Farmland abandonment, as a manifestation of the low efficiency of the rural economy, has a profound impact on the process of agricultural and rural modernization. This study uses the 2016 China Labor Force Dynamic Survey data based on 8116 samples from 104 cities, constructs the Tobit model and IV Tobit model to analyze the land abandonment quantitatively from the perspective of environmental pollution. The results show that (1) environmental pollution can significantly increase the probability and area of land abandonment, (2) there is significant regional heterogeneity in the impact of environmental pollution on land abandonment, (3) the impact of environmental pollution on land abandonment varies significantly with different family sizes and land management scales, but the land management scale is relatively more sensitive. This study provides a deeper understanding of the relationship between environmental pollution and land abandonment in China and provides a basis for formulating relevant policies to strengthen the treatment of environmental pollution to solve the dilemma of land abandonment, which is of great practical significance to sustainable development of rural economy and the guarantee of food security in China.

Given the dominant role of oil in terms of foreign exchange earnings in Nigeria, this study revisits the oil rents and output growth nexus, using the novel dynamic autoregressive distributive lag (DYNARDL) model and kernel-based regularized least squares (KRLS) approach over the period 1973–2020. The major finding from this study is that oil rents are less significant for output and also exhibit decreasing marginal effect on output growth in Nigeria. However, our robustness result shows that oil revenue is positive and significantly affects output growth, while corruption dampens output growth. Result from the oil revenue model with a minimum root square mean error, when compared with the oil rents model, corroborate the finding. We are thus of the opinion that oil revenue is more important for output growth in Nigeria than oil rents. Having established this fact, it is recommended that policymakers and the government should accord utmost attention to boosting oil revenue via transparency and accountability. They should also ensure a lasting solution to the nation’s high dependency on refined crude oil products importation for a sustainable economic growth and development. Also, more efforts should be directed at developing the seven identified strategic solid minerals to further enhance the revenue base of the government.

Wastewater treatment using constructed wetlands (CWs) based on natural wetlands constitute a viable alternative with excellent cost and benefit, presenting themselves as efficient technologies in the secondary and tertiary treatment of wastewaters with low implementation, operation, and maintenance costs. The present study aims to evaluate the use of bamboo species, as an alternative to macrophytes, frequently used in CWs, through bibliometric analysis, besides to a review based on case studies. The maps generated by the VOSviewer software and by the analyses of the Web of Science and Scopus databases allowed for a review of typical concepts of CWs, in addition to revealing potential benefits of using bamboos in CWs, such as their hyperaccumulation capacity and bioproduct generation. Other promising aspects were identified, for example the use of bamboo charcoal as a substrate used in subsurface wetlands and the application of ornamental bamboo species for landscape improvements, among other observations. The efficiencies found in six case studies showed values between 89–99.7%, 47.6–99.7%, 58.3–99.9%, and 85.5–99.8% for BOD₅, COD, total nitrogen (TN), and total phosphorus (TP), respectively. Despite the promising results, the lack of studies using bamboos in CWs for the treatment of wastewaters limits an assertive statement about the use of this technology, requiring further research, focusing on the morphological functions of bamboos in this treatment with landscape integration and resources recovery.

Significant hydropower projects have resulted in fragmentation of the rivers and alteration of flow regimes with consequent adverse effects on the river’s ecosystems. To conserve aquatic ecosystems, the minimal desired river flow regime—environmental flows—is advised to maintain in the river system. While maintaining environmental flows, it is equally important to carry out the impact of environmental flows over the hydro-energy generation capacity of hydropower projects. In the present study, the energy generation reduction of provisioning environmental flows has been assessed for five major hydro electric projects on Rivers Bhagirathi and Alaknanda, the two significant head-streams of India’s national river Ganga, located in the Himalayan uplands. The E-Flows assessment done by Tare et al., (2017) is used in the present study, which rationally integrates the ecological and geo-morphological needs of the river. Tare et al., (2017) recommended monthly E-Flows for the upper Ganga basin from ~ 23 to ~ 40% and ~ 29 to ~ 53% of natural flows for the wet and lean periods, respectively. They assessed E-Flows using flow data of the Bhagirathi and Alaknanda rivers for 1972–1982 and 1977–1987, respectively. The annual average reduction in potential energy production due to E-Flows provision in the Alaknanda-Bhagirathi basin is found in between 14.9 and 21.0% for these hydro electric projects. The estimated reduction in energy generation is higher in the lean flow period than in the wet period. This study shows that about 79 to 85% of capacity power generation is possible in the basin after provisioning E-Flows.

The coupling of ever-increasing consumption of fossil fuels around the globe with the decrease in the availability of fossil fuel supplies has led to an increased cost of energy commodities, which together with ever-expanding requirements for reducing the level of environmental pollutions has resulted in an ever-increasing deal of attention to alternative transportation schemes such as electric vehicles (EVs). Since decades ago, national governments and environmental activists have initiated various efforts towards reducing atmospheric pollutions. A part of such effort has been focused on reducing the use of internal combustion vehicles and rather replacing them with EVs. In this research, we attempt to fill in this research gap by presenting a mathematical model for minimizing the sum of traveled distance and recharging cost of EVs per a given period and then solving it by simulated annealing (SA) algorithm. Results of the proposed algorithm were then compared to those of coding in GAMS for 30 different sample problems with different counts of customers, EVs, and charging stations. Numerical results indicated good efficiency of the metaheuristic algorithm in terms of processing time and solution quality. Indeed, with the SA algorithm, the processing time was seen to increase gradually with increasing the problem complexity, while the rate of increase in processing time was much steeper with the GAMS.

Landfill leachate has been documented as a significant source of trace organic pollutants, comprising an expansive family of per- and polyfluoroalkyl substances (PFAS). This study presents the findings on the distribution of 13 perfluoroalkyl carboxylates (PFCAs) and 4 perfluoroalkyl sulfonates (PFSAs) in leachates from 6 municipal solid waste (MSW) landfills in western China. The total concentrations of 17 PFAS in sampled leachates ranged from 1805 to 43,310 ng/L, and 15 compounds were detected in all samples. The short-chain compounds perfluorobutane sulfonate (PFBS, mean mass fraction 23.1%) and perfluorobutyric acid (PFBA, mean mass fraction 20.6%) were dominant. There were higher PFAS concentrations in leachates from operating landfills (mean: 12,194 ng/L) compared to closed landfills (mean: 2747 ng/L), but there was no significant difference between young (< 10 years) and old landfills (> 10 years). Moderate to weak correlations were observed between PFAS concentrations and leachate properties, e.g., TN, NH₄⁺-N, TOC, and pH. This is the first report on the distribution of PFAS in landfill leachates from western China. The results have identified landfill leachate as an underestimated source of PFAS in the environment and have contributed to a more comprehensive evaluation on PFAS presence across China.

To combat groundwater pollution, in situ chemical oxidation (ISCO) has been extensively adopted to degrade groundwater pollutants. A critical factor associated with the success of ISCO is the stability (or persistence) of the chemical oxidant. A higher oxidant stability can result in a higher integrity and a sustained oxidation capacity for the oxidants. Both potassium permanganate (KMnO₄) and persulfate (PS) are two most commonly employed chemical oxidants for ISCO operations. Although a number of experimental studies have been conducted to evaluate the persistence of these two oxidants, systematic investigations of the persistence of KMnO₄ and PS and especially the impact of different subsurface materials on oxidant stability are still limited. To fill these knowledge gaps, the stability of both KMnO₄ and PS oxidants has been systemically evaluated in this study. For each type of oxidant, the impact of solution pH and the presence of matrix anions on oxidant stability were evaluated. Furthermore, the persistence of these oxidants was examined in the presence of a number of soils and subsurface minerals with the natural oxidant demand value of each subsurface material being determined. It is found that KMnO₄ can directly react with the reducing constituents in the soils via chemical oxidation where PS requires to be activated first in order to produce sulfate radical to react with reducing species. This study provides the essential information of the stability of KMnO₄ and PS under different physiochemical conditions and in the presence of different subsurface materials for groundwater ISCO treatment. The conclusions from this study can substantially facilitate the ISCO operations by use of KMnO₄ and PS in a more efficient and cost-effective manner.

The rapid growth of the agriculture sector has been facing environmental issues with agriculture waste generation. Agriculture biomass is a good source for biochar production through the pyrolysis process. Biochar is a highly carbonaceous material and has been widely studied on its potential to improve soil quality. It is essential to understand and have a good prediction of biochar quality for biomass pre-screening. The elemental ratios and surface area both play an important role in determining the suitability of biochar as a soil amendment. In this study, a feedforward neural network (FFNN) with a backpropagation algorithm was developed to model the pyrolysis process in predicting the elemental ratios and surface area of various types of biochar using literature data. The O/C and H/C ratio are important parameters in soil quality to determine the stability of biochar in soil. Surface area is equally important to determine the porosity of biochar on its capability to retain water and nutrients. The optimization of the model was done by comparing the algorithm, transfer function, and hidden neurons. The prediction of the elemental ratios and surface area were based on the effect of pyrolysis temperature, heating rate, residence time, ultimate and proximate analysis. It was found that Levenberg–Marquardt backpropagation with ultimate analysis as input variable had the best results in terms of MSE (0.0087 and 0.0278), MAE (0.0594 and 0.0999), MAPE (17.835 and 11.891%), and R² (0.8601). A validation test was done on the developed model to test its capability to predict the outputs on a wide range of biomass feedstock. The test has shown good alignment with experimental data as a low MSE of 0.0161 is obtained. The model has the capability to achieve high accuracy in prediction with a high overall R² value and low MSE, MAE, and MAPE.

Previously, we showed that the chicken LMH cell line cultured as 3D spheroids may be a suitable animal free alternative to primary chicken embryonic hepatocytes (CEH) for avian in vitro chemical screening. In this study, cytotoxicity and mRNA expression were determined in LMH 3D spheroids following exposure to bisphenol A (BPA), five BPA replacement compounds (BPF, TGSH, DD-70, BPAF, BPSIP), and 17β estradiol (E2). Results were compared to an earlier study that evaluated the same endpoints for these chemicals in CEH. BPA and the replacement compounds had LC50 values ranging from 16.6 to 81.8 μM; DD-70 and BPAF were the most cytotoxic replacements (LC50 = 17.23 ± 4.51 and 16.6 ± 4.78 μM). TGSH and DD-70 modulated the greatest number of genes, although fewer than observed in CEH. Based on the expression of apovitellenin and vitellogenin, BPAF was the most estrogenic compound followed by BPF, BPSIP, and BPA. More estrogen-responsive genes were modulated in LMH spheroids compared to CEH. Concentration-dependent gene expression revealed that DD-70 and BPAF altered genes related to lipid and bile acid regulation. Overall, cytotoxicity and clustering of replacements based on gene expression profiles were similar between LMH spheroids and CEH. In addition to generating novel gene expression data for five BPA replacement compounds in an in vitro avian model, this research demonstrates that LMH spheroids may represent a useful animal free alternative for avian toxicity testing.

Previous studies have indicated aquifer heterogeneity has an important influence on the removal of Cr(VI) in groundwater, but little attention is paid to the effects of aquifer heterogeneity during the process especially under conditions like actual groundwater temperature and hydraulic gradient in the field. Thus, in this study, in situ remediation of Cr(VI)-contaminated shallow groundwater in a sandbox was conducted, and the influences of the heterogeneous aquifer composed of coarse, medium, and fine sand on Cr(VI) diffusion and removal before and after emulsified vegetable oil (EVO) injection were investigated, under the conditions of 19±0.5 °C and hydraulic gradient 3‰. The results show that Cr(VI) diffused consistently with groundwater from top left to bottom right; Cr(VI) spread faster in the horizontal direction than in vertical direction, and the horizontal diffusion of Cr(VI) in coarse, medium, and fine sand was 0.054 m/day, 0.036 m/day, and 0.018 m/day, respectively; a high performance of EVO toward Cr(VI) removal by over 95% was mainly because different concentrations of microorganisms migrated among heterogeneous aquifers vertically and horizontally; compared with coarse and medium sand, fine sand, with a better adsorption capacity and a lower permeability, retained relatively more microorganisms, providing favorable conditions during the remediation; a stable and unified effective removal zone, similar to the shape of Ʃ (approximately 1357.87 cm²), was ultimately formed downstream of the injection well.