Nanoscale zero-valent iron (nZVI) was prepared and used as a heterogeneous Fenton-like catalyst for the degradation of nuclear-grade cationic exchange resin. The properties of nZVI before and after reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) surface area analysis. The results showed that nZVI–H₂O₂ system exhibited the enhanced degradation of cationic resins, compared with Fe²⁺–H₂O₂, Cu⁰–H₂O₂, and Fe⁰/Cu⁰–H₂O₂ systems. The effects of initial temperature, nZVI dose, and H₂O₂ concentration were studied, and the higher temperature and nZVI dose with relatively low H₂O₂ concentration brought faster degradation rate. The degradation of cationic resins followed the pseudo-first-order kinetics with the apparent activation energy of 53.29 kJ/mol. According to the experimental and calculated infrared and UV-visible spectra, the carbon skeleton of cationic resins was broken with the detachment of benzene ring and the desulfonation of resin polymer by hydroxyl radicals (•OH), generating long-chain alkenes. These intermediates were further oxidized through the hydroxyl substitution, hydrogen abstraction, ring cleavage, or carbonylation reactions, finally forming carboxylic acids remained in solution.

This paper seeks to answer an empirical question of whether clean biomass energy consumption lowers CO₂ emissions while controlling for technical innovation in eight selected countries from Africa for the 1980–2015 period. The countries which are chosen based on availability of data on biomass energy and technological innovation include Egypt, Algeria, South Africa, Mauritius, Kenya, Morocco, Tunisia, and Zambia. Applying pooled mean group, mean group, and dynamic fixed effect panel estimators, the results indicate that clean biomass energy use decreases CO₂ emission in the long run. But the effect of biomass energy consumption on CO₂ emission is insignificant in the short run. The findings imply that CO₂ emission can be reduced by increasing clean biomass energy in the energy mix of these countries. Similarly, environmental quality and economic growth can be achieved simultaneously by increasing the share of biomass energy in large-scale production process. Furthermore, the environmental Kuznets curve (EKC), which hypothesizes an inverted U-shaped relationship between CO₂ emission and economic growth, was validated in the long run. This suggests that the EKC pattern is only observed in the long run. Thus, as part of recommendation from this study, policy makers in these countries should formulate more policies that will enhance clean biomass energy production and its usage to substitute significant percentage of fossil fuel use in production process.

Eutrophication models are of great importance and are valuable tools for the development of policy and legislation. However, the parameter uncertainty and substantial computational cost lead to difficulties in decision-making, especially for complex models with multiple indicators. A multicriteria uncertainty analysis and parameter estimation (MUAPE) method, which selected behavioral parameters combined with Pareto domination and simultaneously obtained acceptable values for modeling by the maximum likelihood concept and kernel density estimation, was shown. This method, which did not assign thresholds and weights, was applied to analyze the uncertainty of the Chaohu Lake eutrophication model and estimate parameters. The results of the behavioral parameters were compared using different criterion sets, the relative error (RE) and the root mean square error (RMSE), and the results showed little discrepancy in terms of the effects on parameter uncertainty represented by the marginal probability density. The uncertainties of the parameters related to algal kinetics (i.e., BMR, PM, and KESS) were smaller than those of nutrient- and temperature-related parameters (i.e., KDN, Nitm, KTB, and KTHDR) for both sets of criteria. However, the reduction in the joint uncertainty of the two parameters was greater when RE was used than when RMSE was used. The acceptable values for the key parameters of the Chaohu Lake eutrophication model were also obtained by the RE criterion. The results strongly agreed with the observed values, and parameters could be applied for model prediction. This result indicated that the combination method was not only practical for reducing parameter uncertainty but also useful for determining parameter values. This method provides a basis for multicriteria uncertainty analysis and parameter estimation in eutrophication modeling.

The levels of trace elements (As, Hg, Cr, Cd, Pb, Co, Ni, Cu, Mn and Zn) in commercially important fish species sampled from fish markets of Adelaide, Australia; canned fish from South Australian supermarkets; and fish markets of West Bengal, India were determined by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion. Mercury was determined by using triple quadrupole ICP-MS. The accuracy of the methods was assessed with a certified standard reference material (NRCC-DORM-3 dogfish protein), and the results were compared with values reported in the literature. The results indicated considerable variations in the accumulation of trace elements among the fish species. The relationship between species with respect to trace element concentrations was examined using cluster analysis, which showed Indian fish species forming distinct groups from the others. Other than As in sardines, whiting and snapper and Hg in swordfish and snapper, the trace element concentrations were within permissible limits recommended by various standards. Based on the estimated daily intake (EDI), fish samples analysed in this study can be considered safe for human consumption as per the recommended daily dietary allowance limit fixed by various agencies. Continuous monitoring and assessments of fish metal(loid) content are needed to generate more data and safeguard human health.

Phenanthrene (PHE), a tricyclic polycyclic aromatic hydrocarbon (PAH), is ubiquitously found in aquatic environments. It is one of the major components in PAH mixtures. It has been identified as one of the 16 priority PAHs for toxicological evaluations. PHE is reported to induce lethal and sub-lethal toxicity in various aquatic indicator organisms. However, no toxicological data of PHE in anuran amphibians could be found. Amphibian larvae (tadpoles) develop in aquatic habitats. Therefore, exposure to PHE could negatively impact their development and fitness in later periods as they move in to the terrestrial habitat following metamorphosis. In the present study, we have analyzed the effects of PHE in Euphlyctis cyanophlyctis tadpoles. PHE induced concentration-dependent lethal effects in the tadpoles. The estimated LC₅₀ values were 16.52, 15.29, 13.69, and 12.28 mg/L at 24, 48, 72, and 96 h of exposure respectively. These LC₅₀ values are significantly higher than the reported environmental concentration of PHE. However, the strong negative correlation (R² = 0.997, p < 0.001) between the LC₅₀ value and exposure time indicates that longer exposure to lower concentration may cause significant lethal effects. Besides, PHE at environmentally relevant concentrations induced significant sub-lethal toxicities. Exposure to sub-lethal concentrations was found to be genotoxic in erythrocyte micronucleus as well as comet assays. Sub-lethal concentrations of PHE significantly increased superoxide dismutase activity and tissue glutathione level as well as induced lipid peroxidation. The present findings clearly indicate that PHE is a potential threat to the early life stages of amphibians. Further investigations are necessary to ascertain the implications of these early effects during adult life stages.

Organophosphate esters (OPEs), as a class of emerging flame retardant and plasticizers, have attracted particular attention due to their ubiquitous existence in the environment and potential effects on human health. Here, we investigated the levels of OPEs in human serum and examined the role of demographic variables on the body burden of such compounds. Of 11 OPEs screened, 8 were detected in human serum samples collected from a population (n = 89) in Bohai Bay, North China. The ∑OPE concentrations ranged from 4.7 to 948 ng/g lipid weight (lw), with a median concentration of 243 ng/g lw. Tris(2-chloroethyl)phosphate (TCEP) was identified as the most abundant OPEs with a median concentration of 214 ng/g lw. The concentrations of the triphenyl phosphate (TPhP) in older adults were higher than those in young adults (p < 0.05), and lower concentrations of tri-iso-butyl phosphate (TIBP) were observed in female samples compared to males. Furthermore, significant differences were observed in tri-n-propyl phosphate (TPrP) concentrations between urban and rural residence groups (p < 0.05). This study provides important information on the accumulation potential of OPEs in human bodies and suggests the need for further investigation to understand the potential human health risk.

Understanding the hydrodynamic behavior of side jets in compound open channels with vegetated floodplain is crucial to jet dilution, sediment transport, and bank stability. Large eddy simulation was used to study horizontal side jets in compound open channels with vegetated floodplain. Predicted mean velocity, turbulent kinetic energy, and secondary currents were compared with experimental data, with a good agreement between measured and calculated data. Analyses of bed shear stress showed that vegetation in the floodplain increases the total drag and decreases bed shear stress, thus governing sediment transport and protecting the bank. The transport mechanism was quantitatively investigated by the quadrant analysis, concentration, and Reynolds flux. The ejection and sweep events were major contributors to the momentum and scalar flux transport. Analyses of concentration and Reynolds flux showed that the secondary flow influenced the spreading of the jet and the location of the concentration peaks, and the distribution of concentration and Reynolds flux did not strictly follow Fickian law in the whole region due to the effect of secondary flow on the concentration distributions. Additionally, the typical vortexes and spatiotemporal evolution of vortex structures in compound open channels, especially those near the junction between the main channel and floodplain, were successfully demonstrated.

Zinc is one of the important essential trace minerals to human health due to its antioxidant properties. The present study was conducted to elucidate its potential protective role against maneb-induced nephrotoxicity. For this purpose, animals were randomly divided into four groups of six each. Mice of group I (negative controls) have received daily 0.5 ml of distilled water, a solvent of maneb. Mice of group II (MB) have received 30 mg/kg bw of maneb daily by intraperitoneal way. Mice of group III (MB + Zn) have received the same dose of maneb as group II, along with ZnSO₄ (30 mg/kg bw) daily. Mice of group IV (Zn), considered as positive controls, have received the same dose of ZnSO₄ as group III daily. Our results revealed that ZnSO₄ co-administration to maneb-treated mice decreased kidney levels of malondialdehyde, hydrogen peroxide, protein carbonyls, and advanced oxidation protein products; the levels of non-enzymatic antioxidants like vitamin C, glutathione, and metallothionein. It recovered the alteration of antioxidant enzyme activities (catalase, superoxide dismutase, and glutathione peroxidase) and attenuated DNA fragmentation. Furthermore, this essential trace element was also able to alleviate kidney biomarkers’ alterations by lowering plasma levels of creatinine, urea, uric acid, and lactate dehydrogenase. In addition, the histopathological changes induced by maneb were improved following zinc administration. Our results indicated that zinc might be beneficial against maneb-induced renal oxidative damage in mice.

Fipronil (FIP) is a highly effective, broad-use insecticide that belongs to the phenylpyrazole chemical group. It is extensively used in the agriculture and veterinary medicine for controlling a wide variety of pests. Though FIP showed lower toxicity in vertebrates than in insects, it was recognized to have a variety of toxic effects in mammals. The present study was undertaken to evaluate FIP-induced alterations in the blood biochemical markers and oxidative stress parameters in male albino mice via oral sub-acute toxicity exposure. The possible ameliorative effect of the pretreatment with selenium plus α-tocopherol (vitamin E) against the harmful effects of FIP was also investigated. Mice in FIP-test groups were exposed to different sublethal doses, i.e., 1.43, 2.87, and 4.78 mg active ingredient (AI)/kg body weight (b.w.), equal to 1/100, 1/50, and 1/30 LD₅₀ of FIP, respectively, for 28 days. Mice in the amelioration groups were orally administered with selenium + vitamin E (0.3 mg + 22.5 mg/kg b.w., respectively) 14 days prior to exposure to the higher dose (4.78 mg/kg) of FIP for another 14 days. Fipronil exposure at medium and high doses showed lowered values of red blood cell count (RBC), hematocrit (HCT), hemoglobin (HGB), white blood cell (WBC), and platelet (PLT) counts after 28-day exposure, compared to the control. All three doses caused significant increases in levels of liver-function biomarkers, i.e., aspartate amino transaminase (AST), alanine amino transaminase (ALT), alkaline phosphatase (ALP), cholesterol, and bilirubin levels compared to the control. Levels of biomarkers related to kidney functions, i.e., urea, uric acid, and creatinine, increased significantly than these of the control. Likewise, the oxidative stress indices, i.e., hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), significantly increased at the higher and medium doses, while antioxidant enzymes, catalase (CAT) and superoxide dismutase (SOD), decreased significantly. On the other hand, prior administration of selenium + vitamin E in the FIP-exposed mice led to restore values of most hematological parameters nearly to these of the control. Also, the levels of AST, total protein, and creatinine seemed to be restored to the control values. Interestingly, pretreatment with selenium + vitamin E restored the levels of antioxidant enzymes, CAT and SOD, to the control values, whereas, oxidative stress indices, H₂O₂ and MDA, remained significantly high. It is our thought that the sublethal dose less than 1.43 mg/kg b.w. of commercial formulation of FIP (COACH® 200 SC) could be considered as no-observed-adverse-effect-level(NOAEL) under our present experimental conditions at short-term toxicity study. On the other hand, the higher sublethal doses, 4.78 and 2.87 mg/kg b.w., induced significant adverse effects in biomarkers and may be deleterious to human health following long-term exposure.

This study investigates the effects of energy consumption, democracy and globalization on environmental degradation in the context of the environmental Kuznets curve (EKC) for South Africa between 1971 and 2014. To this end, the study applies the combined Bayer-Hanck cointegration test and the fully modified ordinary least squares (FM-OLS) estimation approach. The empirical results confirm the presence of cointegration among the variables, and thus validate the EKC hypothesis for South Africa. In addition, while energy consumption increases environmental degradation, the effect of democracy is positively insignificant. The finding also suggests that globalization condenses environmental degradation. The results of the long-run causal relationship divulge that economic growth, energy consumption, democracy and globalization Granger-cause environmental degradation. The results also find causality running from CO₂ emissions, economic growth, democracy and globalization to energy consumption. In the short run, a causality is found running from globalization to CO₂ emissions, energy consumption to CO₂ emissions and globalization to energy consumption. In addition, economic growth is said to Granger-cause democracy while democracy Granger-causes CO₂ emissions. These results are validated by the innovation accounting tests.