Recently nanoparticles (NPs) are ubiquitous in the environment because they have unique characteristics which are the reason of their wide use in various fields. The release of NPs into various environmental compartments mainly ends up in the soil through water bodies which is a serious threat to living things especially plants. When present in soil, NPs may cause toxicity in plants which increase significance to minimize NPs stress in plants. Although gibberellic acid (GA) is one of the phytohormones that has the potential to alleviate abiotic/biotic stresses in crops plant, GA-mediated alleviation of cerium oxide (CeO₂) NPs in plants is still unknown, despite the large-scale application of CeO₂-NPs in various fields. The present study was performed to highlight the ability of foliar-applied GA in reducing CeO₂-NPs toxicity in wheat under soil exposure of CeO₂-NPs. We observed that CeO₂-NPs alone adversely affected the dry weights, chlorophyll contents, and nutrients and caused oxidative stress in plants, thereby reducing plant yield. GA coupled with CeO₂-NPs reversed the changes caused by CeO₂-NPs alone as indicated by the increase in plant growth, chlorophylls, nutrients, and yield. Furthermore, GA alleviated the oxidative stress in plants by enhancing antioxidant enzyme activities under CeO₂-NPs exposure than the NPs alone which further provided the evidence of reduction in oxidative damage in plants by GA. Overall, evaluating the potential of GA in reducing CeO₂-NPs toxicity in wheat could provide important information for improving food safety under CeO₂-NPs exposure.

This paper provides an assessment of energy density and energy efficiency and creates an important indicator of environmental performance. This article applied two mathematical models and econometric techniques to obtain detailed and specific results. The DEA and the non-normative account aggregation mean a collective aggregation to form a mathematical aggregation tool to create an environmental index for the BRICS countries (Brazil, Russia, India, China, and South Africa) based on available data from 2011 to 2016. The advantage of the proposed approach is to manage the irregularities of the data and follow the desired properties of the index number. The current paper is relevant for the broad scope of construction, the environmental index, and the evolution of the rankings of countries based on multiple indicators. Our results indicate that Brazil and Russia have the highest values of the Environmental Performance Index, which range between 67.44 and 60.70, respectively. India has a minimum value of 30.57 of the environmental index. The analysis shows that Brazil, Russia, and South Africa have the best scores and that these countries have the best results, while China and India also have the best results. This study can help form a valuable political tool for the development and development of the country’s politics.

Eutrophication and algal blooms have recently been found in the backwater areas of some tributaries in the Three Gorges Reservoir (TGR), for which phosphorus (P) is an important driving factor. However, P species in the TGR sediments at different water levels were little known. In this study, five P species of the TGR sediments during the high and low water level periods were analyzed with a sequential extraction method. The total P (TP) concentrations were 714.88 ± 37.86 μg/g and 697.57 ± 111.49 μg/g at the low and high water levels, respectively. The concentrations of P species decreased in the orders detrital P > authigenic P > organic P > iron-bound P > exchangeable P at the low water level and detrital P > organic P > authigenic P > iron-bound P > exchangeable P at the high water level. P in the TGR sediment sourced mainly from the upstream input at the low water level but from the inputs of tributaries and hillslope soils at the high water level. The bioavailable P (BAP) possessed > 29.5% of total P in the two periods. The total storages of total P and BAP were estimated to be about 1.34 × 10⁶ t and 1.77 × 10⁵ t, respectively during 2003–2017. It was further found that the BAP concentration significantly increased from periods I (2003–2009), II (2010–2014), to III (2015–2017), while the deposition flux and storage of BAP were the highest in period II. Our findings provide new insight into the P cycle and benefit eutrophication treatment in the TGR.

Arsenic (As) is a prominent metal contaminant of the soil in China. Pot experiments were conducted to examine the effects of corn stem powder biochar (BC) and Fe-Mn-La-impregnated biochar composites (FMLBC₁, FMLBC₂, and FMLBC₃; BC:Fe:Mn:La at different weight ratios) on As accumulation in an indica cultivar of rice (Oryza sativa L.). The application of FMLBCs and BC improved the dry weight of the grains, leaves, stems, and roots of rice. The As uptake in different rice organs was significantly reduced in the FMLBC-amended soils (FMLBC₃ > FMLBC₂ > FMLBC₁) compared with the BC treatment. Compared to the concentration of As in the control, the concentration of As in rice grains decreased by 56.0–89.4% with the addition of 2% FMLBC₃. The application of FMLBCs significantly increased the ratio of essential amino acids in grains and the contents of Fe and Mn plaques on root surfaces. The reduction in As accumulation can be ascribed to the Fe, Mn, and La oxides that enhance the adsorption and retention of As, as well as the FMLBCs that provide nutrients and create a rhizosphere environment, promoting rice growth. This study demonstrated that applications of 2% FMLBC₂ and FMLBC₃ have the potential to remediate As-contaminated soils, reduce As accumulation in rice plants, and improve rice grain quality.

Dye wastewater has been becoming the focus of environmental protection and scientific research because of its serious harm to the environment and living organisms. A supported nano-porous anode alumina-NiO (nano-PAA-NiO) photocatalyst was prepared by calcining nano-PAA-NiCl₂ composite which was grown with a self-organization method. Its morphology and composition were investigated by means of SEM, EDS, and XRD. The specific surface area of nano-PAA-NiO was characterized with the N₂ adsorption and desorption isotherms. The band gap was calculated to be 3.0 eV with the UV–Vis absorption spectra. The species and optical properties of nano-PAA-NiO were investigated by FT-IR spectra and photoluminescence spectra. With the nano-PAA-NiO photocatalyst, the degradation rates of methyl orange (MO) were 94.3% under the optimum conditions, and it could reach 82% when the catalyst was reused for the third time. In addition, the photocatalytic mechanism was proposed, and the reactions followed the Langmuir–Hinshelwood model. The nano-PAA-NiO composite has an excellent effect for organic dye wastewater treatment and practical prospects in environmental protection.

The demand for rare earth elements (REEs) has significantly increased due to their indispensable uses in integrated circuits of modern technology. However, due to the extensive use of high-tech applications in our daily life and the depletion of their primary ores, REE’s recovery from secondary sources is today needed. REEs have now attracted attention to policymakers and scientists to develop novel recovery technologies for materials’ supply sustainability. This paper summarizes the recent progress for the recovery of REEs using various emerging technologies such as bioleaching, biosorption, cryo-milling, electrochemical processes and nanomaterials, siderophores, hydrometallurgy, pyrometallurgy, and supercritical CO₂. The challenges facing this recovery are discussed comprehensively and some possible improvements are presented. This work also highlights the economic and engineering aspects of the recovery of REE from waste electrical and electronic equipment (WEEE). Finally, this review suggests that greener and low chemical consuming technologies, such as siderophores and electrochemical processes, are promising for the recovery of REEs present in small quantities. These technologies present also a potential for large-scale application.

Emission inventories are one of the most critical inputs for the successful modeling of air quality. The performance of the modeling results is directly affected by the quality of atmospheric emission inventories. Consequently, the development of representative inventories is always required. Due to the lack of regional inventories in Brazil, this study aimed to investigate the use of the particulate matter (PM) emission estimation from the Brazilian top-down vehicle emission inventory (VEI) of 2012 for air quality modeling. Here, we focus on road vehicles since they are usually responsible for significant emissions of PM in urban areas. The total Brazilian emission of PM (63,000 t year⁻¹) from vehicular sources was distributed into the urban areas of 5557 municipalities, with 1-km² grid spacing, considering two approaches: (i) population and (ii) fleet of each city. A comparison with some local inventories is discussed. The inventory was compiled in the PREP-CHEM-SRC processor tool. One-month modeling (August 2015) was performed with WRF-Chem for the four metropolitan areas of Brazilian Southeast: Belo Horizonte (MABH), Great Vitória (MAGV), Rio de Janeiro (MARJ), and São Paulo (MASP). In addition, modeling with the Emission Database for Global Atmospheric Research (EDGAR) inventory was carried out to compare the results. Overall, EDGAR inventory obtained higher PM emissions than the VEI segregated by population and fleet, which is expected owing to considerations of additional sources of emission (e.g., industrial and residential). This higher emission of EDGAR resulted in higher PM₁₀ and PM₂.₅ concentrations, overestimating the observations in MASP, while the proposed inventory well represented the ambient concentrations, obtaining better statistics indices. For the other three metropolitan areas, both EDGAR and the VEI inventories obtained consistent results. Therefore, the present work endorses the fact that vehicles are responsible for the more substantial contribution to PM emissions in the studied urban areas. Furthermore, the use of VEI can be representative for modeling air quality in the future.

Quantitative PCR (qPCR) is the method of choice for specific detection and quantification of harmful algal bloom (HAB) species. Development of qPCR assay for simultaneous enumeration of species that frequently co-exist in HABs is required. A high sensitivity TaqMan qPCR assay, using probe and primers, located at ITS1–5.8S–ITS2 rDNA region, detecting, specifically, Karenia selliformis, K. bidigitata, and K. mikimotoi, was designed. ITS1–5.8S–ITS2 rDNA region copy numbers per Karenia cell genome were estimated to 217.697 ± 67.904, allowing cell quantification. An application of the designed methodology in field samples has been conducted, and it showed high sensitivity (detection of around 10⁻¹ cell/100 mg of bivalve mollusk tissue, equivalent to about 20 copies of the target sequence). We suggest that the optimized method could contribute to early detection of three closely related Karenia species in seafood cultivating areas to promote control quality, guarantee a fast and effective intervention, and improve public health prevention.

Political corruption is considered one of the major obstacles to achieving high-quality economic development in developed and developing countries. This study first calculates the ecological footprints of 29 provinces in China based on China’s provincial panel data from 2006 to 2015. The provinces’ ecological efficiencies were then calculated. The relationship between government corruption and ecological efficiency is researched, and the result shows that such a relationship is not linear. At different levels of ecological efficiency, government corruption has different effects on ecological efficiency. Finally, the resource misallocation index is introduced, and the spatial error model is used to further test the impact of government corruption and resource misallocation on ecological efficiency. The regression results show that high levels of government corruption and resource allocation distortion will cause a decrease in regional ecological efficiency, which adversely affects the sustainable development of the economy.

This study presents the latest results of the groundwater monitoring of a research project, which tested an innovative pump and treat method in combination with an in-situ remediation. This technique was assessed on an abandoned site in Austria, where two hot spots of hexavalent chromium (Cr(VI)) were located. For the in-situ remediation, a strong reducing agent (sodium dithionite) was injected into the underground to reduce Cr(VI) to Cr(III) by using different injection strategies. Throughout this treatment, part of the Cr(VI) is mobilized and not instantly reduced. To prevent a further spreading of the mobilized Cr(VI), the pump and treat method, which uses zero-valent iron to clean the groundwater, was installed downgradient of the hot spots. Based on the groundwater sample analyses, it was possible to distinguish different remediation phases, characterized by excess chromate and excess sulfite. During the excess sulfite conditions, Cr(VI) was successfully removed from the system, but after terminating the sodium dithionite injection, the Cr(VI) rebounded.