Abstract Lead is one of the utmost contaminated and dangerous heavy metals. This toxicant ultimately enters into the human body through the food chain and accumulated in the body because the animal/human body has not an appropriate mechanism to excrete it from the body. The main objective of the present research was to assess the toxicological effects of lead on body weights, biochemical, and hematological parameters of chickens and also to measure its bioaccumulation in the brain. Lead acetate was administrated orally at doses of 0, 71, 142, 213, and 284 mg/kg of body weight of chicken for groups A, B, C, D, and E, respectively. Along with determination of biometry of all experimental chicks, hematological [hemoglobin (Hb), packed cell volume (PCV), mean corpuscular hemoglobin concentration (MCHC), total erythrocyte count (TEC), white blood cells (WBCs), leukocyte differential count (LDC)] and biochemical [low density lipoprotein (LDL), total protein, high-density lipoprotein (HDL), and alanine aminotransferase (ALT)] parameters were measured. The present study showed that the bodyweight of chickens was not affected significantly by lead acetate exposure. The levels of MCHC, PCV, TEC, Hb, LDL, HDL, and total protein were found to be significantly decreased while WBC, LDC, and ALT profile were enhanced due to administration of lead acetate. Bioaccumulation of lead acetate was found to be higher in the brain. We conclude that the chronic administration of lead acetate affected the blood and biochemical profile of exposed chicken. These effects might be due to the accumulation of the chemical in certain vital organ(s). However, further studies in the future are suggested to refine such findings.

Abstract Ammonia oxidation is mainly performed by ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Allylthiourea (ATU) has been found to specifically inhibit ammonia oxidation. However, the effect of ATU on AOA and AOB transcription has been infrequently studied. In the present study, we examined the responses of AOA and AOB activity and DNA/cDNA community structure to ATU exposure. The ammonia oxidation activity in the 100-mg/L ATU group was 4.3% of that in the control group after 7 days. When exposed to ATU, the gene abundance of AOA was favored compared with that of AOB, and there were no statistically significant differences in the abundance of AOB amoA in DNA and cDNA between the two groups. Compared with the control group, the gene abundance of AOA significantly increased by 5.23 times, while the transcription of AOA significantly decreased by 0.70 times. Moreover, the transcriptional ratio of AOA in the ATU group was only 0.05 times as high as that in the control group. ATU selectively affected AOB and completely inhibited Nitrosomonas europaea and Bacterium amoA.22.HaldeII.kultur at the genetic level. Under ATU exposure, all AOA clusters were transcribed, but three AOB clusters were not transcribed. Our results indicated that the ammonia oxidation potential of the soil of water level fluctuation areas, based on ATU inhibition, was associated mainly with AOA amoA gene abundance and AOB community shifts in DNA and cDNA.

Abstract The present study employs a novel technique combining Fenton reaction with sinusoidal alternating current electrocoagulation (FSACEC), which is used to remove chemical oxygen demand (COD) in the simulated electroplating wastewater with the advantages of low energy consumption and small sludge. Fe2+, produced from the dissolution of Fe anodes in the FSACEC process, reacts with H2O2 to generate more ·OH and forms the iron hydroxide precipitates. The higher efficiency of COD removal is achieved through both effects of the oxidation reaction and the physical adsorption. The scanning electron microscopy (SEM) analysis shows that the particle size of FSACEC products is between 30 and 40 nm, which is less than the Fenton-direct current electrocoagulation products. The effect of the current concentration (IV), initial pH (pH0), and the addition of hydrogen peroxide (30% H2O2) was discussed on the optimal process parameters. In pH0 2.0 wastewater, applying current concentration of 1 A dm−3, the addition 20 cm3 dm−3 30% H2O2, the removal efficiency of COD reached 94.21% and the residual COD in wastewater was only 60 mg dm−3 after 90 min of operation. In order to investigate the maximum removal efficiency in a certain period of operation, the larger current concentration is applied to remove COD. The FSACEC process exhibits the higher removal COD efficiency and wider operation range of pH0 than the single Fenton technique. The FSACEC process is in accordance with the kinetic law of the pseudo-second-order kinetic adsorption model.

Abstract Mosquitoes are principal vector of several vector-borne diseases affecting human beings leading to thousands of deaths per year and responsible for transmitting diseases like malaria, dengue, chikungunya, yellow fever, Zika virus, Japanese encephalitis, and lymphatic filariasis. In the present study, we evaluated the different solvent extracts of mangrove Avicennia marina for their toxicity against larvae of three major mosquito vectors, as well as selected microbial pathogens. The larvicidal mortality of third instars was observed after 24 h. Highest larval mortality was found for the acetone extract of A. marina against Culex quinquefasciatus (LC50 = 0.197 mg/ml; LC90 = 1.5011 mg/ml), Anopheles stephensi (LC50 = 0.176 mg/ml; LC90 = 3.6290 mg/ml), and Aedes aegypti (LC50 = 0.164 mg/ml; LC90 = 4.3554 mg/ml). GC-MS analysis of acetone extract revealed 5 peaks, i.e., 1-hexyl-2-nitrocyclohexane (3.229%), eicosanoic acid (40.582%), cis-9-hexadecenal (70.54%), oleic acid (4.646%), and di-N-decylsulfone (5.136%). Parallel to larvicidal assay, sub-lethal dosage acetone extracts severely affected the enzyme regulations (α,β-carboxylesterase, GST and CYP450) of third instars. Larval and pupal durations increased in all treatment sub-lethal dosage (0.127, 0.151, 0.177, and 0.197 mg/ml), whereas egg hatchability and means of fecundity decreased compared to control. The survival rate was reduced statistically in Cx. quinquefasciatus (χ2 = 23.77, df = 1, P = 0.001) in all the treatment dosages as compared to the control. Antimicrobial activity assays showed significant growth inhibition post treatment with acetone and methanol extracts against Salmonella typhimurium, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus pneumoniae, Escherichia coli, and Shigella flexneri. Overall, these results indicated the potential employment of A. marina extracts as a source of natural mosquitocidal and antimicrobial compounds of green-based environment.

Abstract Effluents from food, fermentation, and sugar industries contain a large quantity of glucose which has to be removed to limit the chemical oxygen demand (COD) of the water discharged. This work proposes novel thin-film nanocomposite (TFN) membranes incorporated with MgFe2O4 and ZnFe2O4 nanoparticles to address this concern. The nanoparticles synthesized by the sol–gel method was extensively characterized and then incorporated into the active polyamide layer of the thin-film composite polysulfone membranes. The change in membrane morphology, wettability, chemical structure, and mechanical strength with the incorporation of nanoparticles was studied in detail. Membranes with 0.005 wt.% MgFe2O4 nanoparticle exhibited highest glucose rejection (96.52 ± 2.35%) at 10 bar, 25 °C, and sufficiently high pure water flux (50.54 ± 1.92 L/m2h). This membrane also displayed 69.1 ± 5.12% salt rejection when challenged with 2000 ppm synthetic NaCl solution.

Abstract A novel polyaniline@Almond shell (PANI@AS) biocomposite was synthesized via facile in situ chemical polymerization method. The as-synthesized adsorbent was characterized using various analytical techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and potentiometric titration. A batch adsorption system was applied with the aim of investigating as-synthesized adsorbent ability to remove Cr(VI) ions and Orange G (OG) textile dye from aqueous solutions. Obtained results revealed that adsorption process was strongly depended upon the physicochemical parameters. The adsorption of Cr(VI) and OG dye onto PANI@AS was better described by the pseudo second-order-kinetic model and followed the Freundlich isotherm model. The maximum uptakes were 335.25 for Cr(VI) and 190.98 mg g−1 for OG dye. We further evaluated that PANI@AS biocomposite could be regenerated easily with NaOH solution and efficiently reused for Cr(VI) and OG dye removal from aqueous media. Thus, these results indicated the potential practical application of PANI@AS biocomposite for wastewater treatment.

Abstract This study aimed to develop a reliable method for the simultaneous analysis of triflumizole (TRIF) and its primary metabolite FM-6-1 (N-4-chloro-2-trifluoromethylphenyl-2-propoxy-acetamidine) in the soil and treated strawberries using solid phase extraction (SPE) coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS). Using this method, TRIF and FM-6-1 degradation in strawberries and the soil under greenhouse conditions were investigated. The field trials showed that t1/2 of TRIF and total residues (the sum of TRIF and FM-6-1) were 1.6–2.2 days and 2.4–2.9 days in strawberry and 4.3–6.1 days and 5.5–6.9 days in soil, respectively. Terminal total residues were ≤ 0.39 mg/kg in strawberry and ≤ 0.42 mg/kg in soil from 5 to 10 days of harvest. The risk quotient (RQ) of TRIF was below 1.89%, showing that the dietary risk of TRIF in strawberry was low. These findings provide guidance for the use of TRIF on crops and provide reference to establish the maximum residue level (MRL) of TRIF in strawberry.

Abstract Human activities are considered among the main producers of any kind of pollution. This paper, through a Driver-Pressure-State-Impact-Response (DPSIR) model analyses, focuses on the evaluation and assessment of the existing practices, procedures, and results obtained in order to determine whether the municipal solid waste (MSW) management implemented in three major Greek municipalities in the greater urban area of Attica, namely the municipalities of Nea Smirni, Vyronas, and Piraeus, could be considered viable and sustainable. The evaluation indicated that MSW in Greek cities have reduced over the last years, also suggesting a steady downward trend, which could be considered consistent with that of the per capita incomes in Greece due to the extended economic austerity, while at the same time the recycling indicator seems to optimize. The results are very useful for policymakers and local authorities towards taking actions related to the targets set from the circular economy strategies as well as the targets set from United Nation Development Program and the European Green Deal Strategy.

Abstract Krossfjord-Kongsfjord system situated on the west coast of Svalbard archipelago is an ideal location to investigate the impacts of climate change on the environment. As a consequence of global warming, metal concentrations in the Arctic region are increasing due to permafrost melting and changes in biological processes. Therefore, the fjord sediments were studied for identification of provenance, mobility, bioavailability, and potential toxicity of metals in the fjord environment. Finer sediments and organic matter were found to be higher away from the glacier outlets, while coarser sediments were found to be higher near the glacier head. Illite, kaolinite, and chlorite constituted the clay mineral assemblage which had slightly influenced the metal distributions. The variations in metal abundance were attributed largely to the glacial activity along with the influence of Atlantic water mass in western Spitsbergen. Fjord system received sediment from the weathering of rocks indicating an input of terrigenous material. Comparison of metals in bulk sediment with Arctic sediment quality guidelines (ASQGs) showed that Zn and Cu were enriched in the sediment. However, to avoid the overestimation of the risk associated, fractionation of the metals was carried out which revealed higher Mn and Co in labile phases that pose a considerable risk to the biota.

Two-dimensional (2D) perovskites have attracted considerable interest for their promising applications for solar cells and other optoelectronics, such as light-emitting diodes, spintronics, and photodetectors. Here, we review the recent achievements of 2D perovskites for various optoelectronic applications. First, we discuss the basic structure and optoelectronic properties of 2D perovskites, including band structure, optical properties, and charge transport. We then highlight recent achievements using 2D perovskites in solar cells and beyond solar cells, including progress on various synthesis strategies and their impact on structural and optoelectronic properties. Finally, we discuss current challenges and future opportunities to further develop 2D perovskites for various applications.

Sunlight plays an important role in transforming effluent organic matter as wastewater effluents travel downstream, but the corresponding effects on the formation of haloacetonitriles (HANs), a group of toxic disinfection byproducts, in wastewater-impacted surface water has not been thoroughly investigated. In this study, we observed that sunlight preferentially attenuated the formation potential of bromochloroacetonitrile (BCAN-FP) over that of dichloroacetonitrile (DCAN-FP) in chlorine- and UV-disinfected secondary effluents. For four effluent samples from different plants, 36 h irradiation by simulated sunlight removed 28%–33% of DCAN-FP and 41%–48% of BCAN-FP. Across a larger set of effluent samples (n = 18), 8 h irradiation (equivalent to 2–3 d of natural sunlight) decreased the calculated cytotoxicity contributed by dihaloacetonitrile-FP in most samples. Similar behavior was observed for a mixture of wastewater and surface water (volume ratio 1:1). For UV-disinfected effluents, the higher the UV dose, the more likely was there a reduction in DCAN-FP and BCAN-FP in the subsequent sunlight irradiation. Experiments with model compounds showed that fulvic acid and UV photoproducts of tryptophan yield excited triplet state organic matters during sunlight irradiation and play an important role in promoting the attenuation of HAN precursors.

NH3 is the most important gaseous alkaline pollutant, which when accumulated at high concentrations can have a serious impact on animal and human health. More importantly, NH3 emissions will react with acidic pollutant gases to form PM2.5 in the atmosphere, which also poses a huge threat to human activities. The use of adsorbents for NH3 removal from emission sources or air is an urgent issue. However, there are difficulties in the compatibility between high adsorption capacity and recyclability for most conventional adsorbents. In this work, a structural transformation strategy using MOFs is proposed for large-scale and recyclable NH3 adsorption. A series of M(BDC) (M = Cu, Zn, Cd) materials can transform to one-dimensional M(BDC)(NH3)2 after NH3 adsorption, resulting in repeatable adsorption capacities of 17.2, 14.1, and 7.4 mmol/g, respectively. These MOFs can be completely regenerated at 250 °C for 80 min with no adsorption capacity loss. Besides, breakthrough and cycle tests indicate that Cu(BDC) and Zn(BDC) show good performance in the removal of low-concentrations of NH3 from the air. Overall, combining the advantages of high adsorption capacity and recyclability due to the reversible structural transformation, Cu(BDC) and Zn(BDC) can be employed as ideal adsorbent candidates for NH3 removal.

In recent years, there have been remarkable efforts to examine and understand the adverse effects of nanoparticles (NPs) on the environment and human health, not only qualitatively but quantitatively. Mass cytometry has been developed for high-dimensional single-cell analyses and used to quantify the cellular association of inorganic NPs. Here, we have applied this novel technique to investigate the heterogeneity in cellular association and cytotoxicity of polyvinylpyrrolidone-coated silver nanoparticles with diameters of 10 nm and 20 nm in primary human immune cells. Our results revealed the cell-type-dependent heterogeneity in which AgNPs showed higher affinity to phagocytic cells like monocytes and dendritic cells than to other immune cell types. Upon exposure to AgNPs, these cells expressed complex pro-inflammatory and pro-apoptotic responses, such as IκBα degradation, STAT1 phosphorylation and caspase-7 activation. Quantitative analyses of the single-cell dose-response relationship between the cellular AgNP association and signalling activities further revealed heterogeneity even within the monocyte population. The majority of cells belonged to the ‘low affinity’ subset, which showed positive AgNP dose – cisplatin uptake (i.e. viability loss) correlation, as opposed to the remaining cells which belonged to the ‘high affinity’ subset and had insignificant relationship between the cell-associated AgNP amount and cisplatin uptake/viability loss level. These subsets were distinctly responsive to the cellular AgNP content, as they showed different levels of signalling proteins such as IκBα degradation, STAT1 phosphorylation and caspase-7 activation. Our study can be helpful for further understanding on the heterogeneous nature of cell-NP interactions and development of dose-response models in single-cell level for various NPs, which will provide key information for the safe use of nanomaterials in biomedical applications.

In the original publication Fig. 10b was erroneously plotted due to the authors’ carelessness and unintentional misoperation.

Abstract Soil pollution with toxic elements is a recurrent issue due to environmental disasters, fossil fuel burning, urbanization, and industrialization, which have contributed to soil contamination over the years. Therefore, the remediation of toxic metals in soil is always an important topic since contaminated soil can affect the environment, agricultural safety, and human health. Many remediation methods have been developed; however, it is essential to ensure that they are safe, and also take into account the limitation of each methodology (including high energy input and generation of residues). This scenario has motivated this review, where we explore soil contamination with arsenic, lead, mercury, and chromium and summarize information about the methods employed to remediate each of these toxic elements such as phytoremediation, soil washing, electrokinetic remediation, and nanoparticles besides elucidating some mechanisms involved in the remediation. Considering all the discussed techniques, nowadays, different techniques can be combined together in order to improve the efficiency of remediation besides the new approach of the techniques and the use of one technique for remediating more than one contaminant.

Abstract This work reports the thermal degradation behaviour, kinetics and thermodynamics of two different eco-friendly plastics, viz. non-woven plastic and corn starch-based biodegradable plastics, which are commonly used nowadays as an alternative to synthetic plastics. In this context, thermogravimetric analysis of plastic waste samples was carried out at wide range of heating rates of 10, 20, 40, 60, 80 and 100 °C/min in nitrogen atmosphere, and activation energy is determined by first-order model-fitting method while thermodynamic parameters are determined on the basis of Eyring theory of activated complex. The regression coefficient obtained from kinetic study of thermal degradation of these plastics best fits to the first-order kinetic equation. The kinetics and thermodynamic parameters obtained for both the plastics are found very close to each other. So, this study would help design more effective conversion system for the recycling of both the wastes together.

Abstract In this study, a photocatalyst S-doped WO3 was successfully synthesized by the hydrothermal method. The prepared undoped and S-doped WO3 samples were then characterized by XRD, SEM, XPS, and UV-vis DRS. The results showed that the band gap energy of S-doped WO3 was lower than that of the undoped WO3, which led to a better absorption of visible light. Furthermore, the results of XPS analysis suggested that the doping with S element resulted in an increase in lattice oxygen vacancies on the surface of S-WO3, which could effectively improve the photocatalytic activity. The photocatalytic performance of the S-WO3 samples were evaluated by the measurement of methylene blue (MB) degradation under visible light irradiation. The experimental results demonstrated that S-doped WO3 sample exhibited a much better photodegradation performance compared to undoped WO3, with the maximum MB removal efficiency of 78.7% for the 5% S-WO3 sample. Based on the above results, the mechanisms of photodegradation of MB by S-WO3 were discussed.

Abstract A low-cost Cr(III)-incorporated Zr(IV) bimetallic oxide (CZ) was synthesized by simple chemical precipitation method for removal of fluoride from contaminated water. The physicochemical properties of CZ before and after fluoride removal were established with several instrumental techniques such as TEM with elemental mapping, SEM with EDX, XRD, IR, XPS, zeta potential measurement, etc. Batch adsorption technique were carried out to understand the factors affecting fluoride adsorption, such as effects of initial pH, adsorbent dose, co-occurring ions, contact time, and temperature. The maximum adsorption capacity observed at pH between 5 and 7. The fluoride adsorption processes on CZ obeyed the pseudo-second-order rate equations and both Freundlich and DR isotherm models. The maximum adsorption capacity of 90.67 mg g−1 was obtained. The thermodynamic parameters ΔH0 (positive), ΔS0 (positive), and ΔG0 (negative) indicating the fluoride sorption system was endothermic, spontaneous, and feasible. The CZ also successfully used as fluoride adsorbent for real field contaminated water collected from the Machatora district, Bankura, West Bengal, India. Graphical abstract Schematic representation of CZ synthesis and its application for lab as well as field water purification purpose.

Abstract Based on the 1.5 °C temperature control target of the Paris Agreement, the two scenarios in this paper which are 1.5 degree scenario (1.5DS) and 2 degree scenario (2DS) aim to analyze the CO2 emission space and power transition path constrains of the power sector in China. This paper then discusses the possible scenarios of 1.5DS and 2DS power planning schemes in 2050. The conclusions are as follows: (1) China’s electricity consumption saturation period will occur during the period of 2030–2040; (2) Driven by technology learning, the levelized cost of electricity (LCOE) of wind power will have obvious competitive advantages in 2020 and so does solar power in 2030. However, due to the impact of additional grid connection costs of new energy power, economic advantages can only be obtained in the power market after at least 10 years; (3) The installed capacity of coal power in 1.5DS and 2DS will peak in 2020, and CO2 emissions will also peak in 2020, then it shows a trend of decreasing year by year. However, it should be noted that 1.5DS is with possibilities, but with enormous challenges as the same time; (4) Accelerating the green and low carbon transition of power sector must be gradually improving the power market and electricity price mechanism, providing a good transition environment for the power sector, developing emerging power technology, and promoting multi-energy complementary systems.

Abstract Research has shown a relationship between the exposures to a chemical agent called bisphenol-A (BPA), which is extensively used in the production of polycarbonate plastics and the incidence of cardiovascular diseases. This association is most likely caused by the BPA’s ability to disrupt multiple cardiac mechanisms, including mitochondrial functions. Therefore, this study aimed to explore the ability of quercetin (QUER) to limit the cardiotoxic effect of BPA in the rat’s cardiac mitochondria. The experiment was carried out on 32 male Wistar rats, which were randomly assigned to four groups. The negative control group received olive oil; the positive control group received olive oil plus BPA (250 mg/kg); the third group received olive oil, BPA, and QUER (75 mg/kg); and the fourth group received olive oil and QUER, all orally for 14 days. The rats were slaughtered 24 h after the last treatment. The measured parameters included creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) as the biomarkers of cardiotoxicity, triglyceride (TG), total cholesterol (TC), and low-density and high-density lipoprotein cholesterol (LDL-C and HDL-C) as the measures of dyslipidemia, glutathione (GSH) content, catalase activity (CAT), reactive oxygen species (ROS), lipid peroxidation (LPO), and the level of damage to the mitochondrial membranes as the indicators of the impact of QUER on the BPA cardiotoxic effect. Finally, the rats treated with QUER showed better results in terms of serum CK-MB, serum LDH, serum lipid profile, GSH level, CAT activity, mitochondrial membrane potential (ΔΨm), LPO, and ROS. According to the results, QUER could be used as a protective agent against BPA-induced mitochondrial toxicity.

Abstract Given the recent extensive synthesis and application of ionic liquids (ILs), finding a sensitive and visual indicator to provide a fast-initial risk assessment of IL use has become a pressing issue. In this study, we verified that the phototaxis of Chlamydomonas reinhardtii is a valid indicator of the environmental risk associated with chiral ILs L-(+)- and D-(−)-1-butyl-3-methylimidazolium lactate (BMIM L). Briefly, C. reinhardtii was exposed to a 4000-lx side light source for varying lengths of time. Following the allotted exposure time, the algae aggregation was photographed, and then quantitative analysis was conducted using Image-J software to obtain the corresponding relationship between IL stimulation and C. reinhardtii phototaxis. The gray areas from each treatment were measured and the percentage was calculated. After 16 h of side lighting, for control, the percentage of gray areas was − 22%, while for L-(+)- and D-(−)- BMIM L were 17% and 33%, respectively. Then, after 8 h of darkness, where D-(−)-BMIM L and the control showed the positive phototaxis, but the L-(+)-BMIM L-treated group showed virtually no change. This phenomenon is consistent with excessive production of reactive oxygen species (ROS). Moreover, atomic force microscope (AFM) results indicated distinct aggregation between D-(−)- and L-(+)-BMIM L, which caused changes in cell permeability that induced a change in ROS transfer. Furthermore, relationship between phototaxis and changes in cell ultrastructure and photosynthetic efficiency was also investigated. This work demonstrates the potential of phototaxis to serve as a sensitive, convenient, and cost effective qualitative assessment of ILs’ toxic impact, with the understanding that quantitative evaluation requires further improvement.

Abstract An increasing level of carbon dioxide (CO2) in the atmosphere has ultimately resulted in global warming and climate change. The high-performance activated carbon (AC-WL) was synthesized from walnut shell, a low-cost biomass by-product, by physical activation using a tube furnace. The adsorption behavior of CO2 from the CO2/N2 mixture was investigated using a fixed bed. The surface and morphological characterizations of the produced activated carbons were measured using a BET analyzer and a scanning electron microscope (SEM). The effect of temperature, flow rate, CO2 level, and partial pressure on breakthrough behavior was analyzed, and the adsorption response presented in terms of breakthrough point and adsorption capacity. The breakthrough and saturation periods vary significantly with change in temperature. The steepness of the breakthrough curves signifies good utilization of adsorbent capacity at breakthrough point. The increase in temperatures and flow rates lead to an increase in the length of mass transfer zone. The adsorption capacity of 1.58 mmol/g was obtained at 1.30 bars and 293 K with higher capacity utilization factor of 0.8492.These results suggest that the walnut-based activated carbon is favorable for capturing CO2.

Abstract To investigate co-transport behavior of ammonium and colloids in saturated porous media under different hydrochemical conditions, NH4+ was selected as the target contaminant, and silicon and humic acid (HA) were selected as typical organic and inorganic colloids in groundwater. Column experiments were then conducted to investigate the transport of NH4+ colloids under various hydrochemical conditions. The results showed that because of the different properties of colloidal silicon and HA after combining with NH4+, the co-transport mechanism became significantly different. During transport by the NH4+–colloid system, colloidal silicon occupied the adsorption sites on the medium surface to promote the transport of NH4+, while humic acid (HA) increased the number of adsorption sites of the medium to hinder the transport of NH4+. The co-transport of NH4+ and colloids is closely related to hydrochemical conditions. In the presence of HA, competitive adsorption and morphological changes of HA caused NH4+ to be more likely to be transported at a higher ionic strength (IS = 0.05 m, CaCl2) and alkalinity (pH = 9.3). In the presence of colloidal silicon, blocking action caused the facilitated transport to be dependent on higher ionic strength and acidity (pH = 4.5), causing the recovery of NH4+ to improve by 7.99%, 222.25% (stage 1), and 8.63%, respectively. Moreover, transport increases with the colloidal silicon concentrations of 20 mg/L then declines at 40 mg/L, demonstrating that increased concentrations will lead to blocking and particle aggregation, resulting in delayed release in the leaching stage. Graphical abstract

Abstract Three-dimensional cubic ordered mesoporous carbon with chitosan (Ia3d-CS), which was synthesized via exothermic reaction between liquid potassium and carbon monoxide gas, was coated on the active carbon (AC) electrode as a capacitive deionization (CDI) disinfection electrode. The results showed that Ia3d-CS-2 as CDI electrode exhibited the quick ion diffusion and strong charge transfer performance, due to the three-dimensional pore structure and specific surface area. The electrode of Ia3d-CS-2 displayed a specific capacity of 191.22 F/g at a scan rate of 100 mV·s−1 in 0.5 M NaCl aqueous solution. In a CDI recycling system, Ia3d-CS-x electrode showed good cyclic stability, and the electrosorption capacity of Ia3d-CS-2 electrode can achieve 1.31 mg/g at 1.2 V in 100 mg/l NaCl aqueous solutions. Subsequently, Ia3d-CS-2 electrode had an excellent disinfection efficiency of killing about 99.99% Escherichia coli within 30 min during the CDI process at applied 1.2 V. Considering those excellent properties of the fabricated Ia3d-CS-x electrode, which should be a better candidate for high-performance deionization application.

Abstract Microplastic pollution is as an emerging environmental threat. Focus of most of the current researches has been on microplastics in the marine environment. However, there is limited information for microplastic availability in the fresh water, especially in Pakistan. The current study was conducted with the objective of investigating the microplastic presence and concentration in the surface water and sediments of the Rawal Lake, in the capital city of Pakistan. The average microplastic abundance for water and sediments was 0.142 items/0.1 L and 1.04 items/0.01 kg, respectively. Results indicated that the fibers and fragments were the most dominant types of microplastics. The dominant colors were blue, red, black, and transparent. FTIR analysis of visible microplastic particles displayed a greater similarity with polyethylene, polypropylene, polyesters, polyethylene terephthalate, and polyvinyl chloride because of the appearance of characteristic peaks of these polymers. The study also revealed greater concentration of microplastics in the sediments as compared with water of the Rawal Lake. High population density surrounding lake, improper waste disposal, tourism, and recreational activities may be the major reasons for the microplastic contamination of the lake.

Abstract The water-sediment interface of lakes is an important and unique area of the water environment; the geochemical behavior of nutrients in this area has a significant impact on the quality of the water environment and ecosystems, especially in shallow lakes. However, most studies do not provide direct in situ evidence for this in shallow lakes in arid regions; in order to explore the coupling relationship between phosphorus (P) and iron (Fe) in a sediment profile, we conducted a high-resolution analysis of liable Fe and P in sediments taken from the Chaiwopu Lake using ZrO-Chelex thin film diffusion gradient technology (ZrO-Chelex DGT). The results show that (1) the vertical spatial distribution trend of the liable P and Fe in the sediments from each sampling site is essentially similar. The contents of the liable P and Fe ranged from 0.004–0.125 mg/L and 0.050–0.190 mg/L, respectively, and the synchronous distribution of the micro-interface concentration reflects the coupling relationship between them. (2) The correlation analysis of the liable P and Fe concentrations showed that there were significant linear correlations between them (P < 0.05, bilateral). (3) The diffusion fluxes of P and Fe were − 51.76~65.12 μg (m2 d)−1 and − 451.27~457.06 μg (m2 d)−1, respectively, and were shown to be negative at the sediment-water interface for most of the samples, which showed that P and Fe were released from the overlying water into the sediments. (4) This research showed that the diffusive fluxes at the different sites are quite different, which indicates that the phosphorus and iron pollution in the sediments of the Chaiwopu Lake is affected by exogenous inputs. There was no significant correlation between P release flux and pH, ORP, conductivity (EC), the TDS of the overlying water, or the pH, salinity (Ca2+, Mg2+), and nutrient (organic matter) content of the sediment. The release flux of Fe is affected by the pH of the sediment. The results of this study provide references for the research of elements in the water-sediment interface of shallow lakes in arid regions, as well as other areas.

Abstract This study aimed to assess the effectiveness of capping and mixing of calcined dolomite and zeolite for the remediation of sediment contaminated with nitrogen (N) and phosphorus (P). Laboratory incubation experiments were performed to monitor the release of NH4-N, NO3-N, T-N, PO4-P, and T-P from the sediment. pH, electric conductivity (EC), oxidation reduction potential (ORP), and dissolved oxygen (DO) in overlying water for 60 days were evaluated. Dolomite-amended sediment has high pH and EC. Zeolite and dolomite capping effectively interrupted the release of N and P, respectively; capping was found to be more effective than mixing. The mixture of dolomite and zeolite was also effective; however, their efficiencies were influenced by their placement. The remediation efficiencies when the dolomite was placed above the zeolite cap layer (DOL/ZEO_CAP) were 95.9%, 101.6%, and 100.2% for NH4-N, PO4-P, and total, and the total remediation efficiency of DOL/ZEO_CAP was twice that of the opposite placement (ZEO/DOL_CAP). Low remediation efficiencies for NH4-N and T-N were observed in ZEO/DOL_CAP because NH4+ adsorption on zeolite was hindered by Ca2+ and Mg2+ released from the dolomite. The combination of dolomite and zeolite can be used as a capping material for simultaneously interrupting the release of both nitrogen and phosphorus, but their placement should be considered.

Abstract The use of zebrafish (Danio rerio) has arisen as a promising biological platform for toxicity testing of pesticides such as herbicides, insecticides, and fungicides. Therefore, it is relevant to assess the use of zebrafish in models of exposure to investigate the diversity of pesticide-associated toxicity endpoints which have been reported. Thus, this review aimed to assess the recent literature on the use of zebrafish in pesticide toxicity studies to capture data on the types of pesticide used, classes of pesticides, and zebrafish life stages associated with toxicity endpoints and phenotypic observations. A total of 352 articles published between September 2012 and May 2019 were curated. The results show an increased trend in the use of zebrafish for testing the toxicity of pesticides, with a great diversity of pesticides (203) and chemical classes (58) with different applications (41) being used. Furthermore, experimental outcomes could be clustered in 13 toxicity endpoints, mainly developmental toxicity, oxidative stress, and neurotoxicity. Organophosphorus, pyrethroid, azole, and triazine were the most studied classes of pesticides and associated with various toxicity endpoints. Studies frequently opted for early life stages (embryos and larvae). Although there is an evident lack of standardization of nomenclatures and phenotypic alterations, the information gathered here highlights associations between (classes of) pesticides and endpoints, which can be used to relate mechanisms of action specific to certain classes of chemicals.

Abstract In this work, three novel catalysts were prepared by 2.5, 5.0, and 10.0 wt.% facile impregnation with an iron and molybdenum mixed oxide (Fe/Mo) on an aluminum pillared clay (Al-PILC) support. These materials were characterized by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), temperature programed reduction (TPR), and nitrogen (N2) physisorption at 77 K. Characterizations indicated that the metal particles were dispersed on the surface of the three catalysts, and the interlayer d001 spacing of the pillared material remained unchanged after the impregnation process. The catalytic tests showed good results for DBT oxidation using the synthesized catalysts, with high turnover frequency (TOF) values, particularly for the material with 5.0 wt.% Fe/Mo. Theoretical calculations were carried out at the density functional theory (DFT) level, to investigate how the DBT molecules were adsorbed onto the surface of the mixed oxide. The lowest energy proposal was obtained when both Fe and Mo were present at the active sites, indicating a possible synergistic effect of the metals on catalyst activity. Reuse tests indicated that the catalysts could be employed effectively for up to 3 cycles in a row, then a decrease in activity occurred and the active sites needed to be regenerated.

Abstract In the present study, estimation of the atmospheric polycyclic aromatic hydrocarbons (PAHs) was done in particulate samples collected from De Haan, Belgium, during different seasons. The sampling site was situated very close to the north sea and far from the influence of local or industrial activities. The levels of PAHs depicted a distinct seasonal trend, being highest during the spring season. The observations of the study indicated a mean value of 2.6 ng m−3 for concentration of all the 16 US EPA PAHs, thus being significantly lower when compared to results of previous studies focused on other sites. The dominating PAHs species reported were naphthalene, fluoranthene, benzo[a]anthracene, chrysene, and indeno[1,2,3c,d] pyrene. Assessment of the seasonal variation of the PAH levels was also done with respect to diagnostic ratio-based source identification, analysis of back trajectories, and principle component analysis. Burning of fossil fuels was observed to be the prominent source of atmospheric PAHs in the study area. Further, lifetime cancer risk assessment was performed to assess the detrimental health impacts on humans on being exposed to atmospheric PAHs. Particulate PAHs present in the ambient air of Belgium shows no carcinogenic health impacts. However, considering the industrial expansion in the region, efforts are required to prevent the environmental contamination of PAHs. Graphical abstract

Abstract The consumption of rice contaminated with soil cadmium (Cd) threatens human health. It is essential to ensure the production of rice that meets food quality standards. Therefore, a large-scale field survey was conducted in Zhejiang province, southeastern China, to investigate the relationship between Cd accumulation in rice grains and Cd bioavailability in soil, and thus to establish a model to predict Cd contents in rice grains based on soil properties. For this purpose, a total of 156 paired rice and soil samples were collected. Pearson’s correlation analysis revealed that Cd measurements obtained by diffusive gradient in thin films (DGT) had a higher correlation (r = 0.818, p < 0.001) with the Cd in rice grains as compared to the Cd measured by the DTPA, CaCl2, EDTA, and HCl extraction methods, which indicated that the DGT technique was a reliable method for the assessment of Cd bioavailability in soils. In addition, among the four extraction methods, the DTPA-extractable Cd showed the highest correlation with the Cd contents in rice grains. Therefore, we developed two predictive models (modelDGT and modelDTPA) to predict Cd levels in rice grains via Cubist multivariate mixed linear regression, using “soil DGT-measured Cd, pH, and oxide contents of Ca, Si, and Fe” or “soil DTPA-extractable Cd, pH, OM, and oxide contents of Ca and Fe” as explanatory variables, respectively. The overall modelDGT and modelDTPA had R2 values of 0.95 and 0.93, respectively, and relative error values of 0.30 and 0.33, respectively. Simple correlation analysis showed direct and close relationships between the measured Cd in rice grains and the Cd concentrations predicted by the Cubist modelDGT and modelDTPA, with R2 values of 0.979 and 0.922, respectively. Therefore, Cd levels in rice grains could be predicted very well based on the two prediction models, and thus, the two models derived in this study are effective in identifying soils in which the Cd in rice grains will exceed food safety standards, thereby helping to ensure safe rice production.

Abstract This study was performed to determine the concentrations of copper (Cu), zinc (Zn), and lead (Pb) in the gill, liver, muscle, and tail fin tissues of Euthynnus affinis, Katsuwonus pelamis, and Thunnus albacares from Oman Sea. All samples were analyzed using a flame atomic absorption spectrophotometer and the results were expressed as μg g−1 dry weight. Metal concentrations were significantly higher in the liver than other tissues in three species (with some exceptions) (p < 0.05). The concentrations of metal accumulation in tissues of tuna species followed the Zn > Cu > Pb. Correlation matrix and principal component analysis (PCA) revealed that Zn and Pb have anthropogenic sources. Estimated daily intake (EDI) in three tuna species for heavy metals were below the tolerable daily intake (TDI). Also, the mean target hazard quotient (THQ) based on studied metals in three tuna species was below 1, which suggests that consumption of these fish can be safe for human health in the Oman Sea. Graphical Abstract .

Despite the promise of a simple manufacturing via entire solution process at low temperature (< 100 °C), the planar-type inverted perovskite solar cells (PeSCs) based on methylammonium lead tri-iodide (MAPbI3) still suffer from a notorious instability problem under operational conditions. Here, we found that the operational stability of PeSCs with MAPbI3 is significantly related with a high density of ionic defects and correlated amorphous regions at the interface between the electron transport layer and the MAPbI3 film. By recrystailizing the surface of the MAPbI3 layer, we fabricate a defect-free stoichiometric MAPbI3 crystals and demonstrated burn-in loss-free and intrisically stable inverted MAPbI3 PeSCs. The inverted MAPbI3 PeSCs exhibited a power conversion efficiency (PCE) of 18.8% that was maintained over 80% and 90% of their initial PCEs even after 1000 hours of real operation (under AM 1.5G irradiation) and continuous heating conditions (at 85 °C in the dark), respectively. Our work demonstrates that the MAPbI3 layer in an ionic defect-free condition is ‘intrinsically’ stable under operational condition.

Compartment-specific degradation half-lives are essential pieces of information in the regulatory risk assessment of synthetic chemicals. However, their measurement according to regulatory testing guidelines is laborious and costly. Despite the obvious ecological and economic benefits of knowing environmental degradability as early as possible, its consideration in the early phases of rational chemical design is therefore challenging. Here, we explore the possibility to use half-lives determined in highly time- and work-efficient biotransformation experiments with activated sludge and mixtures of chemicals to predict soil half-lives from regulatory simulation studies. We experimentally determined half-lives for 52 structurally diverse agrochemical active ingredients in batch reactors with three concentrations of the same activated sludge. We then developed bi- and multivariate models for predicting half-lives in soil by regressing the experimentally determined half-lives in activated sludge against average soil half-lives of the same chemicals extracted from regulatory data. The models differed in how we accounted for sorption-related bioavailability differences in soil and activated sludge. The best performing models exhibited good coefficients-of-determination (R2 of around 0.8), low average errors (< factor of 3 in half-life predictions) and were robust in cross-validation. From a practical perspective, these results suggest that it may indeed be possible to read across from half-lives determined in highly efficient biotransformation experiments in activated sludge to soil half-lives, which are obtained from much more work- and resource-intense regulatory studies, and that these predictions are clearly superior to predictions based on the output of the publicly available BIOWIN QSBR model. From a theoretical perspective, these results suggest that soil and activated sludge microbial communities, although certainly different in terms of taxonomic composition, may be functionally similar with respect to the enzymatic transformation of environmentally relevant concentrations of a diverse range of chemical compounds.

Pursuing efficient approaches to promote the extracellular electron transfer (EET) of extracellular respiratory bacteria is essential to their applications in environmental remediation and waste treatment. Here, we report a new strategy of tuning electron flux by clustered regularly interspaced short palindromic repeats (CRISPR)-ddAsCpf1 based rediverting (namely STAR) to enhance the EET capacity of Shewanella oneidensis MR-1, one model extracellular respiratory bacterium widely present in environments. The developed CRISPR-ddAsCpf1 system enabled approximately 100% gene repression with the green fluorescent protein (GFP) as reporter. By using WO3 probe, 10 representative genes encoding for putative competitive electron transfer proteins were screened, among which 7 genes were identified as the valid targets for the EET enhancement. Repressing the valid genes not only increased the transcription level of the L-lactate metabolism genes, but also affected the genes involved in the direct and indirect EET. A raised riboflavin production was also observed. The feasibility of this strategy to enhance the bio-reductions of methyl orange, an organic pollutant, and chromium, a typical heavy metal, was demonstrated. This work implies a great potential of the STAR strategy with the CIRPSR-ddAsCpf1 system for enhancing bacterial EET to favor more efficient environmental remediation applications.

Rapid growth in U.S. unconventional oil and gas made energy more available and affordable globally, but brought environmental concerns, especially related to water. We analyzed water-related sustainability of energy extraction focusing on: (a) meeting rapidly rising water demand for hydraulic fracturing (HF), and (b) managing rapidly growing volumes of water co-produced with oil and gas (produced water, PW). We analyzed historical (2009–2017) HF water and PW volumes in ~73,000 wells and projected future water volumes in major U.S. unconventional oil (semiarid regions) and gas (humid regions) plays. Results show a marked increase in HF water use, depleting groundwater in some semiarid regions (e.g. by ≤58 ft [18 m]/yr in Eagle Ford). PW from oil reservoirs (e.g. Permian) is ~15× higher than that from gas reservoirs (Marcellus). Water issues related to both HF water demand and PW supplies may be partially mitigated by closing the loop through reusing PW for HF of new wells. However, projected PW volumes exceed HF water demand in semiarid Bakken (2.1×) and Permian Midland (1.3×) and Delaware (3.7×) oil plays, with the Delaware accounting for ~50% of projected U.S. oil production. Therefore, water issues could constrain future energy production, particularly in semiarid oil plays.

Recently, perfluoroalkyl substances (PFASs) have received great attention from both academia and industry due to their persistence and health risks. Here, we developed a simple ternary self-assembled micelle composite, consisting of photosensitive substance-indole acetic acid, cationic surfactant-cetyltrimethylammonium bromide and contaminant (PFAS). Owing to the rapid hydrated electron transfer from IAA to PFAS in the micelle, PFAS degradation and defluorination were greatly enhanced even under ambient conditions. After 2.5 h UV-irradiation, the perfluorooctanoic acid concentration decreased from 10 mg L-1 to ~60 ng L-1, which is below the drinking water health advisory level of US EPA. Meanwhile, the dissolved organic carbon content of the reaction solution was also reduced to ~3 mg L-1, due to the quick settlement and automatical separation of the micelle. Furthermore, the newly developed composite was also adaptable to a wide pH range (pH 4~8), attributing to the barrier created by the ternary micelle system. This novel self-assembly method is expected to directly treat industrial PFAS-containing wastewater or PFAS-enriched concentrates derived from adsorption processes. The conceptually new advanced reduction technique represents a major breakthrough towards PFASs rapid destruction and efficient usage of hydrated electrons, and might also shed light on other environmental applications.

To achieve low regeneration energy consumption and viscosity, a novel amino functionalized ionic liquid of [TEPAH][2-MI] combined with organic solvents has been proposed for CO2 capture in this work. The results demonstrated that the absorption loading of [TEPAH][2-MI]/NPA/EG was 1.72 mol·mol-1 (28 wt%, 257 g·L-1), which was much higher than that of MEA/water, and the regeneration efficiency was maintained at 90.7% after the 5th regeneration cycle. The viscosities of the solution were only 3.66 and 7.65 mPa·s before and after absorption, which were significantly lower than that of traditional non-aqueous absorbents. The reaction mechanism investigated via 13C NMR and quantum calculations were summarized that CO2 firstly reacted with the amino group of [TEPAH]+ to form the carbamates through the zwitterion formation and protonation process, while CO2 reacted with the N atom of [2-MI]- to directly form carbamate. Then some of them further reacted with NPA and EG to form the carbonates. Moreover, Nπ and Nτ tautomers of [TEPAH][2-MI] could convert into each other continuously when CO2 was absorbed. During CO2 desorption, the carbamates and carbonates reacted with AFILH+ to decompose and released CO2 directly.

Floodplain restoration is popular to address excess nutrients, but its ability to enhance photolysis of emerging contaminants has not been evaluated. We used the numerical model MIKE-21 to simulate photolysis reactions within the inundated surface water of restored floodplains along a mid-size river. We examined both “high” and “low” floodplain scenarios where inundation occurs 5% (storms) and 50% (baseflow) of the year, respectively. We simulated photolysis of the pharmaceuticals morphine, codeine, and methamphetamine, and for context compared it with nitrate removal (denitrification, plant uptake). Pollutant removal due to floodplain restoration was greater for the low floodplain (e.g., 18.8% for morphine) than for the high floodplain (5.6% for morphine) due to greater water exchange relative to channel flow. The fastest- and slowest-reacting pollutants (morphine and methamphetamine, respectively) were always transport- and reaction/kinetics-limited within floodplain surface water, respectively. Yet those with intermediate decay-rate constants switched from reaction-limitation to transport-limitation as floodplain length increased, and removal levelled off at an optimum length of ~1000 m. However, as floodplain width increased, the required floodplain length for 30% removal decreased. Optimal restored floodplain conditions for photolysis would maximize light exposure, which may differ from those for nutrients.

Reports that promote persulfate-based advanced oxidation process (AOP) as a viable alternative to hydrogen peroxide-based processes have been rapidly accumulating in recent water treatment literature. Various strategies to activate peroxide bonds in persulfate precursors have been proposed and the capacity to degrade a wide range of organic pollutants has been demonstrated. Compared to traditional AOPs in which hydroxyl radical serves as the main oxidant, persulfate-based AOPs have been claimed to involve different in-situ generated oxidants such as sulfate radical and singlet oxygen as well as non-radical oxidation pathways. However, there exist controversial observations and interpretations around some of these claims, challenging robust scientific progress of this technology toward practical use. This Critical Review comparatively examines the activation mechanisms of peroxymonosulfate and peroxydisulfate and the formation pathways of oxidizing species. Properties of the main oxidizing species are scrutinized and the role of singlet oxygen is debated. In addition, the impacts of water parameters and constituents such as pH, background organic matter, halide, phosphate, and carbonate on persulfate-driven chemistry are discussed. The opportunity for niche applications is also presented, emphasizing the need for parallel efforts to remove currently prevalent knowledge roadblocks.

Peroxymonosulfate (PMS)-based advanced oxidation processes generate highly reactive SO4•− and are promising for water treatment. In this study, we investigated the reaction mechanism of 6:2 fluorotelomer sulfonate (6:2 FTS) with Co2+ activated PMS. 6:2 FTS was simultaneously transformed to perfluoroalkyl carboxylic acids (C2−C7 PFCAs) of different chain length, with perfluorohexanoic acid (C6) as the predominant one. The mass balance of the intermediates and products versus initial added 6:2 FTS was close to 100% over the reaction period. Using chemical scavenging methods, we identified that •OH, instead of SO4•−, was the oxidant initiating the reaction of 6:2 FTS. •OH was mainly produced from SO4•− reacting with H2O. Thus, the reactivity of 6:2 FTS was controlled by the factors affecting the production and scavenging of both SO4•− and •OH. Density functional theory calculations showed that •OH oxidizes 6:2 FTS by H-abstraction from the ethyl carbons. This is the first study that demonstrates •OH in Co2+ activated PMS can play a significant role in contaminant transformations. The results indicate that great caution should be taken when PMS or other agents that generate •OH are used for treatment of water containing 6:2 FTS or its structural analogs.

Bioaccumulation assessment is important for cationic surfactants in light of their use in a wide variety of consumer products and industrial processes. Since they sorb strongly to natural surfaces and to cell membranes, their bioaccumulation behaviour is expected to differ from other classes of chemicals. Divided over two mixtures, we exposed rainbow trout to water containing 10 alkyl amines and 2 quaternary alkylammonium surfactants for 7 days, analysed different fish tissues for surfactant residues, and calculated the tissues’ contribution to fish body burden. Mucus, skin, gills, liver and muscle each contributed at least 10% of body burden for the majority of the test chemicals. This indicates that both sorption to external surfaces and systemic uptake contribute to bioaccumulation. In contrast to the analogue alkylamine bases, the permanently charged quaternary ammonium compounds accumulated mostly in the gills and were nearly absent in internal tissues, indicating that systemic uptake of the charged form of cationic surfactants is very slow. Muscle-blood distribution coefficients were close to 1 for all alkyl amines, whereas liver-blood distribution coefficients ranged from 13-90, suggesting that the dominant considerations for sorption in liver are different than in blood and muscle. The significant fraction of body burden on external surfaces can have consequences for bioaccumulation assessment.

Iron (Fe) biogeochemistry in marine sediments is driven by redox transformations creating Fe(II) and Fe(III) gradients. As sediments are physically mixed by wave action or bioturbation, Fe gradients re-establish regularly. In order to identify the response of dissolved Fe(II) (Fe2+) and Fe mineral phases towards mixing processes, we performed voltammetric microsensor measurements, sequential Fe extractions, and Mössbauer spectroscopy of 12 h light-dark-cycle incubated marine coastal sediment. Fe2+ decreased during 7 days of undisturbed incubation from approx. 400 to 60 µM. In the first 2-4 days of incubation, Fe2+ accumulated up to 100 µM in the top 2 mm due to Fe(III) photoreduction. After physical perturbation at day 7, Fe2+ was re-mobilized reaching concentrations of 320 µM in 30 mm depth, which decreased to below detection limit within 2 days afterwards. Mössbauer spectroscopy showed that the relative abundance of metastable iron-sulphur mineral phases (FeSx) increased during initial incubation and decreased after perturbation. We show that Fe2+ mobilization in marine sediments is stimulated by physical disturbances impacting the Fe redox distribution. Our study suggests that in addition to microbial Fe(III) and abiotic Fe(III) reduction, including Fe(III) photoreduction, physical mixing processes also provide sediments and the inhabiting microbial community with Fe2+.

Singlet oxygen (1O2) generation quantum yields from chromophoric dissolved organic matter (CDOM) have been reported for many samples over the past four decades. Yet even for standardized isolates such as those from the International Humic Substance Society (IHSS), wide-ranging values exist in the literature. In this manuscript, time-resolved 1O2 phosphorescence was used to determine the 1O2 quantum yields (ΦΔ) of a variety of dissolved organic matter (DOM) isolates and natural waters. In general, the 1O2 quantum yield values in this study are in the middle, though below the median of the range of past reported values (e.g., for Suwannee River Natural Organic Matter IHSS isolate: 1.8% vs. 0.23–2.89%). Notably, hydrophobic neutral fractions of DOM isolates were found to possess the highest 1O2 quantum yields, an interesting result given that these fractions are not retained in typical humic and fulvic acid isolation procedures that use XAD resins. The excitation wavelength dependence of 1O2 generation from CDOM was also examined, and an approximate linear decrease with longer excitation wavelength was observed. This work advances the understanding of CDOM photoprocesses, especially in relation to wavelength-dependent 1O2 production, which is valuable for assessing real-world environmental behavior.

In this study we reveal the capacity of imidacloprid (a neonicotinoid insecticide) to photoinduce nitration and nitrosation of three aromatic probes (phenol, resorcinol, tryptophan) in water. Using a gas-flow reactor and NOx analyzer, the production of gaseous NO/NO2 was demonstrated during irradiation (300-450 nm) of imidacloprid (10-4 M). Quantum calculations showed that formation of NOx proceeds via homolytic cleavage of the RN-NO2 bond in the triplet state. In addition to gaseous NO/NO2, nitrite and nitrate were also detected in water, with the following mass balance: 40±8% for NO2, 2±0.5% for NO, 52±5% for NO3- and 16±2% for NO2-. The formation of nitro/nitroso probe derivatives was evidenced by high resolution mass spectrometry and their yields were found be ranging between 0.08% and 5.1%. The contribution of NO3-/NO2- to the nitration and nitrosation processes was found minor under our experimental conditions. In contrast, the addition of natural organic matter (NOM) enhanced significantly the yields of nitro/nitroso derivatives, likely via production of triplet excited states (3NOM*) and HO.. These findings reveal the importance of investigating the photochemical reactivity of water contaminants in mixture to better understand the cocktail effects on their fate and toxicity.

A FeS/graphene-based catalysts (DMG) was established here through a novel double-network templatedd way for peroxymonosulfate (PMS) activation considering the effect of template and iron species on catalysis performance. For comparison, tThe single-network hydrogel was also used to prepare catalysts named AMG and PMG, respectively. Results proved that DMG had obvious structural improvement compared to AMG and PMG to enhance PMS activation included: (i) lower agglomeration and a , higher specific area, higher S2-/SO42- ratio, higher C=C (sp2) content, more unsaturated C-O bonds and better conductivity. The whichdouble network template showed to provides more contact sites for the pollutant tetracycline; (ii) higher S2-/SO42- ratio, which, enabled ); (iii) higher content of C=C (sp2) and unsaturated C-O bonds; and (iveasier regeneration of Fe(II) and fasterpromote electron transport due to better conductivity. . Density functional theory (DFT) calculations revealed that the effect of sulfur conversion in PMS activation. The results indicate promising applications of double-network templated strategycatalysts for environmental remediation and provide new vision to oxidant activation mechanism.

To compare the phenolic responses under oxidative stressors, plants of two Italian cultivars of durum wheat (Claudio and Mongibello) were (a) exposed to ozone (O3) (80 ppb, 5 hr/day for 70 consecutive days), with the aim to investigate the changes of phenolic compound contents in their leaves, or (b) flooded (seven consecutive days). Plants showed O3‐induced visible injury, but their photosynthetic performance was not affected by the pollutant. Specifically, Claudio showed a higher O3 tolerance than Mongibello. The major value of the present study is undoubtedly the pioneering investigation of phenolic metabolism of durum wheat under O3. We identified 12 foliar phenolic compounds in all leaf samples (i.e. controls, exposed to O3 and flooded): ten phenolic acids, a flavanol (catechin hydrate) and a phenolic aldehyde (syringaldehyde). Overall, O3 exposure resulted in accumulations of phenolic compounds, especially in Claudio. These responses can be likely considered a fine‐regulated repair process that equipped Claudio stressed plants with an antioxidant system capable of scavenging oxidative stress. Different phenolic variations were found in flooded plants, suggesting that phenolic response to environmental constraints is stress specific. Our study confirms that investigations and characterization of specific phenolic profiles of crop cultivars under oxidative stress may be helpful in breeding programmes.

Little is known about net photosynthetic rates (Pn) of potato during and after the end of a high‐temperature episode. We investigated Pn of potato leaves exposed to a high‐temperature episode. Plants were grown in the greenhouse at 22°C. Shortly after tuber initiation, plants were transferred to 30°C for 9 days and then returned to 22°C. High temperatures reduced Pn of older leaves but not of the youngest leaves. Effects were transitory; Pn of leaf 7 initially fell, but then increased to be higher than the control plants. High temperature increased respiration per unit area during the night and morning relative to the control plants. Leaves that emerged during the 30°C episode had higher Pn than the control plants when returned to 22°C. Results emphasise that it is not possible to use single‐leaf measurements to infer effects on photosynthesis throughout the canopy. Similarly, the diurnal variation in effects on respiration means that Pn measurements made only at midday are inadequate. Finally, the dynamic response of Pn to the high temperature and the persistent effects after the end of the episode mean that the impact of high‐temperature episodes cannot be extrapolated from experiments using constant temperature treatments.

Iran has been faced to drought during last decades, and one way to overcome this phenomenon is to improve the water productivity by introducing new crops tolerant to water stresses such as quinoa. Two‐year field experiment was performed to find out the response of quinoa (cv. Titicaca) to deficit irrigation imposed at different growing stages. Hence, the effect of full irrigation (100% irrigation water requirement) and deficit irrigation (50% full irrigation) on physiological parameters, yield, irrigation water productivity and root density of quinoa was investigated during 2016 and 2017 growing seasons. The result showed that there was a significant difference between all variables in two years. Higher average air temperature in 2017 (2.0°C) resulted in a reduction of seed yield and water productivity (55% and 40% of that obtained in 2016, respectively). Application of deficit irrigation during different growing stages reduced crop height, stomatal conductance and seed yield, while it increased the root length density in both years. In conclusion, flowering stage of quinoa was very sensitive to deficit irrigation, and irrigation at grain filling stage would not help to recover the seed yield. Furthermore, the seed yield was lower than that obtained in other studies performed in other countries using same quinoa cultivar, which could be due to higher amount of applied irrigation water and different phenology under different climatic conditions. A decision on cultivating this crop under semi‐arid conditions has to be made considering limited water resources.