To conduct a comprehensive ecological analysis on the solid residues derived from the thermal disposal of hyperaccumulator Pteris vittata, this study focused on the behaviors of As and Pb and the characteristics of environmentally persistent free radicals (EPFRs) in the solid residues under different thermal treatment conditions. The analysis results revealed that the concentrations of As in the biochars and bio-slag were approximately 350 and 1100 mg/kg, respectively. Moreover, the concentrations of Pb in the solid residues varied from 34 to 1050 mg/kg. According to the results of the modified BCR sequential extractions, As is more stable in the biochar while Pb is more stable in the combustion slags. In addition, As showed a higher volatilization temperature compared with Pb. The ecological risk assessment indicated that the correlation index between the contamination factor (Cf) of As and the risk index (R² = 0.995) is considerably larger than the correlation index between the contamination factor of Pb and the risk index (R² = 0.117), which implies that the pyrolysis method should be selected at priority. Moreover, the EPFR concentrations of the biochar declined by approximately 75 times when the pyrolysis temperature increased from 500 to 600 °C. This behavior indicated that high-temperature pyrolysis (> 600 °C) could simultaneously control both the heavy metal behavior and EPFR concentrations.

To study the effects of vermicomposting on the chemical properties and bioavailability of Cd/Zn in sludge, earthworms (Eisenia foetida) at different densities were inoculated into pure sludge, and sludge and earthworms were collected regularly to determine the earthworm biomass, the main chemical indexes, the structure of the functional groups, and the Cd/Zn content in the sludge. The results showed that the growth curve of earthworms in pure sludge could be well fitted by the logistic model. Earthworm activity eventually reduced the total organic carbon (TOC), fulvic acid (FA), and C/N ratio and increased the electrical conductivity (EC), total nitrogen (TN), humic acid (HA), and HA/FA ratio in the sludge. TOC, TN, and pH inhibited the bioavailability of Cd/Zn, while HA and EC promoted the bioavailability of Cd/Zn. Earthworm activity ultimately increased the content of Cd/Zn in the sludge. The bioavailability of Cd/Zn was reduced during the rapid growth period of the earthworms but increased during the stable growth period of the earthworms. A suitable vermicomposting time should be determined to ensure the activation or passivation of Cd/Zn.

Different microalgae species produce varying quantity and quality of the lipids. Fatty acid methyl ester composition, which comprises both saturated and unsaturated contents, critically affects biodiesel properties. Current study compares six locally isolated microalgae strains belonging to three classes (Trebouxiophyceae, Chlorophyceae, and Cyanophyceae) on the basis of lipid content and biodiesel properties. All the six species are grown in similar condition up to the late stationary phase, and their lipid content and fatty acid methyl ester composition are measured experimentally. Multi-criteria decision analysis (MCDA) tool has ranked Calothrix species (class Cyanophyceae) on the top, owing to better cetane number, density and oxidation stability; whereas Chlorococcum species (class Chlorophyceae) is ranked second because of its higher lipid content, better cold flow property, and low viscosity. Property analysis of these two species is extended in the enlarge temperature range for five properties, vapor pressure, latent heat of vaporization, liquid density, liquid viscosity and vapor diffusivity, which are important in spray and combustion modeling. It is found through detailed property estimation that Chlorococcum sp. is a more suitable species in comparison with Calothrix sp. as it is having better properties and its lipid content is much higher than that of Calothrix sp. Although the properties of microalgae biodiesel are poorer in comparison with conventional diesel fuel, a greater number of such studies will help in understanding the requisite changes as required for microalgae biodiesel–based engine and their properties as compared with conventional diesel.

The aim of this work is to synthesize a magnetic magnetite/multi-walled carbon nanotube (Fe₃O₄/MWCNT) catalyst by a method combining co-precipitation and hydrothermal treatments for the efficient removal of diclofenac (DCF) by catalytic wet peroxide oxidation (CWPO). The support (MWCNTs) shows a moderate-large surface area and good adsorption capacity, leading to the improvement of the magnetite (Fe₃O₄) dispersion on its surface. The response surface methodology (RSM) was applied in order to find out the effect of the reaction parameters on DCF removal, allowing to establish the optimum operating conditions (T = 60 °C, [H₂O₂]₀ = 2.7 mM, [catalyst] = 1.0 g L⁻¹). The optimum CWPO experiment showed an outstanding catalytic activity at non-modified pH solution (6.7), obtaining a 95% of DCF removal after 3 h reaction time; this high efficiency can be attributed to the synergistic effect of the iron-based catalyst with the high quantity of •OH radicals generated on the surface of the catalyst. In addition, the Fe₃O₄/MWCNT material exhibited good reusability along three consecutive reaction cycles, finding a pollutant removal close to 95% in each cycle of 3 h reaction time. Additionally, a degradation mechanism pathway was proposed for the removal of DCF by CWPO. The versatility of the material was finally demonstrated in the treatment of different environmentally relevant aqueous matrices (a wastewater treatment plant effluent, surface water, and hospital wastewater), obtaining an effective reduction in the ecotoxicity values.

The emergence of antibiotic resistance genes (ARGs) in microbes can be largely attributed to the abuse and misuse of antibiotics and biocides. Quaternary ammonium compounds (QACs) have been used worldwide as common disinfectants and detergents; however, their potential impact on the spread and diffusion of ARGs is still unknown. In this study, we detected the QAC resistance gene (qacEΔ1), the 1 integron gene (intI1), and 12 ARGs (sul1, sul2, cfr, cml, fexA, tetA, tetG, tetQ, tetX, ermB, blaTEM, and dfrA1) in 48 water samples from three watersheds by quantitative PCR (qPCR). We investigated the evolution of bacterial antibiotic resistance under QAC and antibiotic environmental pressures by long-term continuous culture. In addition, five QACs were selected to investigate the effect of QAC on the efficiency of conjugation transfer. The changes in bacterial cell membrane and production of reactive oxygen species (ROS) were detected by flow cytometry, revealing the mechanism by which QAC affects the spread of antibiotic resistance. Our results showed that the QAC resistance gene was ubiquitous in watersheds and it had significant correlation with intI1 and seven ARGs (r = 0.999, p < 0.01). QACs could increase the resistance of bacteria to multiple antibiotics. Furthermore, all five QACs promoted the conjugation transfer of the RP4 plasmid; the optimal concentration of QACs was about 10⁻¹–10⁻² mg/L and their transfer efficiencies were between 1.33 × 10⁻⁶ and 8.87 × 10⁻⁵. QACs enhanced membrane permeability of bacterial cells and stimulated bacteria to produce ROS, which potentially promoted the transfer of plasmids between bacteria. In conclusion, this study demonstrated that QACs may facilitate the evolution and gene transfer of antibiotic resistance gene among microbiome.

There is an increasing concern over the environmental degradation caused by agricultural activities especially in developing countries which mostly linked to farmer’s behavior. Thus, this study aimed to model the responsible attitude and behavior of Iranian farmers in respect to environment. The Theory of Planned Behavior (TPB) was used as a basis for identification of the main determinants of the farmers’ responsible environmental behavior. A survey of 400 farmers in the Hamedan Province, selected through a multistage stratified random sampling method. Data was gathered using a questionnaire which its validity and reliability were confirmed by a panel of agricultural and environmental experts and calculated Cronbach’s alpha (0.65 ≤ α ≤ 0.80), respectively. Data were analyzed using structural equation modeling (SEM) to evaluate the strength of relationship between the constructs and test the overall model fit. Results of study showed that “using animal manure in the farms” was the most important behavior which farmers are responsibly doing to respect their environment but their least attention is given to “disposing cans and bottles after spraying.” Also, the fitness indices of the model revealed that the TPB partially supported the farmers’ responsible environmental behavior as perceived behavioral control and environmental attitude positively influenced the farmers’ responsible environmental behavior but there was not observed any significant influence by subjective norm. Among the additional incorporated constructs, environmental awareness, ethical commitment, and environmental concern significantly had a positive influence on farmers’ behavior by mediating role of the environmental attitude. The inclusion of new constructs in the TPB model was supported through improving the predictive power of the modified model in predicting farmers’ responsible environmental behavior.

The need to maximize agricultural productivity has made pesticides an indispensable part of current times. Farmers are unaware of the lurking consequences of the pesticide exposure, which endanger their health. It also puts the unsuspecting consumers in peril. The pesticides (from organophosphates, organochlorine, and carbamate class) disrupt the immune and hormonal signaling, causing recurrent inflammation, which leads to a wide array pathologies, including teratogenicity. Numerous farmers have fallen victim to neural disorders–driven suicides and lungs, prostate/breast cancer–caused untimely deaths. Green revolution which significantly escalated agricultural productivity is backfiring now. It is high time that environmental and agricultural authorities act to restrain the excessive usage of the detrimental chemicals and educate farmers regarding the crisis. This review discusses the biological mechanisms of pesticide-driven pathogenesis (such as the activation or inhibition of caspase, serine protease, acetylcholinesterase) and presents the pesticide-exposure-caused health deterioration in USA, India, and Africa. This holistic and critical review should be an eye-opener for general public, and a guide for researchers.

A highly resourceful, eco-friendly, and recyclable magnetic adsorbent based on montmorillonite (CoFe₂O₄/MMT) was fabricated via a facile hydrothermal method to harvest tetracycline (TC) and ciprofloxacin (CIP) from pollutant water. The prepared adsorbent was characterized by XRD, FT-IR, SEM, and VSM methods to comprehend its structure, morphology, and magnetism. Effects of experimental parameters including solution pH, adsorption time, initial concentration, and ion strength were studied in details. The experimental adsorption data of TC and CIP fitted into pseudo-second-order kinetic model and Langmuir isotherm, respectively. The maximum adsorptions of TC and CIP could reach up to 240.91 and 224.00 mg/g. The thermodynamic study indicates that the adsorption process is spontaneous. In addition, the antibiotics can be further degraded under visible light environment and the magnetic sorbent can also be thermally regenerated. Graphical abstract ᅟ

Soil alkalinity caused by salts, such as sodium bicarbonate (NaHCO₃), and the frequently associated waterlogging problems are pervasive in agriculture and have a deleterious impact on crop production. However, various plant growth regulators, including brassinosteroids, are considered to be important against different abiotic stresses experienced by plants due to drought, salinity, and heavy metal stress. We investigated the putative role of 24-epibrassinolide (EBL), an active brassinosteroid, on red rice plants experiencing alkaline stress. Seedlings were pre-treated with 0.01 μM EBL for 30 min and later, exposed to NaHCO₃ (25 mM) and were sampled, 5 days after treatments. Results showed that the pre-treatment of seedlings with EBL under non-stress conditions could promote rice plant growth. Growth parameters including dry weight (DW), root and coleoptile lengths were reduced under alkaline stress, whereas EBL application reduced the level of inhibition, as compared with NaHCO₃ treatment. Enhanced levels of malondialdehyde content, hydrogen peroxide, and superoxide radicals were significantly diminished by EBL pre-treatment. Moreover, pre-treatment of EBL to alkaline-treated rice seedlings largely stimulated the enzymatic activities of ascorbate peroxidase, catalase, and superoxide dismutase. Thus, the results suggest that pre-application of EBL significantly ameliorates alkaline stress in rice.

Financial development is important for the growth of a country which indirectly affects the environment adversely through industrialization. However, in the presence of strong institutions, this adverse effect can be reduced. The main concern of the present study is to estimate the relation between CO₂ and financial development (FD) in the presence of economic institutions as an interactive term. A sample of 101 countries has been selected for econometric analysis for the period from 1995 to 2017. The cross-section dependence test statistics for dependency, CIPS and CADF for panel unit root test, Westerlund test to ascertain the long-run affiliations, and FMOLS to extract the long-run coefficients have been applied. Dumitrescu and Hurlin test is also employed to know about the causal nature of the panel series. The findings show that financial development has a positive relationship with CO₂. However, after inclusion of economic intuitions, the adverse impact of financial development on the environment is reduced. The study also confirms the presence of environmental Kuznets curve in the context of income and financial development. The findings imply that financial development can help to improve environment quality if it is accompanied with strong institutional framework such as assurance of property rights, government integrity, and liberalization in financial sector.