The effectiveness and feasibility of the three biochar materials for remediation of arsenic (As) and lead (Pb) contaminated soil were explored in this study. Significant reduction of bioaccessibility and migration risks of both heavy metals have been explained mechanistically by incubation, column experiments and numerical simulation. Langmuir equation fitted As and Pb sorption isotherms better in the control and biochar (BC) amended soils, while Freundlich model was more suitable for iron modified biochar (Fe-BC) and sulfur/iron modified biochar (S/Fe-BC) amended soils, indicating that modified biochar promoted chemical adsorption process for As and Pb. For the three biochar materials, S/Fe-BC showed the best effects on reducing the bioavailability of As and Pb, with a decrease of 40.42%–64.21%. The reduction in bioaccessibility by metal portioning into available and non-available fractions was better for illustrating the mechanisms including adsorption, precipitation/coprecipitation and As(III) oxidation behind S/Fe-BC efficacy. Moreover, S/Fe-BC can effectively inhibit the leaching behavior of As and Pb under acid rain, which increased by 99.89% and 90.18%, respectively, compared with the control. The HYDRUS-1D modeling indicated that S/Fe-BC could continuously treat As (100 mg/L) and Pb (1000 mg/L) contaminated water for 16.22 years and 40.86 years, respectively, and ensure the groundwater quality criteria being met. Based on these insights, we believe that our study will provide meaningful information about the potentials of biochar derived materials for soil heavy metals’ remediation.

To examine the potential role of acetate in conferring cadmium (Cd) stress tolerance in lentil (Lens culinaris), several phenotypical and physio-biochemical properties have been examined in Cd-stressed lentil seedlings following acetate applications. Acetate treatment inhibited the translocation of Cd from roots to shoots, which resulted in a minimal reduction in photosynthetic pigment contents. Additionally, acetate-treated lentil showed higher shoot (1.1 and 11.72%) and root (4.98 and 30.64%) dry weights compared with acetate-non-treated plants under low-Cd and high-Cd concentrations, respectively. Concurrently, acetate treatments increase osmoprotection under low-Cd stress through proline accumulation (24.69%), as well as enhancement of antioxidant defense by increasing ascorbic acid content (239.13%) and catalase activity (148.51%) under high-Cd stress. Acetate-induced antioxidant defense resulted in a significant diminution in hydrogen peroxide, malondialdehyde and electrolyte leakage in Cd-stressed lentil seedlings. Our results indicated that acetate application mitigated oxidative stress-induced damage by modulating antioxidant defense and osmoprotection, and reducing root-to-shoot Cd transport. These findings indicate an important contribution of acetate in mitigating the Cd toxicity during growth and development of lentil seedlings, and suggest that the exogenous applications of acetate could be an economical and new avenue for controlling heavy metal-caused damage in lentil, and potentially in many other crops.

Engine start-stop (S&S) technology has been substantially incorporated into modern vehicles to save fuel during idling in congested urban areas because fuel economy regulations have become more stringent. However, the potential for increasing particle emissions after engine restarts, especially in cold environments, is of great concern. To investigate the effects of S&S systems on fuel consumption and tailpipe emissions, a chassis dynamometer was employed to measure the fuel consumption, particulate matter (PM), solid particle number (PN), particle number size distribution and black carbon (BC) for a typical gasoline direct injection vehicle when the S&S was on (S&S-on) and when the S&S was off (S&S-off) according to the worldwide harmonized light-duty test cycle in both hot (28 °C) and cold (5 °C) environments. S&S operation resulted in 3.1–4.3% fuel-savings at 28 °C but had a tendency to increase particulate emissions, especially of BC (21.8–31.8%) and PM (19.2–32.8%). Although PN emissions with S&S-on over the entire cycle were slightly lower than those with S&S-off, more particles were emitted during the engine restart moments. In a cold environment, the fuel-savings advantage of the S&S system was weakened, and the negative impacts on the particle emissions during the restart moment worsened. The S&S system resulted in higher abundances of accumulation mode particles, especially under cold ambient conditions. The relationship between the PN reduction rates and idling segments was determining to be exponential. Our results indicate that the S&S system, which may increase particle emissions during restarts, does save fuel, and that a comprehensive evaluation of the system in cold environments is needed to determine the serviceability of new engine technologies and after-treatments.

Energy is vital to human society but significantly contributes to the deterioration of environmental quality and the global issue of climate change. Biomass and fossil fuels are important energy sources but have distinct pollutant emission characteristics during the burning process. This study aimed at attributing radiative forcing of climate forcers, including greenhouse gases but also short-lived climate pollutants, from the burning of fossil and biomass fuels, and the spatiotemporal characteristics. We found that air pollutant emissions from the burning process of biofuel and fossil fuels induced RFs of 68.2 ± 36.8 mW m⁻² and 840 ± 225 mW m⁻², respectively. The relatively contribution of biomass burning emissions was 7.6% of that from both fossil and biofuel combustion processes, while its contribution in energy supply was 11%. These relative contributions varied obviously across different regions. The per unit energy consumption of biomass fuel in the developed regions, such as North America (0.57 ± 0.33 mW m⁻²/10⁷TJ) and Western Europe (0.98 ± 0.79 mW m⁻²/10⁷TJ), had higher impacts of combustion emission related RFs compared to that of developing regions, like China (0.40 ± 0.26 mW m⁻²/10⁷TJ), and South and South-East Asia (0.31 ± 0.71 mW m⁻²/10⁷TJ) where low efficiency biomass burning in residential sector produced significant amounts of organic matter that had a cooling effect. Note that the study only evaluated fuel combustion emission related RFs, and those associated with the production of fuels and land use change should be studied later in promoting a comprehensive understanding on the climate impacts of biomass utilization.

One of the fundamental sustainable development goals has been recognized as having access to clean water for drinking purposes. In the Anthropocene era, rapid urbanization put further stress on water resources, and associated groundwater contamination expanded into a significant global environmental issue. Natural arsenic and related water pollution have already caused a burden issue on groundwater vulnerability and corresponding health hazard in and around the Ganges delta. A field based hydrogeochemical analysis has been carried out in the elevated arsenic prone areas of moribund Ganges delta, West Bengal, a part of western Ganga- Brahmaputra delta (GBD). New data driven heuristic algorithms are rarely used in groundwater vulnerability studies, specifically not yet used in the elevated arsenic prone areas of Ganges delta, India. Therefore, in the current study, emphasis has been given on integration of heuristic algorithms and random forest (RF) i.e., “RF-particle swarm optimization (PSO)”, “RF-grey wolf optimizer (GWO)” and “RF-grasshopper optimization algorithm (GOA)”, to identify groundwater vulnerable zones on the basis of field based hydrogeochemical parameters. In addition, correspondence health hazard of this area was assessed through human health hazard index. The spatial distribution of groundwater vulnerability revealed that middle-eastern and north-western part of the study area covered by very high and high, whereas central, western and south-western part are covered by very low and low vulnerability zones in outcomes of all the applied models. The evaluation result indicates that RF-GOA (AUC = 0.911) model performed the best considering testing dataset, and thereafter RF-GWO, RF-PSO and RF with AUC value is 0.901, 0.892 and 0.812 respectively. Findings also revealed the groundwater in this study region is quite unfavorable for drinking and irrigation purposes. The suggested models demonstrate their usefulness in foretelling sustainable groundwater resource management in various deltaic regions of the world through taking appropriate measures by policy-makers.

Air pollution exposure is a public health emergency, which attributes globally to an estimated seven million deaths on a yearly basis We are all exposed to air pollutants, varying from ambient air pollution hanging over cities to dust inside the home. It is a mixture of airborne particulate matter and gases that can be subdivided into three categories based on particle diameter. The smallest category called PM₀.₁ is the most abundant. A fraction of the particles included in this category might enter the blood stream spreading to other parts of the body. As air pollutants can enter the body via the lungs and gut, growing evidence links its exposure to gastrointestinal and respiratory impairments and diseases, like asthma, rhinitis, respiratory tract infections, Crohn's disease, ulcerative colitis, and abdominal pain. It has become evident that there exists a crosstalk between the respiratory and gastrointestinal tracts, commonly referred to as the gut-lung axis. Via microbial secretions, metabolites, immune mediators and lipid profiles, these two separate organ systems can influence each other. Well-known immunomodulators and gut health stimulators are probiotics, prebiotics, together called synbiotics. They might combat air pollution-induced systemic inflammation and oxidative stress by optimizing the microbiota composition and microbial metabolites, thereby stimulating anti-inflammatory pathways and strengthening mucosal and epithelial barriers. Although clinical studies investigating the role of probiotics, prebiotics, and synbiotics in an air pollution setting are lacking, these interventions show promising health promoting effects by affecting the gastrointestinal- and respiratory tract. This review summarizes the current data on how air pollution can affect the gut-lung axis and might impact gut and lung health. It will further elaborate on the potential role of probiotics, prebiotics and synbiotics on the gut-lung axis, and gut and lung health.

In this study the persistence (based on extractable, Cₜₒₜ) and bioavailability (based on freely dissolved content, Cfᵣₑₑ) of polycyclic aromatic hydrocarbons (PAHs) in biochar-amended soil was investigated. Biochar produced at 500 or 700 °C from sewage sludge (BC) or sewage sludge and willow (W) mixture (BCW) in an atmosphere of nitrogen (N₂) or carbon dioxide (CO₂) was evaluated. The biochars were applied to the real soil (podzolic loamy sand) at a dose of 2% (w/w). The content of Cₜₒₜ and Cfᵣₑₑ PAHs was monitored for 180 days. The biochar production conditions determined the Cₜₒₜ and Cfᵣₑₑ PAHs in the soil. A change of carrier gas from N₂ to CO₂ caused an increase in Cₜₒₜ PAH losses in the soil from 19 to 75% for the biochar produced from SL and from 49 to 206% for the co-pyrolyzed biochar. As regards Cfᵣₑₑ PAHs, the change from N₂ to CO₂ increased the losses of Cfᵣₑₑ PAHs only for the biochar derived from SL at a temperature of 500 °C (by 21%). In the soil with the other biochars (produced at 700 °C from SL as well as at 500 and 700 °C from SL/W), the Cfᵣₑₑ increased from 17 to 26% compared to the same biochars produced in an atmosphere of N₂.

Mitigation of ambient ozone (O₃) pollution is a great challenge because it depends heavily on the background O₃ which has been poorly evaluated in many regions, including in China. By establishing the relationship between O₃ and air temperature near the surface, the mean background O₃ mixing ratios in the clean and polluted seasons were determined to be 35–40 and 50–55 ppbv in China during 2013–2019, respectively. Simulations using the chemical transport model (i.e., the Weather Research and Forecasting coupled with Chemistry model, WRF/Chem) suggested that biogenic volatile organic compounds (VOC) emissions were the primary contributor to the increase in the background O₃ in the polluted season (BOP) compared to the background O₃ in the clean season (BOC), ranging from 8 ppbv to 16 ppbv. More importantly, the BOP continuously increased at a rate of 0.6–8.0 ppbv yr⁻¹ during 2013–2019, while the non-BOP stopped increasing after 2017. Consequently, an additional 2%–16% reduction in anthropogenic VOC emissions is required to reverse the current O₃ back to that measured in the period from 2013 to 2017. The results of this study emphasize the importance of the relative contribution of the background O₃ to the observed total O₃ concentration in the design of anthropogenic precursor emission control strategies for the attainment of O₃ standards.

Global change, including urbanisation, threatens many of the >1400 bat species. Nevertheless, certain areas within highly urbanised cities may be suitable to harbour bat populations. Thus, managing urban habitats could contribute to bat conservation. Here, we wanted to establish evidence-based recommendations on how to improve urban spaces for the protection of bats. In a team effort with >200 citizen scientists, we recorded bat vocalisations up to six times over the course of 2 years at each of 600 predefined sites in the Berlin metropolitan area. For each species we identified the preferred and non-preferred landscape features. Our results show that artificial light at night (ALAN) had a negative impact on all species. For soprano pipistrelles and mouse-eared bats ALAN had the largest effect sizes among all environmental predictors. Canopy cover and open water were especially important for bat species that forage along vegetation edges and for trawling bats, respectively. Occurrence probability of species foraging in open space decreased with increasing distance to water bodies. On a larger scale, impervious surfaces tended to have positive effects on some species that are specialised on foraging along edge structures. Our study constitutes an important contribution to the growing body of literature showing that despite the many negative impacts of urbanisation on wildlife, urban environments can harbour bat populations if certain conditions are met, such as access to vegetation and water bodies and low levels of ALAN. Our findings are of high relevance for urban planners and conservationists, as they allow inferences on how to manage urban spaces in a bat-friendly way. We recommend limiting ALAN to the minimum necessary and maintaining and creating uninterrupted vegetated corridors between areas with high levels of canopy cover and water bodies, in which ALAN should be entirely avoided.