A bibliometric method was used to evaluate the global scientific publications about sulfur oxides and nitric oxides released by coal-fired flue gas and vehicle exhaust from 1995 to 2018 and to provide insights into the characteristics of the articles and tendencies that may exist in the publications. Performance of publications, research tendency, and hotspots were analyzed. The article number had an explosive growth in 2004 and, then, began to grow steadily. China had an absolutely advantage in publication quantities; however, America had a leading position considering publication cited times. The simultaneous removal of mercury, particulate matter, and CO₂ was a research hotpot in sulfur oxide and nitric oxide control process; oxidation, absorption, and catalytic reduction were the central control methods that had the most strength in relation with sulfur dioxide and nitric oxide. Considering the study of traditional flue gas pollutant control method (limestone-gypsum method, selective catalytic reduction, etc.) was perfection, it was speculated that adsorption by ionic liquid, electricity charging, advanced oxidation progress, and multi-pollutant removal, simultaneously, would be the new research orientation in flue gas pollutant control. One of the hot points of controlling the vehicle exhaust was the application of the “green energy” biodiesel; lots of keywords concerning human health suggested that quite a lot studies were focused on the health hazard brought by sulfur oxides and nitric oxide.

The residue concentrations and congener profiles of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) were examined in fly ash and bottom ash released from different thermal industrial processes in Vietnam. PCDD/F concentrations and toxic equivalents (TEQs) in the ash samples varied greatly and decreased in the following order: steel making > aluminum recycling > medical waste incinerator > boilers > municipal waste incinerator > tin production > brick production > coal-fired power plant. Both the precursor and de novo synthesis were estimated as possible formation mechanisms of dioxins in the ash, but the latter pathway was more prevalent. The highest emission factors were estimated for the ash released from some steel-making plants, aluminum-recycling facilities, and a medical waste incinerator. The emission factors of PCDD/Fs in ash released from some steel plants of this study were two to six times higher than the UNEP Toolkit default value. The annual emission amount of ash-bound dioxins produced by 15 facilities in our study was estimated to be 26.2 to 28.4 g TEQ year⁻¹, which mainly contributed by 3 steel plants. Health risk related to the dioxin-containing ash was evaluated for workers at the studied facilities, indicating acceptable risk levels for almost all individuals. More comprehensive studies on the occurrence and impacts of dioxins in waste streams from incineration and industrial processes and receiving environments should be conducted, in order to promote effective waste management and health protection scheme for dioxins and related compounds in this rapidly industrializing country.

In this study, two types of artificial floating islands (AFIs), group A (consists of 1# and 2# traditional AFIs with plant and soil) and group B (consists of 4# and 5# new-type AFIs with plant, substrate, and with luffa sponge and corncob hanging at the bottom), were constructed, respectively. The removal effects and degradation mechanisms of luffa sponge and corncob in group B were compared and investigated. Plant height, root growth, and packing degradation of the two types of AFIs were studied. Temperature, dissolved oxygen (DO), and pH on the decontamination effects of AFI were discussed. The results showed that group A and group B AFIs showed great significant differences in removal of CODCᵣ, TN, NO₃⁻−N, NH₄⁺−N, and TP (p < 0.05). The TP removal of group B was 92.8 ± 0.6%, and the TN removal and NO₃⁻−N removal were significantly higher than that of group A, which was 90.3 ± 0.8% and 96.0 ± 2.2%, respectively; The addition of luffa sponge and corncob could enhance the biodegradability of sewage and the nitrogen and phosphorus removal efficiency of group B. The plant growth height of group B planted with Lythrum salicaria was 2.36 times higher than that of group A. The effect of temperature on TP was significantly greater than that of TN, and both groups of AFIs presented continuous improvement capacities of TN and TP removal when the temperature was above 15 °C. Group B was observed with a lower pH range of 6.69~7.12, which was more suitable for denitrification than group A. The release of carbon source of 5#-corncob AFI was 2.51 times higher than 4#-luffa sponge AFI at the end of the experiment.

This study empirically investigates the agriculture-induced environmental Kuznets curve (EKC) hypothesis in an agrarian framework. Annual time series data from 1981–2014 was employed using augmented Dickey–Fuller and the Phillips–Perron (PP) unit root test complemented by the Zivot and Andrews unit root that accounts for a single structural break to ascertain stationarity properties of variables under consideration. For the cointegration analysis, an autoregressive distributive lag methodology and the recent novel Bayer and Hanck combined cointegration technique are employed. For the direction of causality, the Granger causality test is used as estimation technique. Empirical findings lend support for the long-run equilibrium relationship among the variables under consideration. This study also validates the inverted U-shaped pattern of EKC for the case of Nigeria, affirming that Nigeria remains at the scale-effect stage of its growth trajectory. Further empirical results show that foreign direct investment attraction helps mitigate carbon emissions in Nigeria. Based on these results, several policy prescriptions on the Nigeria energy mix and agricultural operations in response to quality of the environment were suggested for policymakers, stakeholders, and environmental economists that formulate and design environmental regulations and strategies to realise the goal 7 of sustainable development (SDG).

Pharmaceutically active compounds are carried into aquatic bodies along with domestic sewage, industrial and agricultural wastewater discharges. Psychotropic drugs, which can be toxic to the biota, have been detected in natural waters in different parts of the world. Conventional water treatments, such as activated sludge, do not properly remove these recalcitrant substances, so the development of processes able to eliminate these compounds becomes very important. Advanced oxidation processes are considered clean technologies, capable of achieving high rates of organic compounds degradation, and can be an efficient alternative to conventional treatments. In this study, the degradation of alprazolam, clonazepam, diazepam, lorazepam, and carbamazepine was evaluated through TiO₂/UV-A, H₂O₂/UV-A, and TiO₂/H₂O₂/UV-A, using sunlight and artificial irradiation. While using TiO₂ in suspension, best results were found at [TiO₂] = 0.1 g L⁻¹. H₂O₂/UV-A displayed better results under acidic conditions, achieving from 60 to 80% of removal. When WWTP was used, degradation decreased around 50% for both processes, TiO₂/UV-A and H₂O₂/UV-A, indicating a strong matrix effect. The combination of both processes was shown to be an adequate approach, since removal increased up to 90%. H₂O₂/UV-A was used for disinfecting the aqueous matrices, while mineralization was obtained by TiO₂-photocatalysis.

Polychlorinated diphenyl ethers (PCDEs) are a class of potential persistent organic contaminants, which have been widely detected in aquatic environment. In the present study, the effects of 3,4,4′-tri-CDE and its two possible metabolites (2-MeO-3′,4,4′-tri-CDE and 2-HO-3′,4,4′-tri-CDE) on oxidative stress biomarkers in liver of Carassius auratus were evaluated. The fish were treated with these three compounds at different doses (0.1, 1, and 10 μg/L) via semi-static water exposure. The liver samples were individually taken at 3, 7, and 21 days for analysis of oxidative stress indicators, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and malondialdehyde (MDA). Compare to the control group, the hepatic antioxidant enzyme activity and GSH contents showed significant decreases (p < 0.05) at high-dose treatment (10 μg/L) and prolonged exposure time (21 days) in most of the toxicant-treated groups, indicating the occurrence of oxidative stress in fish liver. However, no consistent trend of the variations of antioxidant parameters was observed at low doses (0.1 and 1 μg/L). Meanwhile, the lipid peroxidation was significantly induced with extending exposure time and increasing dose. In addition, the toxicity order of three compounds was discussed using the integrated biomarker response (IBR) index. Notably, 2-HO-3′,4,4′-tri-CDE was indicated to cause the most severe hepatic oxidative stress.

Nitrogen removal by anammox process has been recognized as efficient, cost-effective, and low-energy alternative removal. The longer start-up periods of anammox process hindered the widespread application of anammox-based technology. In this study, four identical unplanted subsurface-flow constructed wetlands (USFCWs) were built up to investigate the effects of electron acceptors (Fe³⁺, Mn⁴⁺, SO₄²⁻) on the start-up of anammox process. Results indicated that the start-up time of anammox process was shortened to 105 days in R1 (with Fe³⁺ addition) and 110 days in R2 (with Mn⁴⁺ addition) with nitrogen removal efficiencies of above 75%, compared with 148 days in R0 (control). The addition of SO₄²⁻ had no significant effect on start-up process. High-throughput sequencing results demonstrated that Shannon index increased significantly from 2.87 (R0) to 5.08 (R1) and 5.00 (R2), and the relative abundance of Candidatus Anammoxoglobus rose from 3.6 to 5.3% in R1. Denitratisoma increased significantly in R2 under addition of Mn⁴⁺, which was beneficial for the occurrence of anammox process. The functional genes that related to signal transduction mechanisms and secondary metabolite biosynthesis, transport, and catabolism were upregulated after addition of electron acceptors. These results demonstrated that adding electron acceptors Fe³⁺ or Mn⁴⁺ could be an effective way to accelerate the start-up of anammox process. Graphical abstract ᅟ

Pistia stratiotes is a common aquatic plant of the northern region of the state of Rio de Janeiro, and its use as adsorbent material was studied in the present work. The preparation process included washing, drying, grinding, and acid activation. The sorption potential for removal of the indigo carmine dye from aqueous solutions was tested under various conditions, such as initial concentration, contact time, and temperature. The tests showed that the obtained biosorbent showed good performance for dye removal with a maximum capacity of 41.2 mg/g. The kinetic studies revealed that the pseudo-second-order equation provided the best fit of the experimental data. The Freundlich isotherm provided the best fit of the experimental sorption data for the system under study. The results obtained show that Pistia stratiotes has great potential to be used as biosorbent for the removal of dyes from aqueous solutions.

Soil contamination with polychlorinated biphenyls (PCBs) is one the most relevant environmental problem in the SIN (Site of National Interest) of Taranto (Apulia Region, Southern Italy) and the surrounding area. Evaluation of PCB contents and their spatial distribution is an essential pre-requisite for soil remediation. Conventional laboratory analyses, although useful and irreplaceable for a precise and detailed evaluation of these contaminants, are costly and time-consuming, thus not very suitable for investigation over large areas. Then, there is a need to develop/validate alternative, rapid and cost-effective techniques, to use as substitutive of integrative to conventional analytical approaches. In this study, the usefulness of soil colour, based on spectrometric measurements, coupled with regression analysis, was assessed. Until now, never an analogous investigation has been realised. Twenty-eight soil samples, previously collected within an area (the ex-MATRA) highly contaminated by the disposal of oil used as dielectric fluid, composed by a mixture of PCB congeners, were used in the investigation. Colour coordinates in different colour systems were calculated from spectroradiometric measurements over the soil samples. Eighteen PCB congeners (i.e. 12 dioxin-like PCBs and six non-dioxin-like “indicator” PCBs), their sum (PCBs₁₈) and the extractable organic halogen content (EOX)—which is an expression of the total content of halogen in organochlorine compounds, including the PCBs—were determined through conventional laboratory analysis. Simple linear regression analysis was carried out to predict the values of PCBs and EOX on the basis of colour variables. Excellent predictive models (R² > 0.80) for PCBs₁₈ and EOX, as well as for some of the individual PCB congener, resulted from the regression analysis. Thus, spectroscopic determination of soil colour can be considered as a promising tool for a rapid screening of PCBs in contaminated soils.

Plants of the order Brassicaceae have evolved a chemical defence against herbivory: the glucosinolate-myrosinase system. Mechanical damage to plant tissues, such as grazing, initiates the production of phenethyl isothiocyanate (PEITC), a compound toxic to invertebrates. Mechanical damage caused during biofumigation and the harvesting and washing of watercress presents routes for PEITC release into waterbodies, such as the chalk stream spawning sites of brown trout (Salmo trutta). This laboratory study exposed developing S. trutta embryos to PEITC at concentrations of 0.01, 0.1 and 1 μg/L. S. trutta exposed to 1 μg/L PEITC during embryonic development resulted in 100% mortality after four dose days. Exposure to 0.1 μg/L PEITC resulted in an approximate fourfold increase in mortality relative to the controls, while exposure to 0.01 μg/L PEITC had a negligible effect on embryo mortality. Embryos exposed to 0.1 μg/L PEITC showed a significant delay in hatching and produced alevins with significantly shorter total lengths, lighter body weights and an approximate threefold increase in spinal deformities relative to those exposed to the controls and 0.01 μg/L PEITC. The results of a motor activity assay demonstrate that alevins exposed to PEITC showed a significant decrease in swimming activity compared with control animals during periods of illumination. The increased mortality, teratogenic effects and impaired behaviour in S. trutta following embryonic exposure to relatively low concentrations of PEITC highlight a need to accurately quantify and monitor environmental levels of PEITC.