Humans are continuously exposed to complex mixtures of environmental contaminants. This kind of multiple exposure occurs when reclaimed asphalt pavements are recycled, since the fumes contain polycyclic aromatic hydrocarbon derivatives (PAHs+) that are primarily been investigated as single compounds. In this study, we assessed the genotoxic potential of an environmentally relevant quaternary mixture composed of 1-nitropyrene, quinoline, 2-naphthol, and 6H-benzo[c,d]pyrene-6-one (6H-BPO) using the human bronchial epithelial BEAS-2B cell line. Cells were exposed according to a Doehlert experimental design and chromosomal damage was evaluated using the cytokinesis-block micronucleus assay. Response surface methodology was applied to model both cytostasis and micronucleus induction and their values were calculated in the whole domain. All quaternary exposure conditions produced acceptable cytostasis (<55%), enabling reliable genotoxicity assessment. The models revealed that 1-nitropyrene was the main driver of cytostatic effects, while oxygenated PAHs, 2-naphthol and 6H-BPO, mainly contributed to chromosomal damage. Moreover, significant response surfaces showed concentration-related interactions, demonstrating that genotoxic responses could not be explained by additive effects. By combining in vitro genotoxicity testing with innovative experimental design, this study provides a robust framework for investigating complex contaminant mixtures while significantly reducing the number of required experimental conditions. These findings also improve the mechanistic understanding of PAHs + mixture toxicity and support the integration of mixture-based approaches into environmental hazard assessment and human health risk evaluation.

Microplastic source attribution remains a major challenge because conventional analytical techniques primarily identify polymer types while providing limited information on the origin and environmental history of plastic materials. This study evaluates the potential and limitations of stable carbon isotope analysis (δ[13]C) for tracing common plastic polymers at the global scale. A total of 460 commercial plastic samples, including 233 polyethylene terephthalate (PET) bottles and 227 polyethylene (PE) caps, were collected from 59 countries across six continents and analysed by elemental analyzer - isotope ratio mass spectrometry (EA-IRMS). A preliminary thermal additive removal experiment showed systematic but minor isotopic shifts (∼0.3‰ for PET and ∼0.5‰ for PE), indicating a minor influence of additives on bulk δ[13]C values. Among petroleum-derived samples, PE exhibited a broad δ[13]C range from -35.2‰ to -24.0‰, with significant interregional variability and country-averaged values ranging from -33.9 ± 0.1‰ (Tunisia) to -25.9 ± 0.1‰ (New Zealand). Continental-scale comparisons revealed significant differences between several regions, consistent with regional differences in petrochemical feedstocks and production pathways. In contrast, PET displayed a narrower δ[13]C range (-33.1‰ to -26.2‰) and no significant interregional differences, consistent with a more homogeneous and globally integrated production system. Overall, the results demonstrate that stable carbon isotopes provide useful first-order constraints on broad PE source domains, while also highlighting important limitations related to overlapping isotopic domains and the globalization of polymer supply chains. Stable isotope analysis therefore represents a promising complementary tool for improving microplastic source attribution within multi-tracer environmental forensic frameworks.

Microplastics (MPs) are emerging contaminants of concern due to their persistence and potential risks to ecosystems and human health. Municipal wastewater treatment plants (WWTPs) act as both sinks and discharge pathways for MPs, receiving contaminants from households and urban sources, while a residual fraction can remain in treated effluent. This study assessed the occurrence and apparent aqueous-phase concentration reduction of MPs across five WWTPs in the London-Middlesex region, Canada, with particular focus on smaller MPs (<25 μm), which are often overlooked in previous research. Total MP concentrations ranged from 380 to 1100 particles/L in primary influents and 190 to 310 particles/L in secondary effluents, with estimated daily discharges of 3.2 × 10[9] to 31 × 10[9] particles into receiving waters. Apparent concentration reductions varied across plants from 21% to 74%, with lower reduction during primary treatment. Larger MPs (150-550 μm) contributed 29%-56% of influent MPs, whereas smaller MPs (20-150 μm) comprised 27%-37%, suggesting that analytical size cutoffs can influence reported MP abundance. Fine MPs remained detectable after treatment, showing that analytical size cutoff strongly affects reported abundance and effluent particle loads. The reported reductions represent apparent aqueous-phase concentration changes within the sampled treatment train; plant-wide MP fate also includes transfer to treatment solids.

This review examines the physicochemical mechanisms governing pharmaceutical persistence, the formation of transformation products (TPs), and the effectiveness and limitations of conventional and advanced treatment technologies for water reuse, focusing on carbamazepine, diclofenac, iodinated contrast media, metformin, and selected antibiotics, which persist through wastewater treatment. The review follows one chain of reasoning: persistence drivers determine which TPs form, which compartments and exposure pathways are reached, and which treatment barriers can act. Conventional activated sludge often provides incomplete removal, whereas integrated trains combining biological processes, adsorption, ozonation, UV/H2O2, membranes, and other advanced oxidation technologies can improve control, although energy demand, membrane fouling, residuals, and TP formation remain constraints. Pilot- and full-scale studies report average abatement of about 80% or more with ozonation or activated carbon, but behavior differs among compounds, and evidence for complete multi-barrier trains is limited. Unlike reviews addressing occurrence, individual technologies, or TPs separately, this review links the drivers of persistence to the selection and sequencing of treatment barriers, and extends the assessment to groundwater migration, soil-plant and food-chain transfer, and antimicrobial-resistance pathways within a common water-reuse framework. This supports adaptive treatment design targeting parent compounds, TPs, and cross-compartment risks. HRMS, non-target screening, and AI/ML-assisted optimization support adaptive monitoring and control. However, identifying a TP does not demonstrate risk, so effect-based methods are needed, and AI/ML applications are mainly predictive and validated on small datasets. Safe and sustainable water reuse likely requires multi-barrier treatment, source control, continuous monitoring, TP assessment, and integrated risk management.

Heavy metal contamination of water resources poses persistent risks to ecosystems and human health, making the development of effective and resilient adsorption strategies a global priority. This study examines how water hardness modulates the adsorption of zinc (Zn[2+]), iron (Fe), and copper (Cu[2+]) onto biochars derived from algae and wood. Continuous adsorption experiments under controlled calcium (Ca[2+]) and magnesium (Mg[2+]) concentrations simulated varying water hardness, with performance evaluated over 24 h. Water hardness affected metal removal, with the magnitude and relative effects of Ca[2+] and Mg[2+] depending on both the target metal and biochar type. Under high Ca[2+] conditions, Zn[2+] removal efficiency decreased by 49.6% and 46.4% relative to the corresponding controls for algae- and wood-derived biochars, respectively. Cu[2+] removal efficiency decreased by 16.2% and 15.8%, respectively, whereas Fe removal remained essentially unchanged for algae biochar but decreased by 12.0% for wood biochar. Under high Mg[2+] conditions, algae biochar showed substantially lower sensitivity, with a maximum relative reduction of 13.7%; however, wood biochar exhibited relative reductions of 24.2%, 28.3%, and 17.5% for Zn[2+], Cu[2+], and Fe, respectively, with Mg[2+] producing greater suppression than Ca[2+] for Cu[2+] and Fe on wood biochar. Density functional theory (DFT) modeling indicated that Ca[2+] preferentially occupies key oxygen- and nitrogen-containing functional groups on the biochar surface, disrupting metal complexation. These results demonstrate that water hardness cations can substantially alter metal-biochar interactions, with the magnitude of interference depending on the hardness ion, target metal, and biochar origin. This work underscores the importance of local water chemistry in designing biochar-based systems for heavy metal remediation.

Mining operations contribute to metal contamination in tropical ecosystems, yet the extent to which terrestrial invertebrates accumulate elements across different land-use types remains poorly understood. Dung beetles have been proposed as potential bioindicators owing to their close interactions with soil and vertebrate dung. In this study, we investigated the accumulation of nine elements (Mn, Cu, Mg, Fe, Cd, Zn, Pb, Hg, and As) in five common dung beetle species across old-growth forests, forest understory habitats, pastures, croplands, and mining-impacted habitats in southern Ecuador. Elemental concentrations were measured by atomic absorption spectrophotometry following acid digestion of dried tissues. Differences among land-use types and species were assessed using linear and linear mixed-effects models, while multielement patterns were examined using PERMANOVA and principal component analysis (PCA). Concentrations varied descriptively across habitats, with mining-impacted sites showing higher mean concentrations of some metals, particularly Fe, Pb, and Zn. However, no statistical significant differences were detected among land-use types or species. Multivariate analyses also revealed substantial overlap in elemental composition among habitats, without a statistically significant land-use effect. Hg and As were below analytical detection limits in most tissue samples and were therefore excluded from statistical comparisons. The detection of multiple elements in dung beetle tissues provides baseline information on elemental accumulation across the study landscape, although the sources of exposure could not be determined. These findings support further investigation of dung beetles as potential biomonitoring organisms but do not establish their ability to reliably distinguish mining-impacted from reference habitats. Future studies incorporating concurrent environmental matrix measurements, standarized temporal sampling, and greater spatial replication are needed to evaluate their reliability as indicators of mining-related contamination.

Waste cigarette butts are abundant and widely dispersed composite solid wastes worldwide. They consist of cellulose acetate filters, residual tobacco, cigarette paper, ash, and carry nicotine, polycyclic aromatic hydrocarbons (PAHs), and heavy metals. During weathering, cellulose acetate filters release microfibers and contribute to microplastic pollution, while toxic components migrate into aquatic and soil environments. Conventional landfilling, incineration, and recycling fail to achieve pollution control and resource recovery. This review focuses on the thermal conversion of waste cigarette butts. It compares feedstock heterogeneity, reaction mechanisms, and the effects of different processes on product formation and toxic-component migration, with the aim of assessing resource-recovery feasibility and environmental safety. During thermal conversion, additives such as triacetin first undergo thermal desorption. Cellulose acetate then undergoes deacetylation and backbone cleavage, producing acetic acid and oxygenated volatiles. Cigarette paper releases phenols and aromatic compounds, while residual tobacco releases nicotine, pyridine, and other nitrogen-containing compounds. Volatiles may condense into pyrolysis oil or undergo cracking, reforming, or gasification into syngas at higher temperatures and under controlled atmospheres or catalytic conditions. The remaining carbon framework forms solid char through condensation, aromatization, and structural rearrangement. Different routes are oriented toward different products, but thermal conversion does not necessarily eliminate toxic components. Complete mass-balance data on their distribution among gas, oil, char, ash, and wastewater remain unavailable. Future studies should strengthen feedstock standardization, validation under realistic and continuous operating conditions, and life-cycle and techno-economic assessments, so that the environmental constraints and engineering requirements of waste cigarette butt thermal conversion can be defined more clearly.

Aerobic granular sludge (AGS) has emerged as a promising biological wastewater treatment technology due to its compact reactor footprint, excellent settleability, and ability to simultaneously remove carbon, nitrogen, and phosphorus within a single sequencing batch reactor (SBR). However, its practical application remains limited by the prolonged granulation period during reactor start-up and the instability of mature granules under continuous operation. This study investigated the use of indigenous extracellular polymeric substance (EPS)-producing bacteria as a bioaugmentation strategy to accelerate granule formation and improve reactor performance. Two laboratory-scale SBRs with a working volume of 2.5 L were operated using real domestic wastewater collected from the Bunus Sewage Treatment Plant, Malaysia, under 3-h operating cycles. Indigenous bacterial isolates obtained from activated sludge were screened based on biofilm formation, fluorescence spectroscopy, and aggregation ability. Two strains, Bacillus albus and Proteus mirabilis, were selected for co-inoculation because of their complementary functional characteristics, namely high surface adhesion and strong protein-like EPS fluorescence. The bioaugmented reactor achieved 50% granulation (dry mass >0.2 mm) within 10 days and complete conversion of flocs into granules by day 40, whereas the control reached only 5% and 80% granulation at the same time points. By day 10, the bioaugmented sludge reached a settling velocity of 2.24 m h[-1] (vs. 1.37 m h[-1] in the control), and its SVI5 decreased to 76 mL g[-1] by day 40 (vs. 108 mL g[-1]). FE-SEM/EDS analysis revealed a dense EPS matrix with higher carbon and silicon contents than the control. The bioaugmented reactor consistently achieved higher pollutant removal efficiencies, reaching nearly 100% for COD, 75-90% for NH3-N, 70-83% for NO3[-]-N, and about 60% for TP. 16S rRNA gene amplicon sequencing further showed enrichment of Nitrospira (0.95% to 9.94%), Candidatus Accumulibacter (0.13% to 1.83%) and Chloroflexi, whereas the inoculated genera were not detected in the mature granules, suggesting that they acted mainly during early aggregation. Overall, the findings demonstrate that bioaugmentation with indigenous EPS-producing bacteria is an effective approach for accelerating AGS start-up and improving granule stability and treatment performance under tropical domestic wastewater conditions.

Portland cement production is a major contributor to global CO2 emissions, while large volumes of mine tailings remain stockpiled as long-term environmental liabilities. This study investigates valorisation of copper mine tailings (CMT) as a supplementary cementitious material within a resource recovery framework. Intrinsic reactivity was quantified using the R[3] test and linked to hydration behaviour through isothermal calorimetry, X-ray diffraction, FTIR and scanning electron microscopy, alongside compressive strength evaluation. The CMT exhibited an R[3] heat release of 156 J/g, confirming its intrinsic pozzolanic reactivity. Isothermal calorimetry showed that a 10% clinker replacement reduced cumulative heat release by only 2.67%, indicating partial compensation of clinker dilution through filler and pozzolanic effects. A cradle-to-gate life cycle assessment employing system expansion quantified environmental benefits from clinker displacement and avoided tailings storage burdens. Climate change impacts decreased from 0.935 to 0.583 kg CO2-eq with increasing CMT replacement, despite an 1800 km transport distance. Impact reductions were predominantly driven by clinker substitution, with additional gains from mitigating waste accumulation. These findings demonstrate a technically viable pathway for integrating CMT into lower-carbon blended cement.

Per- and poly-fluoroalkyl substances (PFAS) present a significant challenge for human, wildlife, and environmental health due to their persistence and bioaccumulative tendencies. Despite growing public concern, information on PFAS in many plants and animals is relatively limited. This information gap includes species harvested for human consumption and traditional Indigenous foods. As PFAS contamination may pose disproportionate risks to Indigenous food sovereignty and lifeways, understanding the potential presence of these contaminants in traditional foods is crucially important. Seeking to address the information gap, this Tribally driven study analyzed PFAS in two species of aquatic plants: Manoomin (Zizania palustris) and Psiŋčiŋča (Sagittaria latifolia). Found across the Great Lakes region, these plants have both ecological importance and cultural significance for Indigenous peoples. In Psiŋčiŋča, no PFAS were detected above the minimum level of detection (LOD). In Manoomin, four PFAS (perfluoro(2-ethoxyethane) sulfonic acid (PFEESA), perfluorohexane sulfonic acid (PFHxS), perfluorooctane sulfonic acid (PFOS), perfluoro-n-pentanoic acid (PFPeA) were detected in varied plant tissues (roots, stalks, and seeds). All PFAS were detected at levels below 2 ng/g that are unlikely to pose a risk for human consumption at this time. This study is the first to investigate PFAS bioaccumulation in Manoomin or Psiŋčiŋča and quantifies PFAS in surrounding environmental matrices (sediment and surface water). These findings highlight potential exposure pathways for harvesters and can help to inform Tribal food sovereignty initiatives. This study establishes a foundation for future research exploring the impacts of PFAS on the health of Manoomin, Psiŋčiŋča, and the overall condition of aquatic ecosystems.

Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants known for their persistence and potential health risks. Stormwater runoff serves as a major pathway for contaminant transport into aquatic ecosystems, yet data on the occurrence, distribution, and transport of PFAS via stormwater runoff remain limited. This study revealed PFAS in stormwater runoff from high- and low-traffic areas in Trenton and Glassboro, NJ, during precipitation events from February to August 2024, and explored the removal of PFAS by drinking water treatment residuals (WTRs). Results showed that perfluorooctanesulfonic acid (PFOS), perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA), and perfluoropentanoic acid (PFPeA) were the most prevalent PFAS compounds in the stormwater runoff in both locations. PFAS concentrations were significantly higher in high-traffic than low-traffic areas in both cities, with Trenton showing higher levels than Glassboro, reaching 444 ng/L and 233 ng/L, respectively. PFAS levels were highest at rainfall onset and gradually declined as precipitation continued. Adsorption studies using Al-WTR for representative legacy and emerging PFAS showed a maximum adsorption capacity of 121 μg/g for PFOS, followed by PFNA (101.5 μg/g), PFOA (96.3 μg/g), HFPO-DA (76 μg/g), PFBS (67 μg/g), and PFHxS (66.7 μg/g). These findings provide critical insights into PFAS distribution, transport, and removal in urban stormwater runoff, emphasizing the roles of traffic and stormwater dynamics in PFAS dispersal.

Airborne microplastics (MPs) have emerged as environmental pollutants that can co-occur with hazardous contaminants; however, evidence of heavy-metal associations with atmospheric MPs remains limited. This study investigated the abundance, characteristics, metal loadings, and health risks of airborne MPs in Metro Manila, Philippines. Air samples were collected from classroom, laboratory, dining room, office, living room, and store environments, followed by polymer identification via μFTIR and metal quantification using ICP-MS. MP concentrations ranged from 0.074 to 0.595 MP/m[3] indoors (mean: 0.297 ± 0.20 MP/m[3]) and from 0.057 to 0.262 MP/m[3] outdoors (mean: 0.173 ± 0.07 MP/m[3]), with no statistically significant difference. Fibers dominated the MP assemblage (52.38%), followed by fragments and films. PP, PET, and PE were the most prevalent polymers. Heavy metal concentrations ranged from 0.35 to 27521.66 mg/kg indoors and from 0.11 to 30556 mg/kg outdoors, with notable contributions from Zn, Cu, Ba, Pb, and Ag. These showed site-specific variations associated with room function and anthropogenic activity, with elevated Cu and Zn in high-activity indoor spaces. Pollution indices (PLI, MPI) indicated moderate pollution levels, while the ecological risk index indicated moderate ecological risk. Spearman analysis showed strong positive correlations between MPI-HM and As, Fe, and Zn (r = 0.70, p < 0.05), while PCA and HCA differentiated sampling sites by metal- and MP-related profiles. Inhalation risk assessment indicated low-to-moderate non-carcinogenic risk; however, the co-occurrence of toxic metals with respirable MPs highlights the occurrence of hazardous substances within the recovered airborne MP fraction. This study provides one of the first assessments of heavy metals associated with airborne MPs in indoor-outdoor urban environments.

Antibiotic pollution in water systems is a critical global challenge that worsens the global water scarcity crisis by contaminating vital freshwater reserves and creating dangerous antimicrobial resistance. Photocatalysis uses solar energy to power green catalytic treatments that clean antibiotic-contaminated water by breaking down persistent pharmaceuticals without using any harsh chemicals. Bismuth-based heterojunction photocatalysts leverage heterojunction engineering that drastically improves charge carrier separation and minimizes electron-hole recombination while enhancing redox potential for the destruction of environmental pollutants. In this article, we reviewed the removal of levofloxacin (LEV) and ciprofloxacin (CIP), the two most detected antibiotics in wastewater and aquatic environments globally, by various bismuth-based heterojunctions. Their photodegradation performance has been compiled and compared, and possible degradation routes, photodegradation mechanisms, and ecotoxicity of the degraded products are discussed. A true comparison of the degradation performance of CIP and LEV by various heterojunctions is difficult because various light sources, radiation intensity, pollutant concentration, and catalyst dose were used in various published studies. Of the heterojunctions so far developed, Fe3O4/Bi2WO6 and Bi2O3/(BiO)2CO3 showed excellent CIP removal, and their photodegradation rate constants were 0.5571 and 0.476 min[-1], respectively. Conversely, for the removal of LEV, Bi2WO6/CuS and BiOCl/Bi2Fe4O9 provided excellent photodegradation, and the rate constants were 0.2639 and 0.0934 min[-1], respectively. Toxicity analyses show that many degradation intermediates of CIP and LEV are toxic and mutagenic if the photodegradation is incomplete. The development of low-cost photocatalytic drug removal technology based on bismuth-based heterojunctions holds significant potential to make drinking water safer for human and animal consumption.

Crude oil spills remain a persistent global environmental challenge, while polyethylene (PE) waste continues to accumulate, particularly in low-resource settings. This study develops a circular-economy approach that directly addresses both issues through the valorisation of post-consumer PE water sachets into effective, low-cost sorbents for oil spill remediation. Waste PE was mechanically processed and modified via NaCl-assisted abrasion to produce shredded polyethylene (S-PE) and surface-roughened polyethylene (SR-PE). Characterisation by scanning electron microscopy (SEM) confirmed increased surface roughness and microcavity formation, while Fourier-transform infrared spectroscopy (FTIR) indicated minor surface oxidation following abrasion. Response surface methodology and I-optimal design were used to evaluate the effects of sorbent type, particle size, sorbent dose, and oil loading. Sorbent morphology was the dominant performance factor, with SR-PE achieving oil uptake capacities of approximately 8 g/g for synthetic crude oil and 5.9 g/g for natural crude oil under optimised conditions using a 5 min operational contact time. Natural crude oil adsorption showed reduced sensitivity to operating conditions, indicating robust performance across the investigated conditions. Regeneration studies showed an initial decline followed by stabilisation of adsorption capacity, demonstrating sustained multi-cycle performance. A techno-economic assessment based on stabilised reuse performance estimated lifecycle oil-removal costs of 0.042-0.130 USD/kg oil, lower than representative literature-based estimates for commercial polypropylene sorbents. Overall, the integration of simple material modification, statistical optimisation, regeneration, and economic assessment demonstrates the potential of recycled PE as a reusable, low-cost sorbent for oil spill remediation.

Plastic fragmentation represents a risk for ecosystems. Hummingbirds (Trochilidae) are nectarivorous birds restricted to the Americas, where they fulfill critical ecosystem roles as pollinators. The aim of this study was to assess the occurrence of meso- and microplastics (MMPs) in the gastrointestinal tract (GIT) of three hummingbird species from the floodplain of the Middle Paraná River (Argentina). Necropsies were conducted to extract the stomach and intestine, which were chemically digested. All particles were counted and classified by morphology, size and color, while a representative sub-sample of fibers (n = 32) and all fragments and films were selected for FTIR characterization. A total of 237 particles were visually identified and grouped by morphology into 228 microfibers, 5 mesofibers, 3 fragments and 1 film. Size fractions between 0.063 and 2 mm accounted for 82.28% of the total of particles. Of the 36 particles chemically characterized by FTIR, 14 were confirmed as synthetic plastic polymers. Two fragments were identified as polyurethane, one as polyamide, and the only film as polyamide, while polyester (n = 6, 19%) and polypropylene (n = 4, 12%) were identified in fibers. The remaining 22 particles, all fibers, were identified as cellulose of uncertain origin (69% of the analyzed fibers). Abundance ranged from 8 to 36 particles/bird. No statistically significant differences were detected among the three species (nCl = 5, nHf = 2, nHc = 4). Multiple potential ingestion routes for MMPs in nectarivorous birds were proposed, including potentially contaminated nectar, pollen, water, and insect prey. These findings highlight a potential exposure concern for hummingbirds that requires further investigation.