Saline-sodic soil is considered the most important low-yield soil in arid and semi-arid regions. Flue gas desulfurization (FGD) steel slag is a kind of by-product from wet FGD process, in which steel slag powder replaces lime as sorbent of SO₂ emitted from coal-fired power plants. It could potentially be used to ameliorate saline-sodic soil. In this study, a large-scale field experiment of applying FGD steel slag as a new amendment of saline-sodic soils was conducted in the middle Yellow River, Inner Mongolia, China. The FGD steel slag was applied at a rate of 180 t/ha in 2015, 2016, and 2018, respectively. After FGD steel slag application for 1, 3, and 4 years, the soil samples were collected. The saline-sodic field without FGD steel slag amendment was used as the control treatment (CK). Compared with control, the application of FGD steel slag significantly (p < 0.05) decreased soil pH, electric conductivity (EC), salt content, sodium adsorption ratio (SAR), and exchangeable sodium percentage (ESP) of surface soil in saline-sodic soil. However, FGD steel slag increased the EC and salt content at the lower depth of soil profile because of the salt accumulation leached from surface soil. The FGD steel slag significantly increased the concentration of Ca²⁺ and reduced the concentrations of Na⁺, Cl⁻, CO₃²⁻, and HCO₃⁻ ions. FGD steel slag was beneficial for improving adverse physical properties of saline-sodic soil. The application of FGD steel slag significantly reduced the plastic index, tensile strength, and the formation of cracking in saline-sodic soil. The FGD steel slag reduced surface area density of crack (Dc) and average crack width (AW) by 49.1% and 58.7%, compared with the control. The reduction of soil cracking was contributed to the release of Ca²⁺ from FGD steel slag to exchange the Na⁺ on the soil cation exchange sites, which decrease the clay dispersion in soil. The findings of this study confirmed that FGD steel slag could effectively and rapidly remediate saline-sodic soils through decreasing soil sodicity and improving poor physical properties.

Mount of embodied carbon emissions flow along industrial chains and form a complex network. In order to reveal the structure and evolution characteristics of embodied carbon emission flow network among China’s industrial sectors, this study applies a complex network theory to construct six embodied carbon emission flow networks with 30 sectors on the basis of China’s input-output tables from 2002 to 2015. Through the analysis of complex network technology indicators, the overall structural characteristics of the network, the key sectors, and the key flow paths are analyzed. Main results show that six embodied carbon emission flow networks all have the small-world characteristics; there is an industrial cluster phenomenon in the network. During the study period, construction, manufacturing, and service-related industry community are the absorption sites for embodied carbon emissions. Coal- and petroleum-related industry communities are the divergent sites for embodied carbon emissions; moreover, electric and heat power and fuel processing are the important “suppliers” of embodied carbon emissions; construction and other service are the important “consumers” of embodied carbon emissions. Non-metallic products are the important “transmitters” of embodied carbon emissions. Metal smelting and chemical industry are at the core of the network because of their high weighted degree and betweenness centrality. The central effect of key sectors continues to increase over time; furthermore, the distribution of embodied carbon emission flows in the six networks all have long-tail characteristics, and this characteristic became more prominent over time. There are key edge-weights in the networks. About 11 to 15% of the edges carry 80% of the embodied carbon emissions. Further based on edge-weight analysis, this study identifies the key paths of embodied carbon emission flow in the six networks, and most key paths pass through construction. Thus, such key sectors and key flow paths should receive more attention when making carbon emission reduction policies.

This study aimed to evaluate the silicon (Si) capacity to attenuate the cadmium (Cd) effects on seed germination and seedling performance of lettuce. The seeds were subjected to three priming levels: without priming, hydropriming, and Si priming. Afterwards, the seeds were placed to germinate on paper moistened with the absence (0 mM) and presence (1 mM) of Cd. Seeds exposed to Cd showed the same percentage of germination verified in seeds unexposed to this metal (99%). Si priming increases 16% the germination speed of seeds not exposed to Cd and promoted greater expression of esterase during seed germination. However, Cd promoted the decrease of the intensity of esterase and acid phosphatase expression, regardless of the seed priming technique used. Although it does not influence the germination percentage of lettuce seeds, Cd markedly reduced the dry weight of seedlings. This harmful effect caused by the Cd was 33% minimized with Si priming. In addition to the lower weight, Cd induced a significant reduction in antioxidant activity in seedlings. However, Si seed priming caused a greater antioxidant activity—with emphasis on catalase—and, consequently, less lipid peroxidation. In conclusion, Si seed priming contributes to minimize the Cd effects in lettuce seedlings.

Cadmium pollution in the environment is ubiquitous and can be a serious health issue. Crop straw-based biochar is a promising adsorbent, yet few studies have systematically examined the effects of both feedstock and pyrolysis temperature on biochar efficacy for cadmium (Cd) sorption. Sorption-desorption experiments were conducted to explore the mechanisms of Cd sorption for biochars derived from wheat straw (WSB), rape straw (RASB), soybean straw (SSB), and peanut straw (PSB) feedstocks, which were produced by pyrolysis at 450 °C and 650 °C. For biochars pyrolyzed at 450 °C, the sorption capacities varied as PSB>SSB>RASB≈WSB, while the order changed as RASB≈WSB>PSB>SSB for 650 °C biochars. With the increase in pyrolysis temperature, for wheat straw biochar and rape straw biochars, Cd sorption capacities increased by 72% and 63%, while there were 61% and 63% decreases for peanut straw biochar and soybean straw biochar, respectively. Compared to the non-legume straw biochars (WSB and RASB), legume straw biochars (SSB and PSB) have higher sorption capacities for Cd. Peanut straw biochar (PSB) produced at 450 °C was found to be the most promising adsorbent for cadmium. Examination of the sorbed biochars using a range of analytical techniques indicated that 450 °C PSB immobilized cadmium by precipitation with non-electrostatic adsorption. The precipitation of Cd on 450 °C PSB was mainly induced by cation exchange between Cd with mineral cations, which caused Cd complexation with carboxyl functional groups.

This research aims to assess the sustainability of the most common earth-retaining walls (Gravity Walls and Cantilever Walls) in terms of environmental impacts, economic issues, and their combination. Gravity walls observed in this study consist of Gabion Wall, Crib Wall, and Rubble Masonry Wall, while Cantilever Walls include Reinforced Concrete Wall. Six different criteria were taken into account, including global warming potential, fossil depletion potential, eutrophication potential, acidification potential, human toxicity potential, and cost. To achieve the aim of this study, life cycle assessments, life cycle costs, and multi-criteria decision-making methods were implemented. The results showed that the most environmental-friendly option among all alternatives was the Gabion Wall, followed by the Rubble Masonry Wall. However, in terms of economic aspects, the Cantilever Concrete Wall was the best option, costing about 17% less than the Gabion Wall. On the other hand, the results of multi-criteria decision-making showed that the Gabion Wall was the most sustainable choice. This study addressed the research gap by carrying out a sustainability assessment of different retaining walls while considering cost and environmental impacts at the same time.

Air quality modeling can be considered as a useful tool to predict air quality in the future and determine the control strategies of emissions abatement. In this study, the AERMOD dispersion model has been applied as a tool for the analysis of the values of pollutant emissions from the flares of the Maroon gas refinery located in the suburb of Ahvaz, Iran. First, the values of pollutant emissions from the refinery’s flares were investigated by measurement and using the emission factors during cold and warm seasons of 2018. The gas burns continuously in two flares and the other 11 flares are used in emergency situations and only their spark plugs are lit. The type of compounds and their molar, volumetric, and weight percentages were determined by gas chromatography (GC) injection. By entering data such as emission rate, flare characteristics, and topographic and meteorological data of the study area into the AERMOD model, dispersion of pollutants was predicted by using the AERMOD model in the region with an area of 2500 km². The statistical evaluation showed that the maximum 8-h concentration of CO in the cold season was 133441 μg/m³ which was higher than the standard and reached 9755 μg/m³ in the warm season that was close to the standard. The maximum hourly concentration of SO₂ was in the cold season with 215 μg/m³ that was higher than the standard value, occurred in a local scale of 50 km². This can be attributed to the high concentration of SO₂ wet deposition. According to the direction of the wind from the northwest, pollutant emissions can lead to adverse health effects on the population of refinery employees, residents around the refinery, and occupants of passing vehicles. The concentration of pollutants generated due to the high volume of heavier compounds in the gas in the winter season was higher than that of the warm season. Comparison of maximum concentrations of the predicted results with the national and international standards showed that SO₂ and CO concentration is higher than standard values. In total, according to the evaluation of the predictions made, the performance of the AERMOD model was acceptable in the prediction of pollutant concentrations in the study area.

There is a growing interest in studying the determinants of climate change concern, but there are few studies conducted on developing countries like Pakistan. This study has three objectives. Firstly, to find whether there are differences in climate change concern levels between Pakistani citizens residing in rural and urban areas. Secondly, whether climate change concern is influenced by the same or different factors in rural and urban areas. Finally, whether the religious denomination one adheres to plays a role. The 2015 database provided by Pew Research Center, a representative sample of the Pakistani population, is used, and ordered logit models are run by including the independent variables in steps. The main finding is that the place of residency matters: rural residents show higher levels of concern than their urban counterparts. Climate change concern is influenced in both areas of residence by the gender of the respondent: females are more concerned than males. Nonetheless, there are differences in other determinants of climate change concern in rural and urban areas, for example, the education level, which affects mainly rural citizens. The religious denomination affects the concern of rural residents: Sunni Muslims show higher levels of climate change concern than Shi’a Muslims. Recommendations include the implementation of policies aiming to increase the education level in rural areas and the incorporation of courses and curricular or extra-curricular activities that would promote more concern among high school students.

In this research, a new android app for smartphones for estimating some water quality parameters in carp fish ponds such as pH, electrical conductivity (EC), total dissolved solids (TDS), and turbidity is presented. Contact imaging was used to acquire images from the samples. To estimate pH, EC, TDS, and turbidity values, 12 features were extracted from each image. Features were used as input to the artificial neural network models. The performance of the models was evaluated by the R² and RMSE parameters. Based on the results, the network with a structure of 12-15-4 was selected as the best model. The values of R² for estimating pH, TDS, EC, and turbidity were 0.913, 0.993, 0.994, and 0.958, respectively, while the corresponding values for the RMSE were 0.054, 1.835, 3.766, and 0.262, respectively. Finally, this model was successfully implemented on an app named WaterApp on the android smartphone. For testing the app on the smartphone, the performance of the model was evaluated again using new images. According to the results, the R² values for validation data by the developed WaterApp for pH, EC, TDS, and turbidity were 0.88, 0.913, 0.884, and 0.944, respectively.

Metal contamination in fishery water may pose a serious threat to aquatic products and human health. In this study, the contents of seven trace metals were assessed in water, sediment, and ten commercially important species (seven fish and three crustaceans) with different trophic guilds, habitat preferences, and motility, collected from the Zhoushan Fishery, northwest East China Sea. In general, the results showed that the concentrations of trace metals in water and sediment were lower than the safety thresholds set by the National Seawater Quality Standard of China and the sediment quality guidelines, except for Cu, As, and Cr in sediment. The high metal concentrations were spatially distributed in the west of the Zhoushan Fishery, which is probably due to the chemical pollution generated from many large international ports and chemical industries in Hangzhou Bay. The metal concentrations in the species were lower than the legislation thresholds established by the Commission Regulation and China National Standard, except for Cd in two crustacean species. However, a health risk assessment indicated that the consumption of the analyzed seafood is safe. However, there is a potential risk to local consumers who prefer crustaceans. From a species-specific bioaccumulation point of view, species in high trophic guilds, benthivores, species with low motility, or those living near the sediment have been found to be most likely to accumulate metals. Our findings could contribute to the understanding of the accumulation tendencies of metals in species of different trophic guilds with varying habitat preferences and motility and provide valuable data to environmental and seafood safety managers.

The United Nations Climate Conference 25, held in December 2019, reached a significant agreement against implementing the Paris agreement come 2020. Bound by the contract, 189 countries who are party to the deal agreed to constrain worldwide temperature to ascend to 1.5° Celsius. To this end, the present study attempts to investigate the readiness of selected countries in the European Union to implement the agreement, which will better the quality of the global environment. In line with this, this study appraises the connection between economic growth, renewable and non-renewable energy consumption, on emissions in 11 countries in the European Union from 1990 to 2016. The study utilises the Pooled Mean Group-Auto Regressive Distributed Lag (PMG-ARDL) model estimator and Dumitrescu and Hurlin Panel Causality analysis to analyse the long-run and short-run impact and direction of causality among these factors, respectively. The long-run study's empirical results show a U-shaped Environmental Kuznets Curve (EKC) and a negative connection between renewable energy use and emissions in the EU-11 countries. In the short-run, non-renewable energy use worsens CO₂ emissions while renewable energy use leads to a fall in emissions. Similarly, causality tests show a feedback mechanism between emissions and renewable energy use and between non-renewable energy and renewable use. Also, there is unidirectional causality from income to CO₂ emissions, non-renewable energy use to CO₂ emissions. The investigation recommends an expanded proportion of renewable energy sources in the EU countries’ energy mix to cut down on emissions.