Identification of Novel Hydrogen-Substituted Polyfluoroalkyl Ether Sulfonates in Environmental Matrices near Metal-Plating Facilities

Environmental occurrence and behaviors of 6:2 chlorinated polyfluoroalkyl ether sulfonate (Cl-6:2 PFESA, with trade name F-53B) have been receiving increased attention recently. Nevertheless, its potential fates under diversified conditions remain concealed. In this study, susceptibility of Cl-6:2 PFESA to reductive dehalogenation was tested in an anaerobic super-reduced cyanocobalamin assay. A rapid transformation of dosed Cl-6:2 PFESA was observed, with a hydrogen-substituted polyfluoroalkyl ether sulfonate (1H-6:2 PFESA) identified as the predominant product by a nontarget screening workflow. With the aid of laboratory-purified standards, hydrogen-substituted PFESA analogues (i.e., 1H-6:2 and 1H-8:2 PFESA) were further found in river water and sediment samples collected from two separate regions near metal-plating facilities. Geometric mean concentrations of 560 pg/L (river water) and 11.1 pg/g (sediment) for 1H-6:2 PFESA and 11.0 pg/L (river water) and 7.69 pg/g (sediment) for 1H-8:2 PFESA were measured, and both analytes consisted average compositions of 1% and 0.1% among the 18 monitored per- and polyfluoroalkyl sulfonate and carboxylate pollutants, respectively. To our knowledge, this is the first to report existence of polyfluoroalkyl sulfonates with both hydrogen and ether functional group in the environment

Identification of Novel Hydrogen-Substituted Polyfluoroalkyl Ether Sulfonates in Environmental Matrices near Metal-Plating Facilities

Environmental occurrence and behaviors of 6:2 chlorinated polyfluoroalkyl ether sulfonate (Cl-6:2 PFESA, with trade name F-53B) have been receiving increased attention recently. Nevertheless, its potential fates under diversified conditions remain concealed. In this study, susceptibility of Cl-6:2 PFESA to reductive dehalogenation was tested in an anaerobic super-reduced cyanocobalamin assay. A rapid transformation of dosed Cl-6:2 PFESA was observed, with a hydrogen-substituted polyfluoroalkyl ether sulfonate (1H-6:2 PFESA) identified as the predominant product by a nontarget screening workflow. With the aid of laboratory-purified standards, hydrogen-substituted PFESA analogues (i.e., 1H-6:2 and 1H-8:2 PFESA) were further found in river water and sediment samples collected from two separate regions near metal-plating facilities. Geometric mean concentrations of 560 pg/L (river water) and 11.1 pg/g (sediment) for 1H-6:2 PFESA and 11.0 pg/L (river water) and 7.69 pg/g (sediment) for 1H-8:2 PFESA were measured, and both analytes consisted average compositions of 1% and 0.1% among the 18 monitored per- and polyfluoroalkyl sulfonate and carboxylate pollutants, respectively. To our knowledge, this is the first to report existence of polyfluoroalkyl sulfonates with both hydrogen and ether functional group in the environment

Occurrence of Synthetic Phenolic Antioxidants and Major Metabolites in Municipal Sewage Sludge in China

Synthetic phenolic antioxidants (SPAs) are one group of widely used additive chemicals, which have not yet had focused attention except for a few compounds such as 2,6-di-<i>tert</i>-butyl-4-methylphenol (BHT). In this study, the occurrence and composition profiles of 12 frequently used SPAs and three BHT metabolites were investigated in fifty-six sludge samples collected from individual wastewater treatment plants in China. Eleven SPAs were positively found in the sludge samples, in which, to our knowledge, eight SPA compounds were identified for the first time in the environment. BHT, 4-<i>tert</i>-octylphenol (4-<i>t</i>OP), and 2,4,6-tri-<i>tert</i>-bultylphenol (AO 246) were the most dominant SPAs in the sludge at mean concentrations of 4.14 μg/g, 374 ng/g, and 98.1 ng/g d.w. (dry weight). Meanwhile, three BHT metabolites, including 3,5-di-<i>tert</i>-butyl-4-hydroxybenzaldehyde (BHT-CHO), 2,6-di-<i>tert</i>-butyl-1,4-benzoquinone (BHT-Q), and 2,6-di-<i>tert</i>-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-quinol), were also found in most of the samples (>98.2%) with mean concentrations of 141, 562, and 225 ng/g d.w., respectively. The activated sludge system (anaerobic, anoxic, and oxic tanks) of a wastewater treatment plant was further investigated for the removal efficiencies of the SPAs. High removal efficiencies (80.1–89.2%) were found for the six detected SPAs in the aqueous phase, while generation of large proportions of the three BHT metabolites was also observed

Distribution and Preliminary Exposure Assessment of Bisphenol AF (BPAF) in Various Environmental Matrices around a Manufacturing Plant in China

Increasing attention has been paid to bisphenol A and bisphenol (BP) analogues due to high production volumes, wide usage and potential adverse effects. Bisphenol AF (BPAF) is considered a new bisphenol analogue which is used as raw material in plastic industry, but little is known about its occurrence in the environment and the potential associated risk. In this work, BPAF levels and environmental distribution were reported in samples collected around a manufacturing plant and a preliminary exposure risk assessment to local residents was conducted. BPAF was detected in most of the samples, with levels in river ranging between 4 ng/L, sediments (0.520–2.00 × 10³ ng/g dry weight, dw), soils

Identification of Novel Polyfluorinated Ether Sulfonates as PFOS Alternatives in Municipal Sewage Sludge in China

A 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFAES) with the trade name F-53B, is an alternative to perfluorooctanesulfonate (PFOS) in electroplating industry that is uniquely used in China. It was developed as a mist suppressant initially in the 1970s, but the environmental behaviors and potential adverse effects of the 6:2 Cl-PFAES have only recently been investigated. In this work, the occurrence and distribution of perfluoroalkyl sulfonate (PFSA), fluorotelomer sulfonate (FTSA), and PFAES analogues were investigated in municipal sewage sludge samples collected around China. Perfluorobutane, perfluorohexane, perfluorooctane, and perfluorodecanesulfonates, 6:2 and 8:2 FTSAs, and the emerging 6:2 Cl-PFAES were detected. Moreover, 8:2 and 10:2 Cl-PFAESs were identified for the first time as new polyfluorinated contaminants using high resolution mass spectrometry. These fluorinated analytes were further quantified with the aid of commercial and laboratory-purified standards. PFOS was the predominant contaminant with a geometric mean (GM) value of 3.19 ng/g dry weight (d.w.), which was subsequently followed by 6:2 Cl-PFAES and 8:2 Cl-PFAES (GM: 2.15 and 0.50 ng/g d.w., respectively). Both 6:2 and 8:2 Cl-PFAES were positively detected as the major components in the F-53B commercial product, and discrete 6:2 Cl-PFAES/8:2 Cl-PFAES ratios in the product and sludge samples might suggest 8:2 Cl-PFAES had enhanced sorption behavior in the sludge due to the increase in hydrophobicity

Perfluorooctyl Iodide Stimulates Steroidogenesis in H295R Cells via a Cyclic Adenosine Monophosphate Signaling Pathway

Perfluorinated iodine alkanes (PFIs) are used widely in the organic fluorine industry. Increased production of PFIs has caused environmental health concerns. To evaluate the potential endocrine-disrupting effect of PFIs, we investigated the effects of perfluorooctyl iodide (PFOI) on steroidogenesis in human adrenocortical carcinoma cells (H295R). Levels of aldosterone, cortisol, 17β-estradiol, and testosterone were measured in H295R culture medium upon treatment with perfluorooctanoic acid (PFOA) and PFIs. Expression of 10 steroidogenic genes (<i>StAR</i>, <i>HMGR</i>, <i>CYP11A1</i>, <i>3βHSD2</i>, <i>17βHSD</i>, <i>CYP17</i>, <i>CYP21</i>, <i>CYP11B1</i>, <i>CYP11B2</i>, and <i>CYP19</i>) was measured by real-time polymerase chain reaction. Levels of cyclic adenosine monophosphate (cAMP) and adenylate cyclase (AC) activity were measured to understand the underlying mechanism of steroidogenic perturbations. Levels of production of aldosterone, cortisol, and 17β-estradiol were elevated significantly, and the level of testosterone generation decreased upon treatment with 100 μM PFOI. Similar to the effect induced by forskolin (AC activator), expression of all 10 genes involved in the synthesis of steroid hormones was upregulated significantly upon exposure to 100 μM PFOI. PFOA had no effect on steroid hormone production or steroidogenic gene expression even though it is highly structurally similar with PFOI. Therefore, the terminal -CF₂I group in PFOI could be a critical factor for mediation of steroidogenesis. PFOI increased AC activity and cAMP levels in H295R cells, which implied an underlying mechanism for the disturbance of steroidogenesis. These data suggest that PFOI may act as an AC activator, thereby stimulating steroidogenesis by activating a cAMP signaling pathway

Immunomodulatory Prodrug Micelles Imitate Mild Heat Effects to Reshape Tumor Microenvironment for Enhanced Cancer Immunotherapy

Physical stimulation with mild heat possesses the notable ability to induce immunomodulation within the tumor microenvironment (TME). It transforms the immunosuppressive TME into an immune-active state, making tumors more receptive to immune checkpoint inhibitor (ICI) therapy. Transient receptor potential vanilloid 1 (TRPV1), which can be activated by mild heat, holds the potential to induce these alterations in the TME. However, achieving precise temperature control within tumors while protecting neighboring tissues remains a significant challenge when using external heat sources. Taking inspiration from the heat sensation elicited by capsaicin-containing products activating TRPV1, this study employs capsaicin to chemically stimulate TRPV1, imitating immunomodulatory benefits akin to those induced by mild heat. This involves developing a glutathione (GSH)-responsive immunomodulatory prodrug micelle system to deliver capsaicin and an ICI (BMS202) concurrently. Following intravenous administration, the prodrug micelles accumulate at the tumor site through the enhanced permeability and retention effect. Within the GSH-rich TME, the micelles disintegrate and release capsaicin and BMS202. The released capsaicin activates TRPV1 expressed in the TME, enhancing programmed death ligand 1 expression on tumor cell surfaces and promoting T cell recruitment into the TME, rendering it more immunologically active. Meanwhile, the liberated BMS202 blocks immune checkpoints on tumor cells and T cells, activating the recruited T cells and ultimately eradicating the tumors. This innovative strategy represents a comprehensive approach to fine-tune the TME, significantly amplifying the effectiveness of cancer immunotherapy by exploiting the TRPV1 pathway and enabling in situ control of immunomodulation within the TME

Identification and Composition of Emerging Quaternary Ammonium Compounds in Municipal Sewage Sludge in China

Quaternary ammonium compounds (QACs) have raised considerable attention due to their wide commercial applications and recent discovery of unknown persistent analogues in aqueous environment. In this work, the occurrence and distribution of alkyltrimethylammonium (ATMAC), benzylakyldimethylethylammonium (BAC) and dialkyldimethylammonium (DADMAC) homologues were investigated in fifty-two municipal sewage sludge samples. ATMAC C10–18, BAC C8–18 and paired DADMAC C8:8-C18:18 as well as emerging homologues such as ATMAC-20, 22 and mixed DADMAC-16:18 and 14:16 were present. Furthermore, paired DADMAC-20:20 and mixed DADMAC-14:18, 18:20 were identified for the first time by nontarget qualitative strategies. A triple quadruple mass spectrometer quantification method was also initially verified with the aid of laboratory synthesized standards for the analysis of the mixed DADMACs with no certificated commercial standards currently available. The total concentrations of ATMACs, BACs and DADMACs were in the range of 0.38–293, 0.09–191 and 0.64–344 μg/g dry weight, respectively, and particularly, mixed DADMACs constituted 39 ± 7% of total DADMAC concentrations. The concentrations and profiles of individual homologues further suggested different QAC applications and fate in China. Significant correlations were also found among the concentrations of various QAC homologues as well as wastewater treatment plant (WWTP) characteristics (total organic carbon contents and daily treatment volumes)

Observation of Emerging Photoinitiator Additives in Household Environment and Sewage Sludge in China

Photoinitiators (PIs) are widely used additives in industrial polymerization process, the contamination of which through migration into foodstuffs has been subjected to increasing public scrutiny. Nevertheless, little attention has been paid to the PI residue levels and potential exposure pathways from other environmental compartments. In the present study, the occurrence of PI additives with discrete molecular structures, that is, nine benzophenones (BZPs), four thioxanthones (TXs), and eight amine co-initiators (ACIs), was investigated in commercial products, indoor dust and sewage sludge samples. Nine PI compounds were positively detected in ultraviolet curable resins with concentrations of ∑PIs (sum of the detected PIs) up to 2.51 × 10⁴ ng/g, and 20 PIs can be found in food contact materials with concentrations of ∑PIs varying from 65.9 to 6.93 × 10³ ng/g. The wide usage of PIs in commercial products led to the occurrence of 19 PIs in indoor dust, with concentrations of ∑PIs in the range of 245–5.68 × 10³ ng/g. Meanwhile, all 21 targeted PIs could be identified in the sewage sludge, with concentrations from 67.6 to 2.03 × 10³ ng/g. Distinct PI composition profiles were observed in different investigated compartments, and BZPs were the dominant homologues in all samples. Most of the target PIs were further identified as class III chemicals by toxic hazard estimation algorithm (Toxtree), which indicates the compounds might be of significant toxicity or have reactive functional groups

Occurrence and Temporal Trends of Benzotriazole UV Stabilizers in Mollusks (2010–2018) from the Chinese Bohai Sea Revealed by Target, Suspect, and Nontarget Screening Analysis

Benzotriazole UV stabilizers (BZT-UVs), including 2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole (UV-328) that is currently under consideration for listing under the Stockholm Convention, are applied in many commodities and industrial products. However, limited information is available on the interannual variation of their environmental occurrence. In this study, an all-in-one strategy combining target, suspect, and nontarget screening analysis was established to comprehensively explore the temporal trends of BZT-UVs in mollusks collected from the Chinese Bohai Sea between 2010 and 2018. Significant residue levels of the target analytes were determined with a maximum total concentration of 6.4 × 103 ng/g dry weight. 2-(2-Hydroxy-3-tert-butyl-5-methyl-phenyl)-5-chloro-benzotriazole (UV-326), 5-chloro-2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole (UV-327), and 2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P) were the predominant analogues, and UV-328 was the most frequently detected BZT-UV with a detection frequency (DF) of 87%. Whereas five biotransformation products and six impurity-like BZT-UVs were tentatively identified, their low DFs and semi-quantified concentrations suggest that the targeted analytes were the predominant BZT-UVs in the investigated area. A gradual decrease in the total concentrations of BZT-UVs was observed, accompanied by downward trends of the abundant compounds (e.g., UV-326 and UV-P). Consequently, the relative abundance of UV-327 increased because of its consistent environmental presence. These results suggest that continuous monitoring and risk assessment of BZT-UVs other than UV-328 are of importance in China