Biological Pollutants Research Articles

Effects of quaternary ammonium disinfectants on human pathogenic bacteria in anaerobic sludge digestion: Dose-response and resistance variation

Sewage sludge is a critical reservoir for biological pollutants, and its harmless disposal remains a major issue. Quaternary ammonium compounds (QACs) as typical household disinfectants are inevitably concentrated in sewage sludge, and have the potential to affect human pathogenic bacteria (HPBs) that remain poorly understood. This study found that the relative abundance of HPBs in digesters was decreased by 10 − 20 % at low QACs dose, but increased by 238 − 591 % at high QACs dose. Mechanistic analysis revealed that low QACs doses promoted functional hydrolytic/fermentative bacteria and their metabolism by stimulating extracellular polymeric substances secretion and enhancing resistance to QACs. Conversely, high QAC doses decreased microbial biomass and developed QACs and antibiotic resistance of HPBs by increasing cell membrane permeability and triggering oxidative stress, resulting in deteriorating sanitation performance. These findings provide advanced insights into the potential function and hazards of exogenous QACs on the biosafety of digestate.

Assessment of dust endotoxins, airborne bacteria, and PM2.5 at old-age nursing homes and children's daycare centers in the Seoul metropolitan area, South Korea

Indoor air pollutants are associated with adverse health effects in people, particularly children and older adults—the most vulnerable groups health-wise who also happen to spend much of their time in indoor environments. To contribute to knowledge on how these groups can be protected, this study sought to determine the relationships between indoor pollutants (dust endotoxins, airborne bacteria (AB), and particulate matter (PM2.5)) and environmental factors (temperature, relative humidity (RH), use of air conditioners (AC), use of windows, and season). For each pollutant, 360 samples were collected from 31 old-age nursing homes and 31 daycare centers in South Korea. The Mann–Whitney U test, Kruskal–Wallis rank sum, Spearman's rank analysis, and multivariate regression were used to determine whether there were significant differences between indoor pollutants and environmental factors. Dust endotoxin values ranged between < LOD and 632 EU/mL and between 306 and 632 CFU/m3 for AB, and ranged from 3.9 to 32.5 µg/m3 for PM2.5. Dust endotoxin levels showed a significant relationship with RH and season in the multiple regression analysis. Periodic AC filter cleaning and exchange, as well as proper RH management in these facilities may help reduce indoor biological pollutants. The findings of this study are informative for addressing the respiratory health issues of older people and children in indoor facilities.

Synthesis and structure of an aqueous stable Cu(II)-based coordination polymer with multifunctional fluorescence sensing property

Advanced methods for both biological and environmental hazardous pollutants are of sustained interest. Herein, a new coordination polymer, namely, [Cu2(OH)(1,2,4-bca)(bmoe)]·H2O (Cu-CP) has been hydrothermally constructed with a mix-ligand strategy, employing 1,2,4-benzenetricarboxylic acid (1,2,4-bca) and 1,1′-bis(1H-benzimidazolyl) oxydiethane (bmoe) as organic ligands. The intrinsic strong blue-light emission and the great stability in water solutions with the broad range of pH values (pH = 4 − 12) of Cu-CP provide a platform for practical fluorescence sensing application in water samples. Fluorescence measurements reveal that Cu-CP displays interesting multi-responsive dection activities toward toxic heavy-metal ions Cr2O72- / CrO42− / MnO4−, nitrofuran antibiotics nitrofurantoin (NFT) / nitrofurazone (NFZ) and acetylacetone (ACAC) in aqueous solutions achieving both high sensitivity and low detection limits (micromolar for Cr(VI) / Mn(VII) / ACAC and nanomolar for NFT / NFZ). Furthermore, the interference experiments have verified its excellent selectivity. A synergetic contribution of internal filtration effect (IFE) and Förster resonance energy transfer (FRET) between Cr2O72- / CrO42− / MnO4− and the framework of Cu-CP realize the fluorescence quenching behavior for Cr(VI) / Mn(VII) detection, while FRET, IFE and photoinduced electron transfer (PET) mechanisms are synergistically responsible in the case of NFT / NFZ, ACAC sensing supported by the molecular simulations and UV−vis spectral overlap experiments. This present work affords precious guidance for the effective and facile design and preparation of multifunctional luminescent coordination polymers with promising performance.

Constructing yeast-modified polypropylene amidoxime membrane toward highly-selective adsorption of U(VI) from seawater

To extract uranium from seawater, the adsorbent needs to have high selectivity for uranium and good hydrophilicity, and could resist biological pollution and prevent Marine microorganisms from blocking chelate sites. For effective uranium extraction, a straightforward crosslinking technique is used to create a highly selective and biofouling-resistant poly(amidoxime) (PAO-Y) membrane. PAO-Y is characterized by FT-IR, SEM, EDS, XPS, BET, WCA and NMR techniques. The effects of solution acidity, concentration, and adsorption time on its adsorption of uranyl ions and vanadyl ions are investigated. The composite material (PAO-Y) exhibits higher selective adsorption and affinity towards U(VI) compared to V(V). In simulated marine environment experiments, the material exhibited an adsorption capacity of 10.39 mg·g−1 for U(Ⅵ), which is five times higher than that for V(V). Furthermore, the adsorption partition constant for U(Ⅵ) is 1.44 × 105 mL·g−1, two orders of magnitude greater than that for V(V). The DFT calculations revealed specific coordination modes between PAO-Y and uranyl/vanadyl ions, elucidating the selective adsorption mechanism of uranium. The pentadentate coordination mode is shown by DFT calculations to be the most stable one. DFT calculations also show that the increase in the number of amino acid groups increases the interaction between the coordinating ligands and uranyl, but decreases the interaction between the coordinating ligands and vanadyl. These findings suggest that PAO-Y effectively enhance the selectivity and affinity towards uranyl ions during uranium extraction from marine environments and may find practical applications. After 15 days of continuous flow of 30 L natural seawater, PAO-Y obtained a total uranium capture capacity of 1.969 mg·g−1 in the fixed-bed adsorption system, making it a suitable candidate for uranium extraction from natural seawater.

ANALYSIS OF COLIFORM BACTERIA IN DUG WELL WATER

In Indonesia, in rural and urban areas, you can find a lot of dug wells, because in general people use a lot of dug wells, because dug wells are relatively easy and cheap to make. However, dug wells have a very high risk of pollution in the form of physical, chemical and biological pollution. Water and health are two things that are interconnected. If the quality of the water consumed by the public is contaminated by coliform bacteria and E coli bacteria, it can cause diseases including diarrhea. This research aims to determine the relationship between the distance of the septic tank and the physical condition of the dug well on the number of coliform bacteria in the dug well water using the Cross Sectional method. Samples were taken using a simple random sampling technique with a total sample of 89 dug wells. The data obtained were analyzed using the Chi-Square test. Univariate analysis. The presence of coliform bacteria was 31.5%, 65.8% absent, septic tank distance did not meet the requirements, 43.8% met the requirements, 56.2%, the physical condition of the dug well met the requirements. 36.0% requirements, 60.0% eligible. Bivariate analysis of septic tank distance obtained a value of 0.000, the physical condition of the dug well had a p value of 0.000. The conclusion was that there was a significant relationship between the distance of the septic tank and the physical condition of the dug well and the presence of coliform bacteria.

Estimation of the ecological integrity of the Guadiana River using Partial Least Squares Path Modelling and simulation scenarios

Ecological integrity is fundamental to human life and ecosystems, so its assessment and management are crucial. This concept assesses ecosystem health by examining physico-chemical and biological characteristics, riparian vegetation and macroinvertebrate communities. In recent decades, water resources have undergone significant changes due to various factors that have contributed to the physical, chemical and biological pollution of water. To address this problem, a specific model has been developed using the Partial Least Squares Path Modelling methodology to analyse and quantify the main factors affecting the ecological integrity of the Spanish part of the Guadiana River (Spain). The variables analysed at the different sampling points in the catchment include forest cover, anthropogenic pressure, water quality and biological integrity. Water quality and biological integrity, in turn, constitute the concept of ecological integrity. The model predicts 60.3 % of the physico-chemical water quality and 56.6 % of the biological integrity, showing that ¨Forest cover¨ negatively impacts water quality (W = −0.476) by reducing pollution, while ¨Anthropogenic Pressure¨ positively impacts it (W = 0.680) by increasing pollution. Based on the modelling, three future scenarios were designed, from the lowest to the highest pressure considering changes in riparian forest quality based on QBR and changes in the number of reservoirs: a favourable scenario with high riparian forest quality and no reservoirs; an intermediate scenario with good riparian forest quality and no change in the number of reservoirs; and an unfavourable scenario, characterised by very poor riparian forest quality and an increase in the number of reservoirs. In this context, the importance of the conservation and enhancement of riparian vegetation as a nature-based solution is highlighted, as well as the pressure generated by industrial activity and agricultural practices on the ecological integrity of the study area. The favourable scenario, with very good quality riparian vegetation, improves water quality by up to 85 %, positively impacting the ecological integrity of the river. In contrast, the unfavourable scenario, with extremely degraded riparian forest, would decrease water quality by up to 62 %, negatively affecting ecological integrity. Modelling and future scenarios is an essential tool in the decision-making process to improve environmental governance and water security. In addition, the PLS-PM methodology allows the identification and quantification of relationships between complex variables, providing a solid basis for the design of effective environmental management strategies.

Synthesis, technological prospects and applications of MXene in biomedicine, supercapacitors and sensors: A review

MXenes are one of the most important classes of materials discussed worldwide by many researchers of diverse fields for diverse applications in recent years. It is a nanomaterial with a wide range of applications due to its multiple forms and structures with fascinating properties, for example, high surface area and porosity, biocompatibility, ease of fictionalizing with various active chemical moieties, benefit of high metallic conductivity, activated metallic hydroxide sites, and sensitivity to moisture. MXenes have great chances for potential applications in environmental issues, water purification, biological applications, and energy storage devices and sensors. MXenes show great selectivity towards the absorption of heavy metals and a good capability to reduce chemical and biological pollutants present in the water. The present review article critically analyzed advancements in water purification using the adsorption and reduction abilities of MXenes and their composites. The mechanism of various procedures, important challenges, and associated problems using MXene and their composites are discussed in detail. The future research directions can be extracted from this article efficiently and comprehensively. The energy storage issues of rechargeable lithium-ion batteries, batteries other than lithium-ion batteries, and electrochemical capacitors are also discussed in detail.

Optimal 4E design and innovative R-curve approach for a gas-solar- biological waste polygeneration system for power, freshwater, and methanol production

BackgroundCogeneration power plants traditionally rely on fossil fuels to produce stable power and heat. However, increasing energy demand and population growth have intensified the emission of biological pollutants due to fossil fuel use. The Global Alliance on Health and Pollution advocates for integrating renewable energy sources to mitigate these issues. ObjectivesThis study aims to evaluate the integration of a solar-biomass polygeneration system with a hybrid solar-waste-fossil fuel cogeneration system. The goal is to analyze the system from technical, economic, and environmental perspectives, focusing on optimizing energy demand and minimizing environmental impact. MethodsTo assess energy demand and supply, the R-curve methodology was applied to the hybrid cogeneration system, with a specific focus on solar and biomass renewable energies. Various scenarios were analyzed, including total annual costs, pollutant emissions, water footprint, and overall environmental impact based on life cycle assessment. The study examined and compared the performance of three types of biomass waste (Municipal solid waste, mixed paper waste, and date palm waste). Multi-objective optimization was performed using artificial intelligence and machine learning techniques, employing four meta-heuristic algorithms. The conditions generated by each algorithm were analyzed and compared. ResultsMunicipal solid waste, being the most readily available fuel, provided the most favorable economic conditions for the system. Environmentally, municipal solid waste ranked in the middle compared to other fuels. Among the optimization algorithms, the Salps swarm algorithm proved to be the most efficient in terms of calculation time and system efficiency improvements. The optimization improved net power generation by 5.25 %, overall energy efficiency by 16.27 %, total cost rate by 10.19 %, and total environmental impact rate by 14.02 %. ConclusionThe integrated system's performance was analyzed across different climatic change throughout the year. The multi-objective Salps swarm algorithm optimization demonstrated significant benefits in enhancing system efficiency and reducing costs and environmental impacts.

Parasite Contamination of Water Source at Pangkalan Masyhur Sub-district, Medan Johor District

According to World Health Organisation (WHO) estimates, at least 1,8 billion people consume contaminated water worldwide, hence most of the diarrheal disease in the world is attributable to unsafe water, and the lack of sanitation and hygiene. Water utilization by humans and animals can generate biological pollutants which may contaminate the water. These contaminants come from waste products that may contain bacteria, protozoa, and other parasites. This was a descriptive study with cross sectional design and simple random sampling to determine the contamination of water source by pathogens, particularly parasites at Region V Pangkalan Masyhur sub-district, Medan Johor district, Medan, North Sumatera in 2012. Samples were obtained from each house, depending on the main water source used, either from tap water, open wells, or the nearby river streams. Modified Caldwell’s sedimentation technique was applied to examine the samples under light microscope. Out of the 103 water samples collected, most were from tap water (78 samples), followed by open wells (19 samples), and only six were from the nearby river streams. We found Paramecium caudatum from nine samples (8,7%) collected from the open wells and the nearby river streams, followed by hookworm larva in one tap water sample (1%). No protozoa such as Entamoeba spp., Cryptosporidium spp., and Giardia spp. found in any of the samples. Based on this data, the abundant presence of P.caudatum represented the condition of high organic debris in the open wells and the nearby river streams. Additionally, the presence of hookworm larva in the tap water indicated the distribution system was contaminated with the surrounding soil. Hence it is imperative to provide counseling about optimal environmental sanitation and clean water management, including proper maintenance for water source and its distribution system. Tap water distribution, including its network of pipe deliverance system, must be checked and maintained regularly.

Advancements in optical biosensing techniques: From fundamentals to future prospects

Optical biosensors that consist of a light source, optical elements, and a photodetector are used to detect chemical and biological species and pollutants. This Tutorial discusses the fundamental details of optical biosensing techniques that include materials, working principle, components, sensor configurations, parameters, and future prospects. Optical biosensing techniques include plasmonic [surface plasmon resonance (SPR) and localized SPR], fluorescence, luminescence, Raman scattering, colorimetric, and interferometric methods. Bioreceptor elements play a significant role in detecting the specific analyte that can be synthetic or natural. Surface functionalization techniques to bind the bioreceptor elements on the surface, to control the bioreceptor orientation, have been discussed in detail. The possibility of integration of techniques on a chip, to develop wearable, implantable sensors, and the associated challenges have been fully demonstrated. This Tutorial provides valuable insights into the present state and future directions of optical biosensors for various applications.

Poaceae Pollen as the Leading Aeroallergen

The relevance of aerobiological topics is evidenced by the fact that from July 1 to July 5, 2024, an unusual event was held in Vilnius (Lithuania), including the 8th European Symposium on Aerobiology (8th ESA), the 12th International Congress on Aerobiology (12th ICA) and the 5th International Ragweed Conference (5th IRC). World Aerobiology 2024 is an event of unprecedented scale. It discussed the use of artificial intelligence (AI) for calculating and interpreting aerobiological monitoring data. But so far, AI cannot identify all taxa, so careful counting and identification of plant pollen and fungal spores is only possible for a human researcher. Aerobiological monitoring using volumetric traps remains the gold standard of research. In the world community, there are networks of biological monitoring of air quality with the study of the concentration of plant pollen and fungal spores in the air. Through an application on a mobile phone, you can find out the forecast of periods of maximum risk, during which patients with hay fever are exposed to the main aeroallergens. Popular queries from Internet users relate to the complex problem of climate change, environmental pollution and aeroallergens. There is no National Aerobiological Monitoring system in Kyrgyzstan, but the Meteonova service has launched a pollen forecast application for mobile phones, which is still in the testing stage and does not reflect the real features of the aerobiological spectrum. It is known that in the world there are more than 12,000 species in the Poaceae family, classified into 771 genera belonging to 12 subfamilies. In Kyrgyzstan, 300 anemophilous species of annual perennial plants grow, releasing a huge amount of pollen into the atmosphere in the spring and summer. Poaceae pollen is still one of the top ten global aeroallergens, being the leading cause of hay fever, by predominant size, classified as biological pollutants (PM10). The concentration of cereal pollen was consistently observed in the air of Karakol during all seasons of the study and ranged from 167 to 174 days. Its daily maximum concentrations were detected in June-July; the distribution of pollen in the air is unimodal. The influence of the anthropogenic triad on fluctuations in the concentration of cereal pollen was established: climate change (temperature) and land use systems, as well as environmental pollution, which manifested itself in the degradation of pollen grains and the appearance of damaged and unidentified biological particles. The purpose of this article is to study the concentration of cereal pollen in the air, their integrative contribution to the aerobiological spectrum in the city of Karakol as dominant pollen allergens.

Biological Pollution of Indoor Air, Its Assessment and Control Methods

The aim of the entry was to write a substantial contribution that analyses and compares the biological pollution of indoor air, the possibilities of its assessment and the control methods. In addition, the aim of our entry was to review journals covering both commercial and residential buildings. By analysing the above topics from the existing articles, one can have the impression that air pollution is one of the most important problems that need to be solved in the modern world. Adequate air quality is important for maintaining human health, affects the health of ecosystems, including animals, and determines crop production. With the development of civilisation, the quality of air in the atmosphere and indoors is constantly deteriorating. Indoor air pollution can be divided into physical (e.g., noise, inadequate lighting, ionising radiation), chemical (e.g., tobacco smoke, household products) and microbiological (bacteria, viruses, fungi and products of their metabolism) factors. Each of these factors can have a negative impact on a person’s health or cause premature death. The entry deals with indoor air pollution, focussing on biological pollutants. It compares different methods available and describes the method of sampling to analyse indoor air pollution and ways to reduce it.

The biological contribution to the weathering of limestone monuments in a vegetated urban area: results of a 5-year exposure

Biological activity, climate and pollution are responsible for the degradation of building stones, especially limestone, which is widely used in the Paris region. In order to determine the respective contribution of physicochemical and biological processes to the degradation of limestone, limestone specimens from the Père-Lachaise cemetery (Paris, France) were exposed for five years under different conditions: sheltered from or exposed to rain and in horizontal or vertical position. After exposure, the collected samples were characterized by light and electron microscopy, X-Ray diffraction and ion chromatography after elution. The results showed an intense biocolonization of the samples exposed to rain, while the sheltered samples were more affected by the pollution (soiling). The characterization of the bacterial and fungal communities using Next Generation Sequencing Illumina 16S for bacteria and ITS for fungi highlighted that five main bacterial phyla were identified: Actinobacteriota, Bacteroidota, Cyanobacteria, Proteobacteria and Deinococcota (major genera Flavobacterium, Methylobacterium-Methylobacter, Sphingomonas, Roseomonas and Nocardiodes). Among the fungi, the phylum Ascomycota was predominant with the genera Cladosporium, Ramularia, Aureobasidium and Lecania. However, the alteration of the limestone is difficult to quantify at this stage. Potassium nitrate of rain origin has been found in the sheltered area, but no gypsum. Therefore, the biocolonization is a fast phenomenon on the stone and the physico-chemical processes derived from it, caused by climate and pollution, are slower. This is in agreement with the long-term observations made on old and unrestored graves of the cemetery described in the literature.

A Review of Water Pollution in Israel and Palestine

Water pollution is a daily risk with a major impact on both populations and ecosystems. An analysis of water pollution types is essential to determine the affected regions and the magnitude of its impact on various components of the geosystem. This study aims to conduct a thorough analysis of water pollution in the Israel and Palestine, focusing on the three main types of pollution: physical, chemical, and biological. The methodology of this article is based on the critical review of 22 scientific papers published between 1972 and 2023, addressing various aspects of water pollution in the analyzed region, from generating sources to their impact. Most studies are authored by researchers affiliated with institutions located in the conflict region, with many samples collected directly from the field and processed in laboratories or GIS environments. The study results highlight chemical pollution often exceeding recommended limits for various analyzed parameters. Biological pollution subjects aquatic ecosystems to significant pressures, including eutrophication and harmful algal blooms. Wastewater is discharged into watercourses in the region, affecting their physical properties. Areas subject to water pollution include the Gaza Strip, the coastal zone, the northern aquifer in Israel, and lakes in the western part of the analysis region, posing potential risks to the health of the populations in Israel and Palestine.

Impacts of habitat alteration on macroinvertebrates in large shallow lakes: An application of a macroinvertebrate-based multimetric index.

Habitat plays a crucial role in shaping the macroinvertebrate community structure in large shallow lakes. In the pursuit of improving the health of freshwater ecosystems, it is imperative to consider their habitat characteristics. To evaluate the impact of habitat variations on lake ecological health, we developed a macroinvertebrate-based multimetric index(MMI) for both the pelagic and littoral zones of Lake Hongze. Additionally, we employed structural equation models to explore the influence of utilization or phytoplankton biomass on ecological health. Historical data served as reference conditions for the pelagic. Seven key attributes were selected for the pelagic MMI, that is, Biological Monitoring Working Party (BMWP), the percentage of Mollusca taxa, the percentage of filter-collector taxa, the percentage of predator taxa, the percentage of gather-collector taxa, and the percentage of sensitive taxa and functional dispersion. The least minimally disturbed conditions and the best attainable conditions were used to develop the littoral. Four key metrics, that is, the percentage of scraper abundance, Mollusca taxa, Biological Pollution Index, and BMWP, were integrated into the littoral MMI. The assessment based on MMI revealed a "poor" health status for the pelagic zone and a "fair" health status for the littoral zone. These findings underscore the high applicability and efficacy of MMIs in assessing and monitoring ecological health in Lake Hongze. Notably, functional feeding groups exhibited heightened sensitivity to disturbance in both zones. Moreover, sediment organic matter strongly influenced the pelagic ecological health, while chlorophyll a and transparency emerged as primary factors influencing the littoral zone, attributable to varying littoral zone utilization. Integr Environ Assess Manag 2024;20:2245-2255. © 2024 SETAC.

Urban Wastewater-Based Surveillance of SARS-CoV-2 Virus: A Two-Year Study Conducted in City of Patras, Greece.

Wastewater-based epidemiology, during the COVID-19 pandemic years, has been applied as a complementary approach, worldwide, for tracking SARS-CoV-2 virus into the community and used as an early warning of the prevalence of COVID-19 infection. The present study presents the results of the 2-year surveillance project, in the city of Patras, Greece. The purpose of the study was to monitor SARS-CoV-2 and implement WBE as an early warning method of monitoring Public Health impact. The presence of SARS-CoV-2 was determined and quantified in 310 samples using RT-qPCR assays. For the years 2022 and 2023, 93.5% and 78.7% of samples were found positive, respectively. Comparison of detection methods have been conducted to select the method with the highest recovery of the viral load. A seasonal variation of the virus was recorded, showing a recession in summer months confirming the country's epidemiological data as indicated by positive correlation of wastewater viral load with registered cases of COVID-19 infections during these years (p < 0.05) and moreover sealed with a significant negative correlation observed with Daily Average (p < 0.01) and Daily Maximum Temperature (p < 0.01). More research was carried out to elucidate a possible association of physicochemical characteristics of wastewater with viral load showing positive correlation with Chlorides (p < 0.01) advocating possible increased use of chlorine-based disinfectants and Electrical Conductivity (p < 0.01) indicates that wastewater during periods of increased infections is more heavily loaded with ions from chemical and biological pollutants. No correlation found with rainfall and physicochemical indicators, such as COD, BOD5, Total Phosphorus, Total Nitrogen, and Total Suspended Solids. According to the findings, WBE represents a useful tool in the management of epidemics based on an environmental approach and it can also shed light on the interacting parameters that capture Public Health since any infections that may lead to epidemics lead to a parallel change in the use of pharmaceuticals, antimicrobials, disinfectants, and microbial load in urban wastewater.

Extended-spectrum β-lactamase-producing bacteria and their resistance determinants in different wastewaters and rivers in Nepal

Wastewaters serve as significant reservoirs of antibiotic resistant bacteria. Despite the evidence of antimicrobial resistance in wastewaters and river water in Kathmandu, direct linkage between them is not discussed yet. This study investigated the prevalence of extended-spectrum β-lactamase (ESBL)-producing bacteria and associated resistance genes in wastewaters and river water. Out of 246 bacteria from wastewaters, 57.72% were ESBL producers and 77.64% of them were multidrug resistant (MDR). ESBL producing E. coli was dominant in municipal and hospital wastewaters (HWW) as well as in river water while K. pneumoniae was common in pharmaceutical wastewater. The blaSHV and blaTEM genes were prevalent and commonly co-occurred with aac(6')-Ib-cr in K. pneumoniae isolated pharmaceutical wastewater. blaCTX-M carrying E. coli from hospital co-harbored aac(6')-Ib-cr while that from municipal influent and river water co-harbored qnrS. Whole genome sequencing data revealed the presence of diverse ARGs in bacterial isolates against multiple antibiotics. In average, an E. coli and a K. pneumoniae isolate contained 55.75 ± 0.96 and 40.2 ± 5.36 ARGs, respectively. Multi-locus sequence typing showed the presence of globally high-risk clones with wider host range such as E. coli ST10, and K. pneumoniae ST15 and ST307 in HWW and river indicating frequent dissemination of antimicrobial resistance in wastewater of Kathmandu. Whole genome sequence data aligned with phenotypic antibiograms and resistance genes detected by PCR in selected isolates. The presence of significant plasmid replicons (IncF, IncY) and mobile genetic elements (IS903, IS26) indicate high frequency of spreading antibiotic resistance. These findings indicate burden and dissemination of antimicrobial resistance in the environment and highlight the need for effective strategies to mitigate the antibiotic resistance.

Insights and machine learning predictions of harmful algal bloom in the East China Sea and Yellow Sea

The increase in harmful algal blooms (HABs) globally has been linked to climate change and anthropogenic activities such as agricultural runoff and urbanization. This study focused on analyzing the impact of these factors on HAB occurrences in the East China Sea and the Yellow Sea, identifying influential factors, and predicting future HAB events. For this study, random forest and numerical modeling were employed, with datasets encompassing physical and chemical properties of river water, seawater, and precipitation to assess the impact of discharge on HABs. Additionally, climate change scenarios derived from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) were employed to predict future HAB occurrences, supported by a sensitivity analysis to identify influential factors affecting HAB occurrence. This study demonstrated that the growth rate and occurrence of HABs in the East China Sea (ECS) and Korean coastal waters (KCW) distinctively increased in July and November after the operation of the Three Gorges Dam (TGD). It is likely affected by the decreasing discharge from the Yangtze River (YR) owing to the operation of the TGD. Using the Random Forest model, future HAB events were predicted in good agreement with observations. The sensitivity results revealed that environmental properties, such as precipitation, water temperature, and salinity are major features affecting the HAB trends in both the KCW and YR basins. Moreover, based on the random forest model and climate change scenarios, HAB events were predicted to increase in frequency in July, September, and October. Therefore, the findings can contribute to preventing biological pollution of the ocean system in the ECS and KCW by supporting efficient environmental management.

Critical factors for the rehabilitation of Hann Bay (Senegal, West Africa): Solutions for sustainable development

The advanced degradation of Hann Bay (Dakar, Senegal) has reached highly elevated levels, with serious environmental, health, and social consequences. Thus, this study focused on the determinants for rehabilitating Hann Bay and proposed solutions for sustainable development. The target area is currently home to 500,000 inhabitants and hundreds of industrial units, with virtually no suitable wastewater treatment systems. Socio-economic surveys and three rounds of effluent sampling were carried out between 2020 and 2022 at eleven sites in Hann-Bel Air, Dalifort Foirail, Thiaroye sur mer, Sicap Mbao, and Mbao. The study showed increased physicochemical, biological, and bacterial pollution of the heavily contaminated wastewater along the bay. The analytical results of the samples collected for the three series show that almost all sampling points exceed the limit value for TSS (50mg/l) and COD (200mg/l). This indicates that physicochemical and organic pollution are still present in the bay, causing fish to escape into the open sea. BOD measurements are also above the standard (N05-061; 80 mg/l) for series 1 and 2, showing an alteration in bay conditions. Analysis of the microbiological quality of the water in terms of oils and fats showed values well above the current standard (NS 05-061, 20-50 mg/l), which explains the frequent fish kills at the Hann marinas, Hann pêcheurs, and Cité ISRA sites. The same situation was observed in samples of fecal coliforms (CFU/100ml), helminth eggs (eggs/L), nitrogen, phosphorus, zinc, and lead at values outside the norm. Through socio-economic surveys of the populations and workers in the industrial units, the recommended solutions focus on protection and prevention measures, enforcement of regulations, communication and awareness-raising, equipment acquisition, and monitoring and surveillance to rehabilitate the bay.

Theoretical Study on the Reaction between Carcinogenic 2,5-Dichloro-1,4-benzoquinone and tert-Butyl Hydroperoxide: Self-Catalysis and Water Catalysis.

The potentially carcinogenic halobenzoquinones (HBQs) have been recently identified in drinking water as disinfection byproducts. Several radical intermediates in the reaction of 2,5-dichloro-1,4-benzoquinone (DCBQ) and t-butyl hydroperoxide (t-BuOOH), which may induce DNA damage, were detected experimentally, and metal-independent decomposition reactions of t-BuOOH by DCBQ were proposed. It has not yet been confirmed by theoretical calculations. The theoretical study in this work provides insights into the details of the reaction. An unprecedented self-catalysis mechanism of organic hydroperoxides, that is, the reactant t-BuOOH also has a catalytic effect, was uncovered at the molecular level. Moreover, as the solvent, water molecules also clearly have an efficient catalytic effect. Due to the catalysis of t-BuOOH and water, the metal-independent reaction of t-BuOOH and DCBQ can occur under moderate conditions. Our findings about the novel catalytic effect of organic hydroperoxides t-BuOOH could offer a unique perspective into the design of new catalysts and an understanding of the catalytic biological, environmental, and air pollution reactions. Furthermore, organic hydroperoxide t-BuOOH could serve as a proton shuttle, where the proton transfer process is accompanied by simultaneous charge transfer. Therefore, organic hydroperoxides may disrupt the vital proton transfer process in biological systems and may give rise to unexpected toxicity.