Journal of hazardous materials最新文献

Delhi experiences some of the highest levels of fine particulate matter (PM_2.5) pollution among megacities worldwide. Here, we integrated radiocarbon (¹⁴C) analysis with organic molecular tracers to quantify the sources of carbonaceous aerosols in Delhi. Through time-resolved seasonal and diurnal PM_2.5 sampling at two representative urban sites and using ¹⁴C as an unambiguous tracer, we provide robust quantitative constraints on source contributions. We found that fossil fuel combustion is the dominant contributor, accounting for 62-65 % of organic carbon and 64-66 % of elemental carbon in PM_2.5. Crucially, primary organic carbon from fossil fuels (POC_FF) constituted the largest fraction of PM_2.5 organic carbon (31-44 %). Its contribution peaked in the post-monsoon season, driven mainly by traffic emissions and coal combustion. Secondary organic carbon from fossil sources (SOC_FF), biomass burning (OC_BB), and cooking emissions (OC_CK) contributed 21-29 %, 10-18 % and 3-7 % of PM_2.5 organic carbon, respectively. Furthermore, comparisons with Positive Matrix Factorization (PMF) results suggest that conventional methods may overestimate the biomass burning contribution, underscoring the value of the ¹⁴C-based approach for accurate apportionment in this complex environment. This study underscores the critical need to reduce fossil fuel reliance and accelerate the shift toward clean energy infrastructure to effectively combat carbonaceous aerosol pollution in Delhi.

Energy-efficient treatment of chloride-containing coal chemical wastewater remains challenging, primarily due to high electricity demand, limited current utilization, and concerns over by-product control. Herein, a chlorine-mediated paired electrocatalysis was established, coupling a mixed metal oxide (MMO) anode with a natural air-diffusion cathode (NADE) in a membrane-separated dual-chamber reactor. In the anode chamber, phenol and ammonia nitrogen (NH₃-N) were proved to be oxidized via a free-radical pathway (^•ClO) and a non-radical pathway (HClO), while hydrogen peroxide (H₂O₂) was produced through the aeration-free oxygen reduction reaction in the cathode chamber. Key parameters of the process and membrane materials were investigated and optimized. Proton exchange membrane (PEM), cation exchange membrane (CEM), and bipolar membrane (BPM) were compared, and PEM exhibited the highest current efficiency (93.48 %) and lowest specific energy consumption for H₂O₂ generation (3.79 kWh/kg). Under the optimal conditions, the process achieved removal efficiencies of 95.25 % for phenol, 75.43 % for chemical oxygen demand (COD), 70.79 % for NH₃-N, and 65.17 % for total nitrogen within 90 min. The cumulative concentration of H₂O₂ reached 761.21 mg/L, and the associated economic benefit completely offset the energy consumption of the integrated electrocatalytic system. Overall electricity costs of the paired electrocatalysis were reduced by ∼59 % versus anodic oxidation alone and by ∼45 % versus single-pollutant operation. The chlorine-mediated paired electrocatalysis enables simultaneous degradation of phenolic and nitrogenous pollutants and in-situ H₂O₂ generation, providing an energy-efficient and economically favorable strategy for advanced treatment of coal-chemical wastewater.

Flualprazolam (FALP), a new psychoactive benzodiazepine structurally related to alprazolam (ALP), is increasingly misused, yet its interspecies metabolism remains unclear. In this study, the in vitro phase I and II metabolism of ALP and FALP was systematically investigated across multiple species under optimized liver microsome incubation conditions (1.5 mg mL^-1, 2 h), using a non-targeted screening strategy with high-resolution mass spectrometry (HRMS). ALP and FALP exhibited similar metabolic profiles, with 11 metabolites each, including 7 phase I and 4 phase II metabolites, of which 6 were newly discovered. Species-specific differences were observed, with humans and mice primarily producing 4- and α-hydroxylated metabolites, while edible animals such as fish, bovine, sheep, and pig mainly generated 4-hydroxylated metabolites. This interspecies discrepancy suggests that the currently designated residue markers for ALP in animal-derived foods may not accurately reflect its actual metabolic fate. Notably, newly identified benzene-ring hydroxylated metabolites were more abundant in rats and livestock, and toxicity predictions indicated that these metabolites, including M1, M5, and M7, may pose higher ecotoxicological or developmental risks than the parent drugs, with greater predicted toxicity than the α-hydroxylated metabolites currently used as residue markers. These findings provide detailed insights into interspecies metabolic patterns, emphasize the need to consider species-specific metabolites in residue monitoring, and inform the toxicological assessment of benzodiazepines in food and environmental contexts.

Plastics in landfills undergo extensive aging and surface cracking, yet it remains unclear whether crack morphology governs the sorption of per- and polyfluoroalkyl substances (PFAS) under realistic landfill conditions. Thus, this study characterized 55 hard and 19 soft plastic samples collected from various landfill depths and investigated their comparative sorption of PFAS. Hard plastics, including HDPE, PP, PET, PS, and PVC, exhibited surface cracks classified into line, curve, and network patterns, with crack density increasing with landfill depth. In contrast, soft plastics (LDPE) showed no visible cracks regardless of depths, which was further confirmed by two-dimensional spectral analysis. PFAS extracted from plastics, following the EPA Method 1633, revealed significantly higher PFAS loads in LDPE plastics (45.9-309.9 µg/kg) than in hard plastics (1.7-16.8 µg/kg), despite higher crack density in hard plastics. Such a contrast indicates that partition-type sorption plays an important role in the retention of PFAS on plastics in landfills, and that soft plastics with high free volume are particularly important hotspots for PFAS accumulation. Crack density was not significantly correlated with PFAS sorbed on hard plastics, indicating that contaminant retention is governed by landfill-mediated processes beyond surface cracking. Quantitative analysis of adsorbed organic carbon on hard plastics demonstrates organic masking that limits direct PFAS-polymer interactions. Consequently, surface cracking plays a secondary or effectively masked role under realistic landfill conditions, refining mechanistic understanding of PFAS fate in engineered waste systems.

Tetracycline antibiotics such as chlortetracycline (CTC) undergo complex pH-dependent self-transformations in the environment, generating isomeric species with distinct reactivity and toxicity. However, the mechanistic understanding of these processes and their simultaneous remediation remains limited. Here, we reveal the transformation pathways of CTC and its isomers across varying pH conditions and uncover their competitive removal processes using sulfidated zero-valent iron (S-ZVI) with different S/Fe molar ratios. CTC underwent decarboxylation under strong acidity, epimerization to ECTC under weak acidity, and transformation to iso-forms (ICTC) under neutral to mild alkaline conditions. Among these, ICTC, with a large HOMO-LUMO gap, displayed the highest persistence and toxicity. S-ZVI significantly enhanced removal efficiency, adsorption capacity, and reductive dechlorination of CTCs, with moderate sulfur incorporation yielding the optimal performance. Mechanistically, FeS_x generated during sulfidation served as electron donors/shuttles for reductive dechlorination, as well as precursors for the in-situ formation of Fe (III)-OH, promoting the adsorption of CTCs and their intermediates. The weaker oxidative activity and stronger steric hindrance of ICTC limited its reduction and adsorption by S-ZVI. Beyond chemical detoxification, S-ZVI effectively alleviated CTCs-induced phytotoxicity, enhanced chlorophyll synthesis and biomass accumulation in Brassica chinensis L., and stabilized soil microbial communities. These findings pave the way for understanding CTC isomer behavior and highlight S-ZVI as a promising strategy for sustainable remediation in antibiotic-contaminated farmland.

Rhizosphere microbiome are pivotal for plant adaptation to extreme environments. However, the regulatory mechanisms underlying their control of the ecological adaptation of native woody plants in mining areas remain unclear. Here, we integrated metagenomic and transcriptomic analyses to elucidate how the rhizosphere microbiome facilitates Betula luminifera adaptation to antimony (Sb) mining sites. Under sterile conditions, B. luminifera from mining sites prioritized shoot growth, whereas control-origin seedlings favored root development. Microbial inoculation mitigated this growth dichotomy, balancing above- and belowground biomass allocation. Notably, B. luminifera from control sites upregulated antioxidant biosynthesis genes (α- and β-tocopherol pathways), while B. luminifera from mining sites enhanced lignin synthesis under Sb stress. After inoculation with rhizosphere microbiome from the mining-site, genes related to Sb/As resistance (ACR3, arsB/C) and soil nutrient cycle (narG, phnM) were significantly enriched in the rhizosphere of B. luminifera, which were contributed by Proteobacteria and Actinobacteria. Transcriptional profiling revealed that microbial inoculation triggered systemic upregulation of phytohormone-related genes (auxin, cytokinin, abscisic acid), enhancing stress resilience and growth. These findings unveil a synergistic plant-microbe adaptation mechanism in Sb polluted soils in mining sites, highlighting microbial-mediated trait trade-offs and transcriptional plasticity as drivers of ecological success in extreme environments.

Perfluorooctane sulfonate (PFOS), a pervasive environmental contaminant, is ubiquitously detected in water, air, soil, and food chains. Emerging evidence has implicated PFOS in the pathogenesis of cardiovascular diseases, particularly atherosclerosis - the fundamental pathological process underlying diverse cardiovascular and cerebrovascular disorders. A previous study demonstrated that PFOS exacerbates atherosclerosis in apolipoprotein E-deficient (ApoE^-/-) mice through pro-inflammatory M1 macrophage polarization. However, the effects of PFOS on vascular smooth muscle cells (VSMCs) and their contribution to intimal hyperplasia and atherosclerosis remain unexplored. Our in vitro investigations revealed that PFOS potentiates proliferation, migration, and phenotypic switching in primary human aortic smooth muscle cells (HASMCs). Moreover, we also demonstrated that PFOS exposure aggravated neointimal formation in a femoral artery injury model and promoted atherosclerosis. To elucidate the role of VSMCs in these processes in vivo, we established a VSMCs lineage-tracing model utilizing Myh11-Cre/ERT2; R26-tdTomato; ApoE^-/- mice. Following 16 weeks of PFOS exposure, atherosclerotic plaque progression exhibited a positive correlation with intraplaque VSMCs accumulation. RNA sequencing analysis and subsequent validation confirmed PFOS-induced tissue plasminogen activator (tPA) upregulation in VSMCs at both transcriptional and translational levels. Notably, tPA knockdown abrogated PFOS-driven proliferation, migration, and phenotypic switching in HASMCs. Mechanistic studies revealed ERK signaling pathway activation as the primary mediator of PFOS-induced tPA expression. Collectively, these findings provide novel mechanistic insights into how PFOS aggravates intimal hyperplasia and atherosclerosis, highlighting its role in exacerbating cardiovascular pathogenesis. They further suggest that ERK inhibitors may mitigate the detrimental effects of PFOS on the vasculature.

The contamination of groundwater by sulfate (SO₄²⁻) and iron (Fe) in mining regions has become an increasingly critical environmental issue. However, the complex interplay between sulfur and iron biogeochemical cycles under mining disturbances remains poorly constrained. This study employs a novel multi-isotope approach (Sr-Fe-S-O-H) combined with Positive Matrix Factorization (PMF) modeling to unravel the iron mobilization mechanisms coupled with sulfur cycling in groundwater systems of a historic deep coal mining area. Key findings reveal that mining-induced pyrite oxidation serves as the predominant source of both SO₄²⁻ and Fe, whereas sulfate evolution in low-flow zones is governed by gypsum dissolution and cation exchange. Iron transformation occurs through oxidation of aqueous Fe(II) to Fe(III) hydroxides with subsequent pore precipitation, concurrent with Fe(II) resorption. Notably, Mn-Fe oxides (MnO₂/FeOOH) facilitate bacterial disproportionation of sulfur intermediates (BDSI), yielding characteristic oxygen-sulfur isotope fractionation (Δδ³⁴S/Δδ¹⁸O ≈ 0.60). Along hydraulic gradients, bacterial sulfate reduction (BSR) emerges as the dominant process, generating sulfides that reduce Fe(III) hydroxides and synergistically with BDSI drive Fe(II) remobilization. Our results demonstrate that the tripartite coupling of BDSI, BSR, and biotic/abiotic iron reduction collectively regulates iron and sulfur cycling and mobilization of Fe and SO₄. These insights advance our understanding of anthropogenic impacts on subsurface iron-sulfur coupling and provide a scientific basis for developing targeted groundwater remediation strategies in mining-affected aquifers.

Background chloride (Cl^-) can inhibit the degradation of emerging contaminants such as carbamazepine (CBZ) by some peroxides-based advanced oxidation processes. This study was aimed at developing a Cl^-/dithionite (DTN)/NaClO system, leveraging in-situ Cl^- and DTN (S₂O₄^2-) to activate sodium hypochlorite (NaClO), a commonly used disinfectant in water treatment. Compared with the Cl^--free DTN/NaClO system, the presence of Cl^- enhanced the CBZ degradation rate constant by approximately 8-fold (0.4280 min^-1) and reduced dependence on dissolved oxygen. Quenching tests and electron paramagnetic resonance spectroscopy confirmed the presence of both reactive chlorine species (RCS) and reactive oxygen species (ROS) in the system. However, Cl^- selectively amplified RCS formation while minimally affecting ROS generation, establishing the dominance of RCS in CBZ degradation. Computational potential energy surface analysis corroborated the role of RCS as the governing species. Effective CBZ degradation occurred across mildly acidic to weakly alkaline conditions. The low activation energy (Ea = 20.29 kJ·mol^-1) indicated the avoidance of high-energy transition states commonly encountered in the degradation of emerging contaminants. Plausible degradation pathways included hydroxyl substitution, skeletal rearrangement, RCS addition/oxidation, and chloro-hydroxyl synergy. The treatment mitigated CBZ developmental toxicity, mutagenicity, and lethality to Daphnia magna. Based on the concept of "waste treating waste", this work offers a novel strategy leveraging in situ Cl^- for effective contaminant control, particularly in Cl^--rich waters.