The cadmium (Cd) is considered one of the widespread toxic metals in the aquatic and terrestrial environments, which is due to its long half-life, non-degradable characteristic, and toxicity. Aqueous extract of freeze-dried Moringa oleifera (Moringaceae family) leaves was examined for protective effect and antioxidant power against Cd toxicity. The results revealed that Moringa aqueous extract (MAE) has contents of total polyphenols and flavonoids about 30.14 mg GAE/g and 18.35 mg QE/g respectively. Furthermore, phenolic compounds in leaves of Moringa were studied using a high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS). Results showed that the largest number of phenolic compounds determined in leaves of Moringa belongs to flavonoids. Moreover, biological properties were determined by radical scavenging capacity (DPPH) and ferric-reducing power (FRAP). Cytoprotective effect and antioxidant power of Moringa extract were assessed using the mitochondrial activity testing method (MTT test), malondialdehyde (MDA), and reactive oxygen species (ROS) production. Results indicate that Moringa aqueous extract have a significant (i) proliferative, (ii) antioxidant, and (iii) cytoprotective effect on HCT116 and HEK293 cells against metal toxicity.

One of the most industrially affected rivers in Taiwan, the Houjing River, was studied in this research. The water and sediment samples were collected at five locations to measure the concentration of eight metals (As, Cd, Cr, Cu, Hg, Pb, Ni, and Zn). In order to assess the heavy metal contamination and its adverse biological effect, the heavy metal pollution index (HPI), the degree of contamination index (DC), the contamination factor (CF), the index of geo-accumulation (Igₑₒ), and hazard quotients (HQs) were employed. The results showed that the Houjing River’s water and sediment were contaminated with heavy metals. The annually averaged values of HPI (128.3) and DC (21.3) indicate that the water is unsafe for potable use and the sediment contamination level is at considerable degree of contamination. CF and Igₑₒ calculation show that Zn, Cu, and Cd are the three main metals contributing to heavy metal contamination in sediment. Evaluation of adverse biological effects suggests that Zn, Cu, and Ni are the major metals that cause adverse effects on organisms. This study provides an overview of the synergistic heavy metal contamination degree of the Houjing River and its adverse biological effects, which should be a reliable reference for future contamination control and management plans.

Many nations have tended to transform their traditional growth paradigm to green growth policy paradigm to ensure environmentally sustainable development. Governments, therefore, have developed and implemented environmental protection programs to ensure environmentally sustainable development. For accelerating the transformation to green production techniques and technologies, the study aims (i) to calculate the opportunity cost of protecting environment, (ii) to estimate the production efficiency of farms, and (iii) to determine the impact of opportunity cost of protecting environment on the production efficiency in TR83 region in Turkey. Farm-level research data have been collected from totally 361 farms (334 farms participated in the environmental protection programs (EFALP) and 27 conventional farms) by using a well-structured questionnaire during the production year of 2016–2017. Minimization of total absolute deviation (MOTAD) programming model as a linearized version of QP was used to elicit the farm plans under both condition of protecting environmental and conventional farming condition. When estimating the technical, allocative, and economic efficiencies, the net farm revenue under prevailing conditions, potential net farm revenue, and optimum farm revenue were used. The net revenue difference between EFALP farm and conventional farm was attributed to the opportunity cost of protecting the environment. The impact of the opportunity cost of protecting the environment on production efficiency was explored by using two-limit Tobit model. Research results show that the opportunity cost of environmental protection is 3060 TRY per hectare and varied spatially in the research area. Government environmental support has not compensated the farmers’ revenue sacrifice completely. The technical efficiency scores of EFALP farms and conventional farms are 0.77 and 0.75, while that of allocative efficiency are 0.83 and 0.86, respectively. The economic efficiency scores of the EFALP farms and conventional farms are 0.62 and 0.63, respectively. Research results further indicate that the opportunity cost of protecting the environment can be said to have a negative impact on the economic efficiency. The variables of labor and farmland have been negatively affected the economic efficiency, while the effects of operating capital, age of operators, and family size seem positive. The study suggests creating regulatory framework providing opportunity to adjust government environmental support spatially based on the farm-level opportunity cost of protecting environment. Government practices should be developed by policymakers to supervise and control the farms participated in the environmental protection programs. Eliminating the conventional decision-making approach and replacing with environmental trade-off analysis-based decision-making techniques, involving stakeholders during the designing environmental policy, and sharing outputs of environmental trade-off analysis may increase the success of the environmental policy and programs. In addition, bringing away the goal mismatch of scientist and users by establishing bridge in between knowledge and action may increase the effectiveness of environmental protection programs.

The main aim of this current study is to empirically scrutinize the determinants of energy consumption for 24 African countries sub-grouped into three panels based on income levels: low-, lower-middle-, and upper-middle-income countries, from 1990 to 2015. Due to the presence of heterogeneity and cross-sectional reliance among country groups, recently developed econometric approaches, which include cross-sectional Im, Pesaran, and Shin together with cross-sectional Augmented Dickey-Fuller stationarity tests, Pedroni and Westerlund–Edgerton cointegration assessment, dynamic common correlated effect estimation approach and Dumitrescu–Hurlin Granger causality test are employed. Empirically, our findings depict analyzed variables are stationary and characterized by long-term stability affiliations for all panels. Economic growth, urbanization, population growth, and oil price with labor and capital stock as intermittent variables had palpable significant positive sway on energy consumption for all panels though their respective weight of contribution differed from one country group to another. The granger test of causation unveiled that (i) among all panels, urbanization and energy consumption are connected bidirectionally, whereas population growth causes energy consumption; (ii) a one-way causal link from economic growth to energy use is evidenced in low-income African countries, whereas a two-sided connection is confirmed in both lower-middle- and upper-middle-income economies; (iii) a bilateral causal association in low-income African nations is observed amid oil price and energy use, while a uni-lateral relationship extends from oil price to energy consumption in both lower-middle- and upper-middle-income nations in Africa. Such new methodologies and findings reveal that the long-term estimated effects as well as causal affiliations amid variables are skewed by different income levels of African countries in an attempt to conserve energy. Policy recommendations are further propose.

Pharmaceutical compounds are considered as emerging contaminants in the aquatic environments that are not easily eliminated by conventional treatment processes. In the present study, the photocatalytic oxidation of acetaminophen and codeine medicines under UV and solar irradiation was investigated in the aqueous solutions using a novel synthesized zeolite from stone cutting sludge as a support for TiO₂ and ZnO. The effect of photocatalyst synthesis conditions including catalyst dose, mixing time, calcination time, and temperature on the efficiency of the pharmaceutical removal were optimized using Taguchi process optimization method. The prepared photocatalysts were characterized using X-ray diffractometer, field emission scanning electron microscopy, energy-dispersive X-ray, the BET surface area, and the Fourier transformation infrared. The results indicated that the performance of ZnO-zeolite for the removal of acetaminophen-codeine under UV and solar radiation with 58.7% and 45.7% was better than that of TiO₂-zeolite with 44.3% and 39.2% efficiency, respectively. Removal efficiency under UV and solar radiation was comparable, suggesting that sunlight could be a promising source for treatment of contaminated water by acetaminophen and codeine using photocatalytic degradation. Regeneration of the prepared photocatalysts after 4 cycles revealed a slight decrease in their efficiency. Overall, photocatalytic degradation of the medicines in the water and wastewater using the ZnO-zeolite and TiO₂-zeolite could be developed as an efficient treatment process.

Understanding the formation of high fluoride (F⁻) groundwater in water-scarce northern China is critical for the sustainable development of the region. This study investigates the effects of F⁻ enrichment in groundwater from seven typical regions of northern China, including Datong, Guide, Junggar, Yinchuan, Taiyuan, and Tarim basins and the North China Plain. A literature survey of 534 samples of selected regions showed that 45.13% of groundwater F⁻ exceeded the 1.0 mg/L of Chinese drinking water guideline. Based on the geological background and hydrogeochemical analysis, in Datong and Yinchuan basins and part of the North China Plain, the main types of groundwater are soda water and controlling processes of F⁻ enrichment are salinization, mineral dissolution, and desorption. In Taiyuan and Guide basins with Cl-Na water type, F⁻ enrichment is mainly affected by salinization, cation exchange, and evaporation. The hydrogeochemical characteristics of high F⁻ groundwater in Tarim and Junggar basins reflect the extent of salinization and weathering dissolution of minerals in groundwater. According to PCA, the contribution of salinization and mineral dissolution to F⁻ enrichment is relatively high. Under the alkaline condition, groundwater with high Cl⁻, HCO₃⁻, and Na⁺ concentration favors F⁻ enrichment. Based on HCA, index clustering category I explains the influence of pH and buried depth on F⁻ enrichment, and category II explains the effect of different ions. It is concluded that F⁻ enrichment in groundwater is related to hydrogeochemical processes and hydrogeological conditions. The hydrogeochemical and alkaline conditions of groundwater are regulated by mineral dissolution, ion exchange, and evaporation, resulting in different degrees of F⁻ enrichment.

Heavy metal contamination is a global issue, where the prevalent contaminants are arsenic (As), cadmium (Cd), chromium (Cr)(VI), mercury (Hg), and lead (Pb). More often, they are collectively known as “most problematic heavy metals” and “toxic heavy metals” (THMs). Their treatment through a variety of biological processes is one of the prime interests in remediation studies, where heavy metal-microbe interaction approaches receive high interest for their cost effective and ecofriendly solutions. In this review, we provide an up to date information on different microbial processes (bioremediation) for the removal of THMs. For the same, emphasis is put on oxidation-reduction, biomineralization, bioprecipitation, bioleaching, biosurfactant technology, biovolatilization, biosorption, bioaccumulation, and microbe-assisted phytoremediation with their selective advantages and disadvantages. Further, the literature briefly discusses about the various setups of cleaning processes of THMs in environment under ex situ and in situ applications. Lately, the study sheds light on the manipulation of microorganisms through genetic engineering and nanotechnology for their advanced treatment approaches.

Landfill is a public and environmental health problem; establishing and understanding methodologies to decrease its toxicity are thus necessary. Leachate samples were collected, at a sanitary landfill, immediately after the exit from the landfill, i.e. raw leachate (collection point A), after conventional treatment (point B) and after treatment by wetlands (point C). D. parodizi specimens were exposed to 3%, 10% and control (0%) dilutions of leachate from these collection points for 7 days. Markers of antioxidant defences and cell damage were analysed. At point B, the gills of D. parodizi showed higher glutathione-S-transferase (GST) and glutathione reductase (GR) activity; the latter is a supplier of glutathione reductase (GSH). The low GST activity at point A was associated with the hormesis effect. Higher levels of superoxide dismutase (SOD), ethoxyresorufin-O-deethylase (EROD) and glutathione peroxidase (GPx) occurred at point A. Glucose-6-phosphate dehydrogenase (G6PDH) was inhibited at the points with the highest pollutant load and at the highest leachate dilutions. Higher levels of markers at point A may be related to the high pollutant charge and specific compounds present in the untreated leachate. The multi-xenobiotic resistance mechanism (MXR), metallothionein-like proteins (MT) and lipid peroxidation (LPO) did not vary among treatments. The biomarker responses showed negative effects of the leachate on the freshwater bivalve and simultaneously showed that the wetland treatment employed at the Caximba sanitary landfill is effective.

To evaluate the adsorption mechanism and performance of phosphate onto the composite of low-cost biochar and iron oxide, four biochar–iron oxides, namely biochar–magnetite (BC-M), biochar–ferrihydrite (BC-F), biochar–goethite (BC-G), and biochar–hematite (BC-H), were prepared by fabricating iron oxide to porous biochar. The biochar–iron oxides had huge surface areas of 691–864 m²/g and average pore diameters of 3.4–4.0 nm. Based on the characterization analysis of FTIR, XRD, XPS, and zeta potential, the interactions of electrostatic attraction, ligand exchange, and deposition dominated the phosphate adsorption onto biochar–iron oxides. The maximum adsorption capacity of phosphate followed the order of BC-G > BC-F > BC-H > BC-M. The isotherm data of BC-M and BC-H were well fitted by the Langmuir and Freundlich models, while those of BC-G and BC-F followed the Langmuir model. In addition, BC-M, BC-F, BC-G, and BC-H owned excellent regeneration ability and adsorption performance in practical (simulated) wastewater environment. Then the biochar–iron oxides exerted extensive and satisfactory prospect in wastewater remediation and recycling application in soil.

The study was conducted to monitor concentration of six toxic metals in faecal pellets of blue rock pigeon from six industrial areas of Jaipur, i.e. Jhotwara, Malviya, Mansarover, Sitapura, Vishwakarma industrial areas and Sanganer industries, by using atomic absorption spectrophotometer. At the same time, trace metals were also analysed for a reference area so that a comparative impact of the metal pollution from the industries could be figured out. From the data obtained, the highest Cd, Cu, Ni, Pb and Zn concentrations were found in the faecal pellets from Sitapura industrial area (1.12 ± 0.60 μg/g; 128.9 ± 11.10 μg/g; 17 ± 2.87 μg/g; 79.6 ± 42.69 μg/g; 2250 ± 1390.16 μg/g) and the highest Cr (18.6 ± 3.65 μg/g) from Jhotwara industrial area. However, industrial environment has high deposition of studied trace metals (except Ni for Sanganer industries) as compared with reference area. The concentration of Cd was below the detectable level in faecal pellets from reference area. The trend of trace metals from Malviya, Sitapura, Jhotwara and reference areas was noticed as Zn > Cu > Pb > Cr > Ni > Cd and almost same for Sanganer industries and Mansarover industrial area as Zn > Cu > Cr > Pb > Ni > Cd. The excretion of heavy metals in fa1ecal pellets from Vishwakarma industrial area was noticed as Zn > Cr > Cu > Pb > Ni > Cd. Further levels of metals were varied significantly among different industrial areas, P ≤ 0.05, as well as between industrial areas and reference area. The observed high concentration of different heavy metals in faecal pellets of bird species shows their exposure to metal contamination which is warning to spiked environmental pollution.