In settlements, special attention is given to the study of anthropogenic aerosol pollution, and insufficient attention is given to natural sources of pollution, especially from active zones of the Earth. The aim of this work was to study atmospheric pollution (the Srednyaya Akhtuba village (Volgograd region, Russia)) using indicators (pH; EC, μS/cm) of aerosol suspensions (washing off aerosols from the leaves of Prunus armeniaca L.) during 2018–2020 and the forecast of pollution sources. Research hypothesis: low mineralization and close to neutral acidity of aerosol suspensions indicate the purity of the atmospheric air, and there is no load of anthropogenic and natural sources. Acid mineralized aerosols were found in the residential area of Srednyaya Akhtuba, which indicates air pollution during 2018–2020. The correlation relationship between pH and EC in μS/cm was investigated using standard least squares regression. The results obtained indicate statistically significant differences between the experimental territory and the (relatively) clean location from 2018 to 2020 in terms of the studied indicators, as well as the revealed correlation between them in Srednyaya Akhtuba village, which indicates the revealed patterns and the influence of the system factor. Anthropogenic and natural sources were the system factors. The authors predict an active underground ancient volcanic zone in the area of Srednyaya Akhtuba with a possible natural load on the residential areas of the village, the assumption of which is based on analysis of heat anomaly maps using the Landsat-8 program and other programs.

The responses of Ceratophyllum demersum to gradient concentrations (0, 0.8, 3.2, and 10 µg/L) of microcystin-LR (MC-LR) were comprehensively investigated by laboratory simulation experiments. The high reduction and accumulation efficiency of MC-LR by C. demersum were verified in this study. Results showed that the reduction ratio of MC-LR in the cultivation medium was up to 99% after 14 days of exposure, and the accumulation of MC-LR in C. demersum was highest at an exposure concentration of 10 μg/L, the value of which was 0.9 ng/g fresh weight (FW). Meanwhile, a series of negative effects on C. demersum was detectable, accompanied by a significant biomass reduction of the plant and changes in microbial community composition. In particular, this study indicated that the amount of Flavobacteria was elevated under the stress of MC-LR, provoking great threats to aquatic ecosystems. Moreover, oxidative damage was evidenced by the changes in total antioxidant capacity, superoxide dismutase, and glutathione. The results also demonstrated significant increases in sugar (0.025 mg/g FW), protein (0.3 mg/g FW), and carotenoids (0.6 mg/g FW) in C. demersum stressed by 10 μg/L of MC-LR, compared with the control without microcystins, which were among the defense strategies for dealing with adverse conditions. These results verified the good potential of submerged macrophytes as an eco-friendly strategy for controlling cyanobacterial blooms. However, the negative effects of MC-LR on the macrophytes themselves were also demonstrated, which would be considered in future practice and management.

This paper illustrates an experimental study on the elimination of Remazol Brilliant Blue R (RBBR) and Basic Red 18 (BR 18) dyes from synthetic aqueous solutions with iron oxide particles activated carbon cloth (IACC). The most important objectives of the experimental tests were to investigate the impacts of the different operating parameters, such as solution pH, adsorbent amount, H₂O₂ concentration and initial dye concentration on both studied colors removal. The experimental results demonstrated that 96.14% RBBR dye and 98.44% BR18 dye removals were observed for initial dye concentration of 100 mg/L with adsorbent amount of 1.0 cm²/100 mL, H₂O₂ concentration of 2.5 µL/L and optimum pH at the end of 60 min of operation. It was observed that, an increase in initial dye concentration decreased the dye removal efficiency. Optimum pH for the highest RBBR dye removal was 2.5 and 3.0 for BR 18 maximum removal efficiency. It was also observed that the increase in hydrogen peroxide (H₂O₂) concentration in the solution reduces the dyes removal efficiency. The loaded iron oxide particles on carbon cloth catalyst revealed to be an effective solution for high removal performance of cationic and anionic dyes.

Chemical pollutants present a substantial threat to the survival of the green turtle (Chelonia mydas). In this study, the concentrations of 12 trace elements (TEs) in seawater, sediments, and green turtle forage and eggshells from the Xisha Islands in the South China Sea, along with their patterns of transfer and accumulation, were identified. The results revealed that the median TE concentrations in seawater and sediments were lower than the first-grade limit values of the national standard in China, indicating a low ecological risk. The concentrations (μg·g⁻¹) of TEs in forage ranged from 0.05–0.69, 3.43–14.4, 157–2391, 27.9–124, 2.05–9.39, 0.30–9.78, 2.01–80.50, 0.18–5.76, 0.06–0.98, 2.00–18.4, 0.02–0.24, and 0.01–0.09 for Cr, Mn, Sr, Fe, Ni, Cu, Zn, Se, Cd, As, Pb, and Hg, respectively. Seawater, sediments, turtle forage, and eggshells exhibited different TE profiles, which were driven by Hg, Sr, Cr, and Pb in seawater and sediments; Fe and Ni in sediments; Cd and As in forage; and Zn, Se, and Cu in eggshells. The contents of Cu, Zn, and Se increased slightly with trophic level, indicating that they were transferred through dietary pathways. Although Cd and As appeared to bioaccumulate in green turtle forage, it was not transferred to their eggshells, which may be related to the excretion and metabolism process in the mother’s body. Thus, eggshells may be a poor bioindicator for the exposure of female green turtles to these toxic elements.

Water is considered one of the most superabundant resources on the earth that covers 75% of the entire earth’s surface, yet numerous countries face problem due to water shortage. Desalination is considered the most efficient process to overcome this rising clean water demand. Solar energy is considered one of the efficient and finest resources to refine brackish water. Therefore, this paper proposes a novel black widow particle swarm optimization–based deep neural network approach to enhance the water productivity from a solar still. The main intension of the proposed BWPSO–based DNN approach is to enhance the performances of DNN by employing BWPSO for optimal water production. Here, the optimal weight of the DNN is determined by utilizing the BWPSO algorithm. The solar still is incorporated with a straight tube and spiral tube solar water collector. In addition to this, the study based on solar still and their experimental analysis is carried out in Coimbatore city located in Tamil Nadu. The evaluation is conducted for various parameters, namely glass temperature, average evaporation temperature, inlet and outlet temperature, water temperature, air temperature, yield, solar intensity, wind velocity, RMSE, MAE, MRE, and ECR, to determine the effectiveness of the system. Also, comparative analysis is made and the evaluation results reveal that the proposed approach outperforms various other approaches.

Developing strategies that counter the ongoing homogenization trends of home-garden agroforestry systems is required to maintain diversity and sustainability. This study aimed to map and characterize traditional enset-based home-garden agroforestry for managing sustainability in the Gurage socioecological landscape in Ethiopia. We generated plots and land use land cover (LULC) spatial data from orthophotomosaic and collected household survey data of the field. Five home-garden types were identified explicitly through integrating the home-garden composition, functional structure, and agroecological zones. Most home-garden types had similar horizontal functional structures in which perennial crops were planted close to homesteads, annual crops grew in outer fields, and woodlots were located at the end of the parcel. Diverse woody species, crop varieties, and plot sizes were identified in individual household parcels, and these varied across the home-garden types. Enset-based home-garden agroforestry production has been declining in the Ethiopian landscape because of socioeconomic changes and a lack of technological inputs. These challenges may compromise the community’s food security with loss of the product diversity provided by the home-garden system. Thus, technological adoptions and scaling up of agroforestry practices according to the home-garden types are necessary for the continue provision of multiple contributions. This study demonstrated site-specific spatial characterization of the agroforestry systems by considering a holistic approach to reduce the local challenges and support the development of sustainable landscape management in an altering socioecological landscape.

The speciation of mercury in various processing units of sewage treatment in autumn and winter were studied to understand the conversion and fate of mercury. The results show that the average concentrations of total mercury (THg) in the influent were 130.5 ± 69.8 ng/L and 231.3 ± 107.2 ng/L in autumn and winter, respectively, and the particulate mercury was the main speciation (accounting for 59.3% and 86.9%, respectively). The proportion of dissolved mercury increased after treatment, and the total removal efficiencies of THg were 78.9% and 90.8%, respectively. The release of mercury into the atmosphere during wastewater treatment was studied for the first time. The dissolved gaseous mercury levels in the influent in autumn and winter were 0.60 ± 0.40 ng/L and 0.34 ± 0.21 ng/L, respectively. The average gaseous element mercury concentration in aerobic tank air was 6.34 ± 0.49 ng/m³. The estimated mercury from aeration was 6.4 kg per year in China. The dissolved gaseous mercury will be released to the air if the sewage treatment plant is open-air. Closed sewage treatment and collection of waste gas treatment can reduce the influence of released mercury. Mercury releases into the atmosphere in the process of sewage treatment are one of the fates of mercury in sewage. Closed sewage treatment and collection of waste gas treatment are necessary to reduce the influence of released mercury. The reactive mercury levels in the influents of autumn and winter were 1.28 ± 0.49 ng/L and 1.96 ± 0.43 ng/L, and these levels account for a small proportion of THg, only 1.7% and 0.8%. Hg²⁺ were released by the degradation of organic matter in the secondary biological treatment. The THg levels in dehydrated sludge were higher than those in biochemical sludge but lower than the maximum limit of THg in agricultural sludge.

Low-carbon city (LCC) pilot is a strategic policy to deal with global climate change and energy poverty. Using the city-level data from 2006 to 2019, this paper applies a multiple difference-in-difference (DID) analysis to explore the impact of LCC policy on urban green total factor energy efficiency(GTFEE) and its potential mechanism. The results show that the LCC pilot policy can significantly improve urban GTFEE, and the finding remains robust with various tests. Secondly, we shed light on the mechanism of the LCC policy and explore the possible channels through green innovation and structural upgrading to improve the urban GTFEE. Third, the policy effect is affected by different levels of urban economic development, urban development scale, and urban development types. In cities with higher levels of economic development, super-large resource-based cities, the pilot policy has a more significant improvement effect on GTFEE. On the other hand, in the less developed regions, pilot policies will hinder the improvement of GTFEE.

Alkylphenols are industrial pollutants commonly present in wastewater. They are difficult to eliminate by conventional treatment processes, ending up in the sludge of wastewater treatment plants. In this study, we propose to use cross-linked cyclodextrin-based polymers (ECP) as sorbents to treat three alkylphenols, namely, one nonylphenol (4-n-NP) and two octylphenols (4-n-OP and 4-tert-OP), present in aqueous solution by a batch method. The experiments were carried out with five cyclodextrin polymers (α-ECP, β-ECP, γ-ECP, α,β,γ-ECP, and HP-β-ECP). Sorption results showed that all polymers, with the exception of α-ECP, had high sorption capacities between 60 and 100% of the alkylphenols in the concentration range studied (between 25 and 100 μg/L). In all cases, HP-β-ECP has shown the highest removals, regardless of the structure of the molecule. The order obtained was HP-β-ECP >> β-ECP ~ α,β,γ-ECP >> γ-ECP > α-ECP. The 4-tert-OP compound was the best adsorbed, regardless the material and the solution studied. Sorption results also indicated that (i) the sorption efficiency decreased with the increasing of alkylphenol concentration; (ii) sodium chloride had a strong negative effect on the sorption process; and (iii) the performance remained unchanged after five sorption-regeneration cycles. The main sorption mechanism of alkylphenols occurring in ECP was the inclusion within the cyclodextrin cavities. The obtained results proved that cyclodextrin polymers could serve as efficient sorbents for the removal of alkylphenols from real effluents.