Polluted Sites Research Articles

Variability of faecal microbiota and antibiotic resistance genes in flocks of migratory gulls and comparison with the surrounding environment

Gulls commonly rely on human-generated waste as their primary food source, contributing to the spread of antibiotic-resistant bacteria and their resistance genes, both locally and globally. Our understanding of this process remains incomplete, particularly in relation to its potential interaction with surrounding soil and water. We studied the lesser black-backed gull, Larus fuscus, as a model to examine the spatial variation of faecal bacterial communities, antibiotic resistance genes (ARGs), and mobile genetic elements (MGEs) and its relationship with the surrounding water and soil. We conducted sampling campaigns within a connectivity network of different flocks of gulls moving across functional units (FUs), each of which represents a module of highly interconnected patches of habitats used for roosting and feeding. The FUs vary in habitat use, with some gulls using more polluted sites (notably landfills), while others prefer more natural environments (e.g., wetlands or beaches). Faecal bacterial communities in gulls from flocks that visit and spend more time in landfills exhibited higher richness and diversity. The faecal microbiota showed a high compositional overlap with bacterial communities in soil. The overlap was greater when compared to landfill (11%) than to wetland soils (6%), and much lower when compared to bacterial communities in surrounding water (2% and 1% for landfill and wetland water, respectively). The relative abundance of ARGs and MGEs were similar between FUs, with variations observed only for specific families of ARGs and MGEs. When exploring the faecal carriage of ARGs and MGEs in bird faeces relative to soil and water compartments, gull faeces were enriched in ARGs classified as High-Risk. Our results shed light on the complex dynamics of antibiotic resistance spread in wild bird populations, providing insights into the interactions among gull movement and feeding behavior, habitat characteristics, and the dissemination of antibiotic resistance determinants across environmental reservoirs.

Can lichens be indicators for air pollution monitoring in Kandy City, Sri Lanka?

The quality of the surrounding environment significantly impacts lichen diversity and composition, but crustose lichens, particularly those in disturbed environments, can persist. Although the effects of habitat disturbances on the morphology, anatomy, chemical composition, and fertility of lichen species have not been extensively researched, understanding their mechanisms is crucial for understanding their persistence in their environment. The study aimed to identify common lichen species in polluted and semi-polluted environments and compare their morphology, anatomy, chemical composition, and fertility. A two-kilometer stretch along the road that passes through the University of Peradeniya was selected as the semi-disturbed site based on previous records, while the area around Kandy Lake was designated as the polluted site. Using conventional keys, lichen species were identified, and using a hand lens, dissecting microscope, and compound microscope, the morphological traits of the thallus, apothecia, soredia, and isidia, as well as the anatomical features of the thallus, apothecia, and ascospores, were compared between the two sites. Thin-layer chromatography was used to separate and elucidate the secondary metabolites of lichen. Thirty-nine species were discovered on the university site, 15 in the area around Kandy Lake, and species gathered from both locations shared commonalities, including Physcia sp., Parmotrema sp., Lecanora sp., Graphis sp., and Lepraria sp. The color difference between all species, as measured by mean dE, is visible to the naked eye and changes from a pale to a dark hue from a semi-disturbed site to a polluted one. In comparison to disturbed sites, the majority of species displayed an increased mean area in semi-polluted sites. Layer thickness increases or decreases depending on how well each layer can withstand disruptions. Depsinose has been recognized as a potential class of metabolites generated by lichens present in both locations. Only lake sites exhibit toxic metal compounds, as opposed to semi-disturbed sites. Every pH value was acidic, and most species at the lake site had more acidic pH than those at the university site. There is no specific trend in apothecial number and ascospore numbers in common lichen species in both sites. The current study showed that changes in certain morphological and anatomical biochemical characteristics can be triggered by the environment, suggesting that the quality of the environment significantly affects the growth and reproductive success of lichens, thereby survival or extinction, and proposed that bioindicator and bioaccumulator species concerning the changes occurred.

Temporal changes in the morphological and microbial diversity of biofilms on the surface of a submerged stone in the Danube River

Epilithic biofilms are ubiquitous in large river environments and are crucial for biogeochemical processes, but their community structures and functions remain poorly understood. In this paper, the seasonal succession in the morphological structure and the taxonomic composition of an epilithic bacterial biofilm community at a polluted site of the Danube River were followed using electron microscopy, high-throughput 16S rRNA gene amplicon sequencing and multiplex/taxon-specific PCRs. The biofilm samples were collected from the same submerged stone and carried out bimonthly in the littoral zone of the Danube River, downstream of a large urban area. Scanning electron microscopy showed that the biofilm was composed of diatoms and a variety of bacteria with different morphologies. Based on amplicon sequencing, the bacterial communities were dominated by the phyla Pseudomonadota and Bacteroidota, while the most abundant archaea belonged to the phyla Nitrososphaerota and Nanoarchaeota. The changing environmental factors had an effect on the composition of the epilithic microbial community. Critical levels of faecal pollution in the water were associated with increased relative abundance of Sphaerotilus, a typical indicator of “sewage fungus”, but the composition and diversity of the epilithic biofilms were also influenced by several other environmental factors such as temperature, water discharge and total suspended solids (TSS). The specific PCRs showed opportunistic pathogenic bacteria (e.g. Pseudomonas spp., Legionella spp., P. aeruginosa, L. pneumophila, Stenotrophomonas maltophilia) in some biofilm samples, but extended spectrum β-lactamase (ESBL) genes and macrolide resistance genes could not be detected.

Cleaning Oily Sludge Using Colloidal Gas Aphrons: Optimizing Process Conditions and Analyzing Mechanisms.

Colloidal gas aphrons (CGAs) are applied in pollutant removal due to their large specific surface area and high surface activity. The structure and properties of the prepared CGAs were investigated in the process of oil removal from oily sludge. The prepared CGAs had a liquid film thickness was 5-10 μm with high stability. CGA interfacial tension was as low as 3.157 mN/m. Then it was found that the oil removal rate of CGAs was higher than that of chemical treatments, showing that CGAs could increase the mass transfer surface area and provide additional attachment sites for pollutants, enhancing the oil removal. The treatment conditions of the oil removal were optimized through response surfaces, showing that under optimal treatment conditions, the oil removal rate of oily sludge reached 96.07%. Additionally, the interaction between surfactant concentration and temperature was the most significant of all of the influencing factors. The behavior and mechanism of CGAs in the cleaning process of oily sludge were further investigated using an inverted fluorescence microscope, SEM, FTIR, and two-dimensional fluorescence spectrometer, showing that pollutants transferred from the liquid film surface of CGAs to the inside the film, and CGAs could specifically adsorb negatively charged organic compounds and aromatic hydrocarbons. The results show that CGAs achieved liquid membrane solubilization. Many negatively charged organic compounds and aromatic hydrocarbons are adsorbed onto the CGAs liquid membrane surface via electrostatic and hydrophobic interactions and then migrated to the hydrophobic layer of the CGAs liquid membrane due to the distribution effect, thus enabling rapid pollutant migration between solid and liquid phases.

Reduction in reproductive activity from degeneration of testicular follicles in Megapitaria squalida (Mollusca: Bivalvia) exposed to metal pollution in the Gulf of California

Over a reproductive cycle, the prevalence and intensity of degeneration of testicular follicles in Megapitaria squalida collected from the mining port of Santa Rosalia (a highly metal-polluted area), and San Lucas (a less polluted site), Gulf of California, Mexico, were evaluated. At San Lucas, most individuals had a typical testicular structure, and degeneration of testicular follicles was present in 9.5 % of spawning organisms. In contrast, at Santa Rosalia, 68 % of males, mainly in the ripe stage, had testicular degeneration (72 % severe intensity, mostly in medium and large-sized). Degeneration was characterized by intense hemocyte infiltration, identified as dense masses with numerous melanized cells in the follicle lumen. In both sites, males with testicular follicles degeneration had a lower condition index compared to males without degeneration. Degeneration of testicular follicles before spawning compromises and decreases the reproductive activity of M. squalida males at Santa Rosalia, which may ultimately affect the population sustainability.

Phytoremediation mechanism and role of plant growth promoting rhizobacteria in weed plants for eco-restoration of hazardous industrial waste polluted site: a review.

Plants have numerous strategies for phytoremediation depending upon the characteristic of pollutants. Plant growth promoting rhizobacteria (PGPR) are essential to the process of phytoremediation and play a key part in it. The mechanism of PGPR for phytoremediation is mediated by two methods; under the direct method there is phytohormone production, nitrogen fixation, nutrient mineral solubilization, and siderophore production while the indirect method includes quorum quenching, antibiosis, production of lytic enzyme, biofilm formation, and hydrogen cyanide production. Due to their economic and environmental viability, most researchers have recently concentrated on the potential of weed plants for phytoremediation. Although weed plants are considered unwanted and noxious, they have a high growth rate and adaptability which opens a high scope for its role in phytoremediation of contaminated site. The interaction of plant with rhizobacteria starts from root exudates containing various organic acids and peptides which act as nutrients essential for colonization and siderophore production by the rhizospheric bacteria. The rhizobacteria, while colonizing, tend to promote plant growth and health either directly by providing phytohormones and minerals or indirectly by suppressing growth of possible phytopathogens. Recently, several weed plants have been reported for phytoextraction of heavy metals (Ni, Pb, Zn, Hg, Cd, Cu, As, Fe, and Cr) contaminants from various agro-based industries. These potential native weed plants have high prospect of eco-restoration of polluted site with complex organo-metallic waste for sustainable development.

Atomic-Level Engineered Cobalt Catalysts for Fenton-Like Reactions: Synergy of Single Atom Metal Sites and Nonmetal-Bonded Functionalities.

Single atom catalysts (SACs) are atomic-level-engineered materials with high intrinsic activity. Catalytic centers of SACs are typically the transition metal (TM)-nonmetal coordination sites, while the functions of coexisting non-TM-bonded functionalities are usually overlooked in catalysis. Herein, the scalable preparation of carbon-supported cobalt-anchored SACs (CoCN) with controlled Co─N sites and free functional N species is reported. The role of metal- and nonmetal-bonded functionalities in the SACs for peroxymonosulfate (PMS)-driven Fenton-like reactions is first systematically studied, revealing their contribution to performance improvement and pathway steering. Experiments and computations demonstrate that the Co─N3C coordination plays a vital role in the formation of a surface-confined PMS* complex to trigger the electron transfer pathway and promote kinetics because of the optimized electronic state of Co centers, while the nonmetal-coordinated graphitic N sites act as preferable pollutant adsorption sites and additional PMS activation sites to accelerate electron transfer. Synergistically, CoCN exhibits ultrahigh activity in PMS activation for p-hydroxybenzoic acid oxidation, achieving complete degradation within 10min with an ultrahigh turnover frequency of 0.38min-1, surpassing most reported materials. These findings offer new insights into the versatile functions of N species in SACs and inspire rational design of high-performance catalysts in complicated heterogeneous systems.

Biodegradation of monocrotophos by Stenotrophomonas maltophilia and its potential in vitro plant growth promoting activities

Extensive field application of monocrotophos (MCP), an organophosphate pesticide to protect agricultural crops and yields, imposes severe environmental issues due to its long-term persistence in soil and water. Indigenous bacterial strain CAB5 was isolated from a severely monocrotophos-contaminated agricultural field in Mysuru, Karnataka. The strain was assessed for its ability to biodegrade monocrotophos and plant-growth promoting factors. CAB5, identified as Stenotrophomonas maltophilia (OQ861256). It exhibited monocrotophos tolerance up to 1000 ppm by utilizing it as sole carbon source for metabolism and growth. S. maltophilia can produce several plant growth-promoting (PGP) traits, including ammonia, cellulase, IAA, catalase, and phosphate solubilization. The optimal condition for CAB5 growth observed as pH 8, 37 ℃ temperature, and 96 h of incubation time, respectively. Biodegradation was analyzed by combining hyphenated techniques like UV spectroscopy and TLC, and the intermediate metabolites were analyzed by FT-IR and LC-MS. Dimethyl-phosphate, Trimethyl phosphate, and Cyclohexanone, 2-cyclohexylidene were the intermediate metabolites formed from biodegradation. It is concluded that S. maltophilia CAB5 could be an advantageous with the consortium-based formulated prototype for the refinement of polluted sites for toxic pollutants along with plant growth promotion.

Measuring the Levels of Heavy Metal Pollution in Al - Diwaniyah River Water Using Oomycetes Fungus

The research included, for a period of 6 months, a study of two aspects. The first was the isolation and diagnosis of oomycetes in the water of Al-Diwaniyah River in five sites. The sites where pollution increased were chosen, namely textile, rubber factories, and sites before water treatment, compared to two sites: Sadr Al-Daghara and a site under Al-Diwaniyah Bridge, which had little pollution, as the percentage of pollution increased. Ovomycetes in pollution sites in order to increase the organic matter in them and to provide many nutrients, knowing that these fungi were isolated from control areas, but in small proportions, in addition to other groups of non-oomycetes and the previously dominant types of Oomycetes. Some physical tests were conducted on the water of the Diwaniyah River in the study sites to observe the suitability of the physical characteristics for the presence of these fungi, namely temperature, PH, alkalinity, hardness, and others. The second aspect is to consider these fungi as indicators of pollution in the river water when they are present in polluted areas by analyzing the enzymatic filtrate to measure The percentages of presence of heavy metals, such as cadmium, mercury, lead, and selenium, which appeared in high percentages that exceeded the permissible limits for their presence, whether in river water or in the bodies of living organisms. The percentages of cadmium were (0.012)% in Saprolegnia sp. and Pythium sp., while the percentages of lead were (1.5, 1.3).)% in Saprolegnia sp and Fusarium sp, while mercury recorded a percentage of (0.3, 0.05, 1.2)% in Achlya., Apodachlya sp.,. Fusarium sp. Selenium appeared at a rate of (0.2)% in Apodachlya sp, Arsenic in Pythium sp. At a rate of (0.02%) also for the purpose of comparison of these results, tests were conducted for heavy metals in the water at the selected sites (L3, L2, L1) (fabric, rubber, and site before treatment) respectively. The results showed the appearance of heavy metals (cadmium, lead, mercury, arsenic, selenium). In high percentages compared to sites L4 and L5, their percentages were very small, almost reaching zero.

Can water mites’ parasitism influence the number of microplastics ingested by aquatic insects?

Microplastic pollution endangers both aquatic and terrestrial ecosystems. Their spread across the food chain also endangers human health. Wastewater treatment plants (WWTPs) can be viewed as the final barrier between microplastics and the environment. In addition, it is well-known that water mites are abundant parasites in aquatic ecosystems, and nearly all insect orders with aquatic stages are considered potential hosts for at least one water mite species. However, no studies have been conducted to test the direct and indirect effects of parasites on population dynamics in freshwater ecosystems or the role of predators in shaping the behavior and life histories of aquatic organisms. Thus, this work aimed to study the seasonal abundance, distribution, composition, and risk assessment of MPs in surface water, aquatic insects (Coroxide and Notonectidae), and for the first time, water mites (Hydrachnidiae), as well as the effect of water mites’ parasitism on the number of MPs ingested by aquatic insects in two of the most polluted wastewater sites (S1 and S2) in Sohag Governorate, Egypt. The two wastewater sites receive different wastewater inputs (domestic and industrial). The results showed that the MPs abundance in surface water was higher in S2 than in S1 during the four seasons of the year, where the microplastic abundance in surface water was 2.05 ± 0.79 and 3.01 ± 0.9 particles/L in S1 and S2, respectively. Also, MPs were significantly higher in S2 in two insect taxa (Corixidae and Notonectidae) that are known to be infected by water mites. In contrast, the number of MPs was lower in S1, where water mites were absent. In addition, our results showed that adult water mites accumulated MPs. Overall, the 500–2000 µm size range was the most prevalent for both wastewater sites. Fibers were the most common MP morphotype discovered, followed by fragments. The dominant colors of MP were blue, red, and black. Furthermore, FTIR spectroscopy revealed the existence of three distinct polymers, namely polyester (PES), polypropylene (PP), and polyethylene (PE). To the best of our knowledge, this is the first study to examine the effect of water mites’ parasitism on the number of MPs ingested by aquatic organisms. However, Further research is needed to confirm our suggestion.

Actinomycetes as a Possible Source of Bioremediation of Heavy Metal Cadmium from Contaminated Soil

Annually, a significant volume of chemicals, encompassing fertilizers and pesticides, is administered to agricultural soils. Using pesticides and fertilizers, agricultural practices contribute to heavy metal Cadmium (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) pollution. Heavy metals and pesticides are high at the peak of ecological contaminants, presence of this has introduced grave risks to the health of the population and agronomics. Among heavy metals, cadmium (Cd) is recognized for its high mobility in various environmental settings. Cd has a deleterious effect on plant phenotypic, cytotoxicity (e.g., lowering chlorophyll concentration and limiting photosynthetic effectiveness), and metabolic activities (e.g., chlorosis and necrosis). Microbial bioremediation by using microorganisms is one of the secure, pure, cost operative and eco-friendly technology for decontaminating polluting sites as compared to physical and chemical techniques. Among microbes, Actinobacteria hold a paramount position, serving as key players in numerous biological processes, utilize toxins as carbon source and turn into high concentrations of pesticides, chemical complexes and heavy metals into commercially viable antibiotics, enzymes, proteins, and plant growth promoting hormones. This study is an effort to explore the potent cadmium resistance actinomycetes to reduce cadmium levels to enhance degradation. For this purpose, 53 actinomycetes strains were tested for heavy metal resistance and tolerance to Cadmium against different concentrations. After secondary screening Four potent isolate have the potential to grow at 1000 mg/L concentration of Cadmium in the medium. When they are able to grow on heavy metal containing media it could be beneficial for reduction and elimination of toxic metals from contaminated environment. When it comes to achieving a suitable level of metal tolerance, this potent powerful actinomycetes strain Streptomyces pactum have been identified to be promising.

Understanding the dynamics of enhanced light non-aqueous phase liquids (LNAPL) remediation at a polluted site: Insights from hydrogeophysical findings and chemical evidence

This study intricately unfolds a pioneering methodology for remediating contaminants in a persistent light non-aqueous phase liquids (LNAPL)-contaminated site. The remediation strategy seamlessly integrates enhanced desorption and in-situ chemical oxidation (ISCO), orchestrating the injection of PetroCleanze® (a desorbent) and RegenOx® (an oxidizer) through meticulously designed wells. These injections, based on detailed geological and hydrogeological assessments, aim at mobilizing residual contaminants for subsequent extraction. Real-time subsurface dynamics are investigated through geophysical monitoring, employing electrical resistivity tomography (ERT) to trace reagent migration pathways via their effect on bulk electrical conductivity. The integration of groundwater sampling data aims at providing additional insights into the transformations of contaminants in the spatiotemporal context. Vivid two-dimensional time-lapse ERT sections showcase the evolution of resistivity anomalies, providing high-resolution evidence of the heterogeneity, dispersion pathways of desorbent and oxidant, and residual LNAPL mobilization. Hydrochemical analyses complement this, revealing effective mobilization processes with increasing aqueous concentrations of total petroleum hydrocarbons (TPH) over time. Speciation analysis unveils the intricate interplay of desorption and oxidation, portraying the dynamic fractionation of hydrocarbon components. The hydrogeophysical and data-driven framework not only delivers qualitative and quantitative insights into reagent and contaminant distribution but also enhances understanding of spatial and temporal physio-chemical changes during the remediation process. Time-lapse ERT visually narrates the reagent's journey through time, while chemical analyses depict the unfolding processes of desorption and oxidation across space and time. The coupling of hydrogeophysical and chemical findings pictures the transformations of pollutants following the sequence of product injection and the push and pull activities, capturing the removal of mobilized contaminants through hydraulic barrier wells. This enhanced understanding proves instrumental towards optimizing and tailoring remediation efforts, especially in heterogeneous environmental settings. This study establishes a new standard for a sophisticated and innovative contaminant remediation approach, advancing environmental practices through the harmonized analysis of geophysical and chemical data.

Does transplanted Posidonia oceanica act as a sink or source of trace elements? Ecological implications for restoring polluted coastal areas

Despite the high potential of seagrass restoration to reverse the trend of marine ecosystem degradation, there are still many limitations, especially when ecosystems are severely degraded. In particular, it is not known whether restoring polluted ecosystems can lead to potentially harmful effects associated with contaminant remobilisation. Here, we aimed to investigate the role of P. oceanica transplanted from a pristine meadow to a polluted site (Augusta Bay, Italy, Mediterranean Sea) in two seasons of the year, as a sink or source of trace elements to the environment. The main results showed i) higher accumulation of chromium (Cr), copper (Cu) and total mercury (THg) in plants transplanted in summer than in winter, as well as an increase in Cr and THg in plants from sites with higher trace element loads; ii) an increase in leaf phenolics and a decrease in rhizome soluble carbohydrates associated with As and THg accumulation, suggesting the occurrence of defence strategies to cope with pollution stress; iii) a different partitioning of trace elements between below- and above-ground tissues, with arsenic (As) and Cr accumulating in roots, whereas Cu and THg in both roots and leaves. These results suggest that P. oceanica transplanted to polluted sites can act as both a sink and a source, sequestering trace elements in the below-ground tissues thus reducing their bioavailability, but also potentially remobilising them. However, the amount of trace elements potentially exported from P. oceanica to the environment through transfer into food webs via leaves and detritus appeared to be low under the specific conditions of the study site. Although further research into seagrass restoration of polluted sites would improve current knowledge to support effective ecosystem-based coastal management, the benefits of restoring polluted sites through seagrass transplantation appear to outweigh the potential costs of inaction over time.

Biomonitoring potentially toxic elements in atmospheric particulate matter of greater Dhaka region using leaves ofhigher plants.

In this study, four different plant species, namely Artocarpus heterophyllus, Mangifera indica, Psidium guajava, and Swietenia mahagoni, were selected from seven different locations to assess the feasibility of using them as a cost-effective alternative for biomonitoring air quality. Atmospheric coarse particulate matter (PM10), soil samples, and leaf samples were collected from residential, industrial, and traffic-congested sites located in the greater Dhaka region. The heavy metal concentrations (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the leaves of the different species, PM10, and soil samples were analyzed. The highest Pb (718ng/m3) and Zn (15,956ng/m3) concentrations were found in PM10 of Kodomtoli which is an industrial area. On the other hand, the highest Fe (6,152ng/m3) and Ni (61.1ng/m3) concentrations were recorded in the PM10 of Gabtoli, a heavy-traffic area. A significant positive correlation (r = 0.74; p < 0.01) between Pb content in plant leaves and PM fraction was found which indicated that atmospheric PM-bound Pb may contribute to the uptake of Pb by plant leaves. The analysis of the enrichmentfactor (EF)revealed that soils were contaminated with Cd, Ni, Pb, and Zn. The abaxial leaf surfaces of Psidium guajava growing at the polluted site exhibited up to a 40% decrease in stomatal pores compared to the control site. Saet's summary index (Zc) demonstrated that Mangifera indica had the highest bioaccumulation capacity. The metal accumulation index (MAI) was also evaluated to assess the overall metal accumulation capacity of the selectedplants. Of the four species, Swietenia mahagoni (3.05) exhibited the highest MAI value followed by Mangifera indica (2.97). Mangifera indica and Swietenia mahagoni were also found to accumulate high concentrations of Pb and Cr in their leaves and are deemed to be good candidates to biomonitor Pb and Cr contents in ambient air.

Spatio-Temporal Dynamics of crAssphage and Bacterial Communities in an Algerian Watershed Impacted by Fecal Pollution

This study investigates the influence of urban pollution and climate dynamics on water quality and the bacterial communities in an Argelian watershed. Twenty-one sampling campaigns were conducted over two years at six sites along the Oued Boussellam, a river impacted by the effluent of a sewage treatment plant, from a low-polluted site to a water reservoir within a 50 km distance. Fecal indicators and the human fecal marker crAssphage were monitored. Illumina 16S rRNA amplicon sequencing was used to assess water microbial populations’ changes. Urban sewage discharge had an impact on the river quality and microbial ecosystem, which was attenuated along the river course. Significant reductions (&gt;4 log10 for E. coli and somatic coliphages, &gt;3 log10 for crAssphage) occurred, particularly during high-temperature periods. crAssphage correlated strongly with somatic coliphages downstream the river. Seasonal differences were observed in the diversity of the bacterial communities, with higher values during the high-temperature period. The genus-level community structure was similar at highly polluted river sites, also displaying seasonal differences. Despite high pollution levels, natural processes reduced fecal indicators to acceptable levels in the reservoir as well as shaped the bacterial communities along the river, highlighting the importance of understanding indicator persistence and microbial community resilience for effective water quality management within the context of the global warming scenario.

Effective Activation of Peroxymonosulfate by Oxygen Vacancy Induced Musa Basjoo Biochar to Degrade Sulfamethoxazole: Efficiency and Mechanism.

Biochar materials have garnered attention as potential catalysts for peroxymonosulfate (PMS) activation due to their cost-effectiveness, notable specific surface area, and advantageous structural properties. In this study, a suite of plantain-derived biochar (MBB-400, MBB-600, and MBB-800), possessing a well-defined pore structure and a substantial number of uniformly distributed active sites (oxygen vacancy, OVs), was synthesized through a facile calcination process at varying temperatures (400, 600, and 800 °C). These materials were designed for the activation of PMS in the degradation of sulfamethoxazole (SMX). Experimental investigations revealed that OVs not only functioned as enriched sites for pollutants, enhancing the opportunities for free radicals (•OH/SO4•-) and surface-bound radicals (SBRs) to attack pollutants, but also served as channels for intramolecular charge transfer leaps. This role contributed to a reduction in interfacial charge transfer resistance, expediting electron transfer rates with PMS, thereby accelerating the decomposition of pollutants. Capitalizing on these merits, the MBB-800/PMS system displayed a 61-fold enhancement in the conversion rate for SMX degradation compared to inactivated MBB/PMS system. Furthermore, the MBB-800 exhibited less cytotoxicity towards rat pheochromocytoma (PC12) cells. Hence, the straightforward calcination synthesis of MBB-800 emerges as a promising biochar catalyst with vast potential for sustainable and efficient wastewater treatment and environmental remediation.

Potassium peroxoborate: A sustained-released reactive oxygen carrier with enhanced PAHs contaminated soil remediation performance

Seeking for a safe, efficient, inexpensive, and eco-friendly oxidizer is always a big challenge for in-situ chemical oxidation (ISCO) technology. This study adopted the potassium peroxoborate (PPB), a novel peroxide, for soil remediation for the first time. PPB based chemical oxidation system (PPB-CO) could efficiently degrade polycyclic aromatic hydrocarbons (PAHs) without other reagents added, reaching 72.1 %, 64.2 %, and 50.0 % removal rates for naphthalene, phenanthrene, and pyrene after 24 h reaction, respectively. The superior total PAHs removal efficiency (60.6 %) was 3.6–4.7 times higher than that of other commercial peroxides (2Na2CO3•3H2O, CaO2, and H2O2). Mechanism analysis revealed that varieties of reactive oxygen species (ROS) can be generated by PPB through Fenton-like or non-Fenton routines, including H2O2, perborates species, O2•−, •OH, and 1O2. The sustainable generation of H2O2 reduced the disproportionation effect of H2O2 by 86 %, significantly improving the utilization rate. Moreover, sandbox experiments and actual contaminated soil remediation experiments verified the feasibility of PPB-CO in a real polluted site. This work provides a novel strategy for effectively soil remediation, highlighting the selection and application of new oxidants.

Construction of a food waste biochar model and determination of contaminant adsorption sites: Combining experimental characterisation with quantum chemical calculations

Increasing urbanization has made it a serious challenge to deal with food waste (FW) from people and wastewater with pollutants from industry. Biochar from FW pyrolysis(FWB) can be used as an adsorbent to adsorb pollutants from wastewater, but its molecular structure is still unknown, limiting the understanding of its adsorption mechanism and its application in industry. In this paper, a series of combined methods of experimental characterization and quantum chemical calculations, such as solid-state 13C nuclear magnetic resonance spectroscopy (13C NMR), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to investigate and successfully construct a model of the molecular structural features of FWB under the optimal contaminant adsorption preparation conditions. Based on the electrostatic potential distribution and adsorption experiments, the adsorption sites of the pollutants were elucidated. The results showed that the FWB prepared at different temperatures, 450 °C had a variety of oxygen-containing functional groups and polarity favorable for adsorption. In the molecular structure of FWB with the molecular formula C60H49N7O8, oxygen is present in the form of carboxyl, carbonyl, ether, alcohol hydroxyl, and phenol hydroxyl groups with numbers 1, 1, 1, 1, 2, 1, 2. Nitrogen is present in the form of pyridinyl nitrogen, pyrrolidinyl nitrogen, and primary amines with numbers 1, 1, and 5, respectively. In addition, nitrogen-containing and oxygen-containing functional groups are possible adsorption sites for pollutants on FWB, and alcohol hydroxyl and amino groups can bind better to Cu2+, which provides scientific guidance for improving the adsorption performance of biochar. This provides a solid foundation for the study of the microscopic adsorption mechanism of FWB and a method for the modeling of biochar from other biomasses.

ASSESSMENT OF SOIL PHYSICOCHEMICAL PROPERTIES AND TOTAL PETROLEUM HYDROCARBON OF A THREE-DECADE-OLD POLLUTED SITE AT EVBAREKE, BENIN CITY

Monitoring of polluted sites require their assessment for effective management and environmental protection. This study assessed the soil properties including heavy metals (Fe, Zn, Mn, Cu, Cr, Pb, Cd and Ni) and total petroleum hydrocarbon (TPH) of a three-decade-old automobile workshop in Benin City. Top soil samples collected from outside the workshop and a control were analyzed using standard laboratory methods and their mean values were compared with critical limits for interpreting soil fertility as well as pollution status. The results showed that the texture of the polluted soil was unchanged but the pH has been modified from strongly to slightly acidic. Relatively slightly higher concentrations of the measured fertility parameters of the polluted site were not substantial for the very low organic C, N and Mg as well as the low for Ca, Na and EC because their ratings were not different from those of the control unlike the high ratings for K and P compared to medium and low in the control, respectively. Concentration of EA of the polluted soil was rated low as the control while effective CEC (cmol/kg) was low for the polluted (6.42) site compared to very low (4.80) of the control. Higher concentrations (mg/kg) of heavy metals in polluted soil were &lt; their DPR target values, except Cd (5.1) which exceeded its limit (0.8). Increased concentration (mg/kg) of TPH from 0.22 to 825 was &lt; its target value of 1,000. Decontamination of Cd from site should be carried out to avoid ill health of workers. &#x0D;

Life goes on: Spatial heterogeneity promotes biodiversity in an urbanized coastal marine ecosystem.

Both human populations and marine biodiversity are concentrated along coastlines, with growing conservation interest in how these ecosystems can survive intense anthropogenic impacts. Tropical urban centres provide valuable research opportunities because these megacities are often adjacent to mega-diverse coral reef systems. The Pearl River Delta is a prime exemplar, as it encompasses one of the most densely populated and impacted regions in the world and is located just northwest of the Coral Triangle. However, the spatial and taxonomic complexity of this biodiversity, most of which is small, cryptic in habitat and poorly known, make comparative analyses challenging. We deployed standardized settlement structures at seven sites differing in the intensity of human impacts and used COI metabarcoding to characterize benthic biodiversity, with a focus on metazoans. We found a total of 7184 OTUs, with an average of 665 OTUs per sampling unit; these numbers exceed those observed in many previous studies using comparable methods, despite the location of our study in an urbanized environment. Beta diversity was also high, with 52% of the OTUs found at just one site. As expected, we found that the sites close to point sources of pollution had substantially lower diversity (44% less) relative to sites bathed in less polluted oceanic waters. However, the polluted sites contributed substantially to the total animal diversity of the region, with 25% of all OTUs occurring only within polluted sites. Further analysis of Arthropoda, Annelida and Mollusca showed that phylogenetic clustering within a site was common, suggesting that environmental filtering reduced biodiversity to a subset of lineages present within the region, a pattern that was most pronounced in polluted sites and for the Arthropoda. The water quality gradients surrounding the PRD highlight the unique role of insitu studies for understanding the impacts of complex urbanization pressures on biodiversity.