In this study, MgAl-LDHs and MgFe-LDHs were synthesized via co-precipitation method and in situ coated on pre-washed zeolites through dipping process in beaker. The obtained modified zeolites and original zeolites were utilized as substrates of constructed rapid infiltration systems (CRIS) to remove hexavalent chromium (Cr(VI)) in wastewater. Micro-morphology features and chemical composition of zeolites before and after modification were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence spectrometer (XRF). The SEM, XRD, and XRF results demonstrated the feasibility of LDHs coated on the surface of the original zeolites. Purification experiments in simulated CRIS showed that the Cr(VI) removal rates of zeolites/MgAl-LDHs increased by 110.03% on average every concentration (0.5–16 mg L⁻¹) compared with the original zeolites under 24-h HRT. The adsorption capacity of zeolites/MgAl-LDHs reached 66.98 mg kg⁻¹ at 32 mg L⁻¹ initial Cr(VI) concentration, which is nearly twice that of the original zeolites (33.24 mg kg⁻¹) and 1.5 times higher than that of zeolites/MgFe-LDHs (42.01 mg kg⁻¹). Isothermal adsorption tests showed that the Freundlich isotherm equations gave better fitting to the adsorption process. And zeolites/MgAl-LDHs showed a best fit with pseudo-second-order model which meant that the adsorption of Cr(VI) by zeolites/MgAl-LDHs was dominated by chemisorption. Thermodynamic parameters showed that the process of adsorption for the three substrates was spontaneous and endothermic intrinsically. Zeolites/MgAl-LDHs also displayed nearly 60% desorption rate with low concentration eluent (0.01 mol L⁻¹ NaCl). Therefore, zeolites/MgAl-LDHs were chosen out as an optimal substrate for removing Cr(VI) from wastewater in CRIS. Graphical Abstract

Fixation reactions reduce the concentration of soluble phosphorus (P) and affect crop growth in alkaline calcareous soils. In lab and greenhouse studies, phosphoric acid (PA) or diammonium phosphate (DAP) were evaluated at various P rates (0, 18, 36 and 54 mg kg⁻¹ soil), either as non-mix (designated as NM-PA and NM-DAP, respectively) or after premixing with farmyard manure (FYM) at 400 mg kg⁻¹ soil (designated as PM-PA and PM-DAP, respectively). The amended soil was incubated at 25 °C and 70% water holding capacity for 7 weeks; thereafter, ³²P dynamics were measured using the Freundlich kinetic model. A greenhouse study was also conducted using the same thirteen treatments (as used in incubation experiment) and wheat cultivar (Galaxy 2013) was grown following standard agronomic practices. The results showed that application of PM-PA at the highest rate, which caused maximum change in Pr (ΔPr = 59%) in laboratory condition, also produced maximum P uptake by grain (190.3 mg pot⁻¹) and grain yield (44.1 g pot⁻¹) of wheat in greenhouse experiment. Similarly, regression analysis showed that an increase in Pr values caused a corresponding increase in crop parameters. The results suggested that pre-mixing P fertilizer with FYM could be a viable technique to increase P supply and enhance productivity of wheat in alkaline calcareous soils.

This work examines the strategies adopted by an arbuscular mycorrhizal symbiotic system to ameliorate environmental Pb stress by examining the concentrations of P, Fe, and Pb in the fungal microstructures and the host’s root. In vitro cultures of Ri-T DNA-transformed carrot (Daucus carota L.) roots were inoculated with Glomus intraradices and treated with Pb(NO₃)₂ solution and the extraradical spores and mycelia (S/M) and the root with the vesicles, mycelia, and root cells were subsequently analyzed by polarized energy dispersive x-ray fluorescence (PEDXRF) spectrometry. Upon Pb treatment, within the root, the percentages of mycorrhizal colonization, the vesicles, and mycelia increased as well as the areas of the vesicles and the (extraradical) spores, although the number of spores and arbuscules decreased. The S/M and the mycorrhizal root showed enhanced concentrations of Pb, Fe, and P. These were particularly marked for Fe in the Pb-treated cultures. This indicates a synergistic relationship between the arbuscular mycorrhizal fungus and the host that confers a higher Pb tolerance to the latter by the induction of higher Fe absorption in the host. The intraradical vesicle, mycelia, and arbuscule numbers are interpreted as a “tactic to divert” the intraradical Pb traffic away from the root cells to the higher affinity cell walls of the arbuscular mycorrhizal fungi (AMF) microstructures in the apoplast. The results of this work show that the symbiosis between the AMF G. intraradices and the host plant D. carota distinctly improves the latter’s Pb tolerance, and imply that the appropriate metal tolerant host-AMF combinations could be employed in process designs for the phytoremediation of Pb.

The Huai River basin (located in eastern China) has a population of 180 million and has the highest risk of esophageal cancer (EC) mortality in China. Some studies found that contaminants in drinking water are a major risk factor for cancers of the digestive system. However, the effect of water pollution in the historical period on the current EC mortality remains unclear. Data were collected on the EC mortality rate in 2004 in the Huai River basin in 11 counties, and data on the surface water quality in the region from 1987 to 2004 were used. The Pearson correlation and the GeoDetector q-statistic were employed to explore the association between water pollution and the EC mortality rate in different lag periods, from linear and nonlinear perspectives, respectively. The study showed apparently spatial heterogeneity of the EC mortality rate in the region. The EC mortality rate downstream is significantly higher than that in other regions; in the midstream, the region north of the mainstream has a lower average mortality rate than that south of the area. Upstream, the region north of the mainstream has a higher mortality rate than that in the southern area. The spatial pattern was formed under the influence of water pollution in the historical period. 1996, 1997, and 1998 have the strongest linear or nonlinear effect on the EC mortality rate in 2004, in which the Pearson correlation coefficient and the q-statistic were the highest, 0.79 and 0.89, respectively. Rapid industrialization in the past 20 years has caused environmental problems and poses related health risks. The study indicated that the current EC mortality rate was mainly caused by water pollution from the previous 8 years. The findings provide knowledge about the lag time for pollution effects on the EC mortality rate, and can contribute to the controlling and preventing esophageal cancer.

The chemical and cytotoxicity properties of fine particulate matter (PM₂.₅) at indoor and outdoor environment were characterized in Xi’an, China. The mass concentrations of PM₂.₅ in urban areas (93.29~96.13 μg m⁻³ for indoor and 124.37~154.52 μg m⁻³ for outdoor) were higher than suburban (68.40 μg m⁻³ for indoor and 96.18 μg m⁻³ for outdoor). The PM₂.₅ concentrations from outdoor environment due to fossil fuel combustion were higher than indoor environment. An indoor environment without central heating demonstrated higher organic carbon-to-elemental carbon (OC / EC) ratios and n-alkanes values that potentially attributed to residential coal combustion activities. The cell viability of human epithelial lung cells showed dose-dependent decrease, while nitric oxide (NO) and oxidative potential showed dose-dependent increase under exposure to PM₂.₅. The variations of bioreactivities could be possibly related to different chemical components from different sources. Moderate (0.4 < R < 0.6) to strong (R > 0.6) correlations were observed between bioreactivities and elemental carbon (EC)/secondary aerosols (NO₃⁻, SO₄²⁻, and NH₄⁺)/heavy metals (Ni, Cu, and Pb). The findings suggest PM₂.₅ is associated with particle induced oxidative potential, which are further responsible for respiratory diseases under chronic exposure.

Non-renewable energy sources have detrimental environmental effects, which directly and indirectly affect the biosphere as environmental deposits from their use for energy generation exceed a threshold. This study performs a streamlined life cycle assessment (LCA) of a coal-fired plant in South Africa. The cradle-to-grave LCA focuses on the coal cycle to determine hotspots with high environmental impacts in the process. Four impact categories were considered in this study: global warming potential, photochemical ozone creation potential, eutrophication potential, and acidification potential. Coal transportation, coal pulverization, water use, and ash management were identified as hotspots in the coal cycle. The coal process has 95% potential for global warming, 4% potential for eutrophication, 1% potential for acidification, and a negligible percentage for photochemical ozone creation. Susceptibility to climate change, eutrophication, acid rain, soil degradation, and water contamination among others are major concerns of the coal cycle. Outsourcing coal from nearby mines with train as medium of transportation reduces environmental impact. Similarly, the use of mitigation technologies like flue gas desulphurization, carbon capture storage, or selective catalytic reduction will reduce the concentration of the flue gas emitted. Ultimately, substituting the coal process with renewable energy sources will ensure environmental sustainability in South Africa. This study will serve as a good resource for further studies on LCA of coal power plants not only in other African countries but in other developing countries with similar situation.

The issue of urban river pollution has attracted great attention due to high concentrations of ammonia nitrogen (NH₄⁺-N) and low concentrations of dissolved oxygen (DO) in polluted water bodies. In order to investigate the effects of aeration-enhanced horizontal subsurface-flow constructed wetlands on polluted river water, unaerated aeration (NA), continuous aeration (CA), and intermittent aeration (IA) constructed wetlands were established. The purification effects of the wetland on various pollutants and the form of effluent nitrogen, influences of temperature on the removal rates of pollutants, the change of redox potential—oxidation reduction potential (ORP)—and the difference of dissolved oxygen (DO) between influent and effluent were investigated. The results indicated that aeration enhancement can improve the purification efficiencies of chemical oxygen demand (COD) and NH₄⁺-N in constructed wetlands. The purification efficiencies of TN in IA and CA constructed wetlands were 91.9% and 53.7%, respectively, indicating that IA is the optimized aeration method for removal of various pollutants in wetlands. Changes of DO and ORP in effluent under IA and CA suggested improvement of aeration on the water environment. Meanwhile, DO was more sensitive to temperature compared with ORP. Additionally, a study of the nitrogen content in effluent suggested that the aeration method had a significant influence on the nitrogen content in effluent. The removal rates of both NH₄⁺-N and TN degraded as the temperature dropped. The results also demonstrated that the removal rate of NH₄⁺-N under aeration condition was more sensitive to temperature than that under NA condition and the effect of temperature on the removal rate of NH₄⁺-N was greater than that of TN.

The developmental triangle earlier comprises economic growth, income inequality, and poverty, while in this study, we extended it by incorporating environmental and resource factors, health and education factors, sectoral value added, and some other growth-specific factors for assessing pro-poor growth, by considering Bolivian economy as a case study. The elasticity estimates show that agriculture and industrial sector growth is not pro-poor due to account of high income inequality, while services sector played a vital role in country’s economic development and supports poor livelihood in a country. Energy and environmental resources negatively impact on quality of life of the poor relative to non-poor, which create income differences among them. Health and education expenditures give favors to the poor and supported the notion of pro-poor growth, while country’s per capita income and foreign direct investment inflows increase income inequality that lead towards pro-rich growth. The results conclude that, in general, Bolivian economy growth is fairly unstable, polluted, and unhealthy that biased to the poor relative to non-poor.

The natural catastrophic events largely damage the country’s sustainability agenda through massive human fatalities and infrastructure destruction. Although it is partially supported the economic growth through the channel of “Schumpeter creative destruction” hypothesis, however, it may not be sustained in the long-run. This study examined the long-run and causal relationships between natural disasters (i.e., floods, storm, and epidemic) and per capita income by controlling FDI inflows and foreign aid in the context of Malaysia, during the period of 1965–2016. The study employed time series cointegration technique, i.e., autoregressive distributed lag (ARDL)-bounds testing approach for robust inferences. The results show that flood, storm, and epidemic disasters substantially decrease the country’s per capita income, while FDI inflows and foreign aid largely supported the country’s economic growth in the short-run. These results are disappeared in the long-run, where flood and storm disasters exhibit the positive association with the economic growth to support the Schumpeter creative destruction hypothesis. The foreign aid decreases the per capita income and does not maintain the “aid-effectiveness” hypotheses in a given country. The causality estimates confirmed the disaster-led growth hypothesis, as the causality estimates running from (i) storm to per capita income, (ii) epidemic to per capita income, and (iii) storm to foreign aid. The results emphasized for making disaster action plans to reduce human fatalities and infrastructure for sustainable development.

Effective landfill management and operation require an accurate evaluation of the occurrence and extent of odour emission events, which are among the main causes of resident complaints and concerns, in particular in densely urbanised areas. This paper proposes a fuzzy optimal protection system (FOPS) based on fuzzy logic to manage odour production from a municipal solid waste (MSW) landfill. The case study is a MSW landfill in an old quarry site located 6 km north-west of Naples city centre (Italy). The aim is to reduce the odour nuisance in the area surrounding the landfill where there are several sensitive receptors. FOPS is based on logical relationships between local atmospheric dynamics, number and intensity of odour pollution events detected by certain fixed receptors and odour emission rate via an optimal fuzzy approach. Such system allows to start, in real time, established mitigation actions required to further reduce the odorous emissions from the landfill itself (e.g. spraying of perfumed substances and activation of extraction wells), especially when weather conditions might not be favourable and cause by causing a higher odour perception. The fuzzy system was coupled with the air pollutant transport software CALPUFF to simulate the odour dispersion in the considered area taking into account both different odour emission rates and local weather conditions. FOPS results show that this approach can be very useful as, by measuring the odour concentrations, a significant reduction of the odour exceedances over the thresholds fixed, to minimise the olfactory harassment, was observed in the whole area studied.