9 research outputs found
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
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
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 × 10<sup>4</sup> ng/g, and
20 PIs can be found in food contact materials with concentrations
of ∑PIs varying from 65.9 to 6.93 × 10<sup>3</sup> 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 × 10<sup>3</sup> ng/g. Meanwhile, all
21 targeted PIs could be identified in the sewage sludge, with concentrations
from 67.6 to 2.03 × 10<sup>3</sup> 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
Exploring Prenatal Exposure to Halogenated Compounds and Its Relationship with Birth Outcomes Using Nontarget Analysis
Halogenated organic compounds (HOCs) are a class of contaminants
showing high toxicity, low biodegradability, and high bioaccumulation
potential, especially chlorinated and brominated HOCs (Cl/Br-HOCs).
Knowledge gaps exist on whether novel Cl/Br-HOCs could penetrate the
placental barrier and cause adverse birth outcomes. Herein, 326 cord
blood samples were collected in a hospital in Jinan, Shandong Province
from February 2017 to January 2022, and 44 Cl/Br-HOCs were identified
with communicating confidence level above 4 based on a nontarget approach,
covering veterinary drugs, pesticides, and their transformation products,
pharmaceutical and personal care products, disinfection byproducts,
and so on. To our knowledge, the presence of closantel, bromoxynil,
4-hydroxy-2,5,6-trichloroisophthalonitrile, 2,6-dibromo-4-nitrophenol,
and related components in cord blood samples was reported for the
first time. Both multiple linear regression (MLR) and Bayesian kernel
machine regression (BKMR) models were applied to evaluate the relationships
of newborn birth outcomes (birth weight, length, and ponderal index)
with individual Cl/Br-HOC and Cl/Br-HOCs mixture exposure, respectively.
A significantly negative association was observed between pentachlorophenol
exposure and newborn birth length, but the significance vanished after
the false discovery rate correction. The BKMR analysis showed that
Cl/Br-HOCs mixture exposure was significantly associated with reduced
newborn birth length, indicating higher risks of fetal growth restriction.
Our findings offer an overview of Cl/Br-HOCs exposome during the early
life stage and enhance the understanding of its exposure risks
Photophysical Properties and Singlet Oxygen Generation of Three Sets of Halogenated Corroles
The luminescence, excited-state absorption, and singlet
oxygen
generation measurements were performed on three kinds of halogenated
corroles: monohydroxyl halogenated corroles (Corrole-F, Corrole-Cl,
Corrole-I), peripherally fluorine-substituted corroles (F0, F5, F10,
F15), and gallium complexes (F10-Ga, F15-Ga). The fluorescence intensities
progressively decrease whereas the triplet quantum yields, oxygen
quenching rates, and singlet oxygen quantum yields increase with the
increasing of the monohydroxyl halogen atomic weight. Replacing hydrogen
atoms of meso-phenyl groups with fluorine atoms induces the blue-shifts
of the emission spectra, higher triplet quantum yield, and smaller
oxygen quenching rates. Of all peripherally fluorine-substituted corroles,
F10 exhibited the highest singlet oxygen quantum yield. In comparison
with the free base corroles, both gallium corrole complexes display
much stronger fluorescence with the large blue-shifts of emission
peaks and slightly higher triplet quantum yields but smaller oxygen
quenching rates and singlet oxygen quantum yields. The reasons for
the different photophysical behaviors of these corroles are discussed
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