Resistance to grain protectants in Tribolium castaneum (Herbst) is a serious threat to international grain trade. Frequent and overdose application of chemical insecticides is becoming a serious health hazard and cause environmental pollution. Resistance management approaches by using various synergists along with novel compounds has become more imperative to increase efficacy of environmentally safe insecticides. We have evaluated piperonyl butoxide (PBO) and emamectin benzoate mixtures for management of resistant field populations of T. castaneum. The collected strains had demonstrated 50 to 200% resistance already developed against emamectin benzoate as compared with deltamethrin susceptible reference strain. The inclusion of PBO along with emamectin significantly reduced this resistance by at least 28% and the LC₅₀ were lowered from 5.12 to 1.9 μg/ml with the highest synergism ration of 2.7 in resistant strain. Enzymatic assays clearly demonstrated that the specific activities of catalase and acetylcholinesterases were significantly decreased at an average of 80% and 60%, respectively, when PBO was included as a synergist at 1:2 ratio with emamectin benzoate. The results highlight the mechanism that renders the field population resistant to emamectin benzoate and suggests the synergistic role of piperonyl butoxide as a potent additive in grain protectants for resistance management.

Tobacco stalk, a common agricultural waste derived from the harvest of tobacco, caused serious environmental pollution in China. In this study, the performance of biomethane production and characteristics of four varieties of tobacco stalk were investigated for the first time. The results showed that the highest cumulative methane yield of 130.2 mL/g-VS was obtained from Nicotiana tabacum L., Yunyan114, which had lower lignin content than other varieties of tobacco stalk. Moreover, different kinetic models were used to describe the biomethane production process, and it was found that the modified Gompertz model was more suitable to simulate the anaerobic digestion (AD) of tobacco stalk. The findings of this study not only showed a feasible method for minimizing the pollution issues of tobacco stalk waste but also gave fundamental information for future AD application.

Due to the lack of appropriate wastewater treatment facility in rural areas, the discharging of wastewater without sufficient treatment results in many environmental issues and negative impact on the local economy. In this study, a novel integrated gravitational-flow wastewater treatment system (IGWTS) for treating domestic wastewater in rural areas was developed and evaluated. As the core module of IGWTS, the multi-soil-layering (MSL) system showed good performances for removing organic matters and nutrients in lab-scale experiments. Aeration was found to be the dominant positive factor for contaminant removal in factorial analysis, while bottom submersion had the most negative effect. Based on the critical operational factors obtained from lab-scale tests, the full-scale IGWTS consisting of multifunctional anaerobic tank (MFAT), MSL, and subsurface flow constructed wetland (SFCW) was designed, constructed, and operated successfully in the field application. The final effluent concentrations of COD, BOD₅, TP, NH₃-N, and TN reached 22.0, 8.0, 0.3, 4.0, and 11.0 mg/L, with removal rates of 92, 93, 92, 86, and 76%, respectively. The feasibility of IGWTS was also quantitatively evaluated from the perspectives of resource consumption, economic costs, water environment impact, and life cycle greenhouse gas (GHG) emissions. IGWTS has been proved to be a sound approach to mitigate GHG emissions compared with centralized wastewater treatment plant. It can also be featured as an eco-friendly technology to improve rural water environment, and an economic scenario with low construction and operation costs. Graphical abstract

The main objective of this study is to evaluate 22 explanatory variables on ecological footprints and rank each of them by using the two approaches of Bayesian model averaging and weighted averaging least square in developing countries. The data is in a 20-year period of 1996–2016. According to the negative weighted averaging coefficient of square of gross domestic production (GDP), the Environmental Kuznets Curve (EKC) hypothesis can be confirmed with a high degree of certainty. The probability of the effect of this variable is 95% and is part of the components of all five optimal models. The two variables of energy consumption and population density were ranked second and third with the probability of the effectiveness of 0.89 and 0.75, respectively. They have positive effects on ecological footprint index. Population growth and value added of the industrial sector have a positive and almost important relationship with ecological footprint. Other variables in this study are not strongly related to the quality of the environment. For example, the variables such as urbanization rate, literacy rate, and foreign direct investment acquired the next ranking with respect to affecting the ecological footprint, respectively. Regarding the positive effect of foreign direct investment, we can say that this leads to environmental degradation. Human development with inclusion probability of 0.26 and a coefficient of 0.009 has resulted in the reduction of environmental degradation. The intensity of economic activities has inclusion probability of 0.48 and a negative impact, which is unexpected. Indicators of financial openness and trade openness have positive and negative coefficients with fewer probabilities. The square of the capital to labor ratio has a negative sign. The square of the capital to relative labor ratio has a negative coefficient and reduces environmental degradation. The product of the trade openness in the capital to relative labor ratio (and its square) is increasing the degradation of the environment. The square of the financial development has a negative sign. This is indicative of a non-uniform relationship between financial development and the ecological footprint, which follows a U-inverse form. The interaction of financial development–economic growth has a negative sign and the inclusion probability of it is 0.31 in the model, which indicates its weak relationship with the ecological footprint. In addition, the results of the analysis of optimal models confirm largely the previous findings based on BMA and weighted averaging least squares methods.

Wastewater discharge evidently increased bacterial diversity in the receiving waterbodies. The objective of this study was to evaluate the effectiveness of a constructed wetland in reducing fecal indicator bacteria (FIB) and antibiotic resistant genes (ARGs). We determined the prevalence and attenuation of fecal indicator bacteria including Escherichia coli and enterococci, along with ARGs, and human-associated Bacteroidales (HF183) markers by quantitative polymerase chain reaction (qPCR) method. Three types of water samples (inlet, intermediate, and outlet) from a constructed wetland were collected once a month from May to December in 2013. The overall reduction of E. coli was 50.0% based on culture method. According to the qPCR result, the overall removal rate of E. coli was only 6.7%. Enterococci were found in 62.5% of the wetland samples. HF183 genetic marker was detected in all final effluent samples with concentration ranging from 1.8 to 4.22 log₁₀ gene copies (GC)/100 ml. Of the ARGs tested, erythromycin resistance genes (ermF) were detected in 79.2% of the wetland samples. The class 1 integrase (intI1) was detected in all water samples with concentration ranging from 0.83 to 5.54 log₁₀ GC/100 ml. The overall removal rates of enterococci, HF183, intI1, and ermF were 84.0%, 66.6%, 67.2%, and 13.1%, respectively.

Brines from table olive elaboration were co-digested with pig manure, obtaining high methane productions. In particular, the methane yields obtained for pig manure total solid (TS) initial concentrations of 2%, 7%, 9% (wet basis, wt.) were 106, 213 and 247 mL CH₄ gVS⁻¹ₐdd, respectively, using mixtures of two types of brine (acid (A) and basic (B)) generated in the elaboration process. Moreover, an experiment with only basic brine was made, using a pig manure TS concentration of 7% wt. In this case, a methane yield of 224 mL CH₄ gVS⁻¹ₐdd was obtained. The methane production rate was calculated in experiments of 7% pig manure TS concentration and a high kinetic constant of 0.31 d⁻¹ was obtained for the mixture of residual brine. Finally, the effect of Na⁺ cation concentration was evaluated in the mixture A:B during co-digestion processes with a 7% wt. pig manure TS concentration and inhibition was detected in this process with a [Na⁺] of 0.56% wt. of the total sample. An energy and economical study on the treatment of these wastewaters by means of anaerobic co-digestion demonstrated a great economic benefit for the producer industry, a reduction in the diesel consumption used to produce its energetic demand and a reduction cost of 3.63 €/m³ generated of A:B brines mixture with ratio 2:1.

A series of Ce-doped LaMnO₃ (La₁₋ₓCeₓMnO₃) were prepared and were tested for gaseous toluene oxidation in order to investigate the effect of cerium doping in LaMnO₃ on activity under photothermal conditions. It was found that the activity and CO₂ yield of the catalyst can be effectively increased when x = 0.25. A group of characterization is used to characterize the morphology, composition, and physical properties of the as-prepared catalysts. Results show that the Ce-doped LaMnO₃ can form coexistence of La₁₋ₓCeₓMnO₃ and CeO₂, the reaction of CeO₂/La₁₋ₓCeₓMnO₃ under photothermal conditions follows the Mars-van Krevelen redox cycle mechanism, and the prepared CeO₂/La₁₋ₓCeₓMnO₃ can form a highly efficient Z-scheme heterojunction, which can enhance the electrons transfer speed of the catalyst. Moreover, in the photothermal catalytic degradation, lattice oxygen is the most important active substance, a small amount of cerium doping can increase the lattice oxygen content of perovskite and increase the activity of the reaction.

Discharge of unprocessed coloured waste water from industries gives rise to water contamination. In the current work, we propose the application of CuO nanoparticles supported on cellulose kitchen wipe sponge as a heterogeneous catalyst for the reductive decolourization of various toxic cationic and anionic dye molecules. The catalytic activity of the CuO nanoparticles under normal light for reduction has been examined in which sunlight irradiation is not necessitated. The CuO nanoparticles were synthesized by a simple wet chemical method and characterized using High Resolution Transmission Electron Microscope (HRTEM), SEM, EDX, XRD, XPS and TGA analyses. In the presence of CuO@CS catalyst and sodium borohydride, decolourization reaction of dyes such as acid red, acid green, methylene blue, rhodamine B and solochrome black-T was carried out. The catalytic reduction behaves as a pseudo-first-order reaction and is found to be superior in comparison with other reported catalysts in terms of reaction velocity. The reduction reaction can be further accelerated by increasing the reaction temperature. The developed catalyst drives the reduction faster on exposing the reaction mixture to sunlight confirming the usage of the catalyst at normal light and sunlight conditions. The catalyst retains 100% efficiency even after 5 cycles and remains suitable even for further use. Thus, a low-cost heterogeneous catalyst has been successfully developed and employed to decolourize various dye molecules in short duration with good recyclability and therefore can be used as the potential candidate in environmental remediation.

Atmospheric contamination by heavy metal(loid)–enriched particulate matter (metal-PM) is highly topical these days because of its high persistence, toxic nature, and health risks. Globally, foliar uptake of metal(loid)s occurs for vegetables/crops grown in the vicinity of industrial or urban areas with a metal-PM-contaminated atmosphere. The current study evaluated the foliar uptake of arsenic (As), accumulation of As in different plant organs, its toxicity (in terms of ROS generation, chlorophyll degradation, and lipid peroxidation), and its defensive mechanism (antioxidant enzymes) in spinach (Spinacia oleracea) after foliar application of As in the form of nanoparticles (As-NPs). The As-NPs were prepared using a chemical method. Results indicate that spinach can absorb As via foliar pathways (0.50 to 0.73 mg/kg in leaves) and can translocate it towards root tissues (0.35 to 0.68 mg/kg). However, health risk assessment parameters showed that the As level in the edible parts of spinach was below the critical limit (hazard quotient < 1). Despite low tissue level, As-NP exposure caused phytotoxicity in terms of a decrease in plant dry biomass (up to 84%) and pigment contents (up to 38%). Furthermore, several-fold higher activities of antioxidant enzymes were observed under metal stress than control. However, no significant variation was observed in the level of hydrogen peroxide (H₂O₂), which can be its possible transformation to other forms of reactive oxygen species (ROS). It is proposed that As can be absorbed by spinach via foliar pathway and then disturbs the plant metabolism. Therefore, air quality needs to be considered and monitored continuously for the human health risk assessment and quality of vegetables cultivated on polluted soils (roadside and industrial vicinity). Graphical abstract ᅟ

The objectives of this study were to investigate the response of cadmium (Cd) distribution and stability in soil aggregates as affected by applying different amendments and to understand the relationship between changes in soil aggregates and alleviation of Cd phytotoxicity to rice after amendment application. In the present study, rice (Oryza sativa L.) was cultivated on a Cd-polluted soil. Five soil amendments were applied, which are as follows: rice husk biochar (BC), Fe-added rice husk biochar (Fe-BC), attapulgite-based mixture (AM), zeolite-based mixture (ZM), and cow manure-based mixture (MM). The effect on Cd redistribution in soil and Cd accumulation in rice plant was evaluated. The results showed that the five amendments applied at the rate of 3% (w/w) significantly increased soil pH and decreased Cd mobility in soil and Cd accumulation in rice plants. The reduction rate of Cd content in rice grains ranged from 41 to 62% after amendment application. The remediation efficiency of the different amendments for decreasing Cd accumulation in rice tissues followed the order of Fe-BC > MM > BC > ZM > AM. Adding amendments promoted the formation of large aggregates (0.2–2.0 mm) with more mass loading of Cd and enhanced aggregate stability. Comparatively, Fe-BC was more effective than others for remediation of acid Cd-polluted paddy soil, as a significantly decreased Cd concentration in rice grain after its application was observed. Structural equation modeling (SEM) analysis revealed that DTPA-extractable Cd in small aggregates was the main factor affecting Cd accumulation in rice grain; soil pH directly affected aggregate stability; and aggregate stability was closely related to Cd availability in different size soil particles. These results indicated that the applied amendments were effective in reducing Cd bioavailability, most likely through raising the soil pH, improving aggregate stability, and re-distributing Cd from smaller soil aggregates to larger ones.