Guangzhou Institute of Geochemistry
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Co-occurrence of organophosphate diesters and organophosphate triesters in daily household products: Potential emission and possible human health risk
No full textEight paired organophosphate diesters (Di-OPs) and organophosphate triesters (Tri-OPs) were investigated in wipes from analytical instruments and 47 material samples related to household products, including textiles, electrical/electronic devices, building/ decoration materials and children's products. The total concentrations of Di-OPs ranged in 3577-95551 ng/m(2) in the wipes and limit of detection-23002 ng/g in the materials. The Tri-OPs concentrations varied significantly in the ranges of 107218-1756892 ng/m(2) and 2.13-503149 ng/g, respectively. Four industrial Di-OPs were detected in > 65% of the studied samples suggesting their direct application in the studied materials. Furthermore, we demonstrated for the first time that four non-industrial Di-OPs, e.g., bis(2-chloroethyl) phosphate, bis(1-chloro-2-propyl) phosphate, bis(1,3-dichloro-2-propyl) phosphate, and bis(butoxyethyl) phosphate, identified as degradation products of their respective Tri-OPs were also detected in these studied samples, which might act as important emission sources of Di-OPs in indoor environments. We estimated the burden of Di-OPs and Tri-OPs in a typical residential house and instrumental room, which both exhibited important contributions from furniture, building and decoration materials, and electrical/electronic devices. Limit health risk was posed to local people via air inhalation
Regulating asymmetric oxygen vacancies in copper-ceria catalysts for achievement of excellent toluene catalytic oxidation
No full textRegulation of oxygen vacancy upon metal oxide catalysts is an effective strategy for improving the catalytic activity in the oxidation of volatile organic compounds. Herein, copper (Cu) ions were introduced into ceria (CeO2) catalysts via the modulation of preparation methods (ball-milling, co-precipitation and sol-gel method) to generate asymmetric oxygen vacancies (AOVs) with varying concentrations at the Cu-CeO2 interface, thereby enhancing the catalytic performance towards toluene. The presence of abundant AOVs promotes the rapid conversion of the redox couples of Ce4+/Ce3+ and Cu+/Cu2+ according to Cu+-OV-Ce3+ Cu2+-O2- (ad)-Ce4+, enhancing the redox property and lattice oxygen mobility of the catalyst synthesized by ball-milling strategy (BM-CuCe). Moreover, the AOVs expedite the backfilling and activation of gaseous oxygen, leading to a transformation of rate-determining steps into the cracking of aromatic rings, significantly improving the catalytic activity towards toluene. The BM-CuCe catalyst, with the highest AOVs concentration, exhibits the excellent catalytic activity, water-resistance capability as well as stability. This work sheds light on the promoting effect of AOVs in the catalytic oxidation of toluene and contributes an attractive strategy for designing highly efficient metal oxide catalysts
Magnetic photocatalytic nano-semiconductors prepared from carbon quantum dots compounded with copper ferrate and their application in dye wastewater treatment
No full textTo investigate new and potent photocatalytic materials for organic pollutants, in this work, copper ferrate (CuFe2O4) nanoparticles were synthesized by sol-gel combustion method and then combined with the microwave synthesis method to prepare CQDs/CuFe2O4, which was used for the degradation of methylene blue (MB) dye. Firstly, scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), UV-visible diffuse reflectance spectroscopy (UV-vis DRS), and electrochemistry were employed to validate the composite effect of CQDs/CuFe2O4. The MB removal (99.86%) was maximized under the optimal conditions (1.5% CQDs/CuFe2O4, 10 mg/L, pH 7.0). Meanwhile, the recycling performance after magnet adsorption and recovery and the effects of carbon quantum dots (CQDs) dosing (0.5% similar to 3%), dye concentration (10 mg/L similar to 30 mg/L), and pH (3.0 similar to 11.0) on the degradation of MB dye by the CQDs/CuFe2O4 system were comprehensively investigated. Finally, based on the findings of the free radical scavenging experiments, the photocatalytic mechanism is proposed that the high catalytic activity of CQDs/CuFe2O4 is owed to its high specific surface area, narrow bandgap, and multiple active sites. On account of the introduction of the CQDs, the rate of electron mobility is improved and carrier complexation is reduced. In conclusion, the present work provides an effective photocatalytic system for removing organic pollutants by CQDs/CuFe2O4 composites at room temperature under neutral conditions
Transcriptomics and physiological analyses reveal that sulfur alleviates mercury toxicity in rice<i> (Oryza</i> sativa L.)
No full textMercury (Hg) is one of the most dangerous contaminants and has sparked global concern since it poses a health risk to humans when consumed through rice. Sulfur (S) is a crucial component for plant growth, and S may reduce Hg accumulation in rice grains. However, the detailed effects of S and the mechanisms underlying S-mediated responses in Hg-stressed rice plants remain unclear. Currently, to investigate the effects of S addition on rice growth, Hg accumulation, physiological indexes, and gene expression profiles, rice seedlings were hydroponically treated with Hg (20 pmoVL HgCl2) and Hg plus elemental sulfur (100 mg/L). S application significantly reduced Hg accumulation in Hg-stressed rice roots and alleviated the inhibitory effects of Hg on rice growth. S addition significantly reduced Hg-induced reactive oxygen species generation, membrane lipid peroxidation levels, and activities of antioxidant enzymes while increasing glutathione content in leaves. Transcriptomic analysis of roots identified 3,411, 2,730, and 581 differentially expressed genes in the control (CK) vs. Hg, CK vs. Hg + S, and Hg vs. Hg + S datasets, respectively. The pathway of S-mediated biological metabolism fell into six groups: biosynthesis and metabolism, expression regulation, transport, stimulus response, oxidation reduction, and cell wall biogenesis. The majority of biological process-related genes were upregulated under Hg stress compared with CK treatment, but downregulated in the Hg + S treatment. The results provide transcriptomic and physiological evidence that S may be critical for plant Hg stress resistance and will help to develop strategies for reduction or phytoremediation of Hg contamination.(c) 2023 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V
Unravelling biosynthesis and biodegradation potentials of microbial dark matters in hypersaline lakes
No full textBiosynthesis and biodegradation of microorganisms critically underpin the development of biotechnology, new drugs and therapies, and environmental remediation. However, most uncultured microbial species along with their metabolic capacities in extreme environments, remain obscured. Here we un-ravel the metabolic potential of microbial dark matters (MDMs) in four deep-inland hypersaline lakes in Xinjiang, China. Utilizing metagenomic binning, we uncovered a rich diversity of 3030 metagenome-assembled genomes (MAGs) across 82 phyla, revealing a substantial portion, 2363 MAGs, as previously unclassified at the genus level. These unknown MAGs displayed unique distribution patterns across different lakes, indicating a strong correlation with varied physicochemical conditions. Our analysis revealed an extensive array of 9635 biosynthesis gene clusters (BGCs), with a remarkable 9403 being novel, suggesting untapped biotechnological potential. Notably, some MAGs from potentially new phyla exhibited a high density of these BGCs. Beyond biosynthesis, our study also identified novel biodegradation pathways, including dehalogenation, anaerobic ammonium oxidation (Anammox), and degradation of polycyclic aromatic hydrocarbons (PAHs) and plastics, in previously unknown microbial clades. These findings significantly enrich our understanding of biosynthesis and biodegradation processes and open new avenues for biotechnological innovation, emphasizing the untapped potential of microbial diversity in hypersaline environments.(c) 2023 The Authors. Published by Elsevier B.V. on behalf of Chinese Society for Environmental Sciences, Harbin Institute of Technology, Chinese Research Academy of Environmental Sciences
Preface to "atmospheric geochemistry: A special issue endorsed by IGAC China working group and IAGC China working group"
No full textSize-fractionated distribution of glycerol dialkyl glycerol tetraether core lipids in surface sediments of a large-river delta-front estuary
No full textGlycerol dialkyl glycerol tetraether core lipids (GDGTs) are microbial biomarkers ubiquitously distributed in terrestrial and marine environments. Dispersal and fate of GDGTs in an estuary largely depends on sediment grain size, however, their size distribution patterns remain poorly understood. Here, surface sediments collected from the Changjiang Estuary were separated into 125 mu m fractions, and analyzed for GDGTs as well as total organic carbon (TOC), stable isotopic composition (delta 13C) of TOC and lignin phenols, to investigate the size and spatial distributions of GDGTs and the particle size effects on GDGTs proxies in this large river delta -front estuary. The concentrations of isoprenoidal GDGTs (isoGDGTs) were higher in the finest fractions and in off-estuary sites. On the contrary, branched GDGTs (brGDGTs) were high not only in the finest fractions but in coarser fractions (>32 mu m fractions), and thus at both near- and off-estuary sites. The branched and isoprenoid tetraether (BIT) index increased with increasing grain size, and decreased sharply from the estuary (-0.52) to the shelf (-0.16). BrGDGTs were positively correlated with crenarcheaol in both high and low BIT regions. The brGDGTIIIa/IIa ratios in all size fractions were <0.59, further indicating that the brGDGTs were mainly derived from terrestrial input with minimum in -situ production. Fractional TOC source assignments derived from the BIT index was significantly positively correlated with the fractions of terrestrial OC from a mixing model based on delta C-13-TOC and lignin contents, indicating that BIT may track a broader pool of terrestrial OC than just soil OC. This work provides novel, yet preliminary insights into the size fractionated distribution characteristics of GDGTs and the applicability of BIT as a proxy for OC sources in estuarine sediments. More work is needed to further clarify the particle size effects on other GDGTs proxies in estuarine systems
Origin of the Permian high silica A-type granites in Halajun, South Tienshan, NW China: Implications for crystal-liquid segregation and rare metal fertilization
No full textHigh silica A-type granites (HSAGs) are important carriers of rare metal elements. Formation of HSAGs by crystal-liquid segregation would facilitate fertilization of rare metals and rare earth elements (REE). In this work, we present detailed petrology, whole-rock geochemistry, and in-situ zircon UPb ages and HfO isotopic compositions of the Halajun HSAGs in the South Tienshan Orogenic Belt (STOB). In combination with the previous study of the Halajun syenite and monzonite, we unravel the genetic connection of these granitoids and further explore the metallogenetic potentiality of HSAGs along the STOB in China. The Halajun granites have geochemical affinities of HSAGs with high SiO2 contents (> 70 wt%), whole-rock zirconium saturation thermometry (680-860 degrees C), high Ga/Al ratios and high field strength elements (HFSE) contents. The HSAGs (273-279 Ma), monzonite (280 Ma) and syenite (283 Ma) have similar formation ages, identical mineral assemblages, and consistent variations in major elements, implying a common magma reservoir of their parental magma. The Tamu and Huoshibulake HSAGs have high SiO2 (74.5-78.1 wt%) contents, low Sr (5-28 ppm) and Ba (7-60 ppm) contents, high Rb/Sr ratios (11.6-87.5), and strong negative Eu anomalies (0.01-0.08). Combined with the petrographic features, these geochemical variations suggest that they are the extracted melt. Conversely, the geochemical (high Sr and Ba concentrations, and Eu/Eu* near unity) and petrographic features of monzonite and syenite represent the residual silicic cumulate (crystals +/- trapped melt). The Kezi'ertuo and Halajun II HSAGs have SiO2 (71.9-76.5 wt%) contents, Sr (35-101 ppm) and Ba (60-541 ppm) contents, Rb/Sr ratios (1.9-8.9), and negative Eu anomalies (0.04-0.43), indicating the intermediate component (extracted melt + fractional crystals) in the consecutive system of crystal-liquid segregation. In-situ zircon HfO isotopes for the Halajun granitoids indicate a complex trans-crustal magmatic process involving crystal-liquid segregation and wall-rock assimilation. The long-time span of Tarim Large Igneous Province (TLIP) sustained injection of mantle-derived magma and/or advective heat to the magma chamber (> 1 Ma). Owing to the prolonged magma evolution, the highly fractionated silicic magma with high incompatible elements and F contents was extracted from the magma mush, and formed the HSAGs
Molecular signatures and formation mechanisms of water-soluble chromophores in particulate matter from Karachi in Pakistan
No full textExcitation -emission matrix (EEM) fluorescence spectroscopy is a widely -used method for characterizing the chemical components of brown carbon (BrC). However, the molecular basics and formation mechanisms of chromophores, which are decomposed by parallel factor (PARAFAC) analysis, are not yet fully understood. In this study, we characterized the water-soluble organic carbon (WSOC) in aerosols collected from Karachi, Pakistan, using EEM spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). We identified three PARAFAC components, including two humic-like components (C1 and C2) and one phenolic -like species (C3). We determined the molecular families associated with each component by performing Spearman correlation analysis between FT-ICR MS peaks and PARAFAC component intensities. We found that the C1 and C2 components were associated with nitrogen -enriched compounds, where C2 with the longest emission wavelength exhibited a higher level of aromaticity, N content, and oxygenation than C1. The C3 associated formulas have fewer nitrogen -containing species, a lower unsaturation degree, and a lower oxidation state. An oxidation pathway was identified as an important process in the formation of C1 and C2 components at the molecular level, particularly for the assigned CHON compounds associated with the gas -phase oxidation process, despite their diverse precursor types. Numerous C2 formulas were found in the "potential BrC" region and overlapped with the BrC-associated formulas. It can be inferred that the compounds that fluoresce C2 contributed considerably to the light absorption of BrC. These findings are essential for future studies utilizing the EEM-PARAFAC method to explore the sources, processes, and compositions of atmospheric BrC
Multi-task machine learning models for simultaneous prediction of tissue-to-blood partition coefficients of chemicals in mammals
No full textTissue-to-blood partition coefficients (P-tb) are crucial for assessing the distribution of chemicals in organisms. Given the lack of experimental data and laborious nature of experimental methods, there is an urgent need to develop efficient predictive models. With the help of machine learning algorithms, i,e., random forest (RF), and artificial neural network (ANN), this study developed multi-task (MT) models that can simultaneously predict P-tb values for various mammalian tissues, including liver, muscle, brain, lung, and adipose. Single-task (ST) models using partial least squares regression, RF, and ANN algorithms for each endpoint were established for comparison. Overall, the performances of MT models were superior to those of ST models. The MT model using ANN algorithms showed the highest prediction accuracy with determination coefficients ranging from 0.704 to 0.886, root mean square errors between 0.223 and 0.410, and mean absolute errors ranging from 0.178 to 0.285 log units. Results showed that lipophilicity and polarizability of molecules significantly influence their partition behavior in organisms. Applicability domains (ADs) of the models were characterized by weighted molecular similarity density, and weighted inconsistency in molecular activities of structure-activity landscapes. When constrained by ADs, the models displayed enhanced predictive accuracy, making them valuable tools for the risk assessment and management of chemicals