Generation of environmentally persistent free radicals on photoaged tire wear particles and their neurotoxic effects on neurotransmission in Caenorhabditis elegans.

Tire wear particles (TWP) are a prevalent form of microplastics (MPs) extensively distributed in the environment, raising concerns about their environmental behaviors and risks. However, knowledge regarding the properties and toxicity of these particles at environmentally relevant concentrations, specifically regarding the role of environmentally persistent free radicals (EPFRs) generated during TWP photoaging, remains limited. In this study, the evolution of EPFRs on TWP under different photoaging times and their adverse effects on Caenorhabditis elegans were systematically investigated. The photoaging process primarily resulted in the formation of EPFRs and reactive oxygen species (O2•-, ⋅OH, and 1O2), altering the physicochemical properties of TWP. The exposure of nematodes to 100 µg/L of TWP-50 (TWP with a photoaging time of 50 d) led to a significant decrease in locomotory behaviors (e.g., head thrashes, body bends, and wavelength) and neurotransmitter contents (e.g., dopamine, glutamate, and serotonin). Similarly, the expression of neurotransmission-related genes was reduced in nematodes exposed to TWP-50. Furthermore, the addition of free-radical inhibitors significantly suppressed TWP-induced neurotoxicity. Notably, correlation analysis revealed a significantly negative correlation between EPFRs levels and the locomotory behaviors and neurotransmitter contents of nematodes. Thus, it was concluded that EPFRs on photoaged TWP induce neurotoxicity by affecting neurotransmission. These findings elucidate the toxicity effects and mechanisms of EPFRs, emphasizing the importance of considering their contributions when evaluating the environmental risks associated with TWP.

Activation of persulfate by g-C3N4/nZVI@SBC for degradation of total petroleum hydrocarbon in groundwater.

In this study, we synthesized a high removal efficiency catalyst using biochar-supported nanoscale zero-valent iron and g-C3N4, denoted as g-C3N4/nZVI@SBC, to activate persulfate (PS) for the degradation of total petroleum hydrocarbon (TPH) in groundwater. We characterized the morphology and physiochemical properties of g-C3N4/nZVI@SBC with scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), BET surface area analysis, and X-ray photoelectron spectroscopy (XPS). To assess the performance of the g-C3N4/nZVI@SBC catalyst, we investigated various reaction parameters, such as the mass ratio of g-C3N4 to nZVI@SBC, PS concentration, initial pH, initial TPH concentration, and the presence of coexisting ions in the system. The results from batch experiments and repeated use trials indicate that g-C3N4/nZVI@SBC exhibited both excellent catalytic activation capability and impressive durability, making it a promising choice for TPH degradation. Specifically, when the PS concentration reached 1 mM, the catalyst dosage was 0.3 g/L, and the g-C3N4 to nZVI@SBC mass ratio was 2, we achieved a remarkable TPH removal efficiency of 93.8%. Through electron paramagnetic resonance (EPR) testing and quenching experiments, we identified sulfate radicals, hydroxyl radicals, and superoxide radicals as the primary active substance involved in the TPH degradation process. Moreover, the g-C3N4/nZVI@SBC composite proved highly effective for in-situ TPH removal from groundwater and displayed an 86% removal rate, making it a valuable candidate for applications in permeable reactive barriers (PRB) aimed at enhancing environmental remediation. In summary, by skillfully utilizing g-C3N4/nZVI@SBC, this study has made notable advancements in synthesis and characterization, presenting a feasible and innovative approach to addressing TPH pollution in groundwater.

Enhanced nitrate reduction in hypotrophic waters with integrated photocatalysis and biodegradation.

Addressing nitrate contamination in water bodies is a critical environmental challenge, and Intimately Coupling Photocatalysis and Biodegradation (ICPB) presents a promising solution. However, there is still debate about the effectiveness of ICPB in reducing nitrate under hypotrophic conditions. Further research is needed to understand its microbial metabolic mechanism and the functional changes in bacterial structure. Here we explored microbial metabolic mechanisms and changes in bacterial structure in ICPB reactors integrating a meticulously screened TiO2/g-C3N4 photocatalyst with biofilm. We achieved a 26.3% increase in nitrate reduction using 12.2% less organic carbon compared to traditional biodegradation methods. Metagenomic analysis of the microbial communities in ICPB reactors revealed evolving metabolic pathways conducive to nitrate reduction. This research not only elucidates the photocatalytic mechanism behind nitrate reduction in hypotrophic conditions but also provides genomic insights that pave the way for alternative approaches in water remediation technologies.

Evaluation of pharmaceutical consumption between urban and suburban catchments in China by wastewater-based epidemiology.

Wastewater-based epidemiology (WBE) is amply used for estimating human consumption of chemicals, yet information on regional variation of pharmaceuticals and their environmental fate are scarce. Thus, this study aims to estimate the consumption of three cardiovascular, four non-steroidal anti-inflammatory pharmaceuticals (NSAIDs), and four psychoactive pharmaceuticals between urban and suburban catchments in China by WBE, and to explore their removal efficiencies and ecological risks. Eleven analytes were detected in both influent and effluent samples. The estimated consumptions ranged from

Exposure to OPFRs Is Associated with Obesity and Dysregulated Serum Lipid Profiles: Data from 2017-2018 NHANES.

Widespread exposure to organophosphorus flame retardants (OPFRs) has been observed in the general population. Emerging studies have revealed OPFRs possess endocrine-disturbing properties. The present study aims to assess the association between urinary metabolites of OPFRs, BMI, and serum lipid profiles. Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 were obtained, with 1334 adults enrolled in the current study. Urinary concentrations of bis (1-chloro-2-propyl) phosphate (BCIPP), bis(2-chloroethyl) phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), dibutyl phosphate (DBUP), and diphenyl phosphate (DPHP) were quantified to assess OPFR exposure. Covariate-adjusted linear and logistic regression models were conducted to explore the associations between log2-transformed concentrations of OPFR metabolites, BMI, obesity, and serum lipid profiles. Stratified analyses were performed to assess the heterogeneity of associations by age, gender, race, etc. Positive associations were found between OPFR exposure and the risk of obesity. The multivariate linear analysis indicated that a one-unit increase in log2-transformed urinary concentrations of BCEP and BDCPP was associated with 0.27 (95% CI: 0.02-0.52, p = 0.0338) and 0.56 (95% CI: 0.25-0.87, p = 0.0004) higher BMI value, respectively. One log2-unit increase in urinary BCEP and BDCPP concentrations was associated with 1.1-fold (95% CI: 1.02-1.18, p = 0.0096) and 1.19-fold (95% CI: 1.09-1.30, p = 0.0001) risk for developing obesity. Furthermore, the non-linear relationship between exposure to OPFRs and obesity was identified. Additionally, multivariable linear regression showed that urinary DPHP concentrations were inversely correlated with serum triglyceride (TG) levels (ß = -7.41, 95% CI: -12.13 to -2.68, p = 0.0022). However, no other OPFR metabolites were found to be significantly statistically associated with serum lipid levels after adjusting for potential confounders. In conclusion, environmental exposure to OPFRs might contribute to obesity and dysregulated TG concentrations in adults. Future prospective research is warranted to confirm the causal relationship between metabolites of OPFRs and obesity.

Insight into the interaction of tetrabromobisphenol A with sediment-derived dissolved organic carbon in a multiphase system by direct immersion solid phase microextraction.

Tetrabromobisphenol A (TBBPA), a ubiquitously used commercial brominated flame retardant (BFR), has been widely detected in aquatic environments, and has aroused much attention due to its potential adverse effects on aquatic organisms. However, current research on the environmental fate and transport of TBBPA in the sediment-dissolved organic carbon (DOC)-water polyphase system is lacking. In this study, the sorption behavior of TBBPA in a water-DOC-sediment system was investigated using the direct-immersion solid-phase microextraction (DI-SPME) method, and the free dissolved concentration (Cw-SPME) and DOC adsorption concentration (CDOC) of TBBPA in water were measured by applying this DI-SPME approach. In addition, the effects of pH, ionic strength, and soluble organic concentration on the adsorption of TBBPA in the multiphase system were evaluated. The adsorption kinetics experimental results show that the adsorption behavior of TBBPA on sediments conforms to a linear model, suggesting that it could be mainly absorbed by sediments. The solid-water partition coefficient (Kd) of TBBPA was artificially reduced 1.54 times using the traditional liquid-liquid extraction method because the sorption behavior of the DOC was ignored, which could be accurately corrected using the DI-SPME method. The logKd and logKOC of TBBPA in the multiphase system were 4.12 ± 0.25 and 6.48 ± 0.25, respectively. Finally, the interference experiment revealed that the sorption behavior of TBBPA was affected by the pH, ionic strength (calcium ion), and humic acid concentration, apart from the lead ion concentration itself.

Applying thallium isotopic compositions as novel and sensitive proxy for Tl(I)/Tl(III) transformation and source apportionment.

Thallium is a rare metal known for its highly toxic nature. Recent research has indicated that the precise determination of Tl isotopic compositions using Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP MS) provides new opportunities for understanding Tl geochemical behavior. While isotopic fractionation of Tl derived from anthropogenic activities (e.g., mining, smelting) have been reported, there is limited information regarding Tl influenced by both natural weathering processes and anthropogenic origins. Herein, we investigated, for the first time, the Tl isotopic compositions in soils across a representative Tl-rich depth profile from the Lanmuchang (LMC) quicksilver mine (southwest China) in the low-temperature metallogenesis zone. The results showed significant variations in Tl isotope signatures (ε205Tl) among different soil layers, ranging from -0.23 to 3.79, with heavier isotope-205Tl enrichment observed in the bottom layers of the profile (ε205Tl = 2.18-3.79). This enrichment of 205Tl was not solely correlated with the degree of soil weathering but was also partially associated with oxidation of Tl(I) by Fe (hydr)oxide minerals. Quantitative calculation using ε205Tl vs. 1/Tl data further indicated that the Tl enrichment across the soil depth profile was predominantly derived from anthropogenic origins. All these findings highlight that the robustness and reliability of Tl isotopes as a proxy for identifying both anthropogenic and geogenic sources, as well as tracing chemical alterations and redox-controlled mineralogical processes of Tl in soils. The nascent application of Tl isotopes herein not only offers valuable insights into the behavior of Tl in surface environments, but also establishes a framework for source apportionment in soils under similar circumstances.

Photoaging enhances combined toxicity of microplastics and tetrabromobisphenol A by inducing intestinal damage and oxidative stress in Caenorhabditis elegans.

Microplastics (MPs) are emerging environmental contaminants that often co-exist with tetrabromobisphenol A (TBBPA) in the environment. However, the joint effect of TBBPA and photoaged MPs at ambient concentrations remains unknown largely. In this study, the combined toxicity of ultraviolet-aged polystyrene (UV-PS) and TBBPA was investigated in Caenorhabditis elegans. UV irradiation could change the physical and chemical characteristics of polystyrene (PS), and UV-PS (90.218 µg/g) showed a stronger adsorption capacity than PS of 79.424 µg/g. Toxicity testing showed that 1 µg/L UV-PS enhanced the toxic effect of 1 µg/L TBBPA by reducing body length, locomotion behavior, and brood size in nematodes. Using ROS production, lipofuscin accumulation, and expression of gst-4::GFP as endpoints, the combined exposure of UV-PS and TBBPA induced stronger oxidative stress than TBBPA alone. Joint exposure to UV-PS and TBBPA significantly increased of Nile red and blue food dye in its intestinal tract compared to that in the TBBPA exposure group, indicating that co-exposure enhanced intestinal permeability. After co-exposure to UV-PS and TBBPA, the expression of the associated genes detected increased significantly. Therefore, UV-PS enhances the adverse effects of TBBPA through intestinal damage and oxidative stress in nematodes. These findings suggest that the co-presence of photoaged PS and TBBPA results in high environmental risks.

Removal of organophosphorus flame retardant by biochar-coated nZVI activating persulfate: Synergistic mechanism of adsorption and catalytic degradation.

Triphenyl phosphate (TPhP) is a typical aromatic-based non-chlorinated organophosphorus flame retardant, which has been widely detected in a variety of environments and poses high environmental and human health risks. In this study, biochar coated nano-zero-valent iron (nZVI) was fabricated to activate persulfate (PS) to degrade TPhP from water. A range of biochars (BC400, BC500, BC600, BC700, and BC800) was prepared as potential support to coat nZVI by pyrolyzing corn stalk at 400, 500, 600, 700 and 800 °C. As outperformed other biochars in adsorption rate, adsorption capacity, and less reluctant to be influenced by environmental factors (pH, humic acid (HA), coexistence of anions), BC800 was to act as support to coat nZVI (labeled as BC800@nZVI). SEM, TEM, XRD and XPS characterization showed that nZVI was successfully supported on the BC800. Removal efficiency of 10 mg L-1 TPhP by BC800@nZVI/PS could reach to 96.9% with a high catalytic degradation kinetic rate of 0.0484 min-1 under optimal condition. The removal efficiency remained stable in a wide pH range (3-9) and moderate concentration of HA and coexistence of anions, demonstrated the promising of using BC800@nZVI/PS system to eliminate TPhP contamination. Results from the radical scavenging and electron paramagnetic resonance (EPR) experiments demonstrated radical pathway (i.e. SO4·- and HO·) and non-radical pathway via 1O2 both play important role in TPhP degradation. The TPhP degradation pathway was proposed based on the six degradation intermediates analyzed by LC-MS. This study illustrated the synergistic mechanism of adsorption and catalytic oxidation removal of TPhP by BC800@nZVI/PS system, and provided a cost-efficient approach for TPhP remediation.

Efficient removal of Tris(2-chloroethyl) phosphate by biochar derived from shrimp shell: Adsorption performance and mechanism study.

Tris(2-chloroethyl) phosphate (TCEP) has been detected all over the world as a typical refractory organic phosphate, especially in groundwater. This work applied a calcium-rich biochar derived from shrimp shell as a low-cost adsorbent for TCEP removal. Based on the kinetics and isotherm studies, the adsorption of TCEP on biochar was monolayer adsorbed on a uniform surface, with SS1000 (the biochar was prepared at the carbonization temperature of 1000 °C) achieving the maximum adsorption capacity of 264.11 mg·g-1. The prepared biochar demonstrated stable TCEP removal ability throughout a wide pH range, in the presence of co-existing anions, and in diverse water bodies. A rapid removal rate of TCEP was observed during the adsorption process. When the dosage of SS1000 was 0.2 g·L-1, 95% of TCEP could be removed within the first 30 min. The mechanism analysis indicated that the calcium species and basic functional groups on the SS1000 surface were highly involved in the TCEP adsorption process.

Asymmetric Alternative Current Electrochemical Method Coupled with Amidoxime-Functionalized Carbon Felt Electrode for Fast and Efficient Removal of Hexavalent Chromium from Wastewater.

A large amount of Cr (VI)-polluted wastewater produced in electroplating, dyeing and tanning industries seriously threatens water ecological security and human health. Due to the lack of high-performance electrodes and the coulomb repulsion between hexavalent chromium anion and cathode, the traditional DC-mediated electrochemical remediation technology possesses low Cr (VI) removal efficiency. Herein, by modifying commercial carbon felt (O-CF) with amidoxime groups, amidoxime-functionalized carbon felt electrodes (Ami-CF) with high adsorption affinity for Cr (VI) were prepared. Based on Ami-CF, an electrochemical flow-through system powered by asymmetric AC was constructed. The mechanism and influencing factors of efficient removal of Cr (VI) contaminated wastewater by an asymmetric AC electrochemical method coupling Ami-CF were studied. Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), and X-ray photoelectron spectroscopy (XPS) characterization results showed that Ami-CF was successfully and uniformly loaded with amidoxime functional groups, and the adsorption capacity of Cr (VI) was more than 100 times higher than that of O-CF. In particular, the Coulomb repulsion effect and the side reaction of electrolytic water splitting were inhibited by the high-frequency anode and cathode switching (asymmetric AC), the mass transfer rate of Cr (VI) from electrode solution was increased, the reduction efficiency of Cr (VI) to Cr (III) was significantly promoted and a highly efficient removal of Cr (VI) was achieved. Under optimal operating conditions (positive bias 1 V, negative bias 2.5 V, duty ratio 20%, frequency 400 Hz, solution pH = 2), the asymmetric AC electrochemistry based on Ami-CF can achieve fast (30 s) and efficient removal (>99.11%) for 0.5-100 mg·L-1 Cr (VI) with a high flux of 300 L h-1 m-2. At the same time, the durability test verified the sustainability of the AC electrochemical method. For Cr (VI)-polluted wastewater with an initial concentration of 50 mg·L-1, the effluent concentration could still reach drinking water grade (<0.05 mg·L-1) after 10 cycling experiments. This study provides an innovative approach for the rapid, green and efficient removal of Cr (VI) containing wastewater at low and medium concentrations.

Trends in elemental Pb concentrations within atmospheric PM2.5 and associated risk to human health in major cities of China.

High concentrations of elemental lead (Pb) in the atmosphere pose a serious threat to human health. This study presents and summarizes data obtained from relevant literature on Pb concentrations within fine particulate matter (PM2.5) recorded in major cities in China from 2008 to 2019. An environmental health risk assessment model was then used to evaluate the health hazards of inhaling Pb among adults and children in China. Owing to the promulgation and implementation of a series of air pollution control measures, the Pb concentrations within PM2.5 measured in major cities in China showed a downward trend after peaking in 2013. The concentrations were higher in winter than in summer, and higher in northern cities than in southern cities. Although the Pb concentrations in most cities did not exceed the limit (500 ng/m3) set by China, they remained much higher than concentrations recorded in developed countries. The results of the environmental health risk analysis showed that the non-carcinogenic risk from atmospheric Pb exposure was higher in children than in adults (adult females > adult males), while the carcinogenic risk was higher in adults than in children. This study shows that even if the health risk of Pb in PM2.5 does not exceed the acceptable limit, stricter Pb pollution control measures are required to safeguard population health due to the dangers of Pb.

Potential of crop straw incorporation for replacing chemical fertilizer and reducing nutrient loss in Sichuan Province, China.

Sichuan Province is rich in crop straw, yet little is known about its spatial distribution pattern, potential in replacing chemical fertilizer and mitigating nutrient loss. Based on the statistical data and literature review, the spatial distribution and potential of nutrient resources in crop straw for replacing chemical fertilizers was evaluated in this study. The nutrient loss with both crop incorporation and chemical fertilizer application were examined using a nutrient release coefficient method and compared. Results showed that Chengdu Plain, Northeast and South Sichuan produced more than 95% of the total straw nutrient resources during the period of 2016-2020. The potential of crop straw to substitute potassium (K), nitrogen (N) and phosphorus (P) fertilizer were K2O 33.08-285.95 kg hm-2, N 9.52-82.32 kg hm-2 and P2O5 4.91-28.71 kg hm-2, respectively. If chemical fertilizer was substituted by all the available straw nutrient resources, N and P loss can be decreased by 55.12% and 65.84% in average in Sichuan Province. 343.93 t of N loss and 20.05 t of P loss can be reduced in plain areas, 122.88 t of N loss and 46.29 t of P loss can be reduced in mountainous and hilly areas, and 5.65 t of t N loss and 3.54 t of P loss can be reduced in plateau areas. It can be concluded that there were rich crop straw nutrient resources in Sichuan Province with obvious spatial variability, solid consideration should be put on to the proper use of crop straw nutrient resources, with the aim of chemical fertilizer reduction, nutrient loss reduction and sustainable development.

One-Step Synthesized Iron-Carbon Core-Shell Nanoparticles to Activate Persulfate for Effective Degradation of Tetrabromobisphenol A: Performance and Activation Mechanism.

Tetrabromobisphenol A (TBBPA), as an emerging endocrine disrupter, has been considered one of the persistent organic contaminants in water. It is urgently necessary to develop an efficient technique for the effective removal of TBBPA from water. Herein, a one-step hydrothermal synthesis route was employed to prepare a novel iron-carbon core-shell nanoparticle (Fe@MC) for effectively activating persulfate (PS) to degrade TBBPA. Morphological and structural characterization indicated that the prepared Fe@MC had a typical core-shell structure composed of a 5 nm thick graphene-like carbon shell and a multi-valence iron core. It can be seen that 94.9% of TBBPA (10 mg/L) could be degraded within 30 min at pH = 7. This excellent catalytic activity was attributed to the synergistic effect of the porous carbon shell and a multi-valence iron core. The porous carbon shell could effectively prevent the leaching of metal ions and facilitate PS activation due to its electron transfer capability. Furthermore, numerous micro-reaction zones could be formed on the surface of Fe@MC during the rapid TBBPA removal process. Radical quenching experiments and electron paramagnetic resonance (EPR) technology indicated that reactive oxygen species (ROS), including OH, SO4-, O2-, and 1O2, were involved in the TBBPA degradation process. Based on density functional theory (DFT) calculation, the carbon atoms linked by phenolic hydroxyl groups would be more vulnerable to attack by electron-rich groups; the central carbon was cracked and hydroxylated to generate short-chain aliphatic acids. The toxicity evaluation provides clear evidence for the promising application potential of our prepared material for the efficient removal of TBBPA from water.

Emerging Plasticizers in South China House Dust and Hand Wipes: Calling for Potential Concern?

Following regulations on legacy plasticizers, a large variety of industrial chemicals have been employed as substitutes to manufacture consumer products. However, knowledge remains limited on their environmental distributions, fate, and human exposure risks. In the present work, we screened for a total of 34 emerging plasticizers in house dust from South China and matched hand wipes collected from volunteers (n = 49 pairs). The results revealed a frequent detection of 27 emerging plasticizers in house dust, with the total concentrations reaching a median level of 106 700 ng/g. Thirteen of them had never been investigated by any environmental studies prior to our work, which included glycerol monooleate (median: 61 600 ng/g), methyl oleate (16 400 ng/g), butyl oleate (411 ng/g), 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (341 ng/g), 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (105 ng/g), isopropyl myristate (154 ng/g), di(2-ethylhexyl) sebacate (69.1 ng/g), triisononyl trimellitate (64.4 ng/g), as well as a few others. Emerging plasticizers were also frequently detected in hand wipes, with a median total level of 4680 ng, indicating potential exposure via hand-to-mouth contact. Several chemicals, including acetyl tributyl citrate, tributyl citrate, di-n-butyl maleate, isopropyl myristate, and isopropyl palmitate, exhibited significant correlations between dust and hand wipe. However, other plasticizers did not follow this pattern, and the chemical compositional profiles differed between dust and hand wipe, suggesting chemical-specific sources and exposure pathways. Although the estimation of daily intake (EDI) indicated no substantial risks through dust ingestion or hand-to-mouth transfer of emerging plasticizers, continuous monitoring is needed to explore whether some of the important plasticizers are safe replacements or regrettable substitutions of the legacy ones.

Long-term exposure of zebrafish to bisphenol F: Adverse effects on parental reproduction and offspring neurodevelopment.

Bisphenol F (BPF), an alternative to bisphenol A (BPA) has potential endocrine and reproductive toxicity; however, the effects of environmental concentrations of BPF on the reproductive and developmental toxicity of offspring following parental exposure to BPF remain unclear. In the present study, the effects of life-cycle BPF exposure at environmental concentrations on zebrafish reproduction, offspring growth, and development were investigated. The results showed that the life-cycle of BPF exposure significantly elevated oxidative stress levels, increased gonadal apoptosis, and reduced zebrafish (F0) spawning. Notably, through maternal transfer, BPF exposure significantly affected offspring development. Developmental parameters such as hatching rate, spontaneous movements, heart rate, body length, and locomotor behavior decreased in zebrafish larvae (F1). In addition, the expression levels of genes related to oxidative stress, apoptosis, and neurodevelopment were altered in F1 larvae. Therefore, the present study provides evidence that BPF, even at environmental concentrations, can be potentially adverse in terms of reproductive defects and offspring neurodevelopmental disorders. Therefore, BPF, as a substitute for BPA, is worthy of in-depth evaluation.

Size-dependent enhancement on conjugative transfer of antibiotic resistance genes by micro/nanoplastics.

Recently micro/nanoplastics (MNPs) have raised intensive concerns due to their possible enhancement effect on the dissemination of antibiotic genes. Unfortunately, data is still lacking to verify the effect. In the study, the influence of polystyrene MNPs on the conjugative gene transfer was studied by using E. coli DH5ɑ with RP4 plasmid as the donor bacteria and E. coli K12 MG1655 as the recipient bacteria. We found that influence of MNPs on gene transfer was size-dependent. Small MNPs (10 nm in radius) caused an increase and then a decrease in gene transfer efficiency with their concentration increasing. Moderate-sized MNPs (50 nm in radius) caused an increase in gene transfer efficiency. Large MNPs (500 nm in radius) had almost no influence on gene transfer. The gene transfer could be further enhanced by optimizing mating time and mating ratio. Scavenging reactive oxygen species (ROS) production did not affect the cell membrane permeability, indicating that the increase in cell membrane permeability was not related to ROS production. The mechanism of the enhanced gene transfer efficiency was attributed to a combined effect of the increased ROS production and the increased cell membrane permeability, which ultimately regulated the expression of corresponding genes.

Exploring antibiotic consumption between urban and sub-urban catchments using both parent drugs and related metabolites in wastewater-based epidemiology.

Consumption of antibiotics leads to the dissemination of antimicrobial resistance worldwide. Better knowledge of temporal and spatial consumption of antibiotics helps public health authorities to control their usage and combat antimicrobial resistance. However, measuring antibiotic consumption with population surveys, sales data, and production statistics remains challenging due to the complexity of prescription preference, patient compliance, and direct disposal of unused drugs. With the approach of wastewater-based epidemiology (WBE), this study aims to evaluate the consumption of eight commonly-used antibiotics between developed urban and developing sub-urban catchments in China and to characterise the ratios of parent drugs to metabolites in studying the consumption. Seven parent antibiotics were detected in all the wastewater samples (n = 56), whereas some metabolites were detected sporadically. The ratios of parent chemicals to metabolites varied among locations and were often higher than the ratios in pharmacokinetic studies. Estimated consumption of antibiotics ranged from 3.2 ± 2.0 mg/day/1000 inhabitants for trimethoprim to 28,400 ± 7800 mg/day/1000 inhabitants for roxithromycin in the studied catchments. Higher consumption of sulfapyridine, sulfadiazine and roxithromycin was observed in urban than suburban catchments, while consumption of sulfamethoxazole, norfloxacin, and trimethoprim was higher in suburban than in urban catchments. Using the literature data, we found more than 95% reduction of antibiotic use in an urban catchment. Our study revealed the geographical pattern in antibiotic use across different urban and suburban catchments via WBE, and the potential of monitoring parent-to-metabolite ratios for WBE in estimating antibiotic use. These results provide a basis for health authorities to plan different drug-specific control policies between urban and suburban catchments, and for future WBE studies to be aware of other sources, such as animal husbandry and disposals of unused drugs, that can influence the estimated consumption.

Interaction of tetrabromobisphenol A (TBBPA) with microplastics-sediment (MPs-S) complexes: A comparison between binary and simple systems.

The presence of microplastics (MPs) and the associated organic pollutants in the aquatic environment has attracted growing concern in recent years. MPs could compete with chemicals for adsorption sites on the surface of sediment, affecting the sorption processes of pollutants on sediment. However, few studies focused on the binary system of microplastics-sediment (MPs-S), which appear much common in aquatic environment. Herein, we investigated the interactions between a continuously used flame retardant tetrabromobisphenol A (TBBPA) and four MPs-S complexes (PVC-S, PE-S, PP-S and PS-S). The equilibrium adsorption capacities were 17.1, 15.6, 15.4, and 14.0 mg/kg for PVC-S, PS-S, PE-S, and PP-S, respectively. Kinetics suggest that adsorption behavior of TBBPA was fitted by pseudo-second-order model. Co-adsorption of TBBPA in binary systems were much lower than the sum of each simple system, which may be due to the mutually occupied adsorption sites. Higher ionic strength and lower dissolved organic matter strengthened the sorption of TBBPA onto MPs-S complexes. The enhanced sorption capacities for TBBPA were observed with elevated proportion and small particle size of MPs in the MPs-S complexes. This study contributes to the knowledge on the impact of MPs in partitioning of organic pollutants in-between solid and aqueous phases in the aquatic environment.

A Prospective Study of Early-pregnancy Thyroid Markers, Lipid Species, and Risk of Gestational Diabetes Mellitus.

CONTEXT: While the associations between thyroid markers and gestational diabetes mellitus (GDM) have been extensively studied, the results are inconclusive and the mechanisms remain unclear. OBJECTIVE: We aimed to investigate the prospective associations of thyroid markers in early gestation with GDM risk, and examine the mediating effects through lipid species. METHODS: This study included 6068 pregnant women from the Tongji-Shuangliu Birth Cohort. Maternal serum thyroid markers (free triiodothyronine (fT3), free thyroxine (fT4), thyroid-stimulating hormone, thyroid peroxidase antibody, and thyroglobulin antibody) were measured before 15 weeks. Deiodinase activity was assessed by fT3/fT4 ratio. Plasma lipidome were quantified in a subset of 883 participants. RESULTS: Mean age of the participants was 26.6 ± 3.7 years, and mean gestational age was 10.3 ± 2.0 weeks. Higher levels of fT4 were associated with a decreased risk of GDM (OR = 0.73 comparing the extreme quartiles; 95% CI 0.54, 0.98, Ptrend = .043), while higher fT3/fT4 ratio was associated with an increased risk of GDM (OR = 1.43 comparing the extreme quartiles; 95% CI 1.06, 1.93, Ptrend = .010) after adjusting for potential confounders. Multiple linear regression suggested that fT3/fT4 ratio was positively associated with alkylphosphatidylcholine 36:1, phosphatidylethanolamine plasmalogen 38:6, diacylglyceride 18:0/18:1, sphingomyelin 34:1, and phosphatidylcholine 40:7 (false discovery rate [FDR] adjusted P < .05). Mediation analysis indicated 67.9% of the association between fT3/fT4 ratio and GDM might be mediated through the composite effect of these lipids. CONCLUSION: Lower concentration of serum fT4 or higher fT3/fT4 ratio in early pregnancy was associated with an increased risk of GDM. The association of fT3/fT4 ratio with GDM was largely mediated by specific lipid species.