Environmental Science & Technology Letters Environ.最新文献

Perchlorate (ClO₄^–) contamination in water poses significant public health risks due to its endocrine-disrupting properties and resistance to degradation by conventional chemical treatment methods. The concerns about oxychlorine anions (ClO_x^–) also impact destruction technologies for perfluoroalkyl and polyfluoroalkyl substances (PFAS). The stepwise reduction of ClO₄^– often shows intriguing chemical challenges due to the unique reactivity of ClO_x^– intermediates, which motivates innovation in process design. This study presents a two-stage treatment train combining photochemical treatment with catalytic reduction to achieve complete ClO₄^– removal in complex water matrices. The optimized UV/sulfite + iodide (UV/S+I) system achieved efficient ClO₄^– reduction. Surprisingly, the chlorate (ClO₃^–) intermediate is more sluggish than ClO₄^– under UV/S+I treatment. To overcome this challenge, we integrated the H₂+Mo–Pd/C catalytic process as a post-treatment and achieved rapid ClO₃^– reduction to Cl^–. The high performance of the treatment train is validated in practical matrices of tap water and synthetic ion exchange resin regenerant brine. The photochemical stage also degraded nitrate (NO₃^–) and PFAS, which inhibited ClO₄^– reduction at various levels. The treatment train overcomes individual technology limitations while maintaining robustness against the challenging water matrices, offering a practical solution to perchlorate-related scenarios that require comprehensive treatment of various pollutants.

Granular activated carbon (GAC) adsorption is the most widely used method for removing per- and polyfluoroalkyl substances (PFAS). Thermal regeneration of spent GAC is currently preferred over solvent-based methods because regenerating both solvents and GAC while preserving the adsorbent performance remains a significant challenge. Here, we proposed an innovative “extract-and-degrade” strategy in which organic solvents, used as GAC extractants, are directly exposed to UV 254 nm irradiation, allowing effective defluorination under mild conditions while simultaneously allowing solvent recycling. Among 18 tested solvents, the aprotic solvent acetonitrile (ACN) resulted in complete PFOA degradation and >70% defluorination within 24 h under UV irradiation. This performance is attributed to the activation of PFOA molecules induced by ACN’s high polarity, which facilitates electron transfer from the negatively charged −C≡N group of ACN to the positively charged −OH group of PFOA. Studies on perfluorocarboxylic acids (PFCAs) with different chain lengths revealed that longer chains are more prone to electron capture for subsequent degradation steps, consistent with their adiabatic electron affinity (AEA) values. Finally, both GAC and ACN demonstrated excellent stability and reusability in cyclic tests. This work sheds light on previously unexplored photochemistry in nonaqueous media and highlights the potential of organic solvents as recyclable platforms for PFCAs defluorination and adsorbent regeneration in water purification systems.

Chlorophenols are prevalent pollutants in aquatic environments that often require advanced oxidation processes (AOPs) for their effective removal. Polymerization has emerged as a promising pathway within AOPs for transforming and eliminating phenolic contaminants. Understanding the early-stage polymerization dynamics of chlorophenols is critical for optimizing the treatment efficiency and minimizing secondary contamination. In this study, surface-enhanced Raman spectroscopy (SERS) was employed to in situ investigate the polymerization of chlorophenols during the initial 2 min of sulfate radical-based AOPs. Structure-dependent interactions distinguished π-mediated physisorption of protonated chlorophenols from the covalent Au–O chemisorption of phenolates. Upon sulfate radical generation, chlorophenols were rapidly oxidized and coupled, forming polymeric radical species with enhanced surface affinity for gold nanoparticle (AuNP) surfaces. Displacement of preadsorbed citrate and chloride by these products served as a proxy for evaluating polymerization potential. Polymerization and adsorption behavior were governed by the halogenation pattern and protonation state, with higher π-electron density correlating with greater reactivity. These findings provide mechanistic insights into radical-mediated surface transformations and offer a potential strategy for in situ AuNP surface functionalization. This work advances the understanding of polymerization kinetics during AOPs and supports the development of plasmonic nanomaterials for environmental sensing and remediation.

Wastewater-based surveillance (WBS) has emerged as a novel public health tool for monitoring the prevalence of community disease. There is great interest in expanding the list of potential targets to those that are difficult to clinically monitor. Lyme disease is the most common tick-borne illness in the United States, accounting for 82% of all clinically reported cases. It is also notoriously hard to diagnose and can become a chronic condition if not treated early. The objective of this study was to determine the feasibility of WBS to monitor Lyme disease and analyze sample data for trends in comparison with public health data, as reported by the Michigan Department of Health and Human Services. Wastewater samples were collected over the course of one year and molecular tests were implemented to detect Borrelia species, the causative bacteria of Lyme disease. Two Borrelia sp. targets (fliD and 16S rRNA) showed significant correlation (p = 0.0028; p < 0.05 is significant) with clinical disease trends (assessed at the county level), with WBS data lagging behind clinical data by 11 weeks. More data are needed to fully understand the connections between WBS data and clinical data. This represents the first study to monitor the causative agent of Lyme disease via WBS.

Light absorption by brown carbon (BrC) represents a major uncertainty in assessing the climatic effects of carbonaceous aerosols. Using 38,622 PM_2.5 samples collected from the U.S. Chemical Speciation Network (2016–2018) and analyzed by a multiwavelength thermal/optical analyzer (TOA), we applied an enhanced spectral/mass balance receptor model to quantify black carbon (BC), BrC, and nonabsorbing white carbon (WtC) while allowing BrC optical properties to vary across samples. The model achieved excellent fits (r² > 0.98) and revealed a wide range of BrC absorption Ångström exponent (AAE_{405–635 nm} = 2.13 ± 0.74) and mass absorption efficiency (MAE_532 nm = 2.03 ± 0.35 m² g^–1). An inverse AAE–MAE relationship was found, with strongly to moderately absorbing BrC being the most prevalent BrC classes. Seasonal patterns showed higher “organic brownness” (i.e., higher BrC mass fraction in organic carbon regardless of BrC class) but lower MAE in winter and the opposite in summer, reflecting the bleaching evolution of BrC with photochemical aging. BrC abundance also influenced the reconciliation between BC- and TOA-derived elemental carbon, likely through altered thermal–optical carbon analysis splits. This study provides the first nationwide characterization of BrC optical variability from national network data, establishing a scalable framework toward long-term monitoring of organic aerosol absorption within existing regulatory programs.

Nitrous acid (HONO) enhances the atmospheric oxidative capacity by generating hydroxyl radicals (OH), which contribute to secondary pollutants such as ozone (O₃) and particulate matter (PM). These pollutants further modulate HONO formation pathways, creating a complex feedback loop. However, the mechanism by which nitrogen oxide (NO_x) emission reduction affects the HONO-O₃ cycle is not fully clarified. To address this knowledge gap, we conducted two distinct field campaigns during the Spring Festival periods in 2022 and 2023, representing low and high NO_x emission scenarios, respectively. Our results demonstrate that COVID-19 restrictions, combined with the holiday effect in 2022, suppressed HONO production from NO_x-related reactions but enhanced its generation via particulate nitrate (pNO₃^–) photolysis. In contrast, an opposite trend was observed in 2023. Chemical transport model simulations and sensitivity analyses further revealed that moderate anthropogenic NO_x reduction elevated O₃ and dinitrogen pentoxide (N₂O₅) levels, which subsequently elevated nocturnal pNO₃^– formation, establishing a positive feedback loop within the HONO-O₃ cycle. Our findings provide observational evidence of the recycling mechanism for atmospheric pNO₃^–-HONO-O₃ chemistry and suggest that moderate NO_x emission reduction alone is insufficient to mitigate HONO and O₃ pollution.

Interactions between endocrine-disrupting chemicals (EDCs) and nuclear receptors (NRs) are extensively used in virtual screening. However, most models overlook receptor dimerization. Here, we systematically investigate the dimerization dependencies of estrogen receptor α (ERα) and androgen receptor (AR) via big data mining, reporter gene assays, and molecular simulations and further construct a dimerization-driven quantitative framework for endocrine disruption prediction. Database analysis revealed that ERα predominantly functions as homodimers whereas AR primarily exists as monomers. Experiments and simulations further demonstrated that ERα forms stable dimeric complexes (agonist–ERα dimer–coactivator and antagonist–ERα dimer–none systems) while AR maintains stability as a monomer (ligand–AR monomer–coregulator system). Based on these mechanistic insights, receptor-specific quantitative models were developed and applied to predict the endocrine-disrupting potential of representative EDCs, including bisphenols and hydroxylated polybrominated diphenyl ethers. These dimerization-informed models showed robust performance for ERα dimers (R² = 0.605–0.726), whereas AR’s monomeric configuration yielded superior predictive accuracy (R² = 0.788–0.909). These predictive patterns match their mechanisms. Estrogenic disruption critically depends on dimerization and coactivator recruitment, while antiestrogenic activity appears to be primarily dependent on dimerization and largely independent of corepressor involvement. In contrast, AR disruption is primarily driven by ligand binding and coregulator interactions with minimal dimerization involvement. This framework provides an effective, mechanism-grounded alternative to EDC screening.

The widespread occurrence of psychoactive pollutants in surface waters raises concerns for aquatic ecosystems, yet impacts beyond behavioral disruption remain poorly understood. Designed to target neurotransmitter (NT) systems in humans, these contaminants may also interfere with conserved NT pathways in fish. Here we provide the first evidence that fish sperm contain NTs and their receptors, indicating an active NT-mediated signaling system essential for sperm function. Using European perch (Perca fluviatilis) exposed to environmentally relevant concentrations of methamphetamine, we quantified NTs in brain, gonads, and sperm, assessed tissue-specific bioaccumulation, and evaluated sperm performance. Methamphetamine accumulated across tissues, modified NT profiles, and altered sperm motility and velocity. These findings reveal a previously unrecognized pathway of reproductive vulnerability, identifying NT signaling in sperm as a novel target of psychoactive pollutants with potential implications for fertilization success and population resilience in aquatic ecosystems.