Evaluation of the natural attenuation capacity of urban residential soils with ecosystem-service performance index (EPX) and entropy-weight methods

Prediction of soil heavy metal contents in urban residential areas and the strength of deep learning: A case study of Beijing

Predicting soil heavy metal (SHM) content is crucial for understanding SHM pollution levels in urban residential areas and guide efforts to reduce pollution. However, current research indicates low SHM prediction accuracy in urban areas. Therefore, we employed a deep learning method (fully connected deep neural network) alongside four other methods (muti-layer perceptron, radial basis function neural network, multiple stepwise linear regression, and Kriging interpolation) to predict SHM content in the urban residential areas of Beijing and demonstrated the strength of deep learning in improving prediction accuracy. We found the contents of the evaluated heavy metals (Cd, Cu, Pb, and Zn) exhibited significant correlations with numerous other soil physicochemical properties and environmental factors. The prediction accuracy for Cu, Pb, and Zn contents was relatively high across different methods. Notably, deep learning showed considerable strength in predicting the contents of the four heavy metals, with the R2 for the test set of the model ranging from 0.75 to 0.91. Compared to other methods, deep learning achieved markedly higher prediction accuracy according to different accuracy evaluation indicators (e.g., deep learning showed increases in the cumulative R2 of the four heavy metals ranging from 53.16 % to 187.36 % compared to other methods). Our study indicates that deep learning can significantly improve SHM content prediction accuracy in urban areas and is highly applicable in urban residential areas with complex environmental influences.

Mapping pesticide residues in soil for China: Characteristics and risks

The widespread application of pesticides in China has led to the accumulation of residues in soil. However, few regional studies have fully elucidated the characteristics of pesticide residues in soil (PRS) and the associated risks to the ecosystem and human health on a national level. Therefore, this study aims to compile a dataset on PRS in China from 2006 to 2020 and analyze the interactions and impacts between PRS and the environment. The average concentration of PRS in China was 243.96 μg/kg which was lower than the levels reported in Euro-Americans and other nations. This study revealed PRS in China predominantly originates from organochlorine pesticide residues, with DDTs and HCHs being significant contributors. Despite the high intensity of pesticide application in the Southeast China, PRS concentrations were comparable to those in the Northeast, due to environmental factors that favor pesticide degradation in the Southeast. Both legacy and in-use pesticides were transported by surface runoff or air current, resulting in their accumulation in soil of the lower Yangtze River basin or the piedmont soil of Qinling Mountains, respectively. The average soil environment carrying capacity of PRS in China was -69.5 kg. The ecological risk contributed by PRS in China was mainly at a negligible level. Carcinogenic risks of PRS to adults (4.6 ×10-4) and children (6 ×10-4) exceeded the tolerable thresholds (10-5) by a small margin.

Comparative study on anthropogenic impacts on soil PAHs: Accumulation and source apportionment in tourist and industrial cities in Hebei Province, China

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic contaminants in urban soils. The accumulation and source identifications of PAHs within a city have been frequently studied. However, impacts of urbanization development modes on PAHs accumulation patterns by taking a city as a whole have been seldom reported. Four cities with two development modes in Hebei province, Chengde and Zhangjiakou (tourist cities) and Handan and Tangshan (industrial cities), were selected. The concentrations of 16 priority PAHs in soils in the study areas were investigated. The results showed that the average concentrations of Σ16PAHs in Handan (2517 μg/kg) and Tangshan (2256 μg/kg) were more than twice of those in Chengde (696 μg/kg) and Zhangjiakou (926 μg/kg) approximately. Lines of evidence, provided by a combination of diagnostic ratios, pairwise correlation, and PMF methods, revealed that the dominant sources of PAHs in either city were industrial emission, vehicle emission, and petrogenic/biogenic process but with different proportions. Linear fittings based on Bayesian kernel machine regression analysis (BKMR) were constructed to illustrate the impact of industrialization on PAHs accumulation. The probability of excessing the 10 % (376 μg/kg) and 50 % (1138 μg/kg) of current ∑16PAHs would be higher than 90 % given the gross industrial production per unit area >5.00 × 106 and 20.5 × 106 CNY/km2, respectively. The proposed threshold values of industrialization are of significance for determining industrial structure and proportion in urban management.

Environmental carrying capacity and ecological risk assessment of pesticides under different soil use types in the Central Plains Urban Agglomeration (CPUA), China

Soil environmental safety has received much attention during the past few decades due to its significance in agricultural production and human health. Special attention is required for soil pesticide residues and ecological risks. This study examined 197 soil samples from industrial, residential and agricultural areas for the presence of 12 organophosphorus pesticides (OPPs) and 8 synthetic pyrethroids (SYPs) in the 16 cities in Henan Province, and the center of CPUA, based on the Central Plains Urban Agglomeration (CPUA) concept proposed by China. The total average concentrations of ∑12OPPs in industrial, residential and agricultural soils were 194, 217, 267 ng/g dry weight, and those of ∑8SYPs were 26.8, 35.7, 25.5 ng/g dry weight, respectively. The two pollutants with the greatest concentrations in the soils were malathion and fenpropathrin, respectively, the dominant components of OPPs and SYPs. The soil environmental carrying capacity (SECC) analysis, representing the maximum residual load that can be supported, shows that acephate and cyhalothrin were overloaded, with a predicted period of over 500 years. Among the 16 cities of CPUA, a higher frequency of high ecological risk could be observed only in Shangqiu. The OPPs in children had total non-carcinogenic risk values of more than 1.0. Similarly, the non-carcinogenic risks of SYPs in adults and children in the residential areas were more than 1.0. The study provides knowledge on how to effectively manage soil safety in Henan Province, which is the center of the CPUA, with a large population and grain province to protect ecosystems and reduce the risks of soil pesticide residues in humans.

Effects of agricultural land use on soil nutrients and its variation along altitude gradients in the downstream of the Yarlung Zangbo River Basin, Tibetan Plateau

Agricultural development in alpine ecosystems can cause significant changes in soil nutrients. With large altitude spans, the combined effect of the two is still unclear in existing research. To answer this problem, this study took the downstream of the Yarlung Zangbo River Basin (YZRB) as the study area, and designed a comparative soil sampling scheme along the altitude gradient. We compared soil nutrient characteristics facility agricultural land (FA) and field cultivated land (FC), using grassland (GL), the main source of agriculture expansion, as a reference. A total of 44 sampling areas were designed within an altitude range of 800-3500 m to reveal the effects of agricultural land development along the altitude gradient on soil nutrients. Research found that the FA significantly improved soil nutrient levels, with most nutrient indicators higher than those of FC and GL (P < 0.05), while the above indicators of FC were only slightly higher than GL. Moreover, the effects of agricultural development decreased with soil depth, and mainly occurred within the 0-30 cm soil layer (P < 0.05). With increasing altitude, most of soil nutrients first decreased and then increased and differences in soil nutrients among different land use modes first expanded and then shrank. This may be related to differences in farmland management methods, vegetation coverage, and temperature under different altitude gradient constraints. Especially in middle-altitude areas, the FA not only breaks through the low-temperature limitations of the plateau, but also has the advantage of large-scale development, which is suggested for future agricultural intensification in the plateau.

Improving assessment quality of soil natural attenuation capacity at the point and regional scales

Soil natural attenuation capacity (NAC) is an important ecosystem service that maintains a clean environment for organisms in the soil, which in turn supports other services. However, spatially varying indicator weights were rarely considered in the traditionally-used soil NAC assessment model (e.g., ecosystem-service performance model) at the point scale. Moreover, in the spatial simulation of soil NAC, the traditionally-used geostatistical models were usually susceptible to spatial outliers and ignored valuable auxiliary information (e.g., land-use types). This study first proposed a novel soil NAC assessment method based on the ecosystem-service performance model and moving window-entropy weight method (MW-EW) (NACMW-EW). Next, NACMW-EW was used to assess soil NAC in a typical area in Guixi City, China, and further compared with the traditionally-used NACtra and NACEW. Then, robust sequential Gaussian simulation with land-use types (RSGS-LU) was established for the spatial simulation of NACMW-EW and compared with the traditionally-used SGS, SGS-LU, and RSGS. Last, soil NAC's spatial uncertainty was evaluated based on the 1000 realizations generated by RSGS-LU. The results showed that: (i) MW-EW effectively revealed the spatially varying indicator weights but EW couldn't; (ii) NACMW-EW obtained more reasonable results than NACtra and NACEW; (iii) RSGS-LU (RMSE = 0.118) generated higher spatial simulation accuracy than SGS-LU (RMSE = 0.123), RSGS (RMSE = 0.132), and SGS (RMSE = 0.135); and (iv) the relatively high (P[NACMW-EW(u) > 0.57] ≥ 0.95) and low (P[NACMW-EW(u) > 0.57] ≤ 0.05) threshold-exceeding probability areas were mainly located in the south and east of the study area, respectively. It is concluded that the proposed methods were effective tools for soil NAC assessment at the point and regional scales, and the results provided accurate spatial decision support for soil ecosystem service management.

Integrating environmental carry capacity based on pesticide risk assessment in soil management: A case study for China

Pesticides are widely used in agriculture and can pose risks to soil health and environmental quality. This study assessed the occurrence, distribution, ecological risk, and environmental carrying capacity of 56 currently used pesticides and three metabolites in agricultural soils of Horqin Left Middle Banner, a typical Northeast China agricultural area. 29 pesticides were detected, with atrazine, clothianidin, and propiconazole the most common. Clothianidin and difenoconazole were high-risk to non-target organisms according to risk-toxicity exposure ratio and risk quotient approaches. This study provides a comprehensive and improvement framework for pesticide soil environmental carrying capacity (SECC) assessment and soil quality protection early warning. The SECC model showed no pesticides surpassed the soil carrying capacity threshold under the current application pattern. Five pesticides (clothianidin, difenoconazole, propiconazole, atrazine, and imidacloprid) may reach the threshold within 10 years, requiring pesticide reduction and soil quality monitoring. An early warning system based on SECC values and cumulative amounts of pesticides predicted that clothianidin may exceed the threshold within 0.1 years. These pesticides should be prioritized for management and regulation to prevent soil environmental degradation. The findings can help inform policymakers and stakeholders on pesticide management and sustainable agricultural development in Horqin Left Middle Banner and similar regions.

Evaluation of heavy metal pollution with uneven spatial sampling distribution based on Voronoi area density

Ecological risk index and Voronoi diagram have been extensively used as a diagnostic guide for heavy metal pollution to support people in-depth analysis of the possibility of various contamination sources causing damage to social production, life, and the ecological environment. However, under the condition of uneven distribution of detection points, there are often situations where the Voronoi polygon area corresponding to a large degree of pollution is small or the area of the Voronoi polygon is great with a low level of pollution, and using the Voronoi area weighting or the Voronoi area density may ignore heavily polluted local areas. This study proposes the Voronoi density-weighted summation to accurately measure the concentration and diffusion of heavy metal pollution in the target area for the above issues. Then, we propose a contribution value method based on k-means to determine the number of divisions to ensure the prediction accuracy and computational cost at the same time. Moreover, applying local entropy deepens the understanding of local regional and overall system situations. Through four representative regions, the results show that the proposed whole scheme based on Voronoi diagram can effectively predict and evaluate the spatial distribution of heavy metal pollution, which provides a theoretical basis for comprehending and exploring the complex pollution environment.

Improving VOC control strategies in industrial parks based on emission behavior, environmental effects, and health risks: A case study through atmospheric measurement and emission inventory

Industrial parks have a very important impact on regional economic development, but the extremely complex and relatively concentrated volatile organic compound (VOC) emissions from industrial parks also result in it being difficult to control VOCs. In this study, we took a large integrated industrial park in the upper reaches of the Yangtze River as an example, conducted a 1-year monitoring campaign of ambient air VOCs, and established a speciated VOC emission inventory based on the measured chemical profiles of the key industries. The comprehensive control index (CCI) of 125 VOCs was evaluated using the entropy weighting method based on comprehensive consideration of three aspects, namely, emission behavior, environmental effects, and health risks of VOCs, to identify priority VOC species and their key sources for VOC control in industrial parks. The total estimated VOC emissions in the industrial park in 2019 were 6446.96 t. Steel production, sewage treatment, natural gas chemical industry, pharmaceuticals, and industrial boilers were the main sources of VOC emissions. In terms of VOC components, halocarbons, aromatics, and OVOCs were the largest groups of VOCs emitted from the industrial park, accounting for 73.75 % of the total VOC emissions. Using the entropy weighting method, we evaluated the index weights of five parameters: emissions, ozone formation potential, secondary organic aerosol formation potential, hazard quotient, and lifetime cancer risk. Based on the CCI, five control levels for VOC species were further established. The VOC species in Level I and Level II, which contain species such as naphthalene, 2-chlorotoluene, benzene, acrolein, and chloroform, should be considered as extremely important priority control species. These results serve as a reference for the development of precise control strategies for VOCs in industrial parks.

Evaluating the impacts of inter-basin water transfer projects on ecosystem services in the Fenhe River Basin using the SWAT model

Inter-basin water transfer (IBWT) projects have been widely constructed to alleviate the pressure on water resources in water shortage basins. However, the ecological effects of IBWT projects have often been ignored. Based on the Soil and Water Assessment Tool (SWAT) model and a constructed total ecosystem services (TES) index, the impacts of IBWT projects on recipient basin ecosystem services were analyzed in this study. The results showed that the TES index was relatively stable from 2010 to 2020, but in the wet season it was 1.36 times that of the other months with high water yield and nutrient loads. Spatially, areas with high index values were mainly distributed in the sub-basins around the reservoirs. The IBWT projects had positive impacts on ecosystem services, and the TES index with IBWT projects was 5.98% higher than that without projects. Water yield and total nitrogen were the two most affected indexes, with increased of 5.65% and 5.41%, respectively, under the impacts of IBWT projects. Seasonally, the change rates of the TES index were less than 3% while the change rates of water yield and nitrogen load peaked at 8.23% and 53.42%, respectively, in March, owing to the large amount of water released from the reservoirs. Areas affected by the three evaluated IBWT projects accounted for 61%, 18%, and 11% of the watershed, respectively. Under the impact of each project, the TES index generally increased, whereas the impact decreased as the distance from the inflow location increased. Intense changes in ecosystem services occurred in sub-basin 23, the sub-basin closest to an IBWT project, with water yield, water flow, and local climate regulation increasing the largest.

Assessment and spatial partitioning of ecosystem services importance in Giant Panda National Park: To provide targeted ecological protection

Giant Panda National Park is crucial for China's ecological security strategic pattern known as "two screens and three belts." The importance assessment and classification of ecosystem services in giant panda national parks has an important guiding role in the protection of giant panda national park ecosystems. In this study, we examined four indicators of habitat quality: carbon storage, water conservation, and soil and water conservation. Combined with data analysis were used to evaluate and classify the importance of ecosystem services in the study area. The results showed that: (1) the overall habitat quality index in the study area was relatively high, and the index was generally greater than 0.5. The total carbon storage was 60.5 × 106 t, and the highest carbon storage in the region was 16.9533 t. The area with the highest water conservation reached 715.275 mm. The total soil conservation was 2555.7 × 107 t. (2) From the perspective of spatial characteristics, the habitat quality in the study area presented a spatial distribution pattern of high-low from west to east. The carbon storage presented a spatial distribution pattern of high-low from east to west. The soil conservation presented a spatial pattern of decreasing from west to east, and the water conservation increased from west to east. (3) We divided the research into four levels of importance: The area of general importance in the study site accounted for 1017.58 km2 and was distributed in the northwest of the study site. The moderately important areas were distributed in the east of the study site, with an area of 1142.40 km2. The highly important areas were distributed in the west of the study site, totaling 2647.84 km2. Extremely important areas were distributed in the middle, with an area of 1451.32 km2. (4) The grid cell scale of the study area was used as the dataset to determine the weighting. This makes the weighting more objective and ensures that the spatial distribution of areas with different degrees of importance will be more accurate.

Influence of pH on the adsorption-desorption of doxycycline, enrofloxacin, and sulfamethoxypyridazine in soils with variable surface charge

In this research, the adsorption/desorption of the antibiotics doxycycline (DC), enrofloxacin (ENR), and sulfamethoxypyradazine (SMP) was studied in 6 agricultural soils with predominance of variable charge, both before and after removing organic matter by calcination. DC adsorption was high at acidic pH, and decreased at pH values above 8. Removal of organic matter with calcination caused just a slight decrease in adsorption, and even in some soils adsorption was similar to that in non-calcined samples. The adsorption coefficients (K_d) were higher for the DC^- species compared to DC⁺, DC⁰ and DC^2-. Regarding DC desorption, the values were very low throughout the pH range covered in the study (2-12), both in the calcined samples and in those not subjected to calcination. ENR showed a similar behavior to DC regarding the effect of pH, since ENR adsorption also decreased at basic pH, but the effect of removing organic matter was different, as it caused a clear decrease in ENR adsorption. The species with the highest K_d was in this case ENR⁰, although ENR⁺ is also quantitatively important as regards K_d value in calcined samples. For this antibiotic, no differences in desorption were observed between calcined and non-calcined samples. Finally, SMP adsorption also decreased as pH increased, and, in addition, similarly to what happened with ENR, in general, there was a strong decrease in SMP adsorption when organic matter was removed. The species with the highest K_d in this case was SMP⁺ in non-calcined samples, but SMP⁰ and SMP^- become more relevant in calcined samples. The percentages of SMP desorption were higher than those for the other two antibiotics, and an increase occurs at intermediate pH values, being higher for calcined samples. These results can be considered relevant in terms of increasing the knowledge as regards the possible evolution and fate of the three antibiotics studied. Specifically, for different pH conditions and with different organic matter contents, when they reach soils and other environmental compartments after being discharged as contaminants. This could have important repercussions on public health and the overall environment.

Ecological risk assessment and environment carrying capacity of soil pesticide residues in vegetable ecosystem in the Three Gorges Reservoir Area

Soil contamination by pesticide residues has become an increasing concern of ecological protection. However, the soil environmental carrying capacity (SECC) of pesticide residues in agricultural ecosystems was limited studied. Based on the concept of ecological risk assessment, a modified system on the environment carrying capacity was proposed for estimate SECC of pesticide residues in agricultural soils. Subsequently, the assessment on ecological risk and SECC of soil pesticide residues in vegetable ecosystem were performed in the Three Gorges Reservoir Area (TGRA). In 201 topsoil samples, 62.1% of the pesticide compounds were detected over limit of quantitation, and exhibit a high proportion of multiple pesticide contamination. Pyrethroid insecticides and herbicide glyphosate showed most frequent occurrence and high levels. The SECC of the TGRA varies with the limit standard, annual cumulative amount and risk quotient of each pesticide contaminant in soils. Except that fenpropathrin has exceeded SECC, chlorfenapyr, β-cyfluthrin and glyphosate posed the greatest threat to SECC in the next 50 years. Additionally, ecological risks by pesticide residues in vegetable ecosystem can be affected by various planting activities. These results will contribute to guide the rational application of pesticides and control soil environmental risks, thereby achieving the agricultural green development in the TGRA.

Analysis of coordination between urban compactness and green total factor energy efficiency: a case study of 35 cities in China

Rapid urban expansion and energy transformation are two major challenges facing China. Many researchers have explored urban compactness and energy efficiency, but there is little literature on the coordinated development of the two. Therefore, this paper takes 35 cities in China as research object: The urban compactness evaluation index system is established, and the score is calculated using the entropy weight method; considering the bad output, SBM is used to calculate the green total factor energy efficiency (GTFEE); and the coupling coordination degree model is used to calculate their coordinated degree. The following conclusions can be inferred: (1) Although China's urban compactness has increased, it has not maintained a steady upward trend. Some more developed cities have the phenomenon of compactness rising first and then falling; (2) The overall GTFEE shows a continuous upward trend, but there is still much room for improvement, and regional disparities are significant; (3) The degree of coordination between the two maintains a steady upward trend, and the city's compactness lags behind GTFEE. Based on the findings of the study, this paper proposes policy recommendations that can serve as a reference for key decision-makers and are critical in promoting China's urbanization and energy transformation.

Influences of impervious surfaces on ecological risks and controlling strategies in rapidly urbanizing regions

Reducing ecological risks is important for promoting regional sustainable development. However, studies on the influence of impervious surfaces on ecological risks and risk control strategies in regions undergoing rapid urbanization are limited. Therefore, this study aimed to demonstrate the spatial-temporal dynamics of regional ecological risks using Beijing as a case study to reveal the influence of impervious surfaces and explore the controlling strategies of risks. We first characterized the ecological risks in Beijing based on the ecosystem service values and mapped the risk levels and temporal variations in risks. We then identified the ecological risk increases caused by impervious surface expansion and built linear regression models for impervious surface coverage (ISC) and risk index. Finally, we formulated ecological risk control strategies for the strategy categories identified based on the ISC thresholds. The results show that the mountainous areas mainly exhibited low ecological risk levels, and the plain areas mainly showed high levels. The expansion of impervious surface was the main cause of the relatively large temporal increase in ecological risks from 2005 to 2015. Moreover, the strategies for ecological risk control can be divided into four categories based on the division of ISC, with 30%, 70%, and 90% as the thresholds. For risk control strategies, reducing ISC is the most important measure to reduce ecological risks for the category with an ISC range of 90%-100%, and increasing the area proportions of forests and water bodies is the most effective measure for the category with an ISC range of 0%-30%. For the other two categories, controlling the ISC and other strategies are required. Our study can increase the understanding of the influences of impervious surfaces on ecological risks in rapidly urbanizing regions and help inform the formulation of strategies for controlling the ecological risks in Beijing.

Amoxicillin Retention/Release in Agricultural Soils Amended with Different Bio-Adsorbent Materials

The antibiotic amoxicillin (AMX) may reach soils and other environmental compartments as a pollutant, with potential to affect human and environmental health. To solve/minimize these hazards, it would be clearly interesting to develop effective and low-cost methods allowing the retention/removal of this compound. With these aspects in mind, this work focuses on studying the adsorption/desorption of AMX in different agricultural soils, with and without the amendment of three bio-adsorbents, specifically, pine bark, wood ash and mussel shell. For performing the research, batch-type experiments were carried out, adding increasing concentrations of the antibiotic to soil samples with and without the amendment of these three bio-adsorbents. The results showed that the amendments increased AMX adsorption, with pine bark being the most effective. Among the adsorption models that were tested, the Freundlich equation was the one showing the best fit to the empirical adsorption results. Regarding the desorption values, there was a decrease affecting the soils to which the bio-adsorbents were added, with overall desorption not exceeding 6% in any case. In general, the results indicate that the bio-adsorbents under study contributed to retaining AMX in the soils in which they were applied, and therefore reduced the risk of contamination by this antibiotic, which can be considered useful and relevant to protect environmental quality and public health.

Interactive effects of natural and anthropogenic factors on heterogenetic accumulations of heavy metals in surface soils through geodetector analysis

The rapid socioeconomic development has led to severe pollution of urban soils by heavy metals. It is vital to identify and quantify the factors that affect trace-element pollution for better preventing and managing soil pollution. In this study, we collected 179 surface soil samples from Zhangzhou City in a coastal area of south China to determine the concentration of seven heavy metals (As, Cr, Cu, Hg, Ni, Pb, and Zn) and used the Nemerow Pollution Index (P_n) to estimate the level of heavy metal pollution in soils. Eighteen environmental factors, including six natural factors (e.g. soil properties, surface topography) and twelve anthropogenic factors (e.g. industry, road network, land use types and landscape pattern), were evaluated with the geodetector statistical method. The results indicate that the heavy metal contamination of soils in Zhangzhou City was highly heterogeneous. We found that the primary influencing factors for heavy metal concentrations were soil organic matter content, agriculture activities, and landscape pattern. Furthermore, the nonlinear relationship between the primary factors and their interaction factors enhanced soil contamination by the heavy metals. Among the anthropogenic factors, landscape pattern enhanced P_n the most when interacting with natural factor. In addition, the buffer zone should be considered when evaluating the effects of factors such as land use and landscape pattern, because the interactions between landscape pattern and slope aspect produce a maximum effect, accounting for 31.0% of the P_n value on the scale of 800 m. Based on this analysis, we identified the key factors of heavy metal pollution in the soils of Zhangzhou City and proposed strategic procedures for effective soil pollution prevention and treatment in the future.

Optimization of Extraction or Purification Process of Multiple Components from Natural Products: Entropy Weight Method Combined with Plackett-Burman Design and Central Composite Design

In this paper, the optimization of the extraction/purification process of multiple components was performed by the entropy weight method (EWM) combined with Plackett-Burman design (PBD) and central composite design (CCD). We took the macroporous resin purification of Astragalus saponins as an example to discuss the practicability of this method. Firstly, the weight of each component was given by EWM and the sum of the product between the componential content and its weight was defined as the comprehensive score, which was taken as the evaluation index. Then, the single factor method was adopted for determining the value range of each factor. PBD was applied for screening the significant factors. Important variables were further optimized by CCD to determine the optimal process parameters. After the combination of EWM, PBD and CCD, the resulting optimal purification conditions were as follows: pH value of 6.0, the extraction solvent concentration of 0.15 g/mL, and the ethanol volume fraction of 75%. Under the optimal conditions, the practical comprehensive score of recoveries of saponins was close to the predicted value (n = 3). Therefore, the present study provided a convenient and efficient method for extraction and purification optimization technology of multiple components from natural products.

The application of urban anthropogenic background to pollution evaluation and source identification of soil contaminants in Macau, China

The anthropogenic background characterized by the accumulation characteristics of contaminants is recognized as an important evidence in pollution assessment and source identification in urban soil due to its less arbitrariness compared with the existing quality standards and the guidelines. A credible approach for pollution index calculation referring to anthropogenic background values (ABVs) combined with entropy weight method was developed. By the approach, the soil pollution degrees in Macau, China (one of the most densely populated region worldwide) were assessed based on the database of the heavy metals, Cd, Cu, Hg, Pb, and Zn, and high molecular weight polycyclic aromatic hydrocarbons (HMW PAHs) from 31 sites spatially distributed all over Macau. It was revealed that approximately half of the sites had no specific point source pollution. Mercury, benzo(a)anthracene (BaA), fluoranthene (FLT), and benzo(b)fluorantene (BbF), which had the highest weights were considered as the main contaminants. Macau Peninsula was identified as the critical polluted area. Then, the positive matrix factorization (PMF) coupled with ABVs as one of the data uncertainty inputs was used to identify the anthropogenic pollution sources of the contaminants. Three main anthropogenic sources with their contributions, including vehicle emissions (51.3%), use of hazard material (24.8%), and municipal or domestic waste (23.9%), could be well identified and quantified in the study area. The error estimation of the results showed that the variation of the contaminants in the derived factors were stable. The approaches which were in conformity with ABVs of soil contaminants are proved applicable in soil pollution assessment and source identification.

Degradation Tendency Prediction for Pumped Storage Unit Based on Integrated Degradation Index Construction and Hybrid CNN-LSTM Model

Accurate degradation tendency prediction (DTP) is vital for the secure operation of a pumped storage unit (PSU). However, the existing techniques and methodologies for DTP still face challenges, such as a lack of appropriate degradation indicators, insufficient accuracy, and poor capability to track the data fluctuation. In this paper, a hybrid model is proposed for the degradation tendency prediction of a PSU, which combines the integrated degradation index (IDI) construction and convolutional neural network-long short-term memory (CNN-LSTM). Firstly, the health model of a PSU is constructed with Gaussian process regression (GPR) and the condition parameters of active power, working head, and guide vane opening. Subsequently, for comprehensively quantifying the degradation level of PSU, an IDI is developed using entropy weight (EW) theory. Finally, combining the local feature extraction of the CNN with the time series representation of LSTM, the CNN-LSTM model is constructed to realize DTP. To validate the effectiveness of the proposed model, the monitoring data collected from a PSU in China is taken as case studies. The root mean square error (RMSE), mean absolute error (MAE) and mean absolute percentage error (MAPE) obtained by the proposed model are 1.1588, 0.8994, 0.0918, and 0.9713, which can meet the engineering application requirements. The experimental results show that the proposed model outperforms other comparison models.

Study of the Allocation of Regional Flood Drainage Rights in Watershed Based on Entropy Weight TOPSIS Model: A Case Study of the Jiangsu Section of the Huaihe River, China

During the flood season, various regions in a watershed often have flood drainage conflicts, when the regions compete for flood drainage rights (FDR). In order to solve this problem, it is very necessary to study the allocation of FDR among various regions in the watershed. Firstly, this paper takes fairness, efficiency and sustainable development as the allocation principles, and comprehensively considers the differences of natural factors, social development factors, economic development factors and ecological environment factors in various regions. Then, an indicator system for allocation of FDR among regions in the watershed is established. Secondly, an entropy weight Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) model is used to construct the FDR allocation model among regions in the watershed. Based on a harmony evaluation model, a harmony evaluation and comparison are carried out on the FDR allocation schemes under three different allocation principles. Finally, taking the Jiangsu section of the Huaihe River watershed as an example, the FDR of eight cities in the watershed are allocated and evaluated to see if the allocation scheme is harmonious. The results show that the allocation scheme of FDR based on the principles of fairness, efficiency and sustainable development has the highest degree of harmony, which can meet the FDR demands in various regions in the watershed, avoid the occurrence of flood drainage conflicts among regions, form an orderly flood drainage situation and promote the harmonious development of the watershed.

Performance Evaluation of Regional Water Environment Integrated Governance: Case Study from Henan Province, China

The performance of the regional water environment integrated governance is affected by many factors. This study took place in Henan Province, China, as the research area, and constructed an index system through the comprehensive consideration of three target layers based on the Ecological-Social-Economic (ESE) framework. Due to advantages such as strong objectivity and operability, the improved entropy-weight technique for the order of preference by similarity to the ideal solution (TOPSIS) model can greatly overcome subjective human interference and render the evaluation results more reliable. Therefore, it was introduced to evaluate the water environment integrated governance in Henan from 2007 to 2016. By applying the obstacle degree model, the obstacle factors were then diagnosed. The results of this study show that the overall performance of the integrated governance was generally improved in Henan from 2007 to 2016. Performance levels of the three target layers exhibited different trends, of which the social and economic benefits presented a linear increase year by year, but the ecological benefits presented a fluctuating downward trend. The obstacle on the Henan water environment integrated governance mainly comes from the ecological and economic benefits index. Therefore, a series of countermeasures have been proposed as a means of improving the governance performance in Henan.

Evaluation and analysis on the green development of China's industrial parks using the long-tail effect model

Industrial parks (IPs) have always been an important driving force for China's economic development. China has a great number of IPs, and this number is continuing to increase. The rapid development of IPs has brought great pressure on national resources utilization and environmental protection. The Chinese government has committed to the green development of IPs. In recent years, a series of policies on the green development of IPs have been introduced and implemented. Different from the limitation on the number of IPs in previous studies, this study used a larger data set containing 911 IPs. These IPs were divided into eight types according to their leading industries. The long-tail effect model was attempted to be used to provide quantitative description and analysis of the numerical distribution patterns of the indicators of economic output, environmental pollution, and resource consumption in IPs. Based on the long-tail effect model, for this paper, the performance of green development (PGD) in different types of IPs and IPs in different regions was further analyzed. The results show that China's IPs exhibit the distribution pattern of a long-tail effect in all three aspects mentioned above. In terms of environmental pollution, for some types of IPs, the individual performance of IPs in the head part of the model is more prominent. For other types of IPs, the cumulative results caused by IPs in the tail part of the model should be of concern. The PGD of IPs is closely related to their types. There are also obvious differences in the PGD of IPs in eastern and western China. Based on detailed discussion of the research results, at the end, policy implications are provided for the government to make decisions on the green development of IPs.

Spatial-Temporal Coupling Analysis of the Coordination between Urbanization and Water Ecosystem in the Yangtze River Economic Belt

As a primary pioneering region in China's ongoing urbanization process, the Yangtze River Economic Belt's (YREB's) urbanization process is itself continually accelerating, causing increasing pressure on the area's water ecosystem. It is necessary to examine the coordination relationship between the urbanization system and the water ecosystem in the YREB for realizing sustainable urban development. To this purpose, we use two comprehensive index systems, along with an improved coupling coordination degree (CCD) model. This method is used to analyze the coordination between urbanization and the water ecosystem across spatial gradients and temporal scales in the YREB, from 2008 to 2017. The factors acting as obstacles were diagnosed by utilizing the obstacle degree model. The results show that: (1) the coordination state of each region gradually improved during the 2008-2017 period. In terms of spatial distribution, the coordination state between two systems gradually increased from east to west. Moreover, the spatial differences across the 11 analyzed regions gradually narrowed with the passage of time. (2) The coordination between the two systems, from 2008 to 2017, evolved from a state of serious imbalance to a state of good coordination. The two systems passed from an initial period of imbalance or antagonism, coupled with rapid growth (2008-2011), through a period of basic coordination with steady growth (2011-2014), and finally toward a period of good coordination with slow growth (2014-2017). (3) Spatial urbanization and pressures on subsystems are the key factors acting as obstacles in the urbanization system and water ecosystem, respectively. Facing the process of rapid urbanization in China, the coupling analysis of the coordination between urbanization and the water ecosystem can help the government to formulate a reasonable new-type urban development strategy. This strategy will play an important role in China's sustainable urban development and water environmental protection. The findings of this study provide important support for urban planning in the future.

Urban River Health Analysis of the Jialu River in Zhengzhou City Using the Improved Fuzzy Matter-Element Extension Model

Urban rivers are valuable elements of urban ecosystems and play a key role in urban socio-economic development. Unfortunately, the functional integrity of urban rivers is being threatened by extensive human activities associated with the social development. Urban river health evaluation is important, as it may provide policy makers with information that is fundamental for river governance and the protection of urban ecosystems. To this purpose, we first constructed an urban river health assessment index system based on the pressure–state–response (PSR) framework. Secondly, we developed an urban river health index (uRHI) using the improved fuzzy matter–element extension assessment model. Finally, we used the uRHI to assess the health state of the Jialu River from 2008 to 2017 in Zhengzhou City, China. The results indicate that the health state of the Jialu River was improved from an unhealthy state in 2008 to a sub-healthy state in 2017. The pressure, state, and response subsystems developed towards a healthier state from 2008 to 2017, thanks to the implementation of a number of actions by the local government. However, the overall health status of the Jialu River is still relatively low. The Jialu River also faces several pressures, such as substantial Chemical Oxygen Demand (COD) emissions and sewage discharge. This paper concludes that it is necessary to further strengthen the health management of the Jialu River and the protection of Zhengzhou’s water environment.

Water Security Assessment of China’s One Belt and One Road Region

The sustainable development of socioeconomic and environmental systems are highly dependent on water capital and water utilization efficiency. Nowadays, a significant portion of the world is facing water security issues due to a combination of various factors. As a result, socioeconomic and environmental systems are threatened. China is also currently experiencing problems. Water security assessment helps to identify key determining factors for optimal water utilization, so the authors present the Driving Forces-Pressures-Carrying Capacity-State-Impacts-Responses (DPSCIR) water security assessment framework. Unlike previous methods, the proposed framework incorporates the carrying capacity of the environment, and as a result, yields assessment results that are more realistic. As a case study, the proposed framework coupled with the entropy method is applied to assess the water security status of the One Belt and One Road (B&R) region in China. In addition, the water security level of the provinces and municipalities in this region are simulated for the time period from 2017 to 2022 using the Grey Prediction Model. The results show that Responses, State, Pressures, and Carrying Capacity Subsystems greatly influence water security of the region. According to the assessment, water security of the area improved from 2011 to 2016. The results portray the following trend among the three subregions of the study area, the water security of the 21st Maritime Silk Road (One Road) area is better than Silk Road Economic Belt (One Belt) and the Strategy Support and Pivotal Gateway (SSPG) of B&R areas. Generally, from the evaluation results it can be concluded that only focusing on the subsystem of Responses cannot entirely address the water security problems within the B&R area. Therefore, to ensure sustainable water security in the region and in the country, the government needs to design water resource management mechanisms that take all the subsystems into account.

Pb speciation in rare earth minerals and use of entropy and fuzzy clustering methods to assess the migration capacity of Pb during mining activities

Ionic rare earth mining is of strategic importance in China; however, the heavy metal pollution it causes is of great concern, both at home and abroad. Data on Pb speciation at a rare earth mine were used to analyse the migration capacity of Pb during the process of ore leaching. The major factors thought to influence the migration capacity of Pb, including the clay mineral content, soil pH, oxidation-reduction potential, organic matter content, and cation exchange capacity (CEC), were quantified. Entropy and fuzzy clustering methods were used to identify the most predictive factors. The results showed that the clay mineral content of the soil exerts the strongest influence on the migration capacity of Pb in rare earth mines; the other factors demonstrated relatively weak influences on the transport processes. The results obtained from the classification of Pb per the potential migration index (PMI) approximated those obtained from fuzzy clustering, and the results of entropy analyses were consistent with those of fuzzy clustering. Thus, the methods upon which the proposed model is based are suitable for predicting the migration capacity of Pb in ore during the mining of ionic rare earth minerals.

Comprehensive Evaluation of Water Resource Security: Case Study from Luoyang City, China

The security of water resources is the core content and ultimate goal of urban water resource management agencies. The management of water resources is directly related to the needs of urban residents’ lives and the area’s socio-economic development. How to determine the effective evaluation indicators and methods is an important prerequisite to solving the water resource security problem. This study took Luoyang City as the research area and constructed a water resource security evaluation index system based on pressure-state-response framework. An analytic hierarchy process and entropy weight method were used to determine the index weight. A set pair analysis model was then introduced to evaluate the security of water resources in Luoyang from 2006 to 2016. The results of this study show that the standard of water resource security generally improved in Luoyang in the latter years of the study period. From 2006 to 2008, Luoyang was graded at the Insecurity Level. This compares to a slightly improved grading of Critical Security Level from 2009 to 2016 (except for 2013). However, the overall grade is still low. The pressure on the Luoyang water resource system mainly comes from the development of the urban socio-economy, which in turn has caused problems for both the quantity and quality of water resources. Therefore, a series of countermeasures have been introduced as a means of improving the water resource security of Luoyang, and these measures have achieved certain results. However, further improvements to the efficiency of water resource utilization and strengthening the management and protection of water resources remain necessary.