Search Results (781)

The widespread occurrence of antibiotics in aquatic environments has raised concern over the dissemination of antibiotic resistance genes (ARGs). Although vertical flow constructed wetlands (VFCWs) efficiently remove antibiotics from wastewater, the relationships between substrate configuration, microbial communities, and ARG abundance remain poorly understood. Here, five laboratory-scale VFCWs with different substrate configurations, including cobalt ferrite (CoFe₂O₄)-modified biochar and its composite with zeolite, were evaluated using synthetic domestic wastewater amended with oxytetracycline (OTC). CoFe₂O₄ modification increased the specific surface area and pore volume of biochar and altered its adsorption behavior. All VFCWs achieved high OTC removal (>97%), despite differences in OTC accumulation within the substrate. In contrast, ARG and mobile genetic element abundances and bacterial community profiles varied among reactors. Combined tetA and tetX abundance ranged from 2.55 × 10² to 1.90 × 10⁵ copies g⁻¹, with the CoFe₂O₄-modified biochar–zeolite reactor showing the lowest mean ARG abundance. Exploratory co-occurrence analysis identified associations of Acinetobacter with tetA and Flavobacterium with tetA and tetX (nominal Spearman p < 0.05), although these correlations do not establish ARG host identity or horizontal gene transfer. Overall, the findings indicate that microbial ecological patterns associated with ARG abundance may differ among VFCWs even when antibiotic removal efficiencies are comparable. Full article

Understanding the hydrochemical characteristics of groundwater in coal mining subsidence areas is of critical scientific significance for water environment protection and ecological restoration in mining regions. A systematic hydrochemical campaign was undertaken in the Luwa collapse zone (Jining city, Shandong Province) to decipher the composition, evolutionary behavior, and governing factors of groundwater within a high-water-table subsidence context. The analytical protocol comprised three complementary components: conventional hydrochemical profiling, ion-ratio-based source identification, and multivariate statistical modeling. The findings revealed that the groundwater in the study area was weakly alkaline (pH = 7.33 ± 0.217), with total dissolved solids (TDS) ranging from 1180 to 2280 mg/L, and all sampled sites exceeded the Class III groundwater quality standard of China. Na⁺, SO₄²⁻, and Cl⁻ were identified as the predominant pollutants, with exceedance rates of 91.3%, 95.7%, and 91.3%, respectively, which were primarily attributed to coal mine drainage and domestic sewage input. The groundwater chemical composition was governed by the combined effects of rock weathering, evaporation–concentration processes, and anthropogenic activities. Specifically, Na⁺ and Cl⁻ originated mainly from the dissolution of silicate minerals and halite, as well as domestic sewage input; SO₄²⁻ was primarily controlled by evaporite dissolution and industrial wastewater discharge; carbonate and silicate mineral weathering was identified as the primary source of Ca²⁺ and Mg²⁺; and NO₃⁻ was predominantly influenced by agricultural activities. Principal component analysis (PCA) extracted three major controlling factors shaping the groundwater hydrochemistry in this area, namely: (1) evaporite dissolution and sewage input, (2) carbonate dissolution and pH buffering processes, and (3) agricultural input. This study reveals a dual-driven evolutionary model of groundwater in high-water-table coal mining subsidence areas, characterized by “natural enrichment superimposed by anthropogenic input,” whose work contributes to the knowledge base for sustainable groundwater stewardship and contamination risk reduction in mining-affected areas with analogous conditions. Full article

Microplastics have emerged as a persistent and prevalent threat to human health and the marine environment due to their widespread use and poor management, including low recycling rates, inadequate waste management, improper disposal, and inadequate control of plastic leakage into the environment. Plastic pollution is transported to the marine ecosystem through both ocean-based and land-based pathways and can be fragmented into microplastics (<5 mm) and nanoplastics (<1 µm). The study explains the sources, distribution, mechanisms of degradation, and transport pathways to the marine environment. Land-based activities are recognized as the dominant source, causing approximately 70–80% of marine plastic pollution. Domestic greywater is highlighted as a significant and common source of microplastics due to the release of microbeads and synthetic fibers from different sources, such as laundry, washbasins, and personal care products (PCPs). Similarly, greywater release from maritime vessels and cruise ships significantly contributes to marine microplastic pollution. The study discusses the biotic and abiotic degradation mechanisms. The health and environmental effects of microplastics are measured across different trophic levels. Ingestion and bioaccumulation of microplastics can cause physiological and reproductive disturbances. Human exposure through seafood consumption and inhalation may result in skin infections, cardiovascular complications, gastrointestinal disorders, and respiratory problems. The mitigation and control measures include improvements in wastewater treatment, public awareness, policy regulations, and biodegradable alternatives to support sustainable protection of the marine environment. Full article

This study presents a screening-level multitemporal assessment of surface water quality in the Atrato River (Chocó, Colombia), a tropical river system heavily influenced by artisanal and illegal gold mining, elevated sediment loads, and untreated domestic wastewater. Using records from 20 monitoring stations (2020–2025) operated by the regional environmental authority (CODECHOCÓ), six water quality indices (ICA, ICOMO, ICOMI, ICOSUS, ICOMINERÍA, ICOTRO) were analyzed through a framework combining Theil–Sen trend estimation, Kendall’s tau correlation, inter-period median comparison, and an index orientation normalization procedure. Results suggest spatially heterogeneous patterns: organic contamination improved in 11 of 17 evaluable stations, while mining contamination (ICOMINERÍA) showed positive directional slopes in 14 of 17 evaluable stations. Of these, four middle-reach stations reached statistical significance (p < 0.05; Kendall’s τ = 0.618–0.667). At the network level, the mean ICOMINERÍA value increased from 0.191 in 2020 to 0.502 in 2025 (+163%), representing a directional signal that should be interpreted as screening-level evidence requiring confirmation through denser temporal sampling. The proposed framework provides support for potential applicability for detecting environmental change in data-scarce monitoring networks and provide screening-level evidence relevant to the enforcement monitoring of environmental rights granted under Colombia’s landmark Sentencia T-622 (2016). Full article

Planted and unplanted recirculating constructed wetland mesocosms maintained under non-aerated (reducing) and aerated (oxidizing) conditions were compared in their ability to remove 1 mg/L As(V) from simulated domestic wastewater over a 33-week period. Each week, one day prior to the addition of arsenic, non-aerated mesocosms removed 70% of the nitrate and 95% of the organic carbon likely through denitrification while aerated mesocosms removed organic carbon only (97%). Upon arsenic addition and treatment for the remainder of the week, non-aerated mesocosms removed more arsenic (72%) than aerated mesocosms (43%). For the first time in the literature, we estimated the proportion of arsenic found in biofilms detached from gravel and incorporated this aspect into mass balance calculations. We discovered that biofilms from non-aerated mesocosms contained a higher proportion of arsenic (28%) than biofilms from aerated mesocosms (5%). Plants from both types of mesocosms removed a negligible amount of arsenic (<0.41%). Through X-ray fluorescence (XRF) analysis, it was discovered that biofilms from non-aerated mesocosms had the highest iron concentrations (35,000 mg/kg), and this iron was identified as pyrite (2–15 wt%) through X-ray diffraction (XRD) analysis. The iron concentration of aerated biofilms was no different from that found in clean gravels (17,500 mg/kg), and no iron minerals were detectable in these samples using XRD analysis. Although some of the arsenic removal in both types of wetlands was thought to be attributable to adsorption onto substrates and biofilms, as well as uptake into biofilms, removal of arsenic in the non-aerated mesocosms was likely enhanced by the presence of pyrite because pyrite can adsorb arsenic directly or indirectly through the formation of iron oxides that can adsorb or coprecipitate with the iron oxides. Full article

Owing to their widespread occurrence, pharmaceutical and personal care products (PPCPs) have emerged as a global environmental concern; however, research on PPCP pollution in karst tourist cities remains limited. This study investigated the concentrations and spatial distribution of 43 PPCPs in the Lijiang River Basin and identified their primary sources together with the associated ecological and health risks. In total, 43 target PPCPs were detected in the Lijiang River Basin in Guangxi, China, with concentrations ranging from 68.6 to 3170 ng/L in wastewater, 53.2 to 1400 ng/L in surface water, and 32.0 to 505 ng/L in groundwater. Caffeine (CAF), 1,7-dimethylxanthine (1,7-DIM), 4-acetaminophenol (APAP), and metformin (MFM) were the predominant contaminants across all three matrices. Notably, concentrations in tributaries exceeded those in the main stem. Principal component analysis (PCA) revealed that domestic sewage and hospital wastewater constitute the principal sources of PPCPs in the Lijiang River. Certain effluents and river reaches containing 1,7-DIM and MFM posed a moderate ecological risk (0.1 < risk quotient (RQ) < 1). The PPCPs detected in groundwater did not exceed health-based thresholds, indicating no direct risk to human health. These findings advance our understanding of PPCP contamination in karst landscapes and provide a scientific basis for water quality management in the Lijiang River Basin. Full article

Background/Objectives: Antimicrobial resistance in microbial communities is a global health concern that leads to millions of deaths each year. Many bacterial pathogens have resistance to multiple antibiotics. Domestic wastewater treatment facilities are reservoirs for antibiotic-resistant bacteria and resistance genes. Wastewater-based epidemiology surveillance is crucial for monitoring antibiotic resistance genes (ARGs). Türkiye has one of the highest levels of antibiotic resistance with a lack of research on resistomes. This study is a focused reanalysis of publicly available wastewater metagenomes from Türkiye, comparing them to global and other country’s results. Methods: Ten metagenomic data of wastewater treatment from Türkiye were downloaded from NCBI-SRA database. Metagenome assemblies were performed and high-quality metagenome-assembled genomes (HQ-MAGs) were included in the study. Taxonomic annotations and antibiotic resistance profiles were identified in both the metagenome assemblies and HQ-MAGs. Results: A total of 401 different ARGs in 25 antibiotic classes have been identified, including Mcr (including mcr-1, mcr-2, mcr-3 and mcr-5 variants) and optrA. The vanR two-component regulatory system genes for controlling vancomycin antibiotic resistance were one of the most dominant along with other vancomycin resistance genes such as vanA and vanB. A total of 115 HQ-MAGs were obtained with at least eight ARGs. The HQ-MAG with the highest number of resistance genes (58) was found to belong to E. coli. The most frequently encountered resistance genes in HQ-MAGs were the multidrug ABC transporter, vanR, bacA and patA which confer resistance to multidrug, glycopeptide, bacitracin and fluoroquinolone antibiotic groups, respectively. Conclusions: To effectively address the problems of antibiotic resistance outbreaks, comparable AMR surveillance at national and global levels is required for the identification and prioritization of ARGs and resistance genes. This is the first report conducted in Türkiye. Full article

A modern approach to the organization of wastewater disposal systems ensures the sustainable development of resort areas. Warm mineral springs (WMSs) located in suburban areas are not only recreational facilities for the population, but also sources of used mineral and communal wastewater. Preventing or reducing the discharge of pollutants in this type of liquid waste can reduce the anthropogenic impact on the environment. The article proposes a method for the chemical precipitation of ammonium ions in a mixture of mineral and domestic wastewater, and the production of struvite, a complex agricultural fertilizer. Three series of experiments were conducted: (1) on a model solution of ammonium ions; (2) on a mixture of a model solution and real mineral water; and (3) on real wastewater and spent mineral water taken from a thermal resort. As a result of an experiment with water samples at an initial concentration of no more than 85 mg/L, optimal doses of reagents were identified: 5.67 g/L of sodium hydrophosphate and 3.21 g/L of magnesium chloride to achieve a residual concentration of ammonium ions in purified water of no more than 1.5 mg/L at pH = 9–10. In the case of mixing of domestic wastewater and used mineral water, it was possible to reduce the use of magnesium chloride by 80%. At the same time it was possible to obtain the amount of sediment containing struvite, which is a valuable agricultural fertilizer. With the introduction of this technology, it is possible to reduce the expenses of reagents and reduce the damage caused by the discharge of liquid waste from a thermal resort, while the profit earned through the sale of fertilizer can partially offset the cost of wastewater disposal. Full article

The multi-media environmental behavior of dissolved organic matter (DOM) is closely related to biogeochemistry and water quality. In this study, we characterized the multi-media distribution patterns and sources of DOM in a human-intensive watershed based on fluorescence measurements and fluorescence quotient (FQ) methods. Clay showed higher proportions in urban areas compared with rural areas. The biological index decreased with the increased similarity of DOM between sediment and a wastewater treatment plant (WWTP)/domestic sewage. The similarity of DOM between sediment and aquaculture was negatively related to coarse silt (Pearson, p < 0.05). In the water, C2 was more abundant in urban areas than in rural areas; among all sources, the WWTP exhibited the highest similarity (98.04%) of DOM with water, which was higher than that between sediment and the WWTP. The fluorescence index decreased with the increased similarity of DOM between waters and the WWTP/domestic sewage. The FQs for some amino acid-like materials and microbial byproducts between sediment and water were negative, while those for humic-like and fulvic-like materials between sediment and water were positive. Structure equation model (SEM) results showed that sediment grain size exerted positive effects on the distribution of C1 between sediment and water and negative effects on the distribution of C3 between sediment and water. The results demonstrated that the distribution of DOM between sediment and water, as well as the source contribution to DOM in sediment, was related to the sediment grain size, revealing the impact of sediment on the multi-media environmental behavior of DOM. Full article

Effective management of wastewater treatment plants often requires real-time measurements of Biochemical Oxygen Demand (BOD). Conventional methods for determining Biochemical Oxygen Demand (BOD) are often time-consuming, labor-intensive and prone to inaccuracies. Microbial Fuel Cells (MFCs) have emerged as a viable alternative technology for BOD measurement, offering real-time monitoring capability. However, challenges remain in its validity for testing different types of wastewater. This study developed a cost-effective dual-chamber MFC with graphite felt electrodes and a CMI-7000 membrane, inoculated with a microbial consortia grown from anaerobic sludge at optimal conditions (35 °C, pH 7, 1000 Ω external resistance). After one month of biofilm formation, the MFC produced 600 mV. Voltage outputs were measured at six BOD₅ concentrations (36 to 583 mg/L) in synthetic wastewater, showing a strong linear correlation between BOD₅ concentrations and voltage outputs. The MFC was also tested with five domestic wastewater samples with BOD₅ values ranging between 81 and 405 mg/L. The output voltages were inserted into the derived voltage–BOD correlation to obtain BOD₅ values within 2.5% to 11% of conventional laboratory results. These findings confirm the potential of MFC-based biosensors as an efficient and accurate tool for real-time wastewater monitoring. Full article

The treatment of domestic wastewater remains a significant environmental challenge, particularly in rural areas where the construction of sewer systems is often not economically viable. Vertical-flow filters offer an alternative, but traditional filter media are prone to clogging, which justifies the search for new waste-based fillers. The aim of this study was to evaluate the potential of synthetic waste wool as a filter medium and biofilm carrier in vertical filters for domestic wastewater treatment, with particular emphasis on the effects of active bed height and hydraulic loading rate. Experimental models were used to assess the influence of these parameters on treatment performance. High removal efficiencies of organic pollutants and suspended solids were achieved. The filter with an active bed height of 0.9 m that operated at a hydraulic loading rate of 80 dm³·m⁻²·d⁻¹ achieved removal efficiencies of 93.06–97.65% for BOD₅, 86.53–94.20% for COD, 62.69–87.53% for TSS, and 65.73–94.31% for NH₄⁺-N. The most favorable treatment results were obtained for a greater bed depth and lower hydraulic load values. An increase in hydraulic load resulted in a deterioration of the quality of the treated wastewater. The results obtained indicate that waste synthetic wool can serve as a promising filtration material in decentralized wastewater treatment systems, aligning with the principles of the circular economy and the sustainable development of environmental technologies. Full article

Unsafe water sources contaminated with fecal bacteria and antibiotic-resistant pathogens represent a critical public health challenge in rapidly urbanizing regions. This study investigates the occurrence, distribution, and antimicrobial resistance (AMR) patterns of Escherichia coli across interconnected water sources in Guwahati, India, including river water, wells, municipal supply, and groundwater. A total of 87 samples were analyzed using membrane filtration, biochemical identification, and automated confirmation, followed by antibiotic susceptibility testing and phenotypic detection of β-lactamase production. Total coliforms were detected in 64.4% of samples, while E. coli was confirmed in 51.7%. According to World Health Organization risk thresholds, 93.3% of river water samples and 50% of groundwater samples fell within the very-high-risk category (>1000 CFU/100 mL), indicating widespread fecal contamination in sources used for domestic purposes. Antibiotic-resistant E. coli was identified across all water types, with 14.1% of isolates exhibiting multidrug resistance (MAR index > 0.2). Notably, 20.6% of isolates produced β-lactamases, including one extended-spectrum β-lactamase (ESBL) producer, while no carbapenemase-producing strains were detected. The co-occurrence of multidrug-resistant E. coli across surface and groundwater systems is consistent with the interconnected nature of urban water contamination and suggests the potential for widespread exposure through drinking water pathways, though direct transfer between water systems was not experimentally confirmed in this study. These findings underscore the urgent need for improved wastewater management, protection of groundwater resources, and strengthened antibiotic stewardship within a One Health framework to mitigate the environmental dissemination of AMR. Full article

Decarbonising domestic heating stands as one of the primary climate challenges, positioning net-zero building technologies as the vital technical response. Wastewater source heat pumps (WWSHPs) serve as a thermally stable solution for household heating. Scaling this system up to an urban network level requires balancing maximum heat extraction against the risks of biological damage to downstream treatment systems from excessive temperature drops. To resolve it, this study couples a quasi-steady-state model, driven by dynamic, 30 min time-series inputs, with a Genetic Algorithm (GA) to optimise a 41-pipe sewer network in Belgium. Significant results demonstrate that the GA configuration enhanced potential heat recovery by 51.7% relative to unoptimised baselines, elevating yields from 29 MW to 44 MW. Furthermore, this research identified a mass compensation effect in winter that effectively counterbalanced seasonal drops in wastewater temperature, resulting in nearly identical winter and summer average heat recovery capacities (17.409 MW vs. 17.492 MW, a variance under 0.5%). From these findings, it can be concluded that while network-scale thermal potential is exceptionally robust year-round, a profound seasonal mismatch exists between available supply and localised consumer heating requirements, which drop to a minimum of 712 kW in July but exceed 51 MW in winter. Full article

Constructed wetlands operated in plateau habitats may experience constrained biological treatment because low temperature, low atmospheric pressure, and low-carbon wastewater can jointly limit microbial metabolism. This 80-day pilot screening study evaluated three nonreplicated modular constructed wetland configurations (MCW1-MCW3) containing different sequences of zeolite, ceramsite, and quartz sand and planted with Veronica anagallis-aquatica. Each configuration consisted of one independent treatment train; therefore, the comparisons were interpreted as configuration-specific and exploratory rather than as statistically generalizable treatment effects. Pollutant-removal performance and microbial community succession were evaluated through repeated water-quality monitoring and 16S rRNA gene sequencing. MCW1 showed the highest observed mean NH₄⁺-N removal efficiency (88.6%), whereas MCW3 showed the highest observed mean TP and COD removal efficiencies (79.56% and 47.40%, respectively) and an NH₄⁺-N removal efficiency of 85.51%. TN removal by MCW3 remained limited at 20.49%, consistent with carbon limitation of denitrification. Under the naturally low-temperature plateau laboratory conditions, the observed COD reduction indicated partial mineralization or retention of organic pollution loads, potentially supported by substrate biofilms and cold-adapted microbial assemblages. Apparent module-contribution analysis suggested that zeolite contributed substantially to NH₄⁺-N reduction, whereas ceramsite contributed to TP and COD removal under the tested sequences. Because plant biomass and tissue nutrient contents were not measured, nitrogen and phosphorus removal could not be attributed quantitatively to hydrophyte uptake. Overall, substrate sequence influenced pollutant-removal patterns and microbial community assembly, providing preliminary evidence for habitat-adapted optimization of modular constructed wetlands for plateau domestic wastewater. Full article

Pharmaceuticals and personal care products (PPCPs) are contaminants of emerging global concern, yet their long-term fate and distribution in strategic trans-boundary water source areas remain underexplored. This study conducted a comprehensive monitoring campaign spanning from 2018 to 2020, with six sampling campaigns carried out in August 2018, December 2018, May 2019, August 2019, December 2019, and May 2020, to investigate the occurrence, spatiotemporal dynamics, source apportionment, and ecological risks of 54 PPCPs in the surface water and sediments of the Taipu River in eastern China. Utilizing non-target screening via liquid chromatography high-resolution mass spectrometry (LC-HRMS), 54 PPCPs across 15 categories were detected, with average total concentrations of 28.60 ng/L in surface water and 13.01 ng/g in sediments. Sulfonamides, quinolones, and non-steroidal anti-inflammatory drugs (NSAIDs) dominated the aqueous phase (with bisphenol A and sulfamethoxazole highly prevalent), while hormones (e.g., estriol) and quinolones (e.g., ciprofloxacin (CIP)) exhibited significant accumulation in the benthic zone. Spatiotemporal analysis revealed a seasonal pattern where PPCP concentrations were higher in the dry season than in the wet season, primarily driven by hydrological dilution and climate-induced degradation. Furthermore, Positive Matrix Factorization (EPA PMF 5.0) extracted five distinct source factors for each matrix. Specifically, surface water pollution was primarily driven by domestic wastewater, municipal effluents, medical discharges, and localized pharmaceutical emissions, whereas sediments acted as a long-term sink predominantly for domestic wastewater, agricultural/veterinary runoff, and municipal/industrial emissions. Ecological risk assessment indicated that while most of the nine high-frequency contaminants posed low risks, specific compounds such as CIP, SM2, and E3 presented medium risks in surface water, whereas ENR, CIP, and SPI posed medium risks in sediments. These findings emphasize that the continuous multi-source input and the resulting pseudo-persistence of PPCPs in sediments warrant prioritized continuous attention and targeted pollution control strategies in the Taipu River Basin. Full article