Search Results (309)

Environmental contaminants (ECs) may impair skeletal health through endocrine disruption, oxidative stress, inflammation, and altered mineral homeostasis. This systematic review and meta-analysis evaluated the associations between EC exposure and osteoporosis-related outcomes in adults. PubMed/MEDLINE, Scopus, and Web of Science were searched in April 2026 for English-language studies published from 2016 onward. Study selection followed PRISMA guidelines, while methodological quality was evaluated using the Joanna Briggs Institute (JBI) checklist and Newcastle–Ottawa Scale (NOS). Evaluated contaminant classes encompassed ambient air pollution (PM2.5, PM10, PM1, NO₂, NO_x, SO₂, CO, O₃), per- and polyfluoroalkyl substances (PFAS), heavy metals and trace elements (e.g., cadmium, lead), pesticides, polycyclic aromatic hydrocarbons (PAHs), phthalates, volatile organic compounds (VOCs), persistent organic pollutants (POPs, dioxins, PCBs), brominated flame retardants (BFRs), and water disinfection by-products. Random-effects meta-analyses using restricted maximum likelihood estimation were conducted when at least 3 studies were available. Forty-eight studies involving 4,510,868 participants were included. Air contaminants showed the most consistent associations with reduced bone mineral density (BMD) and osteoporosis, followed by selected PFAS and cadmium exposures. Evidence for pesticides, PAHs, phthalates, volatile organic compounds VOCs, POPs, flame retardants, and water disinfection by-products was less consistent. PM2.5 exposure was associated with increased osteoporosis risk (OR = 1.24, 95% CI: 1.02–1.51), and to a lesser extend also PM10 (OR = 1.17, 95% CI: 0.96–1.42). The analyses showed extreme heterogeneity and sensitivity to influential studies. ECs, particularly fine particulate matter, may contribute to skeletal deterioration, although the findings require cautious interpretation. PROSPERO ID: CRD420261460078. Full article

Legionella pneumophila, the causative agent of Legionnaires’ disease, remains a major public health concern in water systems. Chlorination is the most widely used disinfection strategy but presents important limitations, including reduced stability in hot water systems and the generation of carcinogenic by-products. This study evaluated ozonation as an alternative disinfection method, comparing its efficacy with chlorination against different physiological states of L. pneumophila, including culturable and viable but non-culturable (VBNC) cells, as well as biofilm-associated bacteria and amoebal hosts. The biocidal effect of ozone and chlorination on planktonic L. pneumophila was assessed by culture and viability-qPCR. Biofilm viability was evaluated using fluorescein diacetate staining, whereas amoeba viability was determined by flow cytometry. Ozonation achieved complete inactivation of both culturable and VBNC L. pneumophila within 5 min. In contrast, chlorination achieved complete loss of culturability only at high concentrations and was associated with the persistence of VBNC cells. Neither ozonation nor chlorination significantly reduced established biofilms or amoebae. These findings indicate that ozonation is a promising strategy for rapid inactivation of planktonic L. pneumophila and may overcome important limitations associated with chlorine-based treatments. Full article

Halogenated ketones (HKs) and aldehydes (HAs) are prevalent emerging disinfection by-products (DBPs) threatening drinking water safety. Although pre-oxidation and coagulation are widely applied in drinking water treatment, critical knowledge gaps remain regarding the precursor-specific effects of KMnO₄ and O₃ pre-oxidation on chlorinated ketone/aldehyde formation potential, as well as the interaction between coagulation optimization and DBP yields. This study systematically investigates the effects of KMnO₄/O₃ pre-oxidation and optimized coagulation on the formation potential (FP) of 1,1-dichloroacetone (1,1-DCP), 1,1,1-trichloroacetone (1,1,1-TCP), and chloral hydrate (CH) from four typical precursors (fulvic acid, citric acid, L-threonine, L-asparagine). Batch pre-oxidation and chlorination experiments were performed; three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy was used to characterize organic-precursor structural changes, while gas chromatography–mass spectrometry (GC-MS) was adopted to quantify target DBPs. Results show that KMnO₄ and O₃ pre-oxidation significantly promote (p < 0.05) DBP formation from fulvic acid but exert precursor-specific effects on small-molecule precursors: KMnO₄ enhances CKs while inhibiting CH from amino acids, and O₃ suppresses all three DBPs from small-molecule precursors. Coagulation pretreatment weakly inhibits DBP formation (reduction rate < 20%) by removing partial precursors. This study clarifies the mechanism of process-driven DBP modulation and provides a theoretical basis for optimizing water treatment processes to control chlorinated ketone/aldehyde DBPs. Full article

Proteases are widely studied hydrolases as “green technologies” for degrading structures within complex matrices, although combining different classes poses challenges for catalytic stability. To the best of our knowledge, this is the first study to specifically evaluate the biochemical control of Cryptosporidium spp. oocysts using plant- and microbial-derived proteases. This study evaluated the compatibility and sanitizing potential of the microbial serine protease subtilisin Carlsberg (HPF-1SCA) and the plant cysteine protease papain (1PPP), both individually and in a 15% (w/v) combination, hypothesizing a synergistic effect due to their distinct catalytic specificities, as a potential biochemical approach to reduce contamination by these zoonotic protozoa of global importance, which are highly resilient to conventional disinfectants. The experimental design comprised five distinct treatment groups: a negative control (distilled water), a positive chemical control (0.04% v/v NaClO), treatment with isolated papain (15% w/v), treatment with isolated microbial HPF formulation (15% w/v), and a combined treatment using both enzymes simultaneously (15% w/v each). Concurrently, an in silico molecular docking investigation was conducted to elucidate the predicted binding scores, structural compatibility, and preferential binding mechanisms of these enzymes toward the Cryptosporidium Oocyst Wall Protein (COWP). In vitro compatibility assays revealed an immediate antagonistic effect due to mutual proteolysis, reducing overall proteolytic activity by 45% after 72 h. Despite this antagonism, the enzyme mixture (G5) and the isolated microbial protease (G4) achieved a 93% reduction in oocysts, equivalent to the conventional 0.04% NaClO treatment (G2), while papain (G3) achieved 65%. All these results represented statistically significant efficacy (p < 0.01) compared to the negative control (G1). In silico molecular docking studies provided a structural predictive basis for the experimental data, suggesting that subtilisin Carlsberg (HPF-1SCA) exhibits more favorable predicted binding scores and structurally compatible interfaces, compared to papain, particularly toward the major oocyst structural proteins COWP8 (estimated ΔG = −15.2 kcal·mol⁻¹) and COWP6 (estimated ΔG = −13.3 kcal·mol⁻¹). This provides robust evidence for initial target recognition and molecular anchoring, although these static models do not definitively confirm catalytically productive cleavage conformations. In summary, this in vitro proof-of-concept demonstrates that microbial proteases show promise for the biochemical destabilization of oocysts without generating toxic chlorinated byproducts. While these baseline findings align with the One Health concept, future field-scale validations assessing enzyme stability under variable environmental conditions and in vivo infectivity assays are required before practical application in sanitation protocols. Full article

The biosynthesis of copper and copper oxide nanoparticles (Cu/CuO-NPs) has attracted considerable interest due to its non-toxic, eco-friendly nature and wide-ranging applications, especially in nanomedicine and biomedical fields. Traditional nanoparticle production methods often involve toxic chemicals and generate harmful byproducts. In contrast, biological synthesis provides a cleaner, safer, more cost-effective, and sustainable alternative. Various biological sources, including plants, bacteria, fungi, and yeast, have been employed for the efficient and non-toxic production of Cu/CuO-NPs. These organisms contain diverse biomolecules such as enzymes, proteins, amino acids, vitamins, flavonoids, and alkaloids that function as reducing, capping, and stabilizing agents during nanoparticle formation. The biologically synthesized Cu/CuO-NPs are characterized using UV-VIS spectroscopy, Raman spectroscopy, TEM, SEM, EDX, XRD, TGA, XPS, FTIR, DLS, zeta potential analyzer, etc. Cu/CuO-NPs hold promise for applications in nanomedicine, primarily because of their strong antimicrobial and anticancer activities and potential use as disinfectants against infectious diseases. Various reports have suggested that the biologically synthesized Cu/CuO-NPs have exhibited significant antimicrobial and anticancer efficacies against pathogenic bacteria, fungi and viruses and various cancer cells. Due to their nanoscale dimensions and extensive surface area, Cu/CuO nanoparticles can readily infiltrate cell walls, disrupt membrane integrity, generate reactive oxygen species, and hinder both DNA replication and protein production, leading to cell death. The present review comprehensively describes the biological synthesis of Cu/CuO-NPs, their characterization techniques, and potential antibacterial, antifungal, antiviral, and anticancer applications. The modes of action for antibacterial, antifungal, antiviral, and anticancer properties have also been explored critically. Full article

Population growth, increasing water demands for data centers, and the need for more sustainable water practices are prompting advancement of next-generation water resource management strategies including water reuse. In the Midwestern United States (U.S.), where non-traditional approaches to augmenting water supply, including water reuse, are relatively new, full advanced water treatment (AWT), which includes microfiltration/ultrafiltration (MF/UF) and reverse osmosis (RO), produces a concentrate stream that is expensive to address (i.e., brine disposal). Carbon-based advanced treatment (CBAT), which combines ozonation, biofiltration, and granular activated carbon, has been shown to be a viable alternative with select advantages over the traditional RO approach, including the lack of brine generation. Two novel pilots were conducted in the Midwestern U.S., one at a large (>100 MGD) and one at a small (~10 MGD) wastewater reclamation facility (WRF), to provide proof of concept that CBAT could meet distinct regional needs. While additional demonstration data are ultimately needed for future regulatory approvals, results from the pilots showed that water quality objectives were met with treated water quality of <0.5 mg/L total Kjeldal nitrogen (TKN), <2 mg/L total organic carbon (TOC), and substantial reduction in constituents of emerging concern (CECs). If nitrate removal is required to meet drinking water standards (10 mg/L), additional treatment optimization at the source WRFs would be required. Areas for further research identified by this effort include mitigating the potential for ozonation to contribute to the formation of disinfection byproducts such as bromate and N-nitrosodimethylamine (NDMA). Along with the treatment performance demonstrated at these pilots, the study provided an opportunity to engage with key stakeholders to build trust in the AWT approach, which is critically important for regulatory and public acceptance. Based on two field-scale pilot studies in the U.S. Midwest, this paper analyzes CBAT application advantages and challenges in municipal water reuse and identifies research directions for the industry. Full article

Reactions between nitrogen-containing compounds and free chlorine in swimming pools produce several undesirable by-products, with trichloramine (TCA) being especially problematic due to its odor and hazardous properties, causing respiratory symptoms and skin and eye irritation for swimmers and personnel. To address this issue, this study investigates electrochemical oxidation as a potential technique for reducing TCA concentrations in various pool water environments. Specifically, the results show that electrolysis, using a mixed metal oxide (MMO) electrode as the anode, affects the amount of free chlorine and significantly reduces TCA in synthetic pool water containing urea and sodium hypochlorite. This approach is further validated in large-scale systems with real swimming pool water. In two long-term experiments, TCA released from the pool water falls from a baseline of 1.42 mg/m³ to 0.94 mg/m³ in a 680 m³ pool, a reduction of 34% ($p<0.001$), and from 0.77 mg/m³ to 0.35 mg/m³ in an 85 m³ pool, a reduction of 55% ($p<0.001$). Water from a third pool was used to map the potential dependence. Importantly, the anode potential is critical for TCA reduction, with 1.8 V vs. RHE identified as optimal and a working window of 1.7–1.9 V. The system operates at approximately 1 A/m² and 2 W/m². Overall, this electrolysis process reduces the trichloramine burden of swimming pool water, which is expected to lower airborne trichloramine in swimming halls and thereby improve conditions for users and personnel. Full article

Chlorophenylacetonitriles are known as one of the emerging nitrogenous disinfection byproducts (N-DBPs) in chlorinated drinking water due to their concerned cytotoxicity and genotoxicity compared to regulated carbonaceous DBPs. However, under low-dose exposure, the in vivo pathological consequences of chlorophenylacetonitriles remain largely unresolved. Here, C57BL/6J mice were exposed to 2-chlorophenylacetonitrile (2-CPAN) via drinking water (100 ug/L) for six months, and an integrated histopathological and genome-wide transcriptomic approach was employed to mechanistically characterize its multi-organ toxicological consequences. 2-CPAN ingestion significantly suppressed body weight (35.9 ± 2.0 g vs. 47.6 ± 11.6 g, p < 0.05) and induced severe gastroenteropathy—including gastric lamina propria inflammatory infiltration, intestinal villous blunting, crypt disorganization, transmural mononuclear infiltration, and abrogating epithelial barrier integrity. Intestinal barrier failure drove portal translocation of luminal PAMPs, potentially triggering splenic white pulp atrophy, red/white pulp boundary dissolution, and parenchymal changes consistent with fibrotic remodeling. Splenic RNA sequencing revealed a bipartite transcriptomic reprogramming: upregulated pathways were enriched in the ribosome, MAPK signaling, cytokine–cytokine receptor interaction, and chemokine signaling pathways. A proteotoxic stress module (Hspa1a, 9.4-fold; Hspa1b, 10.2-fold) and a chemokine effector hub (Ccl2, 3.43-fold; Ccl5, 2.9-fold; Ccl19, 2.58-fold; Ccl21a, 2.15-fold) were identified by the STRING network. Downregulated pathways converged on cell cycle suppression, with concurrent loss of Ccne1/Ccne2 and Cdc6 (G1/S block), Ccnb1 and Plk1 (G2/M arrest), and Rrm2/Tars3/TrnM (dNTP and aminoacyl-tRNA starvation), collectively forcing splenic lymphocytes into irreversible proliferative failure. These findings provide the first mechanistically resolved in vivo evidence that chronic 2-CPAN exposure drives a potential gut–spleen toxicological axis, underscoring the urgent need to incorporate organ endpoints by long-term exposure into N-DBP risk assessment. Full article

Conventional water treatment relies on sequential flocculation and disinfection, which inflates infrastructure costs and heightens the risk of disinfection byproduct formation. Here, we report a magnetic lignin-based flocculant (LS-DMC-AM@Fe₃O₄) that integrates flocculation, sterilization, and rapid magnetic separation within a single material. The composite was synthesized by thermally initiated graft copolymerization of methacryloyloxyethyl trimethylammonium chloride (DMC) and acrylamide (AM) onto sodium lignosulfonate (LS), followed by incorporation of Fe₃O₄ nanoparticles (NPs) at 15 wt% loading; the product exhibited a saturation magnetization of 12.8 emu g⁻¹. LS-DMC-AM@Fe₃O₄ achieved 98.2% kaolin turbidity removal at 1 mg L⁻¹ and 98.6% E. coli removal at 8 mg L⁻¹, and displayed a markedly broader effective dosage window than its non-magnetic analog. We attribute this broadened window to Fe₃O₄-enhanced membrane disruption, which liberates anionic intracellular contents that buffer excess cationic charge and thereby suppress restabilization. The bactericidal efficiency reached 90% at 18 mg L⁻¹, 1.6-fold higher than LS-DMC-AM, governed by a synergistic dual mechanism: quaternary ammonium contact-killing coupled with Fe₃O₄ NP-induced intracellular reactive oxygen species (ROS) accumulation. Under an external magnetic field, flocs underwent rapid phase separation and displayed enhanced shear-regrowth capacity (E. coli floc recovery factor: 53% vs. 26%); Fe₃O₄ NPs were recovered at >95% efficiency over two cycles. Despite higher unit production costs, LS-DMC-AM@Fe₃O₄ delivers competitive per-unit-volume treatment economics through its ultralow effective dosage and magnetic seed recyclability. These results establish a viable strategy for engineering multifunctional, recyclable flocculants from industrial lignin waste. Full article

Microbiological contamination of surface water represents a critical public health concern, while conventional disinfectants face limitations such as the generation of toxic by-products and the emergence of microbial resistance. In this study, the application of an ethanolic peel extract of Citrus paradisi (grapefruit), obtained by sonication at 40 kHz for 90 min at 55 °C using a 1:4 (w/v) solvent-to-solid ratio, was evaluated as a natural alternative for bacterial reduction in contaminated waters. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of the extract were first determined against Staphylococcus aureus and Escherichia coli. The extract was then applied to samples of slightly contaminated surface water with bacterial loads between 10³–10⁴ CFU/mL and turbidity of 150 NTU, as well as to highly contaminated surface water with bacterial loads ≥10⁵ CFU/mL and turbidity of 250 NTU. Bacterial removal was assessed at 6, 12, and 24 h. FTIR and UV-Vis characterization of the extract confirmed the presence of flavonoids (naringin), terpenes (limonene), and phenolic compounds. Results showed MIC/MBC values of 2.5/5.0 mg/mL for S. aureus and 5.0/10.0 mg/mL for E. coli. In slightly contaminated water, the extract at 5.0 mg/mL achieved complete (100%) removal of both microorganisms after 12 h, whereas in highly contaminated water, removals ranged from 80–90% for Staphylococcus spp. and E. coli. Statistical analysis (ANOVA, Bonferroni) demonstrated significant differences (p < 0.05) between the extract and ethanol. These findings indicate that Citrus paradisi extract constitutes an effective, sustainable, and low-cost natural alternative for bacterial reduction in surface waters, contributing to the valorization of agro-industrial residues and to the achievement of Sustainable Development Goal (SDG) 6. Full article

Climate change may intensify the deterioration of river water quality by altering streamflow regimes, precipitation patterns, and organic matter transport pathways. In this study, a Hydrological Simulation Program-FORTRAN (HSPF)-based streamflow and total organic carbon (TOC) water quality model for the Tamjin River Basin, Korea, was developed, and future TOC pollution was evaluated under quantile delta mapping (QDM) bias-corrected Shared Socioeconomic Pathway 5-8.5 (SSP5-8.5) climate scenarios. Unlike previous studies that generally applied climate bias correction, watershed modeling, or pollutant-load assessment as separate procedures, this study links QDM-preserved climate change signals, process-based HSPF simulations, and TOC-specific discharge-load, delivered-load, exceedance-frequency, and load-reduction indicators within a single management framework. The model showed acceptable performance, with Nash–Sutcliffe efficiency (NSE) values of 0.67 and 0.68 for streamflow at Jangheung Dam and Gamcheon Bridge, respectively, and a TOC deviation of volume (DV) of 0.6% at Tamjin5. Under the SSP5-8.5 no-action scenario for the 2040s, the mean streamflow decreased by 33.1%, whereas the mean TOC concentration increased by 76.8% relative to the baseline. The number of days exceeding 4 mg/L TOC increased from 41 to 216 days yr⁻¹, and the Korean TOC-based water quality class deteriorated from Ib to III. In contrast, the 20% and 30% load reduction scenarios offset approximately 33.8% and 67.9% of the climate-driven increase in TOC, respectively, with the 30% reduction scenario showing greater effectiveness during low-flow seasons. Elevated TOC levels may have implications for downstream water treatment because organic matter can increase chemical demand and disinfection-byproduct formation potential. However, these treatment-related effects were not directly evaluated in this study. These results suggest that TOC should be considered as a complementary indicator to conventional biochemical oxygen demand (BOD)-based management when developing climate-resilient water-quality strategies for the Tamjin River Basin. Full article

Access to safe drinking water remains a global public health concern due to its role in the transmission of infectious diseases. Despite the 20th-century achievement of chlorine-based disinfection, drinking water systems face threats from aging infrastructure, climate-induced stressors, and emerging pathogens that evade traditional treatment. This bibliometric review maps three decades of research on microbial contamination in drinking water systems to explain its historical developments, current knowledge, and important updates. Only original and review articles retrieved on 13 April 2026 were screened for inclusion, requiring a focus on detecting, monitoring, or mitigating microbial contamination in drinking water systems. Analysis of 93 records identified a linear growth pattern, shifting from acute enteric pathogen monitoring to the management of opportunistic pathogens (OPs), antimicrobial resistance (AMR), and disinfection by-products (DBPs). Additionally, traditional fecal indicator bacteria (FIB), such as Escherichia coli, may not fully predict the presence of resilient pathogens protected within biofilms or free-living amoebae (FLA), which serve as environmental reservoirs for infection. To address these limitations, this review presents a conceptualization of waterborne pathogens by proposing formal case definitions and diagnostic criteria for critical contamination events (CCE) and chronic low-level exposure (CLLE). Lastly, knowledge gaps and open research questions relevant to future studies on microbial contamination in drinking water systems were identified and discussed. Full article

Chlorinated benzoquinones such as 2,6-dichlorobenzoquinone (DCBQ) are toxic disinfection by-products that may persist in treated waters, requiring post-treatment strategies. In this study, the photo-Fenton process was evaluated for DCBQ degradation, with a focus on the influence of pH on kinetics, oxidation behavior, and water quality evolution. Experiments were conducted using 50.0 mg/L DCBQ, 1.0 mg/L Fe²⁺, and 2.0 mM H₂O₂ under UV irradiation (150 W) within a pH range of 3.0–12.0. Degradation followed apparent second-order kinetics, with maximum rates at acidic pH. At initial pH 3.0–5.0, rapid pollutant removal was accompanied by efficient aromaticity (UV₂₅₄) and color elimination, intense dissolved oxygen consumption, transient turbidity peaks due to intermediate formation, and increases in total dissolved solids, indicating extensive oxidation and a high degree of organic matter transformation, as inferred from indirect physicochemical indicators. At near-neutral pH, oxidation was slower, with delayed aromatic and chromophoric decay and moderate accumulation of intermediates. Mildly alkaline conditions exhibited limited radical activity, stable turbidity, and reduced mineralization. Under strongly alkaline conditions, oxidation was largely inhibited, with persistent aromaticity and negligible oxygen consumption. These findings highlight the importance of integrating advanced oxidation processes with adsorption-based systems for efficient and sustainable water treatment of emerging contaminants. Full article

Trihalomethanes (THMs) are priority disinfection by-products in drinking water, and their effective removal remains a persistent challenge for sustainable treatment. Here, olive mill solid waste (OMSW) was valorized into biochar (BC) and evaluated as a low-cost adsorbent for chloroform, bromodichloromethane (BDCM), chlorodibromomethane (CDBM), and bromoform under environmentally relevant conditions. Among the prepared materials, thermally activated BC (BC-T) performed best, achieving equilibrium removals of 74.7 ± 6.6% for chloroform, 91.1 ± 0.8% for BDCM, 87.2 ± 1.9% for CDBM, and 93.8 ± 0.3% for bromoform at 3000 mg/L. Adsorption increased with bromine substitution, following the order of bromoform > CDBM ≈ BDCM > chloroform, consistent with rising hydrophobicity. In contrast, KOH and Zn/Fe activation increased the BET surface area but did not improve THM removal, suggesting that adsorption was controlled by surface chemistry and site accessibility rather than surface area alone. Persulfate (PSF) addition reduced THM removal, indicating that oxidant activation did not compensate for the loss of adsorption capacity. Adsorption data were well described by the Freundlich isotherm and pseudo-second-order kinetics. BC-T also maintained high removal efficiency in drinking water, demonstrating its promise as a practical polishing adsorbent for THM control and as a route for high-value valorization of an abundant agricultural residue. Full article

Ensuring safe and palatable drinking water is critical for long-duration space travel and part of NASA’s 2022 strategic goals. This study investigated whether the formation of iodoform occurred when iodine reacts with trace levels of dissolved organic carbon (DOC) leaching from spacecraft water system components. A simplified model of the International Space Station’s Environmental Control and Life Support System was constructed, focusing on disinfection. The system included water storage in low-density polyethylene (LDPE) bags followed by activated carbon block filtration. Three scenarios were tested: iodine treatment in the storage tank, iodine treatment in-line after storage, and a control with no iodine. Preliminary results showed I₂ concentrations of 0.1–5.42 mg/L prior to filtration, which decreased below detection after filtration. DOC concentrations ranged from below detection to 1.1 mg/L. Concentrations of iodoform, determined by gas chromatography–mass spectrometry, were assessed to observe potential risks to spacecraft drinking water quality. Iodine-based disinfection did result in significant iodoform formation or increased leaching of DOC. This study supports that long-term water storage can be achieved using iodine disinfection and LDPE storage. These results also inform the use of iodine disinfection in emergency situations by drinking water managers when water supply is interrupted in disaster situations. Full article