The fluidity of arsenic (As) in soil used for rice cultivation under flooding conditions is the main reason for its high accumulation in rice, which poses a serious threat to human’s health. Biochar can immobilize heavy metal (for example lead) of soil because of the strong binding of heavy metals to the inner biochar particles. We conducted a pot experiment to evaluate the effects of biochar (BC) and Fe-Mn-Ce oxide–modified biochar composites (FMCBCs) on the morphology, As accumulation, and grain quality of rice grown in As-contaminated soils. The biochar and FMCBC treatments significantly increased the dry weight of roots, stems, leaves, and rice grains grown in As-contaminated soil (P < 0.05). The As concentration in different parts of rice was significantly lower with treatment FMCBC₃₋₂ (BC, Fe, Mn, and Ce weight ratio of 24:2:3:10) than with the BC and control (no BC) treatments. The application of FMCBC₃₋₂ maximized the yield and quality of rice grains: rice grain yields were 61.45–68.41% higher over control and the proportion of essential amino acids in the rice grains was 31.01–44.62%. The application of FMCBCs also increased the concentration of Fe-Mn plaques, which prevent the uptake of As by rice, thereby mitigating the toxic effects of As-contaminated soil on rice. In summary, Fe-Mn-Ce oxide–modified BC composites fixed As, reducing its fluidity and the As concentration in rice. Our results show that FMCBC₃ could play an important role in reducing As accumulation and increasing the grain yield and quality of rice, thus ensuring food safety in regions contaminated with As.

By collecting daily data on measles cases, air pollutants, and meteorological data from 2005 to 2009 in Chengguan District of Lanzhou City, semi-parametric generalized additive model (GAM) was used to quantitatively study the impact of air pollutants and meteorological factors on daily measles cases. The results showed that air pollutants and meteorological factors had effect on the number of daily measles cases, and there was a certain lag effect. Except for SO₂ and relative humidity, other factors showed statistically significant associations with daily measles cases: NO₂ lag 6 days, PM₁₀ and maximum temperature lag 5 days, minimum temperature and average temperature and average air pressure lag 4 days, visibility, and wind speed lag 3 days had the greatest impact on the number of daily measles cases. Under the optimum lag conditions, the number of daily measles cases increased by 15.1%, 17.6%, 7.0%, 116.6%, 98.6%, 85.7%, and 14.4% with the increase of 1 IQR in SO₂, NO₂, PM₁₀, maximum temperature, minimum temperature, average temperature, and wind speed; with the increase of 1 IQR in average pressure, relative humidity, visibility, and daily measles cases decreased by 12.8%, 9.7%, and 13.1%, respectively. And different factors showed different seasonal effects. The effects of SO₂ and temperature factors on daily measles cases were greater in spring and winter, but PM₁₀ in summer.

At first, naked TiO₂ was prepared by sol-gel method. Silver nitrate and thiourea were respectively used as silver source and sulfur source added to form a TiO₂ sol and Ag₂S polymer blend system. Then, the properties of Ag₂S-TiO₂ was one-step synthesized and investigated by photocatalytic experiment and material characterization. According to the characterization results, Ag₂S-TiO₂ is anatase with a band gap of 3.14 eV, a specific surface area of 39.80 m²/g, and an average pore diameter of 3.56 nm. The results of photocatalytic experiments show that Ag₂S-TiO₂ can efficiently remove ethyl paraben within 2 h. Quenching experiments show that both •OH and photogenerated holes have a large effect on photocatalytic performance.

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.

Street dust and soil samples were collected from three study areas in Jinhua, China: a commercial area and two urban districts. The concentrations of nickel (Ni), lead (Pb), copper (Cu), cadmium (Cd), and particularly zinc (Zn) in street dust exceeded soil background values and Chinese soil screening safe levels in some areas. Zn and Cd concentrations in street dust appeared to pose health concerns in the majority of sample sites, but their levels in soils were noticeably lower, indicating possible contamination from atmospheric deposition. Of the three areas, the most severe pollution occurred in Jindong (JD) District. Practically all the samples from JD District showed contamination to some degree. Based on pollution indices, the contamination levels of heavy metals among the studied sites were ranked in the following descending order: JD District > commercial area (CA) > Wucheng District. Source metal identification assessment revealed that the majority of metals in street dust from Jinhua were significantly related to industrial and traffic activities. Health risk assessment was performed based on the US-Environmental Protection Agency model, and the results showed that virtually, no health risk existed from exposure to individual metals in dust particles. However, the noncarcinogenic risk exponentially increased through exposure to various metals in dust. Thus, the majority of hazard index values surpassed the acceptable level. For carcinogens, the carcinogenic risks of each metal did not supersede the acceptable range for children. This observation demonstrates that although the carcinogenic risk is acceptable, the noncarcinogenic risk remains a genuine health concern for local children.

Understanding the controlling factor of groundwater quality could certainly enhance the promotion of the sustainable development of groundwater resources. In fact, during the last decades, the coastal aquifer of Mahdia–Ksour Essef that belongs to the semi-arid region of Tunisia has been marked by an increase of groundwater extraction for irrigation and water for drinking. Moreover, the water quality shows deterioration due to the septic tanks and intensive agricultural activities especially in the coastal side of the aquifer. This study aimed to (1) assess the water quality using Piper Diagram, Box Plot, ions scatter diagrams, (2) understand the processes of mineralization acquisition in the aquifer, and (3) identify the chemical processes and their spatial distribution in the study area. To solve these objectives, the multivariate statistical analysis such as multiple correspondence analysis and hydrochemical analysis was performed. Accordingly, two types of groundwater are identified through the hydrochemical analysis as Na-Cl and Ca-SO₄. According to multiple correspondence analysis, three water groups are determined (G1, G2, and G3). Indeed, the groundwater quality is controlled by the water-rock interactions and affected by the seawater intrusion and agricultural activities. The generated results would be helpful to provide a managing model highlighting the threatened locations. It could be considered as a basis for future monitoring programs that aspire to protect water resources.

In the process of coal mining, the abnormal gushing of hydrogen sulphide in mines poses a major threat to the health of coal miners and the safe production of mines, as these types of accidents have occurred in many coal-producing countries. China is the largest coal producer and consumer in the world and is one of the countries that are substantially affected by hydrogen sulphide in mines. Based on the existing studies, many investigators in China have conducted research on the actual situation in China and obtained some results. This paper summarizes the previous findings and the current status of hydrogen sulphide in Chinese mines, and predicts the direction of future development. In this paper, we discuss the cause, abnormal distribution, abnormal gushing and prevention and control measures for hydrogen sulphide in mines. In addition, this paper also evaluates the impact of the hydrogen sulphide in mines on the environment and health. This paper outlines a systematic research framework regarding hydrogen sulphide in mines and assesses the interrelationship between subtopics within this system framework. Currently, the scientific research on hydrogen sulphide in mines is not sufficient to meet the needs of the affected individuals Therefore, researchers must increase their efforts in this area to jointly address the challenge of analysing hydrogen sulphide in mines. In addition, we hope that this paper will provide some guidance for the study of hydrogen sulphide in mines.

Among ex situ remediation technologies, stabilization/solidification (S/S) provides for the addition of a binder to dredged materials in order to chemically immobilise the contaminants and improve mechanical behaviour of sediments. The simplest form of treatment is obtained by the addition of Portland cement or lime (calcium oxide), although other additives such as adsorbents may be added. Nevertheless, the success of the S/S treatment may be affected by the contaminants present or by the salt content in the water. In this study, experimental laboratory investigation was carried out on sediments carefully collected from the Mar Piccolo of Taranto in Southern Italy, contaminated by heavy metals, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs); the goal was to explore the effectiveness of S/S treatment by using Portland cement/lime as binders, monitoring over time (28 days) the leaching of the different mixtures of treated sediment. It is noted that the Mar Piccolo of Taranto is one of the sites of national interest subject to remediation by the Italian government. Once taken within the first meter under the sea floor by a team of experienced divers, the samples were stored at a controlled temperature, characterised in terms of grain size and physical-chemical characteristics and treated by S/S laboratory tests. The results indicate that the addition of binders increased the pH of the mixtures with a consequent leachability of different metals. The mobility of the metals appeared to be governed also by the curing time. The performance of the mixtures in terms of immobilised metals was influenced by the presence of organic contaminants (e.g. organic matter, PAHs and PCBs). As a lesson, high organic matter and fine-grained particles can negatively affect the effectiveness of the S/S treatment in terms of metal immobilisation.

In this investigation, Ag@AgCl nanoparticles were synthesized by a green and inexpensive method using Elaeagnus angustifolia leaves, as a reducing and stabilizing agent without using any toxic solvent, external halide source, harsh chemicals, or capping agents. In this protocol, the nanophotocatalyst was synthesized via immobilization of Ag@AgCl NPs on the surface of biowaste Elaeagnus angustifolia seed (EAS) as a green support, which prevents the agglomeration Ag@AgCl NPs and improves the catalytic activity. The biosynthesized nanophotocatalyst were characterized by UV-Vis spectroscopy, Fourier transform–infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE SEM), energy dispersive X-ray spectroscopy (EDS), and transform electron microscopy (TEM) and inductively couple plasma mass spectrometry (ICP). In order to investigate the photocatalytic activity of the biosynthesized nanophotocatalyst, it was used in the degradation of methylene blue (MB) under sunlight. The results showed that nanophotocatalyst had an excellent photo activity without any agglomeration. In addition, the nanophotocatalyst can be easily be recycled and reused several times without losing its activity. Graphical abstract

This study investigates the asymmetric dynamic effects of financial development on ecological footprint in Nigeria over the period 1971–2014 using the nonlinear autoregressive distributed lag (NARDL) framework. Ecological footprint in Nigeria is classified into carbon footprint, non-carbon footprint, and total ecological footprint. The results show that in Nigeria, a positive shock in financial development (an increase in financial development) has significant reducing effect on ecological footprint (i.e., improves environmental sustainability) while a negative shock in financial development (a decline in financial development) has significant increasing effect on ecological footprint (i.e., deteriorates environmental sustainability). Asymmetry test shows that a significant difference exists in how negative and positive shocks in financial development impact on carbon footprint and total ecological footprint, but not for non-carbon footprint. On the basis of the total ecological footprint, the adjustment asymmetry from the dynamic multiplier graph shows that the response of ecological footprint to a negative shock in financial development is stronger. Further findings from the analysis show that economic growth, energy consumption, urbanization, and economic globalization are all drivers of environmental sustainability in Nigeria. Overall, the results highlight the need for a deepened financial system, as part of the strategies for achieving sustainable development in Nigeria.