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Association between urinary phthalate metabolites and dyslipidemia in children: Results from a Chinese cohort study
2022
Gao, Di | Zou, Zhiyong | Li, Yanhui | Chen, Manman | Ma, Ying | Chen, Li | Wang, Xijie | Yang, Zhaogeng | Dong, Yanhui | Ma, Jun
Rising evidence of both experimental and epidemiological studies suggests that phthalate exposure may contribute to increased risks of metabolic disorders. But there is limited research on the childhood dyslipidemia. Our cohort study was conducted in Xiamen city, Fujian Province, China. A total of 829 children (mean age 8.5 years) were included with collection of urine, blood samples and demographic data in May 2018 and followed up once a year from 2018 to 2020. We performed adjusted log-binomial regressions to examine associations between sex-specific tertiles of seven phthalate metabolites and dyslipidemia in visit 1, as well as persistent dyslipidemia and occasional dyslipidemia. We also used generalized estimating equation models (GEE) to explore the relationships between log-transformed phthalate metabolites and lipid profiles. In adjusted models, the prevalence and RRs of dyslipidemia increased with tertile group of mono-n-butyl phthalate (MnBP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), and summed di-(2-ethylhexyl) phthalate (∑DEHP) metabolites with a dose-response relationship in visit 1, as well as persistent dyslipidemia. Higher MnBP, ∑LMWP, MEHHP, MEOHP, and ∑DEHP concentrations were also associated with higher levels of log-transformed triglycerides (TG). Boys were more vulnerable to phthalates exposure than girls. In conclusion, children in China were widely exposed to phthalates, and phthalates exposure during childhood might significantly increase the risk of dyslipidemia and a higher level of lipid profiles, particularly in boys.
Show more [+] Less [-]Wood vinegar facilitated growth and Cd/Zn phytoextraction of Sedum alfredii Hance by improving rhizosphere chemical properties and regulating bacterial community
2022
Zhou, Xueqi | Shi, An | Rensing, Christopher | Yang, Jing | Ni, Wuzhong | Xing, Shihe | Yang, Wenhao
Soil Cd and Zn contamination has become a serious environmental problem. This work explored the performance of wood vinegar (WV) in enhancing the phytoextraction of Cd/Zn by hyperaccumulator Sedum alfredii Hance. Rhizosphere chemical properties, enzyme activities and bacterial community were analyzed to determine the mechanisms of metal accumulation in this process. Results demonstrated that, after 120 days growth, different times dilution of WV increased the shoot biomass of S. alfredii by 85.2%–148%. In addition, WV application significantly increased soil available Cd and Zn by lowing soil pH, which facilitated plant uptake. The optimal Cd and Zn phytoextraction occurred from the 100 times diluted WV (D100), which increased the Cd and Zn extraction by 188% and 164%, compared to CK. The 100 and 50 times diluted WV significantly increased soil total and available carbon, nitrogen and phosphorus, and enhancing enzyme activities of urease, acid phosphatase, invertase and protease by 10.1–21.4%, 29.1–42.7%,12.2–38.3% and 26.8–85.7%, respectively, compared to CK. High-throughput sequencing revealed that the D 100 significantly increased the bacterial diversity compared to CK. Soil bacterial compositions at phylum, family and genera level were changed by WV addition. Compared to CK, WV application increased the relative abundances of genus with plant growth promotion and metal mobilization function such as, Bacillus, Gemmatimonas, Streptomyces, Sphingomonas and Polycyclovorans, which was positively correlated to biomass, Cd/Zn concentrations and extractions by S. alfredii. Structural equation modeling analysis showed that, soil chemical properties, enzyme activities and bacterial abundance directly or indirectly contributed to the biomass promotion, Cd, and Zn extraction by S. alfredii. To sum up, WV improved phytoextraction efficiency by enhancing plant growth, Cd and Zn extraction and increasing soil nutrients, enzyme activities, and modifying bacterial community.
Show more [+] Less [-]Effective Sb(V) removal from aqueous solution using phosphogypsum-modified biochar
2022
Li, Ling | Liao, Lu | Wang, Bing | Li, Wei | Liu, Taoze | Wu, Pan | Xu, Qingya | Liu, Shirong
Antimonate is the dominant form of antimony (Sb) in Sb mine water. The treatment of high-Sb mine water essentially reduces the discharge of antimonate oxyanions ([Sb(OH)₆]⁻) in it. Biochar obtained from phosphogypsum-modified anaerobic digested distillers’ grain (PADC) can effectively adsorb antimonate from water. In this work, using batch adsorption experiments, mathematical models, and characterization methods, the mechanism of Sb(V) adsorption by PADC was studied. Compared with pristine biochar, PADC biochar showed abundant lamellar and vesicular structures with significant calcium ion loading on the surface. The kinetics data of the adsorption of Sb(V) on the PADC biochar followed the Elovich equation (R² = 0.992), indicating that heterogeneous adsorption had occurred. The results also showed that intraparticle diffusion played an important role in controlling Sb(V) adsorption by PADC biochar. The Redlich–Peterson model best fit the Sb(V) adsorption isotherm (R² = 0.997), indicating that the adsorption was a combination of the Langmuir and Freundlich models. The maximum adsorption capacity of PADC biochar for Sb(V) is 8123 mg/kg, which is more than twice that of the pristine biochar (3487 mg/kg) and is sufficient for Sb(V) treatment in most mine water. Fourier transform infrared (FTIR) spectra, X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), and Transmission electron microscopy with energy dispersive X-ray spectroscopy (TEM-EDS) analyses revealed that the dominant mechanism of Sb(V) removal by PADC biochar was the formation of Ca–O–Sb complexes or amorphous surface precipitation as well as electrostatic adsorption. This work demonstrated the potential of PADC biochar in the treatment of Sb-contaminated mine water.
Show more [+] Less [-]Adsorption of microplastics on aquifer media: Effects of the action time, initial concentration, ionic strength, ionic types and dissolved organic matter
2022
Li, Shuo | Yang, Mingxiang | Wang, Hao | Jiang, Yunzhong
The adsorption of microplastic (MPs) on aquifer media is affected by their own properties and environmental factors. Research results have shown that the adsorption capacity of MPs on the three media has the following order: fine sand > medium sand > coarse sand, and the adsorption equilibrium times are 8 h, 12 h and 24 h, respectively. The adsorption process has three stages (fast linear distribution, slow adsorption and equilibrium stability), and the action law is compounded by the pseudo-second-order kinetic equation. After adsorption, MPs were observed on the three media, and there were single existence and aggregation phenomena. The energy spectrum analysis indicates that elemental carbon (C) appears on the surface of the medium after the action occurs, and the surface of the media adsorbs MPs to varying degrees. According to the results of infrared spectroscopy, after action, the peak areas of the absorption peaks at 680-880 cm⁻¹ and 1450-1620 cm⁻¹ increase. The absorption peaks are mainly C–H out-of-plane bending vibrations from aromatic hydrocarbons and C–H stretching vibrations on the benzene ring skeleton. As the initial concentration increases, the equilibrium adsorption capacity increases linearly. The isothermal adsorption of MPs in porous media conforms to the Freundlich model. The adsorption process is also affected by different anions and cations. The higher the ionic strength of NH₄⁺ is, the weaker the electrostatic effect of negatively charged MPs, thereby increasing the adsorption capacity of microplastics on porous media. Ca²⁺ can promote the adsorption of MPs by the media through the formation of ternary complexes between cations, MPs and surface functional groups. The increase in SO₄²⁻ and HCO₃⁻ concentrations gradually inhibits the adsorption of MPs.
Show more [+] Less [-]The relationships between soil physicochemical properties, bacterial communities and polycyclic aromatic hydrocarbon concentrations in soils proximal to coking plants
2022
Du, Jingqi | Liu, Jinxian | Jia, Tong | Chai, Baofeng
Microbial degradation of polycyclic aromatic hydrocarbons (PAHs) is the major channel for their decontamination from different environments. Aerobic and anaerobic biodegradations of PAHs in batch reactors with single or multiple bacterial strains have been intensively studied, but the cooperative mechanism of functional PAH-degrading populations at the community level under field conditions remains to be explored. We determined the composition of PAH-degrading populations in the bacterial community and PAHs in farmland and wasteland soils contaminated by coking plants using high-throughput sequencing and high-performance liquid chromatography (HPLC), respectively. The results indicated that the PAH content of farmland was significantly lower than that of wasteland, which was attributed to the lower content of low molecular weight (LMW) PAHs and benzo [k]fluoranthene. The soil physicochemical properties were significantly different between farmland and wasteland. The naphthalene content was related to the soil organic carbon (SOC) and pH, while phenanthrene was related to the nitrate nitrogen (NO₃⁻-N) and water content (WC). The pH, nitrite (NO₂⁻-N), SOC, NO₃⁻-N and WC were correlated with the content of high molecular weight (HMW) PAHs and total PAHs. The relative abundances of the phyla Actinobacteria, Chloroflexi, Acidobacteria, and Firmicutes and the genera Nocardioides, Bacillus, Lysobacter, Mycobacterium, Streptomyces, and Steroidobacter in farmland soil were higher than those in wasteland soil. The soil physicochemical characteristics of farmland increased the diversities of the PAH degrader and total bacterial communities, which were significantly negatively related to the total PAHs and LMW PAHs. Subsequently, the connectivity and complexity of the network in farmland were lower than those in wasteland, while the module containing a module hub capable of degrading PAHs was identified in the network of farmland soil. Structural equation modelling (SEM) analysis showed that the soil characteristics and optimized abundance and diversity of the bacterial community in farmland were beneficial for the dissipation efficiency of PAHs.
Show more [+] Less [-]Field aging alters biochar's effect on antibiotic resistome in manured soil
2021
Cheng, Jian-Hua | Tang, Xiang-Yu | Su, Jian-Qiang | Liu, Chen
Current understanding of biochar's effect on antibiotic resistance genes (ARGs) in soil is limited, and whether the effect could change after long-term field aging remains largely unknown. In this study, we employed high-throughput quantitative PCR to assess the effect of biochar amendment on soil resistome as affected by three years of field aging. Application of fresh biochar significantly elevated the number and abundance of ARGs in the manured soil, but did not show such effect under pakchoi cultivation. The presence of aged biochar caused a marked reduction of ARGs only in the planted manured soil. Results of principal coordinate analysis and structural equation modeling indicate that biochar's effect on soil ARG profile was changed by field aging through altering soil microbial composition. These results highlight the necessity of considering aging effect of biochar during its on-farm application to mitigate soil antibiotic resistance.
Show more [+] Less [-]Bio-based dispersants for fuel oil spill remediation based on the Hydrophilic-Lipophilic Deviation (HLD) concept and Box-Behnken design
2021
Nawavimarn, Parisarin | Rongsayamanont, Witchaya | Subsanguan, Tipsuda | Luepromchai, Ekawan
The high density and viscosity of fuel oil leads to its prolonged persistence in the environment and causes widespread contamination. Dispersants with a low environmental impact are necessary for fuel oil spill remediation. This study aimed to formulate bio-based dispersants by mixing anionic biosurfactant (lipopeptides from Bacillus subtilis GY19) with nonionic oleochemical surfactant (Dehydol LS7TH). The synergistic effect of the anionic-nonionic surfactant mixture produced a Winsor Type III microemulsion, which promoted petroleum mobilization. The hydrophilic-lipophilic deviation (HLD) equations for ionic and nonionic surfactant mixtures were compared, and it was found that the ionic equation was applicable for the calculation of lipopeptides and Dehydol LS7TH concentrations. The best formula contained 6.6% w/v lipopeptides and 11.9% w/v Dehydol LS7TH in seawater, and its dispersion effectiveness for bunker fuels A and C was 92% and 78%, respectively. The application of bio-based dispersants in water sources was optimized by Box-Behnken design. The efficiency of the bio-based dispersant was affected by the dispersant-to-oil ratios (DORs) but not by the water salinity. A suitable range of DORs for different oil contamination levels could be identified from the response surface plot. The dispersed fuel oil was further degraded by adding an oil-degrading bacterial consortium to the chemically enhanced water accommodated fractions (CEWAFs). After 7 days of incubation, the concentration of fuel oil was reduced from 3692 mg/L to 356 mg/L (88% removal efficiency). On the other hand, the abiotic control removed less than 40% fuel oil from the CEWAFs. This bio-based dispersant had an efficiency comparable to that of a commercial dispersant. The process of dispersant formulation and optimization could be applied to other surfactant mixtures.
Show more [+] Less [-]Response surface modeling with Box-Behnken design for strontium removal from soil by calcium-based solution
2021
Song, Hojae | Chung, Hyeonyong | Nam, Kyoungphile
Owing to its physicochemical similarity to strontium (Sr), calcium (Ca) was tested as a key component of a soil washing solution for Sr-contaminated soil collected near a nuclear power plant. A four-factor, three-level Box–Behnken experimental design combined with response surface modeling was employed to determine the optimal Sr washing condition for Ca-based solution. The Ca concentration (0.1–1 M), liquid-to-soil ratio (5–20), washing time (0.5–2 h), and pH (2.0–7.0) were tested as the independent variables. From the Box–Behnken design, 27 sets of experimental conditions were selected, and a second-order polynomial regression equation was derived. The significance of the independent parameters and interactions was tested by analysis of variance. Ca concentration was found to be the most influential factor. To determine whether the four variables were independent, three-dimensional (3D) response surface plots were established. The optimal washing condition was determined to be as follows: 1 M Ca, L/S ratio of 20, 1 h washing, and pH = 2. Under this condition, the highest Sr removal efficiency (68.2%) was achieved on a soil contaminated with 90.1 mg/kg of Sr. Results from five-step sequential extraction before and after washing showed that 84.0% and 82.9% of exchangeable and carbonate-bound Sr were released, respectively. In addition, more tightly bound Sr, such as Fe/Mn oxides-bound and organic matter-bound Sr, were also removed (86.2% and 64.5% removal, respectively).
Show more [+] Less [-]Microbial mechanisms related to the effects of bamboo charcoal and bamboo vinegar on the degradation of organic matter and methane emissions during composting
2021
Guo, Honghong | Gu, Jie | Wang, Xiaojuan | Song, Zilin | Yu, Jing | Lei, Liusheng
In this study, functional microbial sequencing, quantitative PCR, and phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) were employed to understand the microbial mechanisms related to the effects of bamboo charcoal (BC) and bamboo vinegar (BV) on the degradation of organic matter (OM) and methane (CH₄) emissions during composting. BC + BV resulted in the highest degradation of OM. BV was most effective treatment in controlling CH₄ emissions and it significantly reduced the abundance of the mcrA gene. Methanobrevibacter, Methanosarcina, and Methanocorpusculum were closely related to CH₄ emissions during the thermophilic composting period. PICRUSt analysis showed that BC and/or BV enhanced the metabolism associated with OM degradation and reduced CH₄ metabolism. Structural equation modeling indicated that BC + BV strongly promoted the metabolic activity of microorganisms, which had a positive effect on CH₄ emissions. Together these results suggest that BC + BV may be a suitable composting strategy if the aerobic conditions can be effectively improved during the thermophilic composting period.
Show more [+] Less [-]A stable simultaneous anammox, denitrifying anaerobic methane oxidation and denitrification process in integrated vertical constructed wetlands for slightly polluted wastewater
2020
Huang, Tao | Liu, Wei | Zhang, Yi | Zhou, Qiaohong | Wu, Zhenbin | He, Feng
Anaerobic ammonium oxidation (anammox), denitrifying anaerobic methane oxidation bacteria (DAMO) have received great attention for their excellent performance in nitrogen removal. However, not much study focused on the co-existence of anammox, DAMO, and denitrification in constructed wetlands, not to mention the advantage of their application in mitigating the necessary byproduct nitrous oxide (N₂O), methane (CH₄) from the biodegradation process. In this study, the result indicated the construction of integrated vertical constructed wetlands (IVCWs) contributed to the high-efficient stable simultaneous anammox, DAMO and denitrification (SADD) process for the nutrients removal, with denitrification being the least contributor to nitrogen reduction. Besides the succession of SADD process was largely the driver for the variation of N₂O, CH₄ emission. The structural equation method (SEM) further suggested that the three biological pathways of qnorB/bacteria, archaea/qnorB, and anammox/nirK accounted for the N₂O production, as were top-controlled by mcrA/DAMO in IVCWs. Besides the anammox-associated nitrifier denitrification was the main source for N₂O production. And that the trade-off effect between the CH₄ and N₂O production was exerted by the DAMO, while the influence was far from satisfactory under the methane constraints.
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