International Journal of Environmental Research最新文献

The severe lockdown imposed to prevent the spread of COVID-19 decreased the emissions of air pollutants in large cities. A comparative approach was adopted to analyze the effect of the COVID-19 lockdown on ambient air pollution concentrations and the impacts of meteorological parameters on them using data from air quality monitoring stations (AQMS) in Tabriz, Iran. Air quality improvement was significant for all pollutants, except for O₃, in the first phase of the lockdown compared to other phases. The lockdown (restricted social contact, closing of shops, schools, universities, restaurants, and many administrative centers and companies, etc.) temporarily reduced air pollutants. Comparing meteorological parameters between lockdown periods and the same period in previous years showed no statistically significant variations (P-value < 0.05). Therefore, the meteorological parameters did not intervene in reducing air pollutants during the lockdown. The effects of lockdown on the concentration of air pollutants could provide a special way to understand the extent of quarantine compliance by citizens, evaluate additional air quality policies, and assess the impacts of reducing various emission sources.

Bezafibrate (BZF), an extensively used lipid-regulating agent, has been frequently detected in aqueous environments. In this work, we systematically investigated the Fe(II)/sulfite process for degrading BZF and its impact on disinfection byproducts (DBPs) during postchlorination. Degradation conditions were optimized by adjusting the pH, sulfite concentration, Fe(II), and BZF concentration. Under the conditions of pH = 4, [BZF]₀ = 5 μM, [Fe(II)]₀ = 25 μM, and [sulfite]₀ = 250 μM, the BZF removal efficiency reaches 97.9% in 15 min. Sulfate radicals (SO₄^●–) and singlet oxygen (¹O₂) are recognized as the main reactive agents, with Fe(IV) also contributing to the removal of BZF. Common anions (Cl⁻ and HCO₃⁻) and humic acid generally impede the degradation process, except that trace amounts of Cl⁻ can slightly accelerate BZF degradation. A total of ten products are recognized by ultra high performance liquid chromatography and quadrupole time-of-flight mass spectrometry, and four major degradation pathways are proposed: hydroxylation, cleavage of amino bonds, removal of fibrate chains, and dechlorination. Meanwhile, the toxicity assessment shows that the majority of products exhibit lower biological toxicity and less bioaccumulation potential than BZF itself. The Fe(II)/sulfite pretreatment alters the DBP formation potential, especially when Br⁻ is present. The formation of trichloromethane (TCM) is diminished following pretreatment with the Fe(II)/sulfite process, whereas a noticeable increase in the formation of dichloroacetonitrile (DCAN) is found. Moreover, Fe(II)/sulfite pretreatment enhances the formation of brominated DBPs. Therefore, special consideration should be given to DBP formation when a Fe(II)/sulfite system is employed as a pretreatment for the removal of BZF in water.

Graphical abstract

Scrap-iron smelting, a critical industry for metal recycling, is notorious for releasing potentially toxic elements (PTEs) into the environment. This study investigates pollution levels, sources, and health risks of ten PTEs (Fe, As, Cd, Zn, Cu, Mn, Pb, Cr, Co, and Ni) in indoor and outdoor areas surrounding a major scrap-iron recycling plant in northcentral Nigeria. The potential sources of studied PTEs pollution during the rainy and dry seasons were evaluated using Positive Matrix Factorization (PMF) model. Ecological risk assessments of studied PTEs were conducted using different pollution indices such as Enrichment Factor (EF), Geo-accumulation Index (I_geo), Contamination Factor (C_f), Potential Ecological Risks Index (PERI), Nemerov Integrated Pollution Index (NIPI), and Nemerov Integrated Risk Index (NIRI). Out of the 10 PTEs studied, Cd had the highest pollution level and exhibited a high potential to cause cancer in children during the two seasons considered. Sources of PTEs identified for rainy season included recycling process, electronic waste, coal combustion, steel production, and other smelting activities whereas steel production, electronic waste, coal combustion, recycling process, and traffic emission contributed to the PTE levels obtained in the dry season. This study contributes to the understanding of the environmental impact of scrap-iron smelting operations and advocate for the implementation of sustainable practices that protect both human health and the environment.

Graphical Abstract

In this investigation, cationic surfactant cetyltrimethylammonium chloride (CTAC)-modified nanofiltration (NF) membranes were investigated for sodium diclofenac (DFS) removal from aqueous solution. The effects of CTAC incorporation on the membranes at various concentrations below, at, and above the critical micelle concentration (CMC) were evaluated in terms of membrane permeability, morphology, antifouling properties, and performance. CTAC-modified membranes exhibited enhanced structural properties, increased hydrophilicity, higher pure water flux (461 L/m² h), and superior antifouling resistance (98% BSA protein rejection, 82.1% FRR). Consequently, the optimized 0.1 wt% CTAC-modified membrane at CMC concentration exhibited superior rejection efficiency compared to the unmodified membrane, increasing from 35.62 to 65.17% for sodium diclofenac removal. The findings of this study demonstrate that the optimized membrane exhibited the best performance in all parameters, making it suitable for practical application in the removal process of sodium diclofenac.

Graphical Abstract

The COVID-19 pandemic has had profound global repercussions, leading to substantial fatalities and economic losses worldwide. However, amidst these adversities, the pandemic inadvertently offered a unique opportunity to assess the impact of reduced human activity on environmental noise levels. This study focuses on monitoring and mapping noise pollution levels at 101 locations managed by the Bhubaneswar Development Authority (BDA) in Bhubaneswar, Odisha, India, during three distinct periods: pre-COVID, during COVID-lockdown, and post-COVID. Using ArcGIS 10.2.1, noise data are spatially analysed across different zones designated by the Central Pollution Control Board (CPCB), namely Industrial, Commercial, Residential, and Silence Zones. The findings reveal a significant reduction in traffic noise during the COVID-19 lockdown period compared to both pre-COVID and post-COVID periods across all four zones. To assess the potential impact on human health, the study employs equations developed by Miedema and Vos (Acoust Soc Am 104:3432–3445, 1998, https://doi.org/10.1121/1.423927) for calculating percentages of highly annoyed individuals and estimating sleeping disorders. Additionally, Structural Equation Modeling (SEM) is applied to explore associations between noise levels and health outcomes across different time periods. Despite the significant reduction in traffic noise observed during the COVID-19 lockdown, our analysis suggests that this decrease did not have a statistically significant effect on annoyance levels (p-value: 0.0542) or sleeping disorders (p-value: 0.121). This study provides valuable insights into the unintended consequences of urban lockdowns on environmental noise pollution and their potential implications for public health and urban planning.

Rising livestock and poultry production necessitates sustainable manure management practices to curb greenhouse gas (GHG) emissions. This study employs two artificial neural networks, Multi-Layer Perceptron (MLP) and Radial Basis Function (RBF), to forecast manure production in Iranian provinces (2020–2030). The RBF model demonstrated superior accuracy compared to a Multi-Layer Perceptron model. Our forecasts predict the significant potential for biogas and biomethane production from manure by 2030, estimated at 10,782.4 and 6469.44 Mm³.year-1 respectively. This translates to replacing 4.03% and 4.98% of Iran's projected annual gas and electricity consumption in 2030. While this offers a renewable energy source, conventional manure management practices are projected to increase agricultural methane emissions. Our analysis highlights that utilizing biomethane from biogas represents the most effective strategy for reducing GHG emissions in the energy sector. The study projects that by 2030, manure management will still produce 14 million tons of carbon dioxide, equivalent to 16.71% of the agricultural sector's GHG emissions. Scenario analysis indicates that adopting biomethane as a natural gas substitute offers the most significant reduction in energy sector emissions compared to current practices. These findings underscore the importance of effective manure management for climate change mitigation. Furthermore, they highlight the need for long-term pollution reduction policies informed by accurate livestock growth forecasts. This study also contributes by demonstrating the potential of artificial neural network models for accurate manure production forecasting and developing GHG reduction strategies.

This paper provides an overview of literature on the multiple-time recycling of concrete waste and meticulously analyzes the research findings. The paper begins by reviewing the characteristics of recycled materials such as recycled coarse aggregate, recycled fine aggregate, and recycled powder obtained from concrete waste in relation to the recycling cycle. The influence of each of these materials on the mechanical properties and durability of next-generation concrete is analyzed. Moreover, this paper introduces strategies reported in the literature that aim to enhance the performance of multi-recycled concrete. Lastly, this paper identifies and highlights limitations and research gaps, while providing insightful recommendations to drive future exploration of multi-recycling of concrete.

Graphical Abstract

The function of Cytochrome (CYP) P450 in plants to enhance detoxification of herbicide metabolism is well-known. However, the knowledge of gene quantification for detecting and detoxifying pollutants and other toxicants by an indigenous plant growing in a contaminated site is limited. The objective of this research is to evaluate the potential of detecting or degrading 2,3,7,8 Tetrachlorodibenzodioxin (TCDD) in soil using a native plant growing in a contaminated site via the gene expression of Cytochrome P450 monooxygenases (P450s) method. The novelty of this research is that P450s in native plants possibly acts as a bioindicator on contaminated land by increasing its gene expression levels induced by the presence of TCDD. In seedling toxicity test and cytochrome enzyme activity test, a significant difference in the root length (range of value: 580.2–799.2 mm) and enzyme activity (range of value: 31.2–82.3 nmolmin⁻¹ g⁻¹ total protein) of such indigenous plant was found in 10 µg/L TCDD treatment when compared to other treatments. 13- and 20-fold levels of gene expression in CYP71C1 and CYP79A61 of the plant growing in a contaminated site were found after 10 µg/L TCDD treatment. The results revealed that such indigenous plant is sensitive to the detection of such persistent organic pollutant in the field site and involves gene expression change facilitated by a plant‒microbe symbiotic association. The current findings can provide an insight to use another option for pollution monitoring using non-standard plant models.

In the realm of bioprocess technology, microbial fuel cells (MFCs) are regarded as a noteworthy innovation that can simultaneously bioremediate wastewater and utilise as renewable energy applications. The investigation began with synthesizing composite proton exchange membrane (PEM) with sulfonated polysulfone (SPSF) and sulfonated chitosan (SCS) as a separator for MFCs. A composite membrane has been developed by crosslinking a microporous SPSF substrate with a thin layer of chitosan (CS). The membrane was then evaluated for its suitability in MFCs which employ dewatered sludge. The appearance and physico-mechanical properties of this composite were thoroughly examined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), proton conductivity measurements, back-end titration tests, and water uptake studies. Attempts were made to enhance the connection between the duo polymers such as PSF and CS by providing surface changes with the incorporation of sulfonation properties. As a result, two novel types of composite materials were developed: (SPSF/CS) and (SPSF/SCS), which were made by altering a PSF membrane’s surface before adding a chitosan layer using the non-solvent phase inversion technique. The proton conductivity of SPSF/CS and SPSF/SCS composites was measured and contrasted with that of unmodified PSF. The composite, SPSF/SCS-1, 0.5 wt%, showed greater proton conductivity and ion exchange capacity (IEC) (1.7 meq/g, 0.061 S/cm) than the unaltered PSF (0.99 meq/g, 0.009 S/cm). According to the MFCs performance, the SPSF/SCS-1, 0.5 wt% membrane demonstrated a substantial electricity production compared to pristine PSF 38.57 mW/m² and 0.449 mW/m². These results vividly depicted that the composite SPSF/SCS PEM increases the productivity of dual-chamber MFCs.

This research investigates the relationship between the chemical parameters and pollutant concentration of soil and the extent of infection of wood decay fungi across various tree species in urban areas of Hong Kong. Notably, this research uncovered significant differences (p < 0.05) in fungal infection rates among different tree species (0.78–24.3%). The total concentration of PAHs in the soil samples collected ranged from 0.47 to 3.33 mg/kg (dry weight), with 13 out of the 18 sampling sites exceeding the Dutch Target Values (DTVs) of 1 mg/kg (dry weight). Principal components analysis (PCA) results revealed the influence of two principal components on the fungal infection rates among tree species. In particular, the first component was associated with electrical conductivity (EC) (PC1: 99.7%), while the second component involved redox potential and nitrate concentration (PC2: 0.2%). Furthermore, high concentrations of naphthalene were observed in soils at all sites across five major tree species, namely Spathodea campanulata, Ficus microcarpa, Acacia confusa, Cinnamomum camphora, and Lagerstroemia speciosa. The PCA results suggested that PAHs significantly contributed to fungal infection in these tree species. Such valuable baseline information can aid in the further development of effective urban tree management strategies in Hong Kong, mitigating the adverse impacts of soil quality on urban tree health, particularly in the face of global warming and extreme weather conditions.