Mechanisms for the structural dependent transformation of 6:2 and 8:2 polyfluoroalkyl phosphate diesters in wheat (Triticum aestivum L.)

Distribution, uptake, and daily exposure of per- and polyfluoroalkyl substances in a paddy field: A growth cycle study

Rice, a crucial agricultural commodity, is potentially susceptible to contamination by persistent organic pollutants throughout its entire growth cycle in the field. Per- and polyfluoroalkyl substances (PFASs) have attracted great scientific attention due to their environmental persistence, bioaccumulation potentials, and toxicity. However, the occurrence and behavior of PFASs in the paddy ecosystem have not been confirmed. This study explored the uptake, accumulation, and potential risks of PFASs in the irrigation water, soils and paddy tissues from a typical paddy system at the main stages of rice growth. The total PFAS concentrations in irrigation water and soils were in the range of 62.9 -85.5 ng/L and 45.7 -75.4 ng/g dw. The concentrations of PFASs in paddy tissues followed the order of root>stem>leaf>grain. A minor decrease in PFAS concentrations in paddy tissues with growth time may be attributed to biotransformation and growth dilution. PFAS distribution in soils, irrigation water, and different paddy tissues also showed different patterns with the growing time of paddy. ΣPFCAs and ΣPFSAs were the most prevalent PFASs in all samples, which constituted 65.0 -96.3 % of the total PFASs. In addition, the transfer factor (TF) values from root to stem/leaf/grain decreased as Log KOW increased (Log KOW< 5). Significant correlations between the concentrations and protein contents in paddy grains were observed for most long-chain PFASs. Risk assessments have suggested that the current levels do not pose a health risk to humans, but PFAS alternatives cannot be neglected for food safety and environmental impacts.

Evaluation of extraction methodologies for PFAS analysis in mascara: a comparative study of SPME and automated µSPE

Research efforts have primarily focused on identifying per- and polyfluoroalkyl substances (PFAS) in common environmental media like water, air, soil, and biological samples. However, there is limited research on PFAS detection in complex samples such as personal care products, including cosmetics. PFAS are used in cosmetics for emulsification, surfactant action, and stabilization, and have been detected in products such as foundation, powders, and nail polish. The complexity of cosmetic formulations, with various additives, makes the analysis of these samples extremely challenging. This study aimed to explore and develop convenient extraction methods to accurately quantify eight anionic PFAS in mascara products. Solid-phase microextraction (SPME) and automated micro solid-phase extraction (µSPE) were evaluated, and quantification was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Six mascara products, including waterproof and non-waterproof types, were analyzed, optimizing methanol-water mixtures as dispersive media to maximize PFAS recovery. Elution solution composition, volume, and dispensing speed were optimized for the µSPE method to ensure quantitative elution of the PFAS from the extraction phase. For the SPME method, the extraction time was optimized to account for the varying diffusion behavior of PFAS in the mixed-phase medium. Both extraction methods were evaluated in terms of greenness and practicality, with SPME achieving the best overall scores. Method validation demonstrated good linearity (0.025 to 25 ng/g) for both protocols, with µSPE providing lower limits of quantification (LOQ) for the most hydrophobic PFAS. 6:2 diPAP was quantified in real samples at concentrations ranging from 1.26 to 3.48 ng/g in 4 of the 9 mascaras tested.

Unveiling behaviors of 8:2 fluorotelomer sulfonic acid (8:2 FTSA) in Arabidopsis thaliana: Bioaccumulation, biotransformation and molecular mechanisms of phytotoxicity

8:2 fluorotelomer sulfonic acid (8:2 FTSA) has been commonly detected in the environment, but its behaviors in plants are not sufficiently known. Here, the regular and multi-omics analyses were used to comprehensively investigate the bioaccumulation, biotransformation, and toxicity of 8:2 FTSA in Arabidopsis thaliana. Our results demonstrated that 8:2 FTSA was taken up by A. thaliana roots and translocated to leaves, stems, flowers, and seeds. 8:2 FTSA could be successfully biotransformed to several intermediates and stable perfluorocarboxylic acids (PFCAs) catalyzed by plant enzymes. The plant revealed significant growth inhibition and oxidative damage under 8:2 FTSA exposure. Metabolomics analysis showed that 8:2 FTSA affected the porphyrin and secondary metabolisms, resulting in the promotion of plant photosynthesis and antioxidant capacity. Transcriptomic analysis indicated that differentially expressed genes (DEGs) were related to transformation and transport processes. Integrative transcriptomic and metabolomic analysis revealed that DEGs and differentially expressed metabolites (DEMs) in plants were predominantly enriched in the carbohydrate metabolism, amino acid metabolism, and lipid metabolism pathways, resulting in greater energy consumption, generation of more nonenzymatic antioxidants, alteration of the cellular membrane composition, and inhibition of plant development. This study provides the first insights into the molecular mechanisms of 8:2 FTSA stress response in plants.

Hepatotoxicity and lipid metabolism disorders of 8:2 polyfluoroalkyl phosphate diester in zebrafish: In vivo and in silico evidence

8:2 polyfluoroalkyl phosphate diester (8:2 diPAP) has been shown to accumulate in the liver, but whether it induces hepatotoxicity and lipid metabolism disorders remains largely unknown. In this study, zebrafish embryos were exposed to 8:2 diPAP for 7 d. Hepatocellular hypertrophy and karyolysis were noted after exposure to 0.5 ng/L 8:2 diPAP, suggesting suppressed liver development. Compared to the water control, 8:2 diPAP led to significantly higher triglyceride and total cholesterol levels, but markedly lower levels of low-density lipoprotein, implying disturbed lipid homeostasis. The levels of two peroxisome proliferator activated receptor (PPAR) subtypes (pparα and pparγ) involved in hepatotoxicity and lipid metabolism were significantly upregulated by 8:2 diPAP, consistent with their overexpression as determined by immunohistochemistry. In silico results showed that 8:2 diPAP formed hydrogen bonds with PPARα and PPARγ. Among seven machine learning models, Adaptive Boosting performed the best in predicting the binding affinities of PPARα and PPARγ on the test set. The predicted binding affinity of 8:2 diPAP to PPARα (7.12) was higher than that to PPARγ (6.97) by Adaptive Boosting, which matched well with the experimental results. Our results revealed PPAR - mediated adverse effects of 8:2 diPAP on the liver and lipid metabolism of zebrafish larvae.

Perfluoroalkyl acid precursors in agricultural soil-plant systems: Occurrence, uptake, and biotransformation

Perfluoroalkyl acid (PFAA) precursors have been used in various consumer and industrial products due to their hydrophobic and oleophobic properties. In recent years, PFAA precursors in agricultural soil-plant systems have received increasing attention as they are susceptible to biotransformation into metabolites with high biotoxicity risks to human health. In this review, we systematically assessed the occurrence of PFAA precursors in agricultural soils, taking into account their sources and biodegradation pathways. In addition, we summarized the findings of the relevant literature on the uptake and biotransformation of PFAA precursors by agricultural plants. The applications of biosolids/composts and pesticides are the main sources of PFAA precursors in agricultural soils. The physicochemical properties of PFAA precursors, soil organic carbon (SOC) contents, and plant species are the key factors influencing plant root uptakes of PFAA precursors from soils. This review revealed, through toxicity assessment, the potential of PFAA precursors to generate metabolites with higher toxicity than the parent precursors. The results of this paper provide a reference for future research on PFAA precursors and their metabolites in soil-plant systems.