Removal of polycyclic aromatic hydrocarbons (PAHs) from wastewater treatment sludge with appropriate technologies is of great importance for nature and public health. UV technology is one of the most frequently used methods for the removal of PAHs. While various photodegradation applications with UV-C (ultraviolet-C) light and photocatalysts can be performed to remove these compounds, a large number of tests should be implemented to determine optimum removal conditions, which increase time and cost. It is possible to make predictions for the removal efficiency of PAHs by using data mining classification and reveal the hidden knowledge from data. This study aims to determine appropriate machine learning (ML) methods for the prediction of the PAH removal efficiency from wastewater treatment sludges regarding the initial PAH levels. The samples have multi-class imbalanced outputs; thus, random over-sampling and Synthetic Minority Over-sampling TEchniques (SMOTE) are used to improve the prediction results. Well-known data mining classification/machine learning methods, artificial neural network (multi-layer perceptron-MLP), k-means (k-NN), support vector machine (SVM), decision tree (C4.5), random forest (RF), and Bagging, are proposed for the prediction of removal efficiencies. Different evaluation metrics, Accuracy, multi-class AUC (MAUC—multi-class area under ROC curve), F-measure, Precision, Recall, and Specificity are used for the performance comparisons. RF and k-NN perform better with 92.35% and 92.36% average prediction accuracies, respectively. Besides, RF outperforms other methods with 0.97 MAUC value. RF and k-NN can be used for the removal efficiency prediction on the multi-class imbalanced datasets successfully, and removal efficiencies can be highly predicted considering input components with less cost and effort.

In China, the local government’s “land for development” strategy has led to a large number of urban construction land allocated to the industrial field, which has promoted the rapid development of industry and economy in the short term but also brought serious environmental quality losses. This paper systematically sets out how land misallocation works on urban air quality and employs the spatial Durbin model (SDM) to conduct an empirical analysis on the panel data of 283 China cities at or above the prefecture level. The result shows that, stimulated by financial maximization and political promotion, in order to obtain more fiscal revenue and growth performance, local governments prefer to allocate a large number of urban construction land to industry and related fields, which leads to the underestimation of industrial land price and the misallocation of land resources. Land misallocation has exerted significant inhibiting effects on the air quality of local and their surrounding cities through inhibiting the upgrading of industrial structure. Further analysis reveals that the bigger the city, the lesser the inhibition effects of land misallocation on upgrading of industrial structure and urban air quality and vice versa. The conclusions of this paper can provide a useful reference for local governments to optimize land allocation, promote economic restructuring, and environmental quality upgrading.

The consumption of fossil energy is the major cause of environmental pollution. Effectively reducing the fossil energy use has important significance for achieving China’s green development targets. The premise for reducing fossil energy use is accurately measuring the amount of energy use and identifying the key sectors and links of energy use of China’s economic sectors. This paper, by establishing a cross-region input-output model, measured the amount of energy use from the perspective of embodied energy, explored the changing trend of energy use between 2002 and 2015, and identified the key sectors and links of energy use. The results show that the embodied energy intensities of China’s economic sectors are generally higher than the world average level, but its changing trend is declining. Although the amount of energy use shows a growth trend, the growth rate manifests a decline process. The key sectors of energy use assemble in the resource sector and heavy industry sector. The key link is intermediate use, but about 80% of embodied energy of intermediate use has been used by downstream sectors. Approximately 76% of the embodied energy of final demand has been used by gross fixed capital formation and urban residents’ consumption. China has turned from a net exporter of embodied energy to a net importer since 2012. There is a resource mismatch in China’s import and export structure of embodied energy.

Uranium (U) is a highly toxic radioactive element and limited to < 30 μg/L in drinking water by the World Health Organization. In this study, the concentration, distribution, possible source, and correlation with other elements of U were investigated in river sediments of the Ili River Basin. Metal contamination factors (CFs) and geoaccumulation index (Igₑₒ) were calculated, and both of them indicated that U in the survey region was unpolluted, slightly polluted, or moderately polluted (its concentration was ranged from 1.37 to 5.99 mg/kg). Notably, U pollution in the tributaries near the Wusun Mountain was evidently higher than those in the main streams of the Ili River and the Tekes River. Principal component analysis (PCA), cluster analysis (CA), and correlation analysis revealed that U was significantly positively correlated with Pb, and both of them might have originated from the dense coal mines in the areas of the Wusun Mountain. Sediment U in the main streams of the rivers was unpolluted or slightly polluted, which might be strongly influenced by the U contamination in their upstream tributaries. The results from this work showed that the source control of the coal-derived U pollution near the Wusun Mountain was critical to protect the aquatic environment in the Ili River Basin.

A green methodology was developed for the analysis of ten heterocyclic aromatic amines (HAAs) in biomass samples from cigarette combustion such as mainstream smoke, paper ashes, as well as tobacco and paper wraps. The cellulose filter used for sample collection was also evaluated. This strategy was based on ultrasound-assisted extraction (UAE) associated with a solid-phase extraction procedure employing multi-walled carbon nanotubes (MWCNTs-SPE) as a cleanup step followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Under optimal experimental conditions, the linearity of the method was in the range from 0.08 to 160 ng cig⁻¹, with correlation coefficients (R²) higher than 0.991. The limits of detection resulted to be between 0.03 and 0.63 ng cig⁻¹. Concentrations of the HAAs in the mainstream smoke were from 5.7 to 145.2 ng cig⁻¹ and in paper ashes from 0.1 to 0.6 ng cig ⁻¹, while in tobacco were between 1.0 and 38.5 ng cig⁻¹. Meanwhile, no HAA contribution was observed in the case of paper wraps and the filter used for sample collection. The knowledge of the presence and the concentration levels of the selected HAAs in each cigarette’s physical component after its combustion is essential to understand the formation processes and contribution during cigarette burning. Besides, this is the first report about the presence of some HAAs in the proposed samples. Finally, a comparative study was employed to classify the sustainability of several recent approaches for HAA extraction from cigarette combustion samples using Green Certificate as a metric tool.

The binding interaction between emerging pollutant polyvinyl chloride microplastics (PVC MPs) and bovine serum albumin (BSA) was studied by fluorescence spectroscopy, resonance scattering spectroscopy (RLS), UV-visible (UV-vis) absorption spectroscopy, circular dichroism (CD), and Fourier transform infrared (FT-IR) spectroscopy under simulative physiological conditions. Fluorescence results revealed that the fluorescence quenching of BSA induced by PVC MPs was originated from the formation of BSA-PVC complex in static quenching mode. According to Stern-Volmer equation, the binding constants (Kₐ) between PVC MPs and BSA at different temperatures were obtained, and the number of binding sites was 1.62. The thermodynamic parameters, enthalpy change (ΔH), entropy change (ΔS), and free energy change (ΔG) were calculated to be − 41.77 kJ mol⁻¹, 43.17 J mol⁻¹ K⁻¹, and − 54.63 kJ mol⁻¹ via Van’t Hoff equation, indicating electrostatic interaction played a key role in the formation of BSA-PVC complex spontaneously. In addition, the alterations of microenvironment and secondary structure in BSA induced by PVC MPs were further confirmed by synchronous fluorescence spectra, UV-vis, FT-IR, and CD. This work not only provides further information for better understanding the binding interaction of PVC MPs with BSA, but also elucidates the potential biological toxicity of MPs at a molecular level.

Blackwater events are frequently reported over the world and become a serious environmental problem. However, the mechanisms of blackwater occurrence are not fully understood yet. This study simulated the process of blackwater with the combined pollution in an orthogonal experiment, which had 4 factors (TOC, TP, NH₄⁺-N, and NO₃⁻-N) and 4 levels (None, Low, Middle, and High). Results showed that the process of water condition changes was divided into two parts, which were “exogenous” and “algae-derived” blackwater, and the influence of four different pollutants on the occurrence of the blackwater was ranked as follows: TOC > TP > NO₃⁻-N > NH₄⁺-N. With the increase of organic matter addition, the anaerobic condition in water was prolonged and the concentration of Fe²⁺ had a significant increase. In addition, under the None phosphorus condition, the descent rates of DO and COD in the water were reduced, and the algae bloom was obviously deferred. Moreover, the addition of organic matter or phosphorus changed the microbial community structure and led to different water processes. Particularly, only on the condition of the high content of TOC and phosphorus, the diversity of sulfate-reducing bacteria (e.g., Pseudomonas, Paludibacter, and Bacteroides) increased significantly, which accounted for 51.4%, causing the significant production of S²⁻ in the water. Water’s lack of phosphorus showed a low rate of decomposition of organic matter, which might be the result of a considerable increase in the abundance of aerobic Trichococcus and Malikia. This study shows that organic matter and phosphorus have synergistic effect on blackwater occurrence. In the treatment of blackwater, the exogenous pollutant control should reduce the discharge of organic pollutants, and endogenous control should focus on phosphorus abatement and reduce nitrogen control.

Worldwide, black shales and shale waste are known to be a potential source of metals to the environment. This project demonstrates ongoing weathering and evaluates leaching processes at a 100-m-high shale waste deposit closed in the 1960s. Some deep parts of the deposit are still burning with temperatures exceeding 500 °C. To demonstrate ongoing weathering and leaching, analyses of groundwater and solid samples of shale and shale waste have been undertaken. Largest impact on groundwater quality was observed downstream the deposit, where elevated temperatures also indicate a direct impact from the burning waste deposit. Groundwater quality is largely controlled by pH and redox conditions (e.g., for arsenic, nickel, molybdenum, uranium and vanadium), and the mixture of different waste materials, including pyrite (acidic leachates) and carbonates (neutralizing and buffering pH). Analyses of shale waste from the deposit confirm the expected pyrite weathering with high concentrations of iron, nickel and uranium in the leachates. No general time trends could be distinguished for the groundwater quality from the monitoring in 2004–2019. This study has shown that black shale waste deposits can have a complex long-term impact on the surrounding environment.

The present work evaluated the performance of a consortium designed and formed by five fungal species and four bacterial species isolated from the wastewater of a bovine cattle slaughterhouse to biodegrade organic matter in synthetic slaughterhouse wastewater (SSWW). Individual microorganism’s capability evaluation to remove COD and biodegrade SSWW substrates, together with bacteria-fungus confrontation assays, allowed the formation of nine defined consortia of fungi-bacteria according to a design of two factors with three levels (3²). Seven defined consortia exhibited a higher COD removal from SSWW (81.9 to 93.0%) than that achieved by the bacteria or fungi consortia alone (74.7 to 77.6%). Moreover, three defined consortia of fungi-bacteria achieved the highest substrate (protein, carbohydrate, and fat) biodegradation in SSWW. The microbial growth in the defined consortia was characterized by adjustment to the logistic model (0.041 < μ < 0.091 h⁻¹, 0.9006 < R² < 0.9454), whereas the COD removal efficiency was adjusted to a parabolic statistical model (R² = 0.6201), which showed that a bacterial inoculum between 7 to 20 times greater than the fungal one can lead to the highest consortium capacity to remove COD. This work provides elements that allow designing and forming defined consortia of fungi-bacteria to treat slaughterhouse wastewater with high organic matter levels.

Extensive use of surfactants in numerous fields resulted in their discharge into various environmental compartments including soil, sediment, and water. Alcohol ethoxysulfates (AES) together with alcohol ethoxylates (AE), alkyl sulfates (AS), and linear alkyl benzene sulfonates (LAS) find wide variety of applications in consumer products including both domestic and industrial applications. Consequently, all these surfactants pose several concerns to both aquatic and human health. In the context of environmental impacts, AES has almost equal importance as that of LAS though the literature on this topic is only emerging. This review provides a detailed overview on the various aspects of the anionic surfactant, AES, such as toxicity of AES, its fate in the ecosystem, technical advancements in the area of identification and quantification, its occurrence and distribution in different environmental compartments spanning across the world, and finally a remark of its potential removal strategy from the environment.