase of infection degree, red edge slope and yellow edge slope decrease, while green peak reflectance, red valley reflectance, and blue edge slope all increase. Blue shift was detected in the red edge, green peak, and red valley, while red shift appeared at the blue edge and yellow edge. Finally, the best predictive model was that based on green peak reflectance (y=3.6396–0.0693x, R²=0.5149, RMSE [root-mean-square error] =0.2735), with an R²=0.92 and RMSE=0.0042 between its predicted vs. observed values. Because of its high inversion accuracy, the model can be used to predict the invasion conditions of M. persiciforma by C. gloeosporioides. Our study demonstrated that when plants are infected by C. gloeosporioides, there was a strong trade-off relationship between leaf functional traits. On the global leaf economics spectrum, the leaves tended toward the “slow investment-return” end when infected by C. gloeosporioides.

Lijiang River is an essential drinking water source and natural scenery in the Guilin City. For the first time, implications of rainstorm were taken into consideration by investigating spatial and temporal variation of dissolved heavy metals (HMs) in the Lijiang River water. A total of 68 water samples were collected during low flow (normal) season and high flow (rainstorm) season from 34 sampling sites. Dissolved HMs including Cr, Mn, Co, Cu, Zn, As, Cd, Sb, and Pb were found to meet the respective drinking water standards, while comparatively higher concentration was observed after the rainstorm season, except for Cr. Multivariate statistical analysis showed that Co, Cu, Cr, Zn, Sb, and Pb in normal season were mainly controlled by anthropogenic sources. Furthermore, higher concentrations of Mn, Cu, Cd, Pb, Co, and Zn during the high flow season were attributed to rainstorm. The water quality index (WQI) showed good grades and comparatively lower in rainstorm season. The results of health risk assessment revealed that HMs in Lijiang River posed limited health risk; however, As posed potential health risk specially in rainstorm season. It is suggested to adopt preventive measures for mining activities and industrial waste-water discharge at the river’s upstream and downstream.