Qiuguo Fu

We hypothesized that host-associated microorganisms can alter host behavior by modifying perfluorooctane sulfonamides to produce perfluorooctanesulfonic acid (PFOS) or other potentially neuroactive metabolites. Zebrafish larvae (Danio rerio) were exposed to PFOS (0.28–5 μM), N-ethyl perfluorooctane sulfonamide (N-EtFOSA, 0.07–1.25 μM), or perfluorooctane sulfonamido ammonium iodide (PFOSAmS, 0.83–15 μM) from 5 to 6 days post fertilization (dpf). This resulted in altered dark-phase swimming behavior at 8 dpf. Exposure to PFOS, or N-EtFOSA, but not PFOSAmS caused a similar shift in community structure. We exposed microbiome-depleted (axenic, AX), conventionally colonized (CC), or axenic conventionalized on day 1 (AC1) zebrafish larvae to N-EtFOSA (0.22–0.7 μM) from 5 to 6 dpf. In comparison to CC and AC1 larvae, AX-larvae did not exhibit concentration-dependent hypoactivity at 8 dpf. Chemical analysis at 7 dpf revealed a significant increase in N-EtFOSA levels in AX-larvae and AX-water samples, relative to colonized cohorts. The main metabolite detected was perfluorooctane sulfonamide (FOSA), which was not microbiome-dependent. Perfluorooctane sulfonamidoacetic acid (FOSAA) was detected at lower levels in AX-larvae, relative to colonized groups. This study revealed that the presence of the microbiome enhanced N-EtFOSA-dependent behavior effects at the level of the host. This supports the concept that chemical–microbiome interactions can influence host phenotypic outcomes.

Persistent and mobile chemicals (PMs) threaten groundwater quality and drinking water safety, yet many remain undetected because analytical methods insufficiently address highly polar and ionic substances, while regulatory frameworks lack monitoring requirements for these compound classes. Here, we developed a supercritical fluid chromatography-high-resolution mass spectrometry-based smart-screen approach that integrates three key prioritisation strategies: (i) sampling site prioritisation, (ii) suspect-level prioritisation through tiered suspect lists, and (iii) candidate prioritisation using stepwise scoring. Additionally, the method achieved the sensitive identification and reliable quantification of PMs in groundwater, with a median limit of quantification of 6.8 ng/L, stable recoveries (75%), and low matrix effects (-12%) across diverse groundwater types. Prioritisation reduced 599 groundwater wells to 10 representative sites, yielding an 8.6-fold reduction in analytical workload while maintaining chemical diversity. The tiered suspect lists and stepwise scoring strategies improved confirmation efficiency and facilitated the detection of substances of high environmental relevance. Collectively, 34 PMs were detected across six substance groups including polar per- and polyfluoroalkyl substances, polyfluorinated inorganic species, transformation products, and amide or ether solvents at concentrations of 0.1-22,300 ng/L. Among these, 16 substances were newly detected in ambient groundwater and four were reported for the first time in any environmental compartment. Several substances (e.g. 2-phenylpropane-2-sulphonic acid) are not classified as persistent under EU regulation on registration, evaluation, authorisation and restriction of chemicals (REACH) yet occur ubiquitously in groundwater, suggesting an underestimation of PMs under aquifer conditions. These findings advance monitoring of PMs, supporting their regulation for groundwater and drinking water protection.

Per- and polyfluoroalkyl substances (PFAS) are highly persistent contaminants. Current regulatory monitoring frameworks cover only a narrow set of regulated long- and short-chain PFAS, while ultrashort-chain compounds such as trifluoroacetic acid (TFA) remain largely unaddressed despite their widespread occurrence. Here, we present regional sources and tributary inputs of diverse PFAS (n = 83), including ultrashort-, short-, and long-chain PFAS as well as PFAS precursors along the 1,200 km Elbe River−North Sea continuum. Based on 129 samples from the Elbe, its tributaries, and wastewater treatment plants (WWTPs), we show that short- and long-chain PFAS concentrations in the Elbe were generally below 30 ng/L, but 1,653 ± 377 ng/L when including TFA. Major tributaries such as the Saale, Vltava, and Mulde delivered PFAS mass loads of several thousand g/day (2,340; 6,080; and 1,700 g/day, respectively, when including TFA) and together accounted for a total discharge of 160 m³ s⁻¹, corresponding to approximately 67% of the Elbe’s water flux at Geesthacht (240 m³/s), which represents the downstream reference point for mass balance calculations prior to tidal influence. This suggests source-enriched inputs rather than simple dilution by tributary inflows, given the disproportionate increase in PFAS mass loads relative to discharge. WWTP effluents from Dresden and Pardubice added up to 185 g/day, mainly shaped by short-chain PFAS. The detection of Capstone B (CDPOS) and Bis­(trifluoromethylsulfonyl)­imide (NTf2), non-routinely monitored industrial PFAS, further highlights overlooked sources in the area of the Saale-Elbe confluence. Inclusion of TFA increased the median PFAS load in the Elbe River by nearly 50-fold (up to 39,958 g/day), demonstrating the dominant role of ultrashort-chain PFAS currently absent from regulatory monitoring. By linking source apportionment with river-to-sea transport, our study highlights critical gaps in existing monitoring frameworks and provides a transferable methodology for more comprehensive PFAS assessment and regulation in large river systems.

Persistent and mobile (PM) chemicals, including ultrashort-chain per- and polyfluoroalkyl substances (PFAS), are continuously discharged into the water cycle, and many of them are poorly removed because of high polarity and recalcitrance. Their occurrence in groundwater, an important drinking water resource, remains underexplored. We investigated 180 PM chemicals in 82 groundwater samples across Saxony, Germany, using freeze-drying and supercritical fluid chromatography-high-resolution mass spectrometry (SFC-HRMS). 163 PM chemicals were determined, including pesticides, pharmaceuticals, PFAS, other industrial chemicals, and transformation products; concentrations of 72 compounds are reported in groundwater for the first time; 57 chemicals exhibited detection frequencies >50%. The median total PM chemical concentration was 23 μg L^-1, with pesticides (0.77 μg L^-1) and pharmaceuticals (0.69 μg L^-1) of similar totals and industrial chemicals being much higher (19 μg L^-1). Trifluoroacetic acid was the dominant single compound (median of 3.0 μg L^-1, n = 81). Median concentrations of single chemicals correlated with physicochemical properties (water solubility, lipophilicity, etc.). Site-specific factors (nitrate, dissolved organic carbon, depth) were also associated with PM chemical levels. Chemical co-occurrence revealed benzothiazole and N,N-dimethylformamide as indicators of higher overall PM chemical concentrations. Risk prioritization identified 33 priority chemicals, highlighting chloridazon-desphenyl and N-methylpiperidine as potential indicators of higher overall PM chemical risk. These findings clarify PM chemical behavior in groundwater and support refined monitoring strategies.

Acrylamides are widely used in polymer manufacturing and adhesives, and their electrophilic nature raises toxicological concerns when released into aquatic environments. However, their physicochemical diversity complicates the prediction of environmental fate and toxicity. To elucidate the main drivers of their toxicity in aquatic organisms, we investigated ten structurally diverse monomeric acrylamides and methacrylamides in zebrafish embryos (Danio rerio) (ZFE). Acute toxicity varied over 2 orders of magnitude (0.16-33 mM) and showed a moderate correlation with hydrophobicity (logK_lipw, R² = 0.87) and intrinsic electrophilic reactivity (logk_GSH). Measured bioconcentration factors of highly polar, reactive compounds (e.g., NMBA) for ZFE deviated up to 16-fold from model predictions, indicating limited uptake or significant biotransformation. This indicates an impact of toxicokinetics on their in vivo toxicity. UPLC-HRMS-based nontarget screening revealed 90 transformation products across the ten compounds. Glutathione conjugation and mercapturic acid formation were dominant pathways, with mercapturic acid-taurine conjugates observed for eight compounds, suggesting a previously undescribed detoxification mechanism for (meth)acrylamides in the ZFE. Our results highlight the need to integrate toxicokinetic data into hazard assessment of electrophilic compounds, as in vitro assays may overestimate risks. The ZFE provides a mechanistically informative in vivo model to reduce misclassifications, especially for polar and reactive chemicals.

Persistent and mobile chemicals (PMs) threaten groundwater quality and drinking-water safety, yet many remain undetected because analytical methods insufficiently address to highly polar and ionic substances, while regulatory frameworks lack monitoring requirements for these compound classes. Here, we developed a supercritical-fluid chromatography–high-resolution mass spectrometry (SFC-HRMS) based smart-screen approach that integrates lyophilisation enrichment, tiered suspect-screening strategies and metadata-driven prioritisation to efficiently detect both known and novel PM substances. The method achieved a median limit of quantification of 6.8 ng L⁻¹, stable recoveries (75 %), and low matrix effects (-12%) across diverse groundwater types, enabling reliable trace-level quantification. Prioritisation reduced 599 groundwater wells to 10 representative sites, yielding an 8.6-fold reduction in analytical workload while maintaining chemical diversity. The tiered suspect lists and stepwise candidate prioritisation strategies improved confirmation efficiency and facilitated the detection of substances with environmental relevance (e.g., SVHCs, CMRs). With this approach, 34 PMs were detected across six diverse substance groups including polar PFAS, polyfluorinated inorganic species (PFIS), transformation products, and amide or ether solvents at concentrations ranging from 0.1 to 22,300 ng L⁻¹. Among these, 16 substances were newly detected in ambient groundwater and 5 (2-phenylpropane-2-sulphonic acid, 3,4-diaminobenzoic acid, 3-mercaptopropane-1-sulphonic acid, methylpyrrolidone (NMP), 2-amino-5-methylthiazole) were reported for the first time in any environmental compartment. Several identified substances (e.g. 2-phenylpropane-2-sulphonic acid, 1-(o-tolyl)biguanide, tributylamine) are not classified as persistent under REACH yet occur ubiquitously in groundwater, suggesting potential underestimation of PM substances under aquifer conditions. These findings advance evidence-based monitoring and regulation of PM substances, supporting groundwater protection and drinking water safety.

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants with many unknown variants, posing potential ecosystem and human health risks. To comprehensively assess PFAS contamination and overcome the challenge of unknown PFAS identification, we combined Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and liquid chromatography─quadrupole time-of-flight mass spectrometry (LC-QTOF MS) to identify novel and Legacy PFAS in archived bream liver samples collected in Germany between 1996 and 2020. By leveraging the ultrahigh resolution and mass accuracy of FT-ICR MS, we generated a mass list for cross-comparison with common precursor ion features from LC-QTOF MS. We identified 78 PFAS, including 68 classified into 12 homologue groups and 10 that did not fit into any homologue series, encompassing perfluoroalkyl acids, fluorotelomer-based substances, pentafluorosulfide perfluoroalkyl sulfonic acids, polyfluoroalkyl sulfinates, polyfluoroalkyl sulfonyl sulfonamides, and other novel compounds including ionic liquids. Spatial and temporal analysis revealed that perfluoroalkyl phosphinic acids (C6/C6, C6/C8) and polyfluoroalkyl sulfonic acids (n = 10) have a widespread presence, whereas tris(pentafluoroethyl)trifluorophosphate (FAP) and polyfluoroalkyl sulfonyl sulfonamides (n = 6) are more localized or have only recently emerged in specific regions. These findings underscore the need for continued monitoring to comprehensively understand exposure to PFAS and their long-term environmental impact.

Internal concentrations (ICs) are crucial for linking exposure to effects in the development of New Approach Methodologies. ICs of chemicals in aquatic organisms are primarily driven by hydrophobicity and modulated by biotransformation and efflux. Comparing the predicted baseline to observed toxicity enables the estimation of effect specificity, but biological processes can lead to overestimating ICs and bias the specificity assessment. To evaluate the prediction of a mass balance model (MBM) and the impact of biotransformation on ICs, experimental ICs of 63 chemicals in zebrafish embryos were compared to predictions with physicochemical properties as input parameters. Experimental ICs of 79% (50 of 63) of the chemicals deviated less than 10-fold from predictions, and the remaining 13 deviated up to a factor of 90. Using experimental ICs changed the classification for 19 chemicals, with ICs 5 to 90 times lower than predicted, showing the bias of specificity classification. Uptake kinetics of pirinixic acid, genistein, dexamethasone, ethoprophos, atorvastatin, and niflumic acid were studied over a 96 h exposure period, and transformation products (TPs) were elucidated using suspect- and nontarget screening with UPLC-HRMS. 35 TPs (5 to 8 TPs per compound) were tentatively identified and semiquantified based on peak areas, suggesting that biotransformation may partly account for the overpredictions of ICs.

The increasing recognition of the health impacts from human exposure to per- and polyfluorinated alkyl substances (PFAS) has surged the need for sophisticated analytical techniques and advanced data analyses, especially for assessing exposure by food of animal origin. Despite the existence of nearly 15,000 PFAS listed in the CompTox chemicals dashboard by the US Environmental Protection Agency, conventional monitoring and suspect screening methods often fall short, covering only a fraction of these substances. This study introduces an innovative automated data processing workflow, named PFlow, for identifying PFAS in environmental samples using direct infusion Fourier transform ion cyclotron resonance mass spectrometry (DI-FT-ICR MS). PFlow’s validation on a bream liver sample, representative of low-concentration biota, involves data pre-processing, annotation of PFAS based on their precursor masses, and verification through isotopologues. Notably, PFlow annotated 17 PFAS absent in the comprehensive targeted approach and tentatively identified an additional 53 compounds, thereby demonstrating its efficiency in enhancing PFAS detection coverage. From an initial dataset of 30,332 distinct m/z values, PFlow thoroughly narrowed down the candidates to 84 potential PFAS compounds, utilizing precise mass measurements and chemical logic criteria, underscoring its potential in advancing our understanding of PFAS prevalence and of human exposure. Graphical abstract