Environmental Science and Pollution Research

MnO 2 -loaded microorganism-derived carbon for U(VI) adsorption from aqueous solution Abstract A low-cost industrial microorganism, Saccharomyces cerevisiae, was employed as a precursor to synthesize carbon/MnO2 composites (MMCs) via an oxidation-reduction reaction and one-step carbonization method for U(VI) adsorption. Scanning electron microscopy and nitrogen adsorption measurement indicated that the microorganism’s carbonization could form surface porous structure and increase the specific surface area. Batch experiments showed that the maximum U(VI) adsorption capacity of MMCs reached 207 mg g−1 at [U(VI)]initial = 25 mg L−1 and pHinitial = 4.5. The obtained thermodynamic and kinetic parameters suggested that the process is endothermic, spontaneous, and chemisorption. FTIR and X-ray photoelectron spectroscopy demonstrated that the surface hydroxyl groups of composites might be the reactive adsorption sites for U(VI). Additionally, 0.5 mol L−1 HNO3 solution could desorb ~ 95% uranium from U(VI)-loaded MMCs, and materials exhibited good regenerated availability. This study suggests that MMCs can be a potential adsorbent for U(VI) preconcentration and removal from radioactive wastewater.

Curcumin and quercetin synergistically attenuate subacute diazinon-induced inflammation and oxidative neurohepatic damage, and acetylcholinesterase inhibition in albino rats Abstract The ubiquitous use of diazinon (DZN, an organophosphorus insecticide) has increased the probability of occupational, public, and the ecosystem exposure; these exposures are linked to negative health outcomes. The flavonoids curcumin (CUR) and quercetin (QUE) exert significant anti-inflammatory and antioxidant activities against toxicants, including insecticides. However, it is unclear whether their combination enhances these activities. Therefore, 40 albino rat were divided randomly into the CTR, DZN, CUR + DZN, QUE + DZN, and CUR + QUE + DZN groups, which are treated daily via gavage for 28 days. DZN induced neurohepatic inflammation and oxidative damage, which was confirmed by significant (P < 0.05) induction of aspartate and alanine aminotransferases, alkaline phosphatase, lactate dehydrogenase, γ-glutamyl transferase, and tumor necrosis factor-α and inhibition of acetylcholinesterase activity. Furthermore, the liver and brain of DZN-exposed rats exhibited a notable elevation in MDA level paralleled with reduction in antioxidant molecules, i.e., glutathione, superoxide dismutase, glutathione peroxidase, and catalase. The pretreatment of DZN-intoxicated rats with CUR or QUE substantially mitigated neurohepatic dysfunction and inflammation and improved liver and brain antioxidant status with reducing oxidative stress levels. Furthermore, pretreatment with CUR + QUE synergistically restored the neurohepatic dysfunction and oxidative levels to approximately normal levels. The overall results suggested that CUR or QUE inhibits DZN-mediated neurohepatic toxicity via their favorable anti-inflammatory, antioxidant, and free radical-scavenging activities. Moreover, both QUE and CUR may be mutual adjuvant agents against oxidative stress neurohepatic damages.

Environmental efficiency of Saccharomyces cerevisiae on methane production in dairy and beef cattle via a meta-analysis Abstract The objective of the present study is to examine the effect of yeast (Saccharomyces cerevisiae) on reduction of methane (CH4) production in dairy and beef cattle using meta-analytic methods. After compilation of relevant scientific publications available from the literature between 1990 and 2016, and applying exclusion and inclusion criteria, meta-analyses of data from dairy and beef cattle were applied for the pooled dataset or for each animal category (dairy or beef). The results of meta-analysis of all three datasets (all cattle, dairy cattle, or beef cattle) suggested that effect size of yeast either on daily CH4 production or on CH4 production per dry matter intake (CH4/DMI) was not significant. The results of Q test and I2 statistic suggest that there is no heterogeneity between different studies on CH4 production and CH4/DMI. The results of meta-analysis suggest that use of yeast (Saccharomyces cerevisiae) as feed additive does not offer significant results in terms of reduction of CH4 production in dairy and beef cattle. Further research on the effects of different doses of yeast, use of yeast products, different strains, and experimental designs is warranted to elucidate the effects of yeasts on methane production in the rumen.

Synthesis of graphene by in situ catalytic chemical vapor deposition of reed as a carbon source for VOC adsorption Abstract Few-layer graphene was synthesized by in situ catalytic carbon vapor deposition (CCVD) method, using reed as a carbon source and Ni, Cu, and Mg salts as the catalyst compounds. The synthesized graphene was also used for adsorption of VOCs. Furthermore, the effect of organic additives, sorbitol, and citric acid on catalyst compounds was investigated by temperature-programmed reduction analysis (H2-TPR). The products’ properties were characterized by thermo-gravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) surface area analysis. TEM and FE-SEM images confirmed the formation of graphene sheets. Activation of the graphene by phosphoric acid at 500 °C and then by CO2 at 800 °C increased the surface area from 298 to 568 m2/g. Gasoline working capacity of the activated graphene was 65.24 g/ladsorbent. Graphical abstract Few-layer graphene was synthesized by in situ catalytic carbon vapor deposition (CCVD) method using reed as a carbon source and Ni, Cu, and Mg salts as the catalyst compounds and used for adsorption of VOCs.

Distribution and potential ecological risk assessment of trace elements in the stream water and sediments from Lanmuchang area, southwest Guizhou, China Abstract Trace elements contamination in sediment is regarded as the global crisis with a large share in developing countries like China. Water and sediment samples were collected during (2016) from Qingshui Stream and analyzed for major physicochemical properties and trace elements by using ICP-MS. Our result of sediments showed that studied trace elements (except Pb, Cd, Co) had a concentration higher than Chinese sediment guideline as well as stream water data for studied trace elements (except Cr, Pb, Cd, Cu, and Zn) had a higher concentration than the maximum permissible safe limit of WHO. Contamination factor (CF) confirmed a moderate to high contamination in the sediment samples due to As and Tl, respectively. The values of pollution load index (PLI) were found above one (> 1), describing the progressive sediment quality decline. Pearson correlation showed that there was a significant positive association between Tl and As (r = 0.725, p < 0.05) in sediment samples. Results revealed that water-rock interaction, weathering of Tl sulfide mineralization, and hydrogeological conditions were major sources of stream water and sediments contamination in the study area. This experimental study contributes to a better understanding of the geochemistry and prevention of trace element contamination in sediments from Lanmuchang area.

How does natural resource dependence affect public education spending? Abstract The “resource curse” phenomenon has been the subject of extensive research, with its causes and transmission mechanisms primarily examined from the perspectives of economic development and rent seeking. Education is a major factor contributing to economically sustainable development, owing to its potential for improving cognition and skill levels and thereby enhancing worker productivity. The crowding-out or crowding-in effect of natural resource dependence on public education spending has been identified as one of the key mechanisms of the resource curse or blessing. Using panel data from 31 Chinese provinces, this empirical study revealed a positive correlation between natural resource dependence and public education expenditure, demonstrating the impact of the crowding-in effect, exerted by natural resource dependence, on public education expenditure. Abundant natural resources can provide funds for education expenditure. The sample was further divided into eastern and central and western regions. The results indicate that the crowding-out effect of natural resource dependence only affects public education expenditure in the Eastern region, while the crowding-in effect of natural resource dependence on public education expenditure in the central and western regions. Research shows that the regional differences of crowding-out or crowding-in effect are very obvious, so the government should adopt transfer payment to promote balanced regional development. Better economic and social policies will help to translate wealth from natural resources into economic growth. Thus, a “resource blessing” may emerge to replace the “resource curse.” Fairly distributed and higher quality education will enhance human capital, thereby promoting economic growth from its current resource-driven pattern to a knowledge-driven pattern.

Enhanced nitrogen removal in biochar-added surface flow constructed wetlands: dealing with seasonal variation in the north China Abstract In the present study, the performance of surface flow constructed wetlands (SFCWs) added with different dosage of biochar (group A 0%, group B 10%, group C 20%; v/v) was investigated, to evaluate the effect of biochar on nitrogen removal of a constructed wetland. No significant difference was observed in NH4+-N removal among three groups even during different seasons. Labile organic carbon released from biochar distinctly enhanced denitrification process, which improved NO3−-N removal efficiency by 4.58% in group B and 10.33% in group C. More importantly, compared with group A, biochar addition increased plant N removal by 82.24% and 192.11% in groups B and C, respectively. This result indicated that biochar could increase the accumulation of plant net biomass. In addition, TN removal of group A was much lower at low temperature (4.9 °C). However, no obvious influence of temperature on TN removal was observed in groups B and C with biochar addition. Microbial community analysis showed that, compared with that in group A, the total relative abundance of the main denitrification bacteria (Proteobacteria, Firmicutes, and Bacteroidetes) increased by 0.81% in group B and 13.63% in group C. These results provide a reasonable strategy for improving the performance of SFCWs under cold climate.

Composts as alternative to inorganic fertilization for cereal crops Abstract The use of treated organic products as fertilizers and soil amendments not only results in economic benefits for the small-scale farmer, but it also reduces pollution due to reduced nutrient run-off and N leaching. In this work, the feasibility of using composts as fertilizers and soil improvers has been evaluated at the field level, in barley and soft wheat crops (two successive cultivations of each crop). The applied treatments consisted of two commercial composts (compost manure and sewage sludge compost) added to the soil either alone (T1 and T3) or in combination with inorganic fertilizers (T2 and T4) and a conventional mineral fertilization (T5). Physical, physical-chemical, chemical, microbiological, and biochemical parameters were determined in the soil after each harvest. In both barley and wheat crops, soils treated with composts showed higher organic C, humic substances, and humic acid contents than the inorganically fertilized soil, as well as higher contents of water-soluble P, K, Ca, Mg, and S. In both successive crops, all treatments led to similar yields of total barley and wheat vegetal material (straw + ears) and grain, differences between treatments being not statistically significant (p ≤ 0.05). Organically treated soils showed higher microbial size and activity than inorganically treated soils as well as higher water-holding capacity. It can be concluded that quality organic composts can be used, at suitable rates, alone or in combination with inorganic fertilizers, as a good alternative to inorganic fertilization for cereal cultivation, improving soil characteristics while giving similar yield and crop quality than conventional inorganic fertilization.

Contrastive removal of oxytetracycline and chlortetracycline from aqueous solution on Al-MOF/GO granules Abstract The presence of tetracycline antibiotics (TCS) in the water and wastewater has raised growing concern due to its potential environmental impacts; thus, their removal is of high importance. In this study, a novel aluminum-based MOF/graphite oxide (Al-MOF/GO) granule was prepared as an adsorbent for the removal of TCS including oxytetracycline (OTC) and chlortetracycline (CTC). The adsorbent was characterized via XRD, FTIR, BET, SEM, and XPS methods. The granules exhibited similar crystal structure and some new mesopores appearing compared to the parent Al-MOF/GO powder. In addition, the adsorption behavior of OTC and CTC on samples was explored as a function of initial concentration, contact time, pH, and ionic strength by means of batch experiments. The adsorption capacity reached to 224.60 and 240.13 mg·L−1 for OTC and CTC, at C0 = 60 mg·L−1as well as ambient temperature respectively. Moreover, the adsorption process of OTC and CTC on Al-MOF/GO samples can be better delineated by pseudo-second-order kinetics and Freundlich isotherm models. Besides, the adsorption mechanism over Al-MOF/GO granules was proposed, which could be ascribed to π-π interaction, cation-π bonding, and hydrogen bond. Finally, the great water stability, separation performance, and regeneration efficiency of these novel granules indicated their potential application in the OTC and CTC removals from aqueous solution.

Bisphenol S exposure affects gene expression related to intestinal glucose absorption and glucose metabolism in mice Abstract Bisphenol S, an industrial chemical, has raised concerns for both human and ecosystem health. Yet, health hazards posed by bisphenol S (BPS) exposure remain poorly studied. Compared to all tissues, the intestine and the liver are among the most affected by environmental endocrine disruptors. The aim of this study was to investigate the molecular effect of BPS on gene expression implicated in the control of glucose metabolism in the intestine (apelin and its receptor APJ, SGLT1, GLUT2) and in the liver (glycogenolysis and/or gluconeogenesis key enzymes (glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK)) and pro-inflammatory cytokine expression (TNF-α and IL-1β)). BPS at 25, 50, and 100 μg/kg was administered to mice in water drink for 10 weeks. In the duodenum, BPS exposure reduces significantly mRNA expression of sodium glucose transporter 1 (SGLT1), glucose transporter 2 (GLUT2), apelin, and APJ mRNA. In the liver, BPS exposure increases the expression of G6Pase and PEPCK, but does not affect pro-inflammatory markers. These data suggest that alteration of apelinergic system and glucose transporters expression could contribute to a disruption of intestinal glucose absorption, and that BPS stimulates glycogenolysis and/or gluconeogenesis in the liver. Collectively, we reveal that BPS heightens the risk of metabolic syndrome.