Concerns over the depletion of conventional fuels have increased interest in new renewable energy sources like alcohol- and vegetable-based oils. Major drawbacks of using esters of vegetable oils, known as biodiesel, include reduced engine performance and increased emissions of oxides of nitrogen. In the present study, the effects of ethanol on biodiesel and mineral diesel blends in a diesel engine are experimentally investigated. The ethanol is produced from cashew apple juice by fermentation. Experiments are conducted using B20 Pongamia biodiesel with ethanol in proportions of 5, 7.5, and 10% by volume at varying load conditions. The results indicate that a B20 biodiesel blend with 7.5% ethanol yields a higher brake thermal efficiency and lower brake-specific energy consumption than pure B20 (20% biodiesel + 80% diesel), as well as significantly reduced emissions such as oxides of nitrogen, carbon monoxide, hydrocarbons, and smoke.

This study applies augmented mean group (AMG) along with common correlated effect mean group (CCEMG) estimator and panel heterogeneous causality to examine the interrelationship between GDP, energy consumption, financial development, foreign investment, and ecological footprints for five Belt and Road initiative (BRI) regions and in aggregated panel of BRI over the time 1990–2016. Using a multivariate framework, this study examines four alternative and conceivable hypotheses, including Pollution haven hypothesis, environmental Kuznets curve hypothesis, energy push emission hypothesis, and finance push emission hypothesis. The empirical results supported all four hypotheses for the panel of BRI and partially supported the existence of these hypotheses across the regions. Moreover, a variety of causal nexuses has been discussed in the study. Based on these results, the current research has proposed policy implications to combat the ecological footprints of BRI countries and across the regions.

In this study, the growth and high-valued products accumulation characteristics of three common high-valued microalgae (Chlorella sp. HQ, Scenedesmus sp. LX1, and Chlorella vulgaris) in saline-alkali leachate were compared to select the species with greatest utilization potential. The results showed that after 28 days of cultivation, among three microalgae, Chlorella sp. HQ grew best with its maximum density at peak of 1.16 × 10⁷ cells mL⁻¹ and lipid production per unit cell (0.047 ± 0.006 × 10⁻⁷ mg cell⁻¹) and lipid content (18.18 ± 3.14%) were largest. The triacylglycerol (TAG) yield and content of Scenedesmus sp. LX1 were the highest, reaching 0.005 ± 0.000 × 10⁻⁷ mg cell⁻¹ and 19.74 ± 2.53%, respectively, which was slightly higher than those of Chlorella sp. HQ. According to comprehensive comparison, Chlorella sp. HQ was most suitable to grow in the saline-alkali leachate in terms of algal density, lipid yield, and content. The potential comparison and effects of salinity on the high-valued products accumulation of Chlorella sp. HQ compared with those in SE standard medium, reclaimed water, and tap water were further carried out. It was found that the density order of Chlorella was saline-alkali leachate > SE medium > reclaimed water > tap water. And the Chlorella density in the leachate with a salinity of 0.14% was greater than the other three salinities (0.32%, 0.45%, and 0.6%) at the end of cultivation. While the maximum lipid yield per unit cell and lipid content of Chlorella occurred in the salinity of 0.6%, which indicated that high salinity promoted the accumulation of lipid. Furthermore, other high-valued products (including starch, protein, total sugar, and photosynthetic pigments) accumulation characteristics were analyzed and found that they were all superior than those in SE medium. And with the salinity decreased, the microalgal protein and starch contents decreased. The contents of photosynthetic pigment and total sugar reached a maximum at salinities of 0.32% and 0.45%, respectively.

The alkaline nature of biochar provides a potential for soil arsenic (As) mobilization and, hence, enhancing efficiency of As phytoextraction by combining with As hyperaccumulator. To testify the feasibility and potential risk of the above strategy, biochar effect on As transfer in a paddy soil and accumulation in P. vittata was investigated in a pot experiment. By leaching soil (total As concentration 141.17 mg/kg) with simulated acid rain (pH 4.2), As the concentration in leaching eluate increased proportionally with increasing biochar ratio. Coincident with elevated soil As mobility, apparent enhancement in As uptake and translocation in P. vittata was determined with 1–5% biochar amendment after 40 days of plant growth. Furthermore, diffusive gradients in thin film (DGT) technique were employed to characterize any potential risk in vertical downward migration of As at 2-mm resolution. A significantly increasing profile of DGT-As ranging from on average 20 μg/L in CK to 50–100 μg/L in 1–3% biochar treatments was recorded over 0–60 mm depth, with 25–71% lower labile As in the rhizosphere than non-rhizosphere zone with few exceptions. As compared to Chinese quality standard for groundwater (Class IV 50 μg/L), biochar ratio at ≤ 1% was suggested for local water safety while actual application should take the physicochemical characteristic of tested soil into account. Our results demonstrated the biochar-assisted P. vittata phytoremediation can serve as an emerging pathway to enhance efficiency of soil As phytoextraction. The combination of DGT techniques and greenhouse assay provided a powerful tool for evaluating the gradient distribution of heavy metal in rhizosphere and accessing corresponding ecological risk at more precise scale.

Bisphenol A (BPA) is an estrogenic endocrine disrupting chemical to which humans are frequently exposed during routine daily life. Curcumin and taurine are natural products that have also been used as antioxidants against different environmental toxin–induced hepatotoxicity. Furthermore, they have protective and therapeutic effects against various diseases. The present investigation has been conducted to evaluate the therapeutic potential of curcumin (100 mg kg⁻¹) and taurine (100 mg kg⁻¹) for their hepatoprotective efficacy against BPA (130 mg kg⁻¹)-induced liver injury in rat. BPA significantly elevated the levels of malondialdehyde (MDA), while it reduced the activities of catalase (CAT), total glutathione S-transferase (GST), total glutathione peroxidase (GPx), and total superoxide dismutase (SOD). Besides, these biochemical changes were accompanied by histopathological alterations marked by the destruction of normal liver structure. The histological examinations showed that exposure of BPA caused dilatation of sinusoids, inflammatory cell infiltration, congestion, and necrosis in liver parenchyma. The BPA-induced histopathological alterations in liver were minimized by curcumin and taurine treatment. Furthermore, no necrosis was observed in the liver tissues of curcumin plus BPA and taurine plus BPA-treated rats. Oral administration of curcumin and taurine to BPA-exposed rats significantly reversed the content of lipid peroxidation products, as well as enhanced the activities of GPx and GST, CAT, and SOD enzymes. These findings have indicated that curcumin and taurine might have a protective effect against BPA-induced hepatotoxicity in rats.

This study was performed to evaluate the toxic effects of aflatoxin B₂ (AFB₂) on antioxidant-oxidant balance and vital parameters such as physiological, cytogenetic, and anatomical alterations in Allium cepa L. root tip cells. Toxic effects of AFB₂ on vital parameters were investigated by using the changes in weight gain, germination percentage, chromosomal aberrations (CAs), mitotic index (MI), micronucleus frequency (MN), and anatomical structure. Malondialdehyde (MDA) and reduced glutathion (GSH) levels and superoxide dismutase (SOD) and catalase (CAT) activities in root cells were investigated as antioxidant-oxidant parameters. For this aim, A. cepa bulbs were seperated into five groups as negative control, positive control, and AFB₂ treatment groups. In results, while the rate of germination percentage, weight gain, and MI rates decreased, MN and CA frequency increased in AFB₂-treated groups compared with the negative control. Most common CAs observed in AFB₂-treated groups were fragment and chromosome bridges. It was determined that in 160 μg L⁻¹ AFB₂-treated group there was a 70.8% increase in MDA and a 78.1% decrease in GSH level compared with the negative control group and these changes indicate oxidative damage. In 160 μg L⁻¹ AFB₂ treatment group, SOD and CAT activities decreased importantly due to inhibition. In anatomical examinations, it was determined that AFB₂ treatment caused some anatomical damages in A. cepa root cells such as necrosis, cell deformation, and thickening in cell wall. This study showed that AFB₂, which has the least data among aflatoxins, causes serious in vivo toxic effects in A. cepa root cells.

In energy economics literature, we found few studies on the association between environmental quality energy consumption and financial development. The current study is an attempt to contribute in literature by examining the link between carbon dioxide (CO₂) emissions, financial development, energy consumption, and economic growth, in South East Asian economies for the period 1980–2017 using annual time series data. For empirical analysis, Bound tests for cointegration and error correction approach are used. The estimated results confirm that financial development has positive impact on environmental quality. On the other hand, in the long run, the rise in energy consumption economic growth and trade openness is unfavorable for environment quality. Our results confirm U-shaped relationship between economic growth and environmental quality that is a proof of environmental Kuznets curve (EKC). Additionally, the government needs to design different modes of energy consumption to solve the problem of environmental degradation. Moreover, the major conclusion extends new insight for authority to make a comprehensive trade and financial policies to improve environmental quality.

Electroplating manufacturing processes release industrial effluents that comprise severe levels of heavy metals into the environment. This study investigated the utilization of nanoparticles of zero-valent iron (nZVI) for the treatment of electroplating wastewater industry containing multiple heavy metal ions. In batch experiments using Cu²⁺ as a single solute, the optimum operating condition was pH 7.3, nZVI dosage 1.6 g/L, time 36 min, temperature 30 °C, and agitation speed 180 rpm, achieving almost 100% Cu²⁺ removal efficiency. The adsorption mechanisms were illustrated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FTIR) spectrometer. Moreover, continuous-feed experiments were performed to treat real electroplating wastewater industry via adsorption and sedimentation processes. The system attained removal efficiencies of 91.3% total suspended solids (TSS), 68.3% chemical oxygen demand (COD), 94.2% nitrogen (N), 98.5% phosphorus (P), 66.7% Cr⁶⁺, 91.5% Pb²⁺, 83.3% Ag⁺, 80.8% Cu²⁺, 17.4% Ni²⁺, 47.1% Mn²⁺, 54.6% Zn²⁺, 94.7% Fe³⁺, 100.0% Al³⁺, and 42.1% Co²⁺. The removal mechanisms included reduction of Meⁿ⁺ to Me⁽ⁿ⁻ˣ⁾⁺/Me⁰ by the Fe⁰ core, adsorption to the oxide shell as Me(OH)ₓ and Me-Fe-OOH, oxidation of Meⁿ⁺ to Me⁽ⁿ⁺ᶻ⁾⁺, specific surface bonding, and sequential steps of electron transfer and precipitation. The total cost, including amortized and operating expenses for scaling up the adsorption system, was 4.45$ per m³ of electroplating wastewater. Graphical abstract

Soil surface-dwelling cyanobacteria constitute an important part of the dryland ecosystem. The exopolysaccharide (EPS) matrix they establish plays multiple roles in helping cells cope with harsh environments and also improves soil physicochemical properties. Anthropogenic atmospheric nitrogen or sulfur depositions have arisen as an important environmental change in drylands. The acid moisture derived from the depositions will be absorbed by cyanobacterial EPS matrix and thus may pose a threat to cells. In this communication, we evaluated this potential impact in a dryland cyanobacterium, Nostoc flagelliforme, which is a representative polysaccharide-rich species and shows remarkable resistance to desiccation stress. A strong and resilient pH buffering property was found for the EPS matrix, mainly of the polysaccharide’s role, and this could protect the cells from acid damage of pH 4–6, a general acidity range of rainwater in the world. Unlike in acid aquatic environments, terrestrial xeric environments ensure N. flagelliforme unlikely to undertake lasting severe acidification. Thus, protection of the EPS matrix for dryland cyanobacteria would be conducive to sustain their growth and ecological roles in face of atmospheric acid pollution.

Production of polychlorinated biphenyls (PCB) was banned in the US in 1970s. However, susceptible populations especially those living at/around the contaminated sites continue to be at a risk of elevated exposure to PCBs because information about the contamination (of the environment) and its associated health risks may not reach these populations. A recent study found the second highest concentration of PCBs ever recorded worldwide in the sediment samples of Guánica Bay, located in the southwestern part of Puerto Rico. PCB levels in fish from the bay were also higher than the tolerance limit of Food and Drug Administration (FDA), which motivated this research to initiate a school-based campaign to bring community awareness about the contamination of the bay and engage students in preventive strategies to reduce their exposure to PCBs. Surveys before and after the campaign were administered in the high school as well as in the communities of Guánica Municipality. The analyses of the survey data suggest that the campaign was effective in bringing awareness among schoolchildren (6.6% before versus 69.7% after the campaign; χ² ~ 60.4; p < 0.001) and strategies to reduce PCB exposure and its toxicity such as removing adipose tissues from seafood/fish and exercising. In the community, there was a significant decline in the consumption of seafood/fish harvested from the bay after the campaign (54.6% before versus 33% after the campaign; χ² ~ 10.85; p < 0.001). However, the awareness did not result in significant behavior modifications among schoolchildren, such as avoiding swimming and fishing in the bay. Given hazardous levels of PCBs and some students use the bay for various purposes, including one-third of community members still use seafood/fish harvested from the bay, attention of different stakeholders is warranted for clean-up efforts as well as engaging children and communities in PCB exposure avoidance strategies.