In this work, malachite green was degraded using different advanced oxidation processes (Fenton, photo-Fenton, sono-Fenton and electrochemical process). Malachite green is used as biocide in aquaculture and is usually discarded with the effluents. On higher pollutant concentration, all the Fenton-based reactions achieved excellent absorbance reduction up to 10 min. Classic Fenton was faster after 10 min of reaction and photo-Fenton acting faster before this point. The photocatalytic effect was better on the oxygen demand reduction (COD) with 86.91% against 79.19% of sono-Fenton and 62.72% of Fenton. All four methodologies had excellent absorbance reduction following the order: photo-Fenton (100% up to 30 min) > electrochemical (99.27%) > Fenton (98.11%) > sono-Fenton (73.99%). Despites the slowly initial degradation obtained for electrochemical process, the reaction achieved high capacity after 60 min. Toxicity tests, using Lactuca sativa seeds, indicated a significant reduction in the effluent toxicity following this sequence: sono-Fenton > photo-Fenton > Fenton > electrochemical. The results showed that all processes studied provided high levels of malachite green removal; however, the adequate use of each technique should be conduct with an accurate evaluation of the needed treatment considering the particularity of each method. Such techniques were successfully applied before to remove dye basic blue 99 and the hormone 17-α-methyltestosterone and corroborated by Lactuca sativa toxicity assays. Graphical Abstract

Agroforestry practices coupled with wastewater irrigation systems are sustainable strategies for water management. The performance of these practices could be improved by rhizobioaugmentation. This approach would be particularly useful in developing countries where it can be used as a low-cost tool to control widespread environmental contaminations. The main objectives of the present study are to (1) determine the effects of wastewater on metal/nutrient contents in soils, (2) assess the pattern of metals in Casuarina glauca, and (3) analyze the effects of rhizobioaugmentation of C. glauca growing in industrial wastewater–irrigated agricultural soil using N-fixing Frankia symbionts. Overall, the wastewater treatment significantly increases the levels of total Pb, B, Cr, Mn, Na, Sr, Zn, As, Co, Sb, Sn, and Fe. Only a small portion of total metals/nutrients were phytoavailable. The bioaccumulation in roots of all the metals/nutrients measured was high while the translocation from roots to aerial parts showed insignificant level of movement of the elements tested. Based on bioavailable metals/nutrients, the bioaccumulation factors were 34, 41, 94, 196, 584, 587, 1859, and 9917 for Mg, As, Ni, Mn, Cu, Co, Cr, and Pb, respectively. Hence, C. glauca is classified as a metal excluder. Rhizobioaugmentation with Frankia resulted in an increase or a decrease of metals/nutrients in soil depending on the bacterial strain used and the metal/nutrient element. It also increased significantly the bioaccumulation in roots of some metals and the uptake of key nutrients such as Ca, Na, and K by Casuarina plants. Overall, the results of the present study showed that C. glauca is suitable for phytoremediation of metal-contaminated soils. The use of Frankia represents a potential approach of managing Casuarina glauca wastewater–irrigated soil system.

The pollution of agricultural soil due to heavy metals is a serious environmental problem throughout the world due to their persistence and toxicity. The present study was carried out on agricultural soils of district Bathinda, Punjab where a total of 120 soil samples were collected from 40 different locations during pre-monsoon, monsoon, and post-monsoon season. The total mean concentration of heavy metals (arsenic (As), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), mercury (Hg), lead (Pb)) was estimated by ThermoScientific–iCAP Qc (Germany) inductively coupled plasma–mass spectrometry (ICP-MS). The concentration of heavy metals was of the order of Fe > Zn > Cr > Ni > Cu > Co > As > Pb > Hg > Cd, Fe > Zn > Cr > Ni > Cu > Co > As > Pb > Hg > Cd, and Fe > Zn > Cr > Ni > Cu > Co > Pb > As > Hg > Cd in pre-monsoon, monsoon, and post-monsoon seasons, respectively. The metals such as Fe, Zn, Cr, and Ni indicated higher concentrations at most of the sites, whereas Hg and Cd showed lower concentrations throughout the region. The total mean concentrations (mg/kg) of the metals were found to be lower than their natural background concentration values. Based on enrichment factor (EF), the soils were moderately contaminated at most of the sites with a few cases where the soil was minimally enriched with heavy metals. Other pollution indices such pollution load index (PLI) and degree of contamination (Cd) also indicated low to moderate level of soil contamination. Besides, risk assessment of heavy metals was also determined using potential ecological risk factor (Eᵢ) and ecological risk index (Rᵢ) which indicated low Eᵢ and Rᵢ in the region for most of the metals. Spatial distribution using interpolation technique, Inverse Distance Weighted (IDW) in ArcGIS 10.6.1 software, showed a significant spatial and seasonal variability of heavy metals throughout the region. Pearson’s correlation coefficient (r) between heavy metal variables was found to be significant at p < 0.05 significance level (As-Cr (r = 0.769), As-Fe (r = 0.760), As-Co (r = 0.883), As-Ni (r = 0.886), As-Cu (r = 0.859), As-Hg (r = 0.678) in pre-monsoon samples; As-Fe (r = 0.613), As-Co (r = 0.669), As-Ni (r = 0.619), As-Cu (r = 0.639) in monsoon samples and As-Cr (r = 0.631), As-Fe (r = 0.715), As-Co (r = 0.710), As-Cu (r = 0.690) in post-monsoon samples) indicated a strong relationship between different variables. Principal component analysis (PCA) technique also proved to be significant in studying the behavioral pattern of variables, where PCA biplots showed different behavior as revealed from some strong associations. Finally, continuous monitoring of the sites is suggested to avoid further contamination and degradation of soil quality, despite low contamination levels in the region.

Urinary benzene, toluene, ethylbenzene, and xylenes (BTEX) can be used as a reliable biomarker of exposure to these pollutants. This cross-sectional study aimed to employ biomonitoring to assess BTEX exposure among South Pars Gas Field (SPGF) workers in Assaluyeh, Iran. Forty employees who were working on the site were recruited as the case group. Besides, 31 administrative employees were recruited as the control group. Pre-shift and post-shift spot urine samples were collected from the subjects in the case group, while the subjects in the control group provided mid-morning urine samples. Overall, 111 urine samples, including 80 samples from the case group and 31 samples from the controls, were collected. Gas chromatography-mass spectrometry (GC/MS) was used to determine the urinary levels of BTEX compounds. The median urinary levels of benzene, toluene, ethylbenzene, m,p-xylene, and o-xylene in the post-shift samples of the exposed group were 1.24, 2.28, 0.5, 1.32, and 1.5 μg/l, respectively. Significant differences were observed in urinary BTEX levels among smokers and non-smokers in both studied groups (p < 0.05). Accordingly, the median urinary BTEX concentrations in smokers were 2 to 6.5 times higher than the corresponding values in non-smoker subjects. Smoking status was the only predictor of the urinary BTEX concentration. Our findings revealed that refinery workers are exposed to significant levels of BTEX compounds. Considering the health risks associated with BTEX exposure for refinery workers, implementation of suitable control strategies, such as using appropriate personal protective equipment and improving on-site ventilation systems, are recommended reducing their exposure to BTEX via the inhalation.

Catalysts of Pd-In supported on activated carbon fiber were synthesized, characterized, and evaluated for the removal of nitrogen oxyanions from water. The work was carried out aiming the development of a green synthesis process, and the studies were accomplished with the following objectives: (a) to evaluate whether catalysts produced by wet impregnation (WI) and autocatalytic deposition (AD) have enough catalytic activity for the removal of oxyanions in water; (b) to determine the efficiency of ion removal using formic acid as a reducing agent; (c) to determine which synthesis method produces less waste. It was found that the two synthesis processes modified the properties of the support and that the distribution of the particles of the metallic phase was of the nanometric order, being these particles found predominantly at the support surface. By using formic acid as a reducing agent, although low nitrate conversions were obtained (32%), a selectivity to N₂ higher than 99% was achieved. These findings were attributed to the low decomposition of formic acid on the catalyst surface. The Pd:In (0.45:0.2) catalyst prepared by WI was the most suitable for the catalytic reduction of both nitrate and nitrite oxyanions. Regarding the green point of view of the synthesis method, catalysts prepared by WI generated less waste. Graphical abstract

Recently, there has been renewed interest in the relationship between economic globalization and environmental pollution since various globalization indices are developed. Although several attempts have been made to investigate the impact of globalization on the environment, no known empirical research has focused on exploring the causal relationship between ecological footprint and economic globalization index (provided by KOF Swiss Economic Institute) considering also its subcomponents—trade and financial globalization indices. In this study, a new panel data technique for the causality analysis is developed (namely, panel Fourier Toda-Yamamoto approach) and applied to ecological footprint-economic globalization nexus in 14 MENA (Middle East and North Africa) countries during the period 1981–2016. The empirical results highlight that ecological footprint Granger causes economic, trade, and financial globalization for the panel. Besides, it is found that financial globalization has a predictive power to predict further values of environmental degradation in the MENA countries. The empirical results of this paper have a number of practical implications for policymakers. Especially, policymakers should be careful about implementing environmental policies since they may affect economic (trade and financial) activities negatively.

In this study, La(OH)₃-modified magnetic sodium carboxymethyl cellulose (La-MC) was prepared as adsorbents for phosphate, which exhibited excellent adsorption performance up to 62.98 mg P/g and magnetic property for easy recovery. The recovered adsorbents after phosphate sorption were subsequently used for photocatalytic reduction of Cr(VI) and possessed good photocatalytic activity. This work provided an excellent reference for developing a new way of extending life cycle of adsorbents by combining phosphate adsorption with photocatalysis for sequential removal of pollutants from water in the future.

The main objective of the present study is to determine the kinetics, thermodynamics, and adsorption mechanism of the oxytetracycline (OTC) on rice husk ash (RHA). The adsorbent was characterized by scanning electronic microscopy, Fourier transform infrared spectroscopy, and nitrogen physisorption. Batch studies were carried out to evaluate the influence of the adsorbent dose, initial concentration, contact time, temperature, and initial pH. RHA was characterized as having heterogeneous, fibrous, and porous particles, consisting predominantly of silica. The removal of OTC depends on the pH of the medium, which is favored at acid pH values. The kinetic data followed the Bangham model, which indicated an OTC diffusion in the pores of RHA, although this was not the only process, as demonstrated through the use of the Weber-Morris model (IPD model). The Sips isotherm best represents the experimental results of the equilibrium study. It was found that the adsorption process was spontaneous and endothermic. The highest adsorption capacity was found at a pH in the range of 4–6, when the OTC is in its zwitterion form and the surface of the RHA is positively charged, thus permitting electrostatic interactions and the formation of hydrogen bonds between the adsorbent and adsorbate molecules. These findings demonstrate the potential of rice husk ash to remove oxytetracycline from water.

End-of-life packaging materials (EOLPM) present an important challenge from an environmental and financial perspective at utility-scale solar energy (USSE) sites. Reuse on-site represents, in particular for remote sites, a significant contribution to sustainable business practice as it provides a higher value end use when used to develop on-site mulch to enable soil improvement, reducing transport emissions (from the least preferred option of off-site disposal to landfill), reducing costs, and employing local contractors. The objective of the study was to enable on-site reuse, which was primarily achieved through chemical and physicochemical characterization of EOLPM streams; cardboard, and wood. Given the common occurrence of these materials in the rapidly growing renewable energy sector, it represents an important scope of work for the sector internationally. The methods used for characterization of the EOLPM, the first of its type reported, included a range of organic and inorganic chemical analyses, phytotoxicity testing, followed by an environmental and high-level (or initial) financial benefit cost analysis. Key scientific findings were that only trace concentrations of chemicals of potential concern (COPC) were detected; the material was not phytotoxic and has potential for soil improvement at the site, and the selected option of on-site reuse (of the materials as a mulch) had a global warming potential of 50 times less than the business as usual option (transport to landfill). The results also demonstrated the broader potential for using EOLPMs from USSE sites for soil improvement at remote locations rather than transporting offsite for disposal or reuse. Structural changes will need to be made to the way in which markets operate to achieve circular economy outcomes for these EOLPMs.

Endocrine-disrupting chemicals (EDC) are a wide group of chemicals that interfere with the endocrine system. Their similarity to natural steroid hormones makes them able to attach to hormone receptors, thereby causing unfavorable health effects. Among EDC, bisphenol A (BPA), bisphenol S (BPS), and nonylphenol (NP) seem to be particularly harmful. As the industry is experiencing rapid expansion, BPA, BPS, and NP are being produced in growing amounts, generating considerable environmental pollution. White rot fungi (WRF) are an economical, ecologically friendly, and socially acceptable way to remove EDC contamination from ecosystems. WRF secrete extracellular ligninolytic enzymes such as laccase, manganese peroxidase, lignin peroxidase, and versatile peroxidase, involved in lignin deterioration. Owing to the broad substrate specificity of these enzymes, they are able to remove numerous xenobiotics, including EDC. Therefore, WRF seem to be a promising tool in the abovementioned EDC elimination during wastewater treatment processes. Here, we review WRF application for this EDC removal from wastewater and indicate several strengths and limitations of such methods.