In response to the emergency treatment of trace Pb(II) pollution, taking cost and coordination with existing conventional processes into account, based on the lignite upgrading by-products (waste) as raw materials, a low cost adsorbent lignite-based activated carbon/polyacrylic acid (LAC/PAA) was developed by the in situ grafting of PAA on the surface of LAC. The declination of the pH from 8.71 for LAC to 4.83 for LAC/PAA and FT-IR analyses of LAC/PAA before and after Pb(II) adsorption confirmed the appearance of carboxyl groups on the surface of LAC/PAA. The adsorption experiments reveal that more than 90% of Pb(II) were removed by LAC/PAA within 20 min (only 31% for LAC). Its adsorption behavior obeys the Freundlich isotherm model (R² = 0.973), and the adsorption kinetics agrees with the pseudo-second-order kinetic model (R² = 0.961). The performances for the removal of Pb(II) in XJ River (South of China) were investigated for LAC/PAA and the conventional water treatment processes, respectively. Based on the results, a combination process (LAC/PAA adsorption + conventional water treatment) was developed, which achieved the best Pb(II) removal (99.8%) under a lower LAC/PAA and coagulant dosages (both 20 mg/L) at a pH of 10, 3 times better than that of the conventional water treatment processes (only 30%). Undoubtedly, the above results will provide significant technical support for the emergency treatment of trace Pb(II) pollution of drinking water. Moreover, converting the lignite upgrading by-products (waste) into LAC will add considerable economic value and reduce the costs of waste disposal.

Metformin is widely used as one of the most effective first-line oral drugs for type 2 diabetes. It is difficult to be metabolized by the human body thus commonly exists in both urine and feces samples. Guanylurea is metformin’s main biotransformation product with increased concentrations in the aquatic environments. Liquid chromatography-tandem mass spectrometry (LC-MS)-based methods used for measuring the two compounds have been well developed, but extremely limited studies have tracked gas chromatography-mass spectrometry (GC-MS)-based analysis. To help better track the occurrence of the two non-volatile biguanide compounds in liquid samples, the improvement of existing GC-MS based methods for reliable metformin and guanylurea analysis is conducted. Derivatization of metformin and guanylurea is the key pretreatment procedure before the associated GC-MS analysis. Four selected factors affecting for the derivatization were evaluated, and the optimal factors include temperature (90°C), reacting time (40 min), solvent (1,4-dioxane), and ratio (1.5:1) of reagent to target component. Buformin and N-methyl-bis(trifluoroacetamide) (MBTFA) were used as the internal standard and the derivatization reagent, respectively. Calibration curves were made based on the optimal conditions of derivatization for metformin and guanylurea with the R² values of calibration linearity achieved as 99.35% and 99.2%, respectively. The values of relative standard deviation (RSD%) of metformin and guanylurea based on seven repeated trails are 2.67% and 15.37%, respectively. The optimal conditions for enhancing the sensitization of metformin and guanylurea derivatization performance were obtained. The improved GC-MS analysis method was eventually applied for metformin and guanylurea analysis in real water samples.

A 42-day comparative study was conducted to assess the impact of nanoselenium to other selenium sources on performance, antioxidant activity, immunity, and carcass traits in broilers. Ross 308 (n = 156) 1-day-old broiler chicks, with average initial body weight of 45.80 ± 0.35, were randomly allocated to 4 groups. The first group (G1) fed the basal diet without selenium supplementation. The second group (G2), the third group (G3), and the fourth group (G4) were supplemented with dietary selenium at the level of 0.3 mg kg⁻¹ diet in the form of sodium selenite, seleno-methionine, and nanoselenium, respectively. The results revealed significant improvement on most of the performance parameters of nanoselenium at the level of 0.3 mg kg⁻¹ diet (P < 0.05). Nanoselenium and seleno-methionine achieved the best dressing %, spleen index %, and thymus index %. Concerning to internal organ indices, none of these indices was significantly affected by any selenium sources (P < 0.05). Glutathione peroxidase (GSH-PX) activity and malondialdehyde (MDA) content were not significantly affected by different selenium sources among all experimental groups. Serum interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) showed significant (P < 0.05) decrease in nanoselenium supplemented group compared with other groups. In case of serum IL-10 level, a significant (P < 0.05) increase was reported in nanoselenium supplemented group followed by G3 then G2. There were no statistical differences in the serum alanine transaminase, aspartate transaminase, total protein, albumin concentration, serum creatinine level, and uric acid concentration levels among all experimental groups. It is concluded that nano selenium can be a useful and better source of selenium for broilers.

Effective and substantial remediation of contaminants especially heavy metals from water is still a big challenge in terms of both environmental and biological perspectives because of their adverse effects on the human health. Many techniques including adsorption, ion exchange, co-precipitation, chemical reduction, ultrafiltration, etc. are reported for eliminating heavy metal ions from the water. However, adsorption has preferred because of its simple and easy handlings. Several types of adsorbents are observed and documented well for the purpose. Recently, highly porous metal-organic frameworks (MOFs) were developed by incorporating metals and organic ligands together and claimed as potent adsorbents for the remediation of highly toxic heavy metals from the aqueous solutions due to their unique features like greater surface area, high chemical stability, green and reuse material, etc. In this review, the authors discussed systematically some recent developments about secure MOFs to eliminate the toxic metals such as arsenic (both arsenite and arsenate), chromium(VI), cadmium (Cd), mercury (Hg) and lead (Pb). MOFs are observed as the most efficient adsorbents with greater selectivity as well as high adsorption capacity for metallic contamination. Graphical abstract

A novel magnetic pomelo peel biochar (MPPB) was prepared by hydrothermal pretreatment coupled with pyrolysis at 550 °C. Batch experiments were employed to investigate adsorption properties on biochar for Pb(II) and Cu(II). FTIR, SEM, XRD, XPS, and zeta potential were applied to characterize the biochar. The surface morphology of MPPB was rough, loose, and negatively charged and contained carboxyl and hydroxyl functional groups, which were favorable for adsorption. The MPPB showed excellent adsorption performances for Pb(II) with maximum capacity (205.391 mg/g), and the maximum amount on MPPB for Cu(II) was 81.909 mg/g. Pseudo-second-order kinetic and Langmuir isotherm depicted well with adsorption behavior on biochar. It could be concluded that chemical complexation occurs during metal adsorption from change of the spectra of XPS and XRD. The competitive relation of coexisting cations with target metal inferred that ion exchange is not a key mechanism. Chemical complexation with functional groups and electrostatic attraction between MPPB and metals are the main adsorption mechanisms. The MPPB developed from pomelo peel was testified to be a potential adsorbent for water purification.

Numerous studies have shown that extremely low-frequency electromagnetic field (ELF-EMF) by modulating oxidative-antioxidative balance in the cells achieved beneficial and harmful effects on living organisms. The aim of this study was to research changes of both proliferative capacity and redox homeostasis of human lung fibroblast cell line MRC-5 during exposure to ELF-EMF (50 Hz). The human lung fibroblast cell line MRC-5 were exposed to ELF-EMF once a day in duration of 1 h during 24 h (1 treatment 1 h/day), 48 h (2 treatments 1 h/day), 72 h (3 treatments 1 h/day), and 7 days (7 treatments 1 h/day). After 24 h of the last treatment, the proliferative capacity of the cells and the concentrations and activities of the components of the oxidative/antioxidative system were determined: superoxide anion (O₂.⁻), hydrogen peroxide (H₂O₂), nitric oxide (NO), peroxynitrite (ONOO⁻), reduced glutathione (GSH), oxidized glutathione (GSSG), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR), and glutathione-S-transferase (GST). The results of this study show that ELF-EMF may affect a cell cycle regulation of human lung fibroblast cell line MRC-5 through modulation of oxidative/antioxidative defense system. The effects of ELF-EMF on proliferation and redox balance of human lung fibroblast cell line MRC-5 depend on exposure time.

This study investigates the causal connection between economic growth, foreign direct investment, primary and renewable energy utilization, trade openness, and ecological footprint for 33 upper-middle-income countries (UMICs) from Africa, Asia, Europe, and America during the period from 1994 to 2017. Initially, first- as well as second-generation panel unit root tests are applied to check the integration order after confirming the cross-sectional dependency and heterogeneity. Four different tests (FMOLS, DOLS, FGLS, and AMG) are applied to estimate the long-run elasticity, whereas Dumitrescu and Hurlin (D-H) non-causality test is used to test growth, conservation, and feedback hypothesis. Results show negative relationship of economic growth on ecological footprint in Africa and Europe; renewable energy utilization in Asia, Europe, and America; and trade openness in Asia. Moreover, the results revealed an adverse impact of trade openness on ecological footprint in case of Africa and America. Furthermore, the results of D-H panel non-causality test confirm the growth hypothesis for economic growth to ecological footprint in Africa, Asia, and Europe; foreign direct investment to ecological footprint in Africa and Asia; primary energy utilization to ecological footprint in Asia; renewable energy utilization to ecological footprint in America; and trade openness to ecological footprint in Africa, Asia, and America. Furthermore, the feedback hypothesis was confirmed between economic growth and ecological footprint in Asia and Europe; foreign direct investment and ecological footprint in Africa and Asia; renewable energy utilization and ecological footprint for America; and trade openness and ecological footprint for Asia and America. Finally, in context to efficient policy implications, it is suggested to associate the economic growth with clean energy and environment-friendly technologies by expanding the share of renewable energy in America and economic growth in Africa and Europe. Furthermore, Asian policy makers need to focus on foreign direct investment and trade openness by using green energy to overcome the environmental degradation. Impulsion with these findings, the central authorities of UMICs need to focus on more investments in environmental quality not only through foreign direct investment but also exchanging their clean energy technologies through trade policies such as tax exemption, feed-in tariffs, and subsidies. Government of these countries ought to upgrade the conventional capital which will ultimately improve the human lives by providing clean environment.

Research on pollution caused by gadolinium (Gd) based on compounds as a result of its use in high technological applications, especially in the health sector, has recently become very interesting. This study aims to investigate the determination of the environmental pollution levels of anthropogenic Gd and its possibility of use as an anthropogenic pollutant indicator in the Ankara Stream (Turkey) selected as the pilot stream. Within the scope of the research, Gd levels were determined in water and sediment samples taken in spring and autumn periods in a total of seven different stations, three of which in Ankara Stream and one for each in its tributaries (Çubuk Stream, Hatip Stream, İncesu Creek, Ova Stream). Some parameters related to water and sediment quality were also measured at the stations. Temperature, pH, electrical conductivity, and dissolved oxygen were measured in situ. Gd concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS) technique using samples filtered from 0.45-μm filters at the time of sampling in water samples. The grain sizes of sediment samples were carried out by conventional wet sieve analysis. Gd levels were determined by ICP-MS after digestion of sediment samples passing through 63-μm particle grain size. Also, total organic carbon (TOC) and total phosphorus (TP) levels were measured by classical methods in sediment samples. Although the Gd concentrations measured in the water samples taken from the stations in the Ankara Stream were found to be quite high compared with the tributaries of Ankara Stream. The highest mean Gd concentration (0.347 ± 0.057 μg/L) measured in this study was higher than that of at the most rivers in the world. There was no statistically significant difference between the stations in terms of Gd concentrations in the sediment samples. As a result of this study, it was revealed that Gd can be used as an indicator parameter in the monitoring of anthropogenic pollution of aquatic environment where potential Gd pollution sources.

Atmospheric precipitation in Sri Lanka occurs mainly through rain whose terrestrial composition significantly varies based on the location as the regional geography and anthropogenic factors can largely affect environmental pollutants that are added to the atmosphere. It is therefore very important to have baseline data on the chemical composition of the atmosphere to take regulatory measures to control atmospheric pollution although very limited data available in Sri Lanka. The main objective of this study was thus to quantitatively determine selected trace metals (Al, Cr, Cu, Fe, Mn, Pb, and Zn) in bulk precipitation samples collected weekly in three sampling locations, namely the University of Peradeniya (UoP), Polgolla, and Kandy City Central (KCC), for a period of 1 year from March 2018 to March 2019. Trace metals determined using atomic emission spectrophotometry indicated that the KCC site showed the highest contamination following the sequence (with respective volume-weighted mean (VWM) concentration values) of Al (79.7 μg L⁻¹) > Fe (42.8 μg L⁻¹) > Zn (39.3 μg L⁻¹) > Mn (13.9 μg L⁻¹) > Cu (9.8 μg L⁻¹) > Cr (2.4 μg L⁻¹). The corresponding values of the Polgolla site showed the sequence Zn (64.3 μg L⁻¹) > Al (52.1 μg L⁻¹) > Fe (17.9 μg L⁻¹) > Mn (11.1 μg L⁻¹) > Cu (5.4 μg L⁻¹) > Cr (1.8 μg L⁻¹). Due to less industrialization and less traffic congestion, the UoP site showed low trace metal levels in the order Zn (29.8 μg L⁻¹) > Al (21.3 μg L⁻¹) > Fe (14.2 μg L⁻¹) > Cu (7.4 μg L⁻¹) > Mn (4.3 μg L⁻¹) > Cr (0.9 μg L⁻¹). Principal component analysis indicated that Cu, Mn, and Zn originated mainly from anthropogenic activities, such as combustion of fossil fuel and burning of municipal waste, while Al and Fe mainly originated from natural sources.

Rapid land use and land cover changes have a significant effect on ecology, environment, and human health in urban watersheds. With increase in frequency and intensity of the urban flooding events and repeated inundation of the neighborhoods, it is important to monitor the water and soil chemical characteristics in Greens Bayou Watershed (GBW) region. The objectives of this study were to (1) analyze the nutrient and heavy metal concentrations in water and soil samples along the Greens Bayou, (2) monitor the historical water quality data, and (3) identify and analyze land cover changes in the watershed using Landsat imagery. A total of 12 water and 12 soil samples, from four different sampling locations along the Greens Bayou, were collected during two seasons and processed for chemical analysis. Our water sample analysis revealed that the As, Cd, Pb, and Hg concentrations were higher in the fall compared with the summer and exceeded the critical limit. The soil analysis indicated that the Zn and Pb concentrations were higher in the fall over summer season and exceeded the background concentrations. Remote sensing analysis revealed that the impervious surface in the GBW increased by about 62.2% while the vegetative surface decreased by 30.6% during the period of 1984 to 2018. Environmental chemical analysis coupled with geospatial data demonstrated the impact of land cover changes on water and soil quality along the Greens Bayou by identifying areas vulnerable to change, which can be better managed to preserve the health of this urban watershed ecosystem.