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

Sensitive Electrochemical Determination of Hydrogen Peroxide Using Copper Nanoparticles in a Polyaniline Film on a Glassy Carbon Electrode

<p>Rapid and accurate determination of hydrogen peroxide is necessary in biochemistry and environmental science. In this paper, a sensitive hydrogen peroxide electrochemical sensor was developed by cyclic voltammetry deposition of polyaniline–copper nanocomposite film on a glassy carbon electrode. The synthesized polyaniline/Cu composites were characterized by scanning electron microscopy and X-ray diffraction. With a typical working potential of 0.4 V (versus Ag/AgCl) and a pH value of 6.0, the prepared electrochemical sensor achieved linear range of 1.0–500 µM for hydrogen peroxide detection. A relative standard deviation of 4.9% for <i>n</i> = 7 and 10.0 µM of H₂O₂ and a limit of detection of 0.33 µM at a signal-to-noise ratio = 3 were observed. The sensor was successfully used for the analysis of tap water, and a spiked recovery of 93.0 ± 2.1% was obtained, further confirming the sensor’s accuracy and feasibility.</p

High Time-Resolution Optical Sensor for Monitoring Atmospheric Nitrogen Dioxide

High time-resolution monitoring of nitrogen dioxide (NO₂) is of great importance for studying the formation mechanism of aerosols and improving air quality. Based on the Griess–Saltzman (GS) reaction, a portable NO₂ optical sensor was developed by employing a porous polypropylene membrane tube (PPMT) integrated gas permeation collector and detector. The PPMT was filled with GS reagents and covered with a coaxial jacket tube for gas collection. Its two ends were respectively fixed with a yellowish-green light-emitting diode and a photodiode for optic signal reception. NO₂ was automatically introduced through the collector by two air pumps cooperating with a homemade gas injector. Under the optimized conditions, the device presented good performance for monitoring NO₂, such as a limit of detection of 5.1 ppbv (parts per billion by volume), an intraday precision of 4.1% (RSD, relative standard deviation, <i>n</i> = 11, <i>c</i> = 100 ppbv), an interday precision of 5.7% (RSD, <i>n</i> = 2–3 per day for 5 days, <i>c</i> = 100 ppbv), an analysis time of 4.0 min, and a linearity range extended to 700 ppbv. The developed device was successfully applied to analyzing outdoor air with a comparable precision to that of the standard method of China. The high time-resolution characteristic that includes sampling 15 times per hour and a good stability for 10 days of urban air analysis had also been evaluated

Identification of Emerging Brominated Chemicals as the Transformation Products of Tetrabromobisphenol A (TBBPA) Derivatives in Soil

In contrast to the extensive investigation already conducted on tetrabromobisphenol A (TBBPA), the metabolism of TBBPA derivatives is still largely unknown. In this paper, we characterized unknown brominated compounds detected in 84 soil samples collected from sites around three brominated flame retardant production plants to determine possible transformation products of TBBPA derivatives. In addition to tribromobisphenol A (TriBBPA), dibromobisphenol A (DBBPA), and TBBPA, six novel transformation products, TriBBPA mono­(allyl ether) (TriBBPA-MAE), DBBPA-MAE, hydroxyl TriBBPA-MAE, TBBPA mono­(2-bromo-3-hydroxypropyl ether) (TBBPA-MBHPE), TBBPA mono­(2,3-dihydroxypropyl ether) (TBBPA-MDHPE), and TBBPA mono­(3-hydroxypropyl ether) (TBBPA-MHPE) were identified. The detection frequencies of these identified chemicals in soil samples ranged from 17% to 89%, indicating the widespread presence of the transformation products. To uncover the possible TBBPA derivative transformation pathways involved, super-reduced vitamin B12 (cyanocobalamin, (CCAs)) was used to treat TBBPA derivative and transformation products in this process were characterized. To our knowledge, this is the first study examining the transformation of TBBPA derivatives and the first to report several novel associated TBBPA and bisphenol A derivatives as transformation products. Our research suggests that ether bond breakage and debromination contribute to the transformation of TBBPA derivatives and the existence of the novel transformation products. These data provide new insights into the fate of TBBPA derivatives in environmental compartments

Chlorinated Polyfluoroalkyl Ether Sulfonic Acids in Marine Organisms from Bohai Sea, China: Occurrence, Temporal Variations, and Trophic Transfer Behavior

F-53B, the commercial product of chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs), has been used in Chinese chrome plating industry for 30 years, and was recently identified in the environment, which caused great concerns. So far, limited investigations have been performed on their environmental occurrence, fate and impact. In this study, we demonstrated the wide occurrence of Cl-PFESAs and their trophic transfer behavior in marine organisms from Chinese Bohai Sea. 6:2 Cl-PFESA (<0.016–0.575 ng/g wet weight) was the dominant congener, and 8:2 Cl-PFESA (<0.022–0.040 ng/g) was occasionally detected. Compared to other perfluoroalkyl and polyfluoroalkyl substances (PFASs) of concern, the levels of Cl-PFESAs were relatively lower in marine organisms. Based on the comparative analysis of Cl-PFESA contamination in mollusk samples collected in 2010–2014, both the concentrations and detection frequencies of Cl-PFESAs tended to increase in this region. And this kind of chemicals were more vulnerable to be accumulated in marine organisms at relatively higher trophic levels. Similar to perfluorooctanesulfonate (PFOS) and the long chain perfluorinated carboxylates (PFCAs), 6:2 Cl-PFESA could be magnified along the food chain. Accordingly, the potential threat might be posed to the wildlife and human beings due to unintended exposure to Cl-PFESAs

TBBPA and Its Alternatives Disturb the Early Stages of Neural Development by Interfering with the NOTCH and WNT Pathways

Tetrabromobisphenol A (TBBPA), as well as its alternatives Tetrabromobisphenol S (TBBPS) and Tetrachlorobisphenol A (TCBPA), are widely used halogenated flame retardants. Their high detection rates in human breast milk and umbilical cord serum have raised wide concerns about their adverse effects on human fetal development. In this study, we evaluated the cytotoxicity and neural developmental toxicity of TBBPA, TBBPS, and TCBPA with a mouse embryonic stem cell (mESC) system, at human body fluid and environmental relevant doses. All the three compounds showed similar trends in their cytotoxic effects. However, while TBBPA and TBBPS stimulated ESC neural differentiation, TCBPA significantly inhibited neurogenesis. Mechanistically, we demonstrated that, as far as the NOTCH (positive regulator) and WNT (negative regulator) pathways were concerned, TBBPA only partially and slightly disturbed them, whereas TBBPS significantly inhibited the WNT pathway, and TCBPA down-regulated the expression of NOTCH effectors but increased the WNT signaling, actions which both inhibited neural specification. In conclusion, our findings suggest that TBBPS and TCBPA may not be safe alternatives to TBBPA, and their toxicity need to be comprehensively evaluated

Online High Temporal Resolution Measurement of Atmospheric Sulfate and Sulfur Trioxide with a Light Emitting Diode and Liquid Core Waveguide-Based Sensor

High temporal resolution components analysis is still a great challenge for the frontier of atmospheric aerosol research. Here, an online high time resolution method for monitoring soluble sulfate and sulfur trioxide in atmospheric aerosols was developed by integrating a membrane-based parallel plate denuder, a particle collector, and a liquid waveguide capillary cell into a flow injection analysis system. The BaCl₂ solution (containing HCl, glycerin, and ethanol) was enabled to quantitatively transform sulfate into a well-distributed BaSO₄ solution for turbidimetric detection. The time resolution for monitoring the soluble sulfate and sulfur trioxide was 15 h^–1. The limits of detection were 86 and 7.3 μg L^–1 (<i>S</i>/<i>N</i> = 3) with a 20 and 200 μL SO₄^2– solution injection, respectively. Both the interday and intraday precision values (relative standard deviation) were less than 6.0%. The analytical results of the certificated reference materials (GBW­(E)­08026 and GNM-M07117-2013) were identical to the certified values (no significant difference at a 95% confidence level). The validity and practicability of the developed device were also evaluated during a firecracker day and a routine day, obviously revealing the continuous variance in atmospheric sulfate and sulfur trioxide in both interday and intraday studies

Table_2.pdf

<p>The 14-3-3 gene family members play key roles in various cellular processes. However, little is known about the numbers and roles of 14-3-3 genes in wheat. The aims of this study were to identify TaGF14 numbers in wheat by searching its whole genome through blast, to study the phylogenetic relationships with other plant species and to discuss the functions of TaGF14s. The results showed that common wheat harbored 20 TaGF14 genes, located on wheat chromosome groups 2, 3, 4, and 7. Out of them, eighteen TaGF14s are non-ε proteins, and two wheat TaGF14 genes, TaGF14i and TaGF14f, are ε proteins. Phylogenetic analysis indicated that these genes were divided into six clusters: cluster 1 (TaGF14d, TaGF14g, TaGF14j, TaGF14h, TaGF14c, and TaGF14n); cluster 2 (TaGF14k); cluster 3 (TaGF14b, TaGF14l, TaGF14m, and TaGF14s); cluster 4 (TaGF14a, TaGF14e, and TaGF14r); cluster 5 (TaGF14i and TaGF14f); and cluster 6 (TaGF14o, TaGF14p, TaGF14q, and TaGF14t). Tissue-specific gene expressions suggested that all TaGF14s were likely constitutively expressed, except two genes, i.e., TaGF14p and TaGF14f. And the highest amount of TaGF14 transcripts were observed in developing grains at 20 days post anthesis (DPA), especially for TaGF14j and TaGF14l. After drought stress, five genes, i.e., TaGF14c, TaGF14d, TaGF14g, TaGF14h, and TaGF14j, were up-regulated expression under drought stress for both 1 and 6 h, suggesting these genes played vital role in combating against drought stress. However, all the TaGF14s were down-regulated expression under heat stress for both 1 and 6 h, indicating TaGF14s may be negatively associated with heat stress by reducing the expression to combat heat stress or through other pathways. These results suggested that cluster 1, e.g., TaGF14j, may participate in the whole wheat developing stages, e.g., grain-filling (starch biosynthesis) and may also participate in combating against drought stress. Subsequently, a homolog of TaGF14j, TaGF14-JM22, were cloned by RACE and used to validate its function. Immunoblotting results showed that TaGF14-JM22 protein, closely related to TaGF14d, TaGF14g, and TaGF14j, can interact with AGP-L, SSI, SSII, SBEIIa, and SBEIIb in developing grains, suggesting that TaGF14s located on group 4 may be involved in starch biosynthesis. Therefore, it is possible to develop starch-rich wheat cultivars by modifying TaGF14s.</p

Table_3.pdf

<p>The 14-3-3 gene family members play key roles in various cellular processes. However, little is known about the numbers and roles of 14-3-3 genes in wheat. The aims of this study were to identify TaGF14 numbers in wheat by searching its whole genome through blast, to study the phylogenetic relationships with other plant species and to discuss the functions of TaGF14s. The results showed that common wheat harbored 20 TaGF14 genes, located on wheat chromosome groups 2, 3, 4, and 7. Out of them, eighteen TaGF14s are non-ε proteins, and two wheat TaGF14 genes, TaGF14i and TaGF14f, are ε proteins. Phylogenetic analysis indicated that these genes were divided into six clusters: cluster 1 (TaGF14d, TaGF14g, TaGF14j, TaGF14h, TaGF14c, and TaGF14n); cluster 2 (TaGF14k); cluster 3 (TaGF14b, TaGF14l, TaGF14m, and TaGF14s); cluster 4 (TaGF14a, TaGF14e, and TaGF14r); cluster 5 (TaGF14i and TaGF14f); and cluster 6 (TaGF14o, TaGF14p, TaGF14q, and TaGF14t). Tissue-specific gene expressions suggested that all TaGF14s were likely constitutively expressed, except two genes, i.e., TaGF14p and TaGF14f. And the highest amount of TaGF14 transcripts were observed in developing grains at 20 days post anthesis (DPA), especially for TaGF14j and TaGF14l. After drought stress, five genes, i.e., TaGF14c, TaGF14d, TaGF14g, TaGF14h, and TaGF14j, were up-regulated expression under drought stress for both 1 and 6 h, suggesting these genes played vital role in combating against drought stress. However, all the TaGF14s were down-regulated expression under heat stress for both 1 and 6 h, indicating TaGF14s may be negatively associated with heat stress by reducing the expression to combat heat stress or through other pathways. These results suggested that cluster 1, e.g., TaGF14j, may participate in the whole wheat developing stages, e.g., grain-filling (starch biosynthesis) and may also participate in combating against drought stress. Subsequently, a homolog of TaGF14j, TaGF14-JM22, were cloned by RACE and used to validate its function. Immunoblotting results showed that TaGF14-JM22 protein, closely related to TaGF14d, TaGF14g, and TaGF14j, can interact with AGP-L, SSI, SSII, SBEIIa, and SBEIIb in developing grains, suggesting that TaGF14s located on group 4 may be involved in starch biosynthesis. Therefore, it is possible to develop starch-rich wheat cultivars by modifying TaGF14s.</p