Water, Air, & Soil Pollution最新文献

Iron and Manganese pollution were widespread in the water of northern Chinese mines, exacerbating regional water scarcity and potential ecological issues. This study aimed to remove dissolved iron and manganese from acid mine water using serpentine-loaded manganese oxide (Serp-MO) prepared by a simple coprecipitation-loaded metal method. Serp-MO was microscopically characterized, and the adsorption performance and adsorption mechanism of the Serp-MO composite adsorbent for Fe²⁺ and Mn²⁺ were analyzed. After loading, the specific surface area and pore volume of the particles significantly increased, and the surface pore structure improved, which was conducive to the simultaneous adsorption and removal of iron and manganese. The optimal reaction conditions for Serp-MO treatment of composite water samples with Fe²⁺ and Mn²⁺ mass concentrations of 20 mg/L and 5 mg/L respectively, were as follows: dosage of Serp-MO 550 mg/L, temperature 35 ℃, oscillation rate 180 r/min, and reaction time 140 min. Under these conditions, the removal rates of Fe²⁺ and Mn²⁺ were 99.8% and 99.6%, respectively. The presence of coexistence cations Zn²⁺ and Cu²⁺ can inhibit the removal of Fe²⁺ and Mn²⁺ by Serp-MO, while SO₄^2- can promote the removal. The pseudo-second-order kinetic model and Langmuir isothermal adsorption model well described the adsorption process of Fe²⁺ and Mn²⁺ by the Serp-MO. The maximum adsorption capacities of Serp-MO for Fe²⁺ and Mn²⁺ were 14.31 mg/g and 24.04 mg/g, representing improvements of 470.12% and 626.28%, respectively, compared to Serp-MO. The adsorption thermodynamics showed that ΔG was <0 and ΔH and ΔS were greater than 0 at all test temperatures, which was an entropy-increasing reaction, and that increasing the temperature was favorable for the removal of Fe²⁺ and Mn²⁺. Based on the analysis of adsorption products, Serp-MO primarily facilitates the precipitation of iron in water, while the removal of manganese was mainly by adsorption. A regeneration study over five cycles indicated that Serp-MO possessed promising reusability potential. Furthermore, the safety leaching test indicated that the material caused minimal secondary pollution.

In response to increased desertification in Africa due to climate change, understanding the behavior of particulate matter with aerodynamic diameters less than or equal to 2.5 and 10 (mu m) ((PM_{2.5}) and (PM_{10})) in the Caribbean is crucial. Fine particles originating from the African dust belt significantly impact the health of the Caribbean population. This study employs a multifractal framework to analyze (PM_{2.5}) and (PM_{10}) time series data in Puerto Rico from 2000 to 2010, marking the first such investigation in the Caribbean islands. Multifractal Detrended Fluctuation Analysis (MF-DFA) reveals similar multifractal behavior in (PM_{10}) and (PM_{2.5}) fluctuations, suggesting a shared influence on these pollutants. Hurst exponents of 0.594 for (PM_{10}) and 0.642 for (PM_{2.5}) indicate long-term persistence in particulate matter behavior. African dust notably influences (PM_{10}), displaying slightly greater intermittency. Shuffled and surrogate signal analyses confirm multifractality in PMs time series, representing long-range correlations in small and large fluctuations and broadness in probability density function. The primary contributor to multifractality in (PM_{2.5}) is identified as the broadness of the probability density function. Multifractal Detrended Cross-Correlation Analysis (MF-DXA) reveals anti-persistence in cross-correlated multifractal behavior of PMs. These insights enhance the understanding of (PM_{2.5}) and (PM_{10}) dynamics, aiding predictions of natural occurrences like sand mist and improving health risk management in the Caribbean basin.

Removing heavy metal ions from wastewater reduces health and ecological risks and allows for their reuse. Polymer inclusion membranes with integrated ion carriers offer an efficient solution for removing toxic metal ions from industrial wastewater. These membranes can be further enhanced by using biodegradables polymer blends and incorporating nanofillers to improve their selectivity, stability, extraction efficiency, and biodegradability. In this study, a novel biodegradable polymer blend consisting of 54% poly(lactic acid) (PLA) and 13% polybutylene adipate terephthalate (PBAT) was utilized as the base polymer, with 30% Aliquat 336 as an ion carrier and either 3% graphene oxide (GO) or 3% cloisite 30B (C30B) as nanofillers. The hybrid blend contained a total of 3% nanofillers, with 1.5% graphene oxide (GO) and 1.5% cloisite 30B (C30B). These components were integrated through the evaporation casting method and evaluated for their potential as polymer inclusion membranes (PIMs) for Cr(VI) extraction. Various analytical methods, including X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), were employed to explore the microstructure-property relationships of the fabricated nanocomposite PIMs. The analyses revealed the development of new semi-crystalline membrane structures, resulting in enhanced hexavalent chromium extraction. It was found that the presence of nanofillers altered the bulk structure, creating apparent microvoids in the membranes filled with 3% GO and the hybrid membrane, which were not observed in membranes filled with C30B. This resulted in higher extraction efficiency in the membranes loaded with GO, whereas membranes loaded with C30B exhibited decreased Cr(VI) extraction. An intermediate extraction percentage was found in the hybrid membrane filled with both nanofillers. Additionally, the incorporation of GO and C30B significantly improved membrane stability across various media, reducing mass loss in NaCl/NaOH to 13.36%. The TGA analyses further confirmed that membranes incorporating GO and C30B exhibited improved thermal stability.

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After shale gas well sites are exploited, remediation is essential to restore the ecological environment. Effective bioremediation often has long cycles, so reducing this period is a research focus. To elucidate the intrinsic mechanisms between microorganisms and oil removal and to support the acceleration of bioremediation, gas chromatography–mass spectrometry and high-throughput sequencing technologies were utilized. The oil transformation and microbial response mechanisms during the natural remediation process from August to December at an abandoned shale gas well site in Weiyuan County, Neijiang City, Sichuan Province, were analyzed, revealing the directions of microbial succession. The Results showed that from August to September, the greatest degradation of oil components (C10-C20、C21-C30 alkanes) occurred, with Actinobacteriota, Gemmatimonadota, Proteobacteria, Acidobacteriota, Bacteroidota, and Ascomycota playing major roles. Key contributors to oil degradation included Sphingomonas, Flavisolibacter, Ramlibacter, Mortierella, Fusarium, and Rectifusarium. These microorganisms, along with those such as Chloroflexi, Gemmatimonas, Ellin6067, Cercospora, Sarocladium, Preussia, Calyptrozyma, Staphylotrichum, and Exophiala, which facilitate the cycling of nutrients like carbon, nitrogen, and phosphorus, collectively promote the degradation of oil. Moisture content, electrical conductivity, total nitrogen, total phosphorus, and pH affect the activity of oil-degrading microbes and thus oil degradation. Conversely, microbes alter soil chemistry during degradation, impacting those physicochemical properties. This feedback mechanism influences the activity of other oil-degrading microbes, creating a dynamic interaction network. Ultimately, the microbial community shifts towards populations that aid soil ecosystem restoration. This study reveals microbial succession and its role in oil degradation, offering insights for improving and accelerating bioremediation.

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This study evaluates the influence of micropollutant chemical characteristics on the removal of pharmaceutical substances through three different treatments: membrane bioreactor, full wastewater treatment with final filtration (WWTP), and secondary treatment through a conventional activated sludges system, operated in parallel at realistic sludge retention time (SRT) over three years and four sampling campaigns. Treated wastewater from the WWTP enters the local canal with a low dilution ratio. Therefore, the monitoring of water contamination is of particular interest for a reliable assessment of environmental risk. A total of 39 pharmaceutical substances were screened. While differences among the three types of treatments were found statistically not significant, data analysis performed through a generalized linear model showed that both the influent concentration and the physicochemical characteristics are strong predictors for the removal of micropollutant. SRT had no significance for the three types of treatment of this study. Finally, pharmaceuticals were divided into three major classes based on their influent concentration and removal. A canonical discriminant analysis was used to predict the removals and showed that the pharmaceuticals removal rates are strongly influenced by their hydrophobicity/hydrophilicity and enabled to predict their removal categories with high accuracy (i.e., 65% of correct predictions).

Metal enrichment in aquatic ecosystems has compromised the potential of fish to enhance food security. The uMgeni River drains urban and industrialized catchment and flows through economically disadvantaged rural communities that opt for fish to supplement their protein needs. However, there are uncertainties on the safety of consuming fish from the uMgeni River. The present study aims to explore metal distribution between the water, sediment, and tissues of the preferred Oreochromis mossambicus, and evaluate whether concentrations in the muscle are safe for human consumption. The water, sediment, and fish samples were collected from Inanda and Nagle dams, and metal concentrations were analysed using inductively coupled plasma mass spectrometry. Alkaline pH was observed at both dams and metals were below detectable level in the water column. Even though metal concentrations in the water column were below detectable levels, significant concentrations were found in the sediment. No consistent trend in metal concentrations was observed across tissues, but higher levels were generally found in the liver, followed by the gill, and then the muscle. Nickel (Ni) and lead (Pb) exhibited concentrations exceeding the permissible limit for human consumption. Similarly, the target hazard quotient exceeded the threshold of 1 for Pb, chromium (Cr), and antimony (Sb) at both dams with Inanda Dam showing higher indices for Sb and Pb. The carcinogenic risk for the three metals was also found to be higher than 10^–6. These findings suggest that consumption of O. mossambicus from the uMgeni River should be limited to no more than 150 g per week.

Environmental contamination by plastics poses a significant threat to both fauna and flora, manifesting in lethal and sub-lethal effects. Plastics can enter coastal and marine environments through wind and rain, with microplastics (< 5 mm; MPs) arising from the degradation of larger plastics or being manufactured for commercial use. Despite Brazil's extensive coastline, data on microplastic contamination is scarce. This study aimed to assess microplastic pollution on a beach in Rio Grande do Sul, Brazil. Samples were collected from 30 points along the high tide line, with beach sand processed through density separation and filtration. Microplastics were quantified using Nile Red stain under fluorescence microscopy and chemically identified via the µRaman technique. Results showed an average concentration of 650 MPs/kg of sediment, with higher concentrations near the Mampituba River, indicating a greater transport of plastic contaminants by the river to the coastline. The smallest particles (50–100 µm) were most abundant, and the predominant types of plastics identified were polyethylene (PE), polypropylene (PP), and polyamide (PA). This study provides the first quantification of microplastic pollution in this region, indicating that the concentration and types of microplastics are consistent with findings elsewhere in Brazil and globally. These results highlight the widespread nature of microplastic pollution and underscore the need for coordinated environmental remediation efforts.

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This study explores the recovery and preparation of Pb from Zn plant residues (ZPR), specifically leaching filter cake (LFC), through a hydrometallurgical process that includes the cementation of Pb using Zn and Al powder. The process consists of three key stages: acidic washing of zinc, alkali leaching, and the subsequent cementation of lead using zinc and aluminum powder. The effects of various parameters such as powder amount, temperature, reaction time, and stirring speed on the reaction kinetics were systematically examined. Optimal separation conditions were determined for both zinc and aluminum powder, with Pb cementation achieving 97.56% and 99.95% respectively, under specific conditions. Additionally, a kinetic study was conducted to evaluate the reaction mechanisms and activation energies associated with Pb cementation using zinc and aluminum powder. The results indicated that Pb cementation was powder-controlled in both cases, with reaction activation energies of 8.6 kJ/mol and 4.6 kJ/mol using zinc and aluminum powder, respectively. Furthermore, the use of aluminum powder demonstrated several advantages including enhanced performance, high purity of Pb product, and reduced powder consumption. This research advances the optimization and understanding of Pb recovery processes from ZPR, emphasizing the potential of aluminum powder as a promising alternative for effective lead cementation.

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The environmental implications of tire wear particles (TWPs) have been extensively studied. One notable concern associated with nano-sized TWPs is their potential role as carriers that enhance the spread of co-occurring pollutants, especially in the context of aging processes. This study demonstrated how exposure to acid, ultraviolet (UV) radiation, or ozone (O₃) induced alterations in the physico-chemical properties of TWPs, consequently increasing their mobility within saturated sand environments. In cotransport cases, both original TWPs and aged TWPs inhibited the transport of Cd²⁺ and Ni²⁺ in different degrees, whereas no obvious changes in their intrinsic mobilities. The contaminant-mobilizing ability of TWPs followed the order of original TWPs/UV-TWPs < H⁺-TWPs < O₃-TWPs. Experimental results and model-based analyses indicated the important role of mobility, adsorption affinity and desorption hysteresis in the cotransport of TWPs and heavy metals. In comparison with original TWPs, the adsorption affinity of H⁺-TWPs and O₃-TWPs for Cd²⁺/Ni²⁺ decreased, while that of UV-TWPs was similar to original TWPs. Simultaneously, the desorption rates of TWPs decreased to different extents after aging. The results of this study provide valuable insights on the fate of aged TWPs and their interactions with heavy metals in the natural environment, and help assess the environmental behavior and contaminant mobilization capacity of TWPs, especially considering the distinct effects of different aging processes. It is imperative to emphasise the necessity for targeted management strategies to transport the environmental impacts of TWPs, particularly as they age and interact with heavy metals.

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A recent spontaneous return of a native brown trout population in Lake Laka and its tributaries followed the gradual recovery of the Bohemian Forest (Czechia) from atmospheric acidification. The lake had hosted a vibrant brown trout population in the first half of the 20^th century, which then became extinct around the 1960s due to strong atmospheric acidification, peaking in the 1980s. However, since the 1990s, a gradual reversibility in acidification has occurred. This positive trend was delayed after tree dieback in the lake catchment in the 2000s. The following detailed monitoring showed recurrent critical periods of low pH and ANC, and elevated concentrations of ionic Al. This was especially in spring, lasting until the late 2010s. Electrofishing from 2020 to 2022 indicated suitable conditions for permanent fish populations. In comparison to previous electrofishing (2005–2010), brown trout colonised Lake Laka and formed a stable population in the lake outflow. Downstream of the lake, the fish abundance remained similar to those some ten years earlier. In contrast to the brown trout, the bullhead was only found in the stream below the lake, as it was unable to migrate to the upper areas due to natural barriers. The recovery of the brown trout population in Lake Laka after the acidification phase is an example of the successful restoration of a disturbed aquatic ecosystem under pristine conditions.