Microplastics (MPs) are a contaminant of increasing concern in the environment. However, the impacts of MPs on soil ecosystems and biogeochemical processes like nitrogen cycle have not been well ...elucidated. In this study, we designed an indoor microcosm experiment to investigate the effects of exposure to low density polyethylene (LDPE) MPs on soil bacterial community and nitrogen cycling function over a 90-day incubation. Next-generation sequencing of the 16S rRNA genes revealed that both 2% and 7% LDPE MPs exposure slightly affected the soil bacterial diversity. Further analysis at the genus level showed differential tolerance to LDPE MPs, the genera Pedomicrobium, Steroidobacter, Pseudonocardia, Nitrospira and Turicibacter were enriched in the soil with 2% (w/w) LDPE MPs amendment, while the genera Pedomicrobium, Mycobacterium and Hyphomicrobium were significantly enriched in the soil with 7% (w/w) LDPE MPs amendment on days 15 and 30. Co-occurrence network analysis further suggested that LDPE MPs changed bacterial network complexity and modularity and Acidobacteria formed intimate associations with each other in responding to LDPE MPs exposure. Additionally, LDPE MPs in soil increased the abundance of nifH, AOBamoA and nirK genes involved in nitrogen cycling in different incubation phases compared to the control. The abundance of AOAamoA genes decreased on day 15 and then increased. Conversely, the abundance of nirS genes increased during the first 15 days and then decreased. These results suggested that both 2% and 7% LDPE MPs impact soil bacterial network structure and alters functional groups involved in soil nitrogen cycling processing.
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•LDPE microplastics (MPs) had limited impact on the alpha diversity of soil bacteria.•The genera Pedomicrobium and Nocardia were significantly higher with LDPE MPs amendment.•LDPE MPs affected the network complexity and modularity of soil bacteria.•LDPE MPs stimulated the abundance of nifH, AOBamoA and nirK genes in the soil.
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•6:2 Cl-PFAES and TFA are detected with high levels in serum, second to PFOA and PFOS.•A significant increase in 6:2 Cl-PFAES with age and BMI, and TFA with age are found.•Positive ...associations of several PFASs with fasting glucose and HbA1c are observed.
In recent years, the occurrence of novel per-/polyfluoroalkyl substances (PFASs) such as polyfluoroalkyl ether sulfonates (PFAESs) in human samples have aroused attention due to the change in PFASs production profile, however, the data are still lacking. Furthermore, epidemiological studies have examined the associations of PFAS exposure with glucose homeostasis, but with inconsistent results. Therefore, in this study, fasting serum samples from 252 participants with an age range from 19 to 87 years old were collected in Tianjin, China. A total of 21 target PFASs were determined to analyze the levels and distribution of novel and legacy PFASs in serum and to further evaluate the cross-sectional associations of serum PFAS concentrations with two glycemic biomarkers (i.e., fasting glucose and glycated hemoglobin (HbA1c)). 6:2 chlorinated PFAES (6:2 Cl-PFAES) and trifluoroacetic acid (TFA) were widely detected novel PFASs (greater than90%) with relatively high median concentrations (8.64 ng/mL and 8.46 ng/mL, respectively), which were second only to the two dominant legacy PFASs, i.e., perfluorooctanoic acid (PFOA, 14.83 ng/mL) and perfluorooctane sulfonic acid (14.24 ng/mL). The percentage contributions to the total known PFASs were separately 17.6% and 17.2% for 6:2 Cl-PFAES and TFA. The levels of 6:2 Cl-PFAES were significantly correlated with age and BMI, and the concentrations of TFA were also significantly correlated with age. Furthermore, 1% increase in serum PFOA and perfluorononanoic acid (PFNA) was separately significantly associated with 0.018% 95% confidence interval (CI): 0.004%, 0.033% and 0.022% (95% CI: 0.007%, 0.037%) increment in fasting glucose levels. Similarly, 1% increase in serum perfluorohexanoic acid, PFNA, and perfluorohexane sulfonic acid was significantly associated with 0.030% (95% CI: 0.010%, 0.051%), 0.018% (95% CI: 0.003%, 0.033%), 0.007% (95% CI: 0.003%, 0.011%) increment in HbA1c levels, respectively. These findings suggested that 6:2 Cl-PFAES and TFA showed greater contributions to PFASs in serum and supported an association of exposure to PFASs with fasting glucose and HbA1c.
A nationwide survey was conducted on per- and polyfluoroalkyl substances (PFASs) in precipitation across mainland China. Twenty-two PFASs, including precursors to perfluoroalkyl acids (pre-PFAAs), ...were investigated in thirty-nine precipitation samples collected from twenty-eight cities. Trifluoroacetate (TFA), perfluorooctanoic acid, and perfluorooctane sulfonic acid (PFOS) were ubiquitous in precipitation. TFA displayed the highest concentrations (8.8–1.8 × 103 ng/L), which were particularly elevated in coastal cities. 6:2 chlorinated polyfluorinated ether sulfonic acid, an alternative to PFOS, was detected for the first time in precipitation at a frequency of 43%. Polyfluoroalkyl phosphoric acid diesters and 6:2 fluorotelomer sulfonic acid were also occasionally detected. PFAS fluxes in the northeastern area (C4C12; 2.0 × 102–3.4 × 103 ng/m2/d) with major PFAS manufacturing facilities were higher than those in the southwestern area (63–1.7 × 103 ng/m2/d). Using total oxidizable precursor (TOP) assay, the occurrence of unknown pre-PFAAs was for the first time uncovered in precipitation with maximum estimated fluxes of C6 and C8 pre-PFAAs at 3.1 × 103 and 4.3 × 103 ng/m2/d, respectively. The relative contribution of ultrashort-chain PFCAs (C2C3) ranged from 22% to 91% of ∑PFASs, while unknown pre-PFAAs accounted for 6%–56% of the total molar concentrations of PFASs. This bears critical concerns on underestimation of PFAS mass load from precipitation to surface environment ascribed to monitoring data solely on known PFASs. Unknown precursors of PFAAs in the atmosphere are yet to be identified for their chemical structures and relevant environmental risks as well.
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•TFA, PFOA and PFOS were the predominant PFAAs in precipitation samples in China.•6:2 Cl-PFAES, 6:2 FTSA, 6:2 diPAP and 8:2 diPAP were detected in precipitation.•TFA and unknown PFAA precursors make a significant contribution to PFASs mass loading.•Unknown PFAA precursors can be scavenged effectively by wet deposition.
Distribution of 12 organophosphate flame retardants (OPFRs) was determined in soil and outdoor settled dust samples collected from a multi-waste (electronic, plastic, and rubber wastes and abandoned ...household-appliances and vehicles) recycling area, that encompassed different modes of operation i.e. open (ORS) and semi-closed recycling (SCRS). Among the twelve OPFRs analyzed, eleven were detected at a frequency of 75%–100% in all soil and dust samples. In soil samples, ΣOPFR concentrations were significantly higher at ORS (122–2100ng/g) than at SCRS (58.5–316ng/g) and nearby farmlands (37.7–156ng/g). The ΣOPFR concentrations in dust samples were higher than those in soil samples with spatial distribution similar to that observed for soil, decreasing from ORS (1390–42,700ng/g) to SCRS (914–7940ng/g). Tris(2-chloroisopropyl) phosphate (TCIPP) was the major OPFRs in both soil (<MDL–1370ng/g) and dust (39.9–16,300ng/g) samples. Chlorinated OPFRs TCIPP, tris(1,3-dichloroisopropyl) phosphate (TDCIPP) and tris(2-chloroethyl) phosphate (TCEP) and aryl-OPFRs triphenyl phosphate (TPHP), tris(methylphenyl) phosphate (TMPP) exhibited spatial difference between ORS and SCRS. Principle component analysis (PCA) of OPFR concentrations revealed that TCIPP, TDCIPP, TPHP, TMPP originated from similar sources. TMPP was assessed to pose eco-toxicological risk (risk quotient values: RQs) in the soil ecosystem. The median estimated daily intake (EDI) of OPFRs via soil and outdoor settled dust ingestion (based on average ingestion rate) was 3.14×10−1ng/kgbw/day for adults at ORS. Our results suggest that waste recycling is an important source of chlorinated- and aryl-OPFRs in the environment.
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•Cl- and aryl-OPFRs levels in soil and dust were much higher than alkyl-OPFRs.•Primitive outdoor recycling operation was an important source for OPFRs' occurrence.•Major OPFRs (TCIPP, TPHP and TMPP) in soil and dust had similar sources.•TMPP posed high eco-toxicological risk at the outdoor waste recycling sites.•Outdoor waste recycling lowered OPFRs' exposure to occupational workers.
•OPE metabolites were investigated in urine samples of pregnant women (n = 360).•OPE metabolites were positively associated with maternal and neonatal TSH.•Associations between OPE metabolites and ...thyroid hormones differed by newborn sex.•OPE metabolites were positively associated with maternal urinary 8-OhdG and MDA.•8-OhdG highly mediates (63.1%) the association between DPHP and neonatal TSH.
Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers in consumer and industrial products. Human exposure to OPEs raises concerns due to their endocrine disruptive potentials. Till now, the effects of OPEs on thyroid hormones (THs) and the mediating role of oxidative stress in pregnant women have not been studied. In this study, prenatal urinary concentrations of OPE metabolites (mOPEs), levels of free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), and oxidative stress levels of 8-hydroxy-2-deoxy guanosine (8-OHdG) and malondialdehyde (MDA) were measured in pregnant women (n = 360) from a coastal urbanized region and moderate socioeconomic status. Neonatal TSH in heel blood was also measured in newborns (n = 309). Dibutyl phosphate (DBP) and diphenyl phosphate (DPHP) were extensively detected with a median creatinine-adjusted level of 0.19 μg/g and 0.66 μg/g, respectively, and the median of ∑mOPEs was 1.82 μg/g. DBP and DPHP were included in the analysis. The concentrations of DBP and DPHP were positively associated with either maternal or neonatal TSH levels, while not for maternal FT3 and FT4 levels. Positive associations for maternal and neonatal TSH were particularly observed in girls as stratified by newborn sex suggesting a sex-selective difference. Furthermore, 8-OHdG, the biomarker of DNA damage, was found to be a major mediator (>60%) for the association between neonatal TSH and DPHP, suggesting that DNA damage is involved in fetal thyroid function disruption. On the other hand, MDA showed a partially suppressing effect (<40%) for the associations between mOPEs and neonatal TSH, which needs further clarification. For maternal TSH, both 8-OHdG and MDA showed moderate mediating effects while the direct effects of mOPEs on maternal TSH also contributed. These results suggest thyroid disrupting effects of OPE exposure on mothers and fetuses during pregnancy and the potential influence mediated by the oxidative stresses of DNA damage and lipid peroxidation.
A total of 23 per- and polyfluoroalkyl substances (PFASs) were investigated in the air, dry deposition, and plant leaves at two different landfills and one suburban reference site in Tianjin, China. ...The potential of landfills as sources of PFASs to the atmosphere and the phase distribution therein were evaluated. The maximum concentrations of ∑PFASs in the two landfills were up to 9.5 ng/m3 in the air, 4.1 μg/g in dry deposition, and 48 μg/g lipid in leaves with trifluoroacetic acid and perfluoropropionic acid being dominant (71%–94%). Spatially, the distribution trend of ionizable and neutral PFASs in all three kinds of media consistently showed the central landfill > the downwind > the upwind > the reference sites, indicating that landfills are important sources to PFASs in the environment. Plant leaves were found effective in uptake of a variety of airborne PFASs including polyfluoroalkyl phosphoric acid diesters, thus capable of acting as a passive air sampling approach for air monitoring.
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•19 serum metabolic biomarkers are screened between T2DM cases and controls.•Galactose, amino acid, and pyrimidine metabolism are the main perturbed pathways.•More than half of ...urinary mPAEs are related to most screened metabolic biomarkers.•Few associations are observed between bisphenols and screened metabolic biomarkers.
Emerging evidence has proved the associations between exposure to phthalates (PAEs) and bisphenols and type 2 diabetes mellitus (T2DM), but the underlying mechanisms for these associations are poorly understood. Metabolomics is a powerful tool to identify differential metabolites and metabolic pathways related to diseases and chemical exposure, which may reveal underlying mechanisms. However, little is known about the roles of metabolism in the associations for PAE and bisphenol exposure with T2DM.
The purpose of the study was to investigate the roles of metabolism in the associations for exposure to PAEs and bisphenols with T2DM.
In this study, 60 T2DM cases and 60 controls, who were matched in age, sex, and body mass index (BMI), were selected from the total study population in our previous studies. Fasting blood and spot urine samples of the volunteers were used for non-targeted metabolomics analysis and determination of phthalate metabolites (mPAEs) and bisphenols, respectively. The associations of urinary mPAEs and bisphenols with screened metabolic biomarkers in metabolomics analysis were analyzed using multiple linear regression models.
Based on non-targeted metabolomics, 19 serum metabolic biomarkers were screened between T2DM cases and controls, mostly related to galactose metabolism, amino acid metabolism, and pyrimidine metabolism. More than half of mPAEs were mostly positively associated with up-regulated metabolic biomarkers and negatively associated with down-regulated biomarkers. Different from PAEs, no evident results suggested the roles of metabolism in the associations between bisphenol exposure and T2DM.
Combined with the positive associations between most urinary mPAEs and T2DM in our previous study, our findings indicated that PAE exposure may contribute to T2DM risk through disturbing galactose metabolism, amino acid metabolism (especially arginine biosynthesis and alanine, aspartate and glutamate metabolism), and pyrimidine metabolism.
Polyfluoroalkyl phosphoric acid diesters (diPAPs) have been widely and increasingly detected in various environmental mediums. The degradation of diPAPs brings perfluoroalkyl carboxylic acids (PFCAs) ...concerned of adverse health effects. DiPAPs mainly occur in particulate matter in ambient air and their photo-degradation behaviors have not been investigated. In this study, heterogeneous photo-degradation of 6:2 diPAP was studied on four model mineral components in ambient dust. 6:2 diPAP was found to undergo a fast degradation on titanium dioxide (TiO2) particles as well as on artificial mineral dust containing TiO2 (2.67% in mass) to produce C5–C7 PFCAs and other intermediates. Based on monitored intermediates and further degradation tests on important intermediates, thermodynamic calculation of energy barrier and Gibbs Free Energy was used to explain the observed degradation patterns and accordingly the degradation pathways of diPAPs were proposed. The increase in relative humidity promotes the production of hydroxyl radicals, which enhances the hydrolysis of 6:2 mono- and di-PAPs and the yield of C5 and C7 PFCAs. Oxygen is critical for radical formation, which bypasses the production of fluorotelomer carboxylic acid. Results of this study for the first time demonstrate that diPAP may account for additional PFCA sources in both indoor and outdoor environments and the heterogeneous degradation pathways were different from those of volatile fluorotelomer alcohols.
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•Heterogeneous degradation of 6:2 diPAP is studied with a self-installed reaction cell.•Thermodynamic calculation of energy barrier and Gibbs Free Energy clarifies reactions.•The degradation routes of 6:2 diPAP are different from 6:2 FTOH on TiO2 particles.•Relative humidity and oxygen are key factors for 6:2 diPAP heterogeneous degradation.•6:2 FTUCA may accumulate over PFCAs on environmental mineral dust (2.7% TiO2).
Application of per- and polyfluoroalkyl substances (PFASs) is shifting to short-chain analogs (C ≤ 6) that raises concerns for their potential ecotoxicological risks. In the present study, pot ...experiments were carried out to study the effects of perfluoroalkyl acids (PFAAs), including perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs), with different carbon chain lengths (C4, C6, and C8) on the growth of wheat seedlings and their plant uptake and transfer at two spiking levels (200 and 2000 μg/kg soil). Exposure to C4 PFAAs slightly inhibited chlorophyll activity, whereas exposure to C8 PFAAs showed enhancement. The bioaccumulation factors (BAFs) for C4 PFAAs in wheat were over 10, while BAFs for C8 PFAAs were all below 1. Rhizospheric and root to shoot transfer factors for PFAAs were both negatively correlated with their log
K
ow
(
p
< 0.05). PFCAs exhibited both higher rhizospheric mobility and accumulation potentials than PFSAs of the same chain lengths. Hence, perfluoroalkyl chain governs the mobility of PFAAs in a soil–plant system besides interactions of their head groups, and the substitution with shorter chain PFASs raises concerns for their higher plant accumulation potential that brings higher ecotoxicological and human exposure risks via food chains.
Industrial facilities can be point sources of per- and polyfluoroalkyl substances (PFASs) emission to the surrounding environment. In this study, 25 neutral and ionizable PFASs were analyzed in 94 ...multimedia samples including air, rain, outdoor settled dust, soil, plant leaves, river water, surface sediment, and shallow groundwater from two fluorochemical manufacturing parks (FMPs) in Fuxin, China, to elucidate the multimedia distribution and transfer pattern of PFASs from a point source. The concentrations of individual PFASs in air, outdoor settled dust, and surface river water decreased exponentially as the distance increases from the FMPs, whereas the concentrations of short-chain (C2–C4) perfluoroalkyl carboxylic acids (PFCAs) remained high (3000 ng/L) in the surface water 38 km away. At FMPs, air concentrations of fluorotelomer alcohols and iodides were found dominant with levels of up to 7900 pg/m3 and 920 pg/m3, respectively. Trifluoroacetic acid was directly released from FMPs and occurred in all the environmental matrices at levels 1–2 orders of magnitude higher than other PFCAs. Higher air–water concentration ratios of short-chain PFCAs (C2–C4) suggested their transfer tendency from air to water. Both short-chain (C2) and long-chain (>C6) PFCAs have greater sediment-water distribution coefficients and deposit dust-air coefficients, which have great influences on the long-range transport potential of different analogues.
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