The combined toxicity of polystyrene nano/micro-plastics and triphenyl phosphate (TPHP) on HepG2 cells.

Combined toxicity is a critical concern during the risk assessment of environmental pollutants. Due to the characteristics of strong hydrophobicity and large specific surface area, microplastics (MPs) and nanoplastics (NPs) have become potential carriers of organic pollutants that may pose a health risk to humans. The co-occurrence of organic pollutants and MPs would cause adverse effects on aquatic organism, while the information about combined toxicity induced by organophosphorus flame retardants and MPs on human cells was limited. This study aimed to reveal the toxicity effects of co-exposure to triphenyl phosphate (TPHP) and polystyrene (PS) particles with micron-size/nano-size on HepG2 cell line. The adsorption behaviors of TPHP on PS particles was observed, with the PS-NP exhibiting a higher adsorption capacity. The reactive oxygen species generation, mitochondrial membrane potential depolarization, lactate dehydrogenase release and cell apoptosis proved that PS-NPs/MPs exacerbated TPHP-induced cytotoxicity. The particle size of PS would affect the toxicity to HepG2 cells that PS-NP (0.07 µm) exhibited more pronounced combined toxicity than PS-MP (1 µm) with equivalent concentrations of TPHP. This study provides fundamental insights into the co-toxicity of TPHP and PS micro/nanoplastics in HepG2 cells, which is crucial for validating the potential risk of combined toxicity in humans.

Biodegradation pathway and mechanism of tri (2-chloropropyl) phosphate by Providencia rettgeri.

Tri (2-chloropropyl) phosphate (TCPP) was an emerging contaminant of global concern because of its frequent occurrence, potential toxic effects, and persistence in the environment. Microbial degradation might be an efficient and safe removal method, but limited information was available. In this study, Providencia rettgeri was isolated from contaminated sediment and showed it could use TCPP as unique phosphorus source to promote growth, and decompose 34.7% of TCPP (1 mg/L) within 5 days. The microbial inoculation and the initial concentration of TCPP could affect the biodegradation efficient. Further study results indicated that TCPP decomposition by Providencia rettgeri was mainly via phosphoester bond hydrolysis, evidenced by the production of bis (2-chloropropyl) phosphate (C6H13Cl2PO4) and mono-chloropropyl phosphate (C3H8ClPO4). Both intracellular and extracellular enzymes could degrade TCPP, but intracellular degradation was dominant in the later reaction stage, and the presence of Cu2+ ions had a promoting effect. These findings developed novel insights into the potential mechanism of TCPP microbial degradation.

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

Exploring the molecular mechanism of Chlorella vulgaris in response to androstenedione exposure based on genes continuously up-regulated in transcription analysis.

Androstenedione (ADSD) is one of the widely detected androgens in diverse aquatic environments. However, there were few reports on the molecular mechanism of Chlorella vulgaris exposure to ADSD. In our previous research, we have investigated the genes associated with chlorophyll metabolism in Chlorella vulgaris response to ADSD. In this study, we focus on continuously up-regulated genes to explore the mechanism underlying Chlorella vulgaris resistance to ADSD toxicity. Chlorella vulgaris was exposed to ADSD with five concentration gradients. The continuously up-regulated genes were enriched by Series Test of Cluster (STC) analysis and verified by qRT-PCR. Microalgae Super Oxidase Dimutase (SOD) and Microalgae Malonic dialdehyde (MDA), two indicators of oxidative stress, were determined by ELISA after exposure to ADSD. The results showed that ADSD can stimulate the production of extracellular polymeric substances (EPS) and lead to enlargement in the cell body of Chlorella vulgaris. In addition, steroid biosynthesis and oxidoreductase activity processes were consistently up-regulated upon exposure to ADSD. In conclusion, our study highlighted the crucial role of phenotypic modification, hormone synthesis, and redox mechanisms in protecting Chlorella vulgaris cells from the harmful effects of ADSD contamination.

Granulocyte Colony-Stimulating Factor Improves Endothelial Progenitor Cell-Mediated Neovascularization in Mice with Chronic Kidney Disease.

Patients with chronic kidney disease (CKD) have a higher prevalence of peripheral arterial disease (PAD), and endothelial progenitor cells (EPCs) play a pivotal role. We examined the impact of granulocyte colony-stimulating factor (G-CSF) on EPC function in response to tissue ischemia. Eight-week-old male C57BL/6J male mice were divided into sham operation and subtotal nephrectomy (SNx) groups, received hindlimb ischemic operation after seven weeks, then randomly received G-CSF or PBS intervention for four weeks with weekly follow-ups. SNx mice had significantly reduced limb reperfusion, decreased plasma EPC mobilization, and impaired angiogenesis in ischemic hindlimbs compared to the control group. However, G-CSF increased IL-10 and reversed these adverse changes. Additionally, ischemia-associated protein expressions, including IL-10, phospho-STAT3, VEGF, and phospho-eNOS, were significantly downregulated in the ischemic hindlimbs of SNx mice versus control, but these trends were reversed by G-CSF. Furthermore, in cultured EPCs, G-CSF significantly attenuated the decrease in EPC function initiated by indoxyl sulfate through IL-10. Overall, we discovered that G-CSF can improve EPC angiogenic function through a hypoxia/IL-10 signaling cascade and impede neovascular growth in response to ischemia of SNx mice. Our results highlight G-CSF's potential to restore angiogenesis in CKD patients with PAD via EPC-based methods.

Using artificial intelligence algorithms to predict the overall survival of hemodialysis patients during the COVID-19 pandemic: A prospective cohort study.

BACKGROUND: Hemodialysis (HD) patients are a vulnerable population at high risk for severe complications from COVID-19. The impact of partial COVID-19 vaccination on the survival of HD patients remains uncertain. This prospective cohort study was designed to use artificial intelligence algorithms to predict the survival impact of partial COVID-19 vaccination in HD patients. METHODS: A cohort of 433 HD patients was used to develop machine-learning models based on a subset of clinical features assessed between July 1, 2021, and April 29, 2022. The patient cohort was randomly split into training (80%) and testing (20%) sets for model development and evaluation. Machine-learning models, including categorical boosting (CatBoost), light gradient boosting machines (LightGBM), RandomForest, and extreme gradient boosting models (XGBoost), were applied to evaluate their discriminative performance using the patient cohorts. RESULTS: Among these models, LightGBM achieved the highest F1 score of 0.95, followed by CatBoost, RandomForest, and XGBoost, with area under the receiver operating characteristic curve values of 0.94 on the testing dataset. The SHapley Additive explanation summary plot derived from the XGBoost model indicated that key features such as age, albumin, and vaccination details had a significant impact on survival. Furthermore, the fully vaccinated group exhibited higher levels of anti-spike (S) receptor-binding domain antibodies. CONCLUSION: This prospective cohort study involved using artificial intelligence algorithms to predict overall survival in HD patients during the COVID-19 pandemic. These predictive models assisted in identifying high-risk individuals and guiding vaccination strategies for HD patients, ultimately improving overall prognosis. Further research is warranted to validate and refine these predictive models in larger and more diverse populations of HD patients.

Insights into electrochemical oxidation of tris(2-butoxyethyl) phosphate (TBOEP) in aquatic media: Degradation performance, mechanisms and toxicity changes of intermediate products.

Tris (2-butoxyethyl) phosphate (TBOEP) has gained significant attention due to its widespread presence and potential toxicity in the environment. In this study, the degradation of TBOEP in aquatic media was investigated using electrochemical oxidation technology. The anode Ti/SnO2-Sb/La-PbO2 demonstrated effective degradation performance, with a reaction constant (k) of 0.6927 min-1 and energy consumption of 1.24 kW h/m3 at 10 mA/cm2. CV tests, EPR tests, and quenching experiments confirmed that indirect degradation is the main degradation mechanism and ·OH radicals were the predominant reactive species, accounting for up to 93.8%. The presence of various factors, including Cl-, NO3-, HCO3- and humic acid (HA), inhibited the degradation of TBOEP, with the inhibitory effect dependent on the concentrations. A total of 13 intermediates were identified using UPLC-Orbitrap-MS/MS, and subsequent reactions led to their further degradation. Two main degradation pathways involving bond breaking, hydroxylation, and oxidation were proposed. Both Flow cytometry and the ECOSAR predictive model indicated that the intermediates exhibited lower toxic than the parent compound, resulting in a high detoxification rate of 95.9% for TBOEP. Although the impact of TBOEP on the phylum-level microbial community composition was found to be insignificant, substantial alterations in bacterial abundance were noted when examining the genus level. The dominant genus Methylotenera, representing 17.4% in the control group, decreased to 6.9% in the presence of TBOEP and slightly increased to 8.7% in the 4-min exposure group of degradation products. Electrochemical oxidation demonstrated its effectiveness for the degradation and detoxification of TBOEP in aqueous solutions, while it is essential to consider the potential impact of degradation products on sediment microbial communities.

Metagenomic insights into the mechanisms of triphenyl phosphate degradation by bioaugmentation with Sphingopyxis sp. GY.

Biodegradation of triphenyl phosphate (TPHP) by Sphingopyxis sp. GY was investigated, and results demonstrated that TPHP could be completely degraded in 36 h with intracellular enzymes playing a leading role. This study, for the first time, systematically explores the effects of the typical brominated flame retardants, organophosphorus flame retardants, and heavy metals on TPHP degradation. Our findings reveal that TCPs, BDE-47, HBCD, Cd and Cu exhibit inhibitory effects on TPHP degradation. The hydrolysis-, hydroxylated-, monoglucosylated-, methylated products and glutathione (GSH) conjugated derivative were identified and new degradation pathway of TPHP mediated by microorganism was proposed. Moreover, toxicity evaluation experiments indicate a significant reduction in toxicity following treatment with Sphingopyxis sp. GY. To evaluate its potential for environmental remediation, we conducted bioaugmentation experiments using Sphingopyxis sp. GY in a TPHP contaminated water-sediment system, which resulted in excellent remediation efficacy. Twelve intermediate products were detected in the water-sediment system, including the observation of the glutathione (GSH) conjugated derivative, monoglucosylated product, (OH)2-DPHP and CH3-O-DPHP for the first time in microorganism-mediated TPHP transformation. We further identify the active microbial members involved in TPHP degradation within the water-sediment system using metagenomic analysis. Notably, most of these members were found to possess genes related to TPHP degradation. These findings highlight the significant reduction of TPHP achieved through beneficial interactions and cooperation established between the introduced Sphingopyxis sp. GY and the indigenous microbial populations stimulated by the introduced bacteria. Thus, our study provides valuable insights into the mechanisms, co-existed pollutants, transformation pathways, and remediation potential associated with TPHP biodegradation, paving the way for future research and applications in environmental remediation strategies.

Assessments of the effects of tris(1,3-dichloro-2-propyl) phosphate (TDCPP) on human intestinal health from the aspects of intestinal flora changes and cytotoxicity to human cells.

Organophosphorus flame retardants (OPFRs) are now drawing the public's attention due to their potential toxicity. Given that contaminated food may result in the ingestion of OPFRs to the human intestine, further investigation is required to determine the potential adverse effects of these compounds on human intestinal health. The present study aimed to comprehensively assess the effect of tris(1,3-dichloro-2-propyl) phosphate (TDCPP), a typical OPFR, on human intestinal health by evaluating both intestinal flora and human cell Caco-2. Based on the results, TDCPP exposure altered the composition of intestinal flora and increased the proportion of pathogenic bacteria. PICRUSt2 analysis revealed that certain pathways were affected by TDCPP, and the resulting metabolic disorders might cause health problems. Orthologous genes of glutathione S-transferase and multidrug efflux system were up-regulated, demonstrating that the bacteria resisted TDCPP to maintain their vitality. Compared to the other two OPFRs, TDCPP induced greater cytotoxicity, and the results were consistent with the dose-effect relationship. Three OPFRs, especially TDCPP, caused the release of lactate dehydrogenase, accumulation of ROS, decline in mitochondrial membrane potential and increase in intracellular Ca2+, which could consequently induce cell death. The simultaneous effects of TDCPP on both intestinal cells and intestinal flora are likely to engender more severe intestinal health issues.

Dermoscopic Image Classification Method Using an Ensemble of Fine-Tuned Convolutional Neural Networks.

Aiming at the problems of large intra-class differences, small inter-class differences, low contrast, and small and unbalanced datasets in dermoscopic images, this paper proposes a dermoscopic image classification method based on an ensemble of fine-tuned convolutional neural networks. By reconstructing the fully connected layers of the three pretrained models of Xception, ResNet50, and Vgg-16 and then performing transfer learning and fine-tuning the three pretrained models with the ISIC 2016 Challenge official skin dataset, we integrated the outputs of the three base models using a weighted fusion ensemble strategy in order to obtain a final prediction result able to distinguish whether a dermoscopic image indicates malignancy. The experimental results show that the accuracy of the ensemble model is 86.91%, the precision is 85.67%, the recall is 84.03%, and the F1-score is 84.84%, with these four evaluation metrics being better than those of the three basic models and better than some classical methods, proving the effectiveness and feasibility of the proposed method.

Urinary concentrations of bisphenol analogues in the south of China population and their contribution to the per capital mass loads in wastewater.

Bisphenol analogues (BPs) are heavily used and negatively affect the health of human beings, however, there is little knowledge regarding human exposure to BPs other than BPA. This study aims to assess human exposure to BPs through investigating pooled urine and wastewater samples. Twenty-four pooled urine samples were prepared from 960 specimens (classified by age and gender). Wastewater samples were collected from six major wastewater treatment plants (WWTPs) in Guangzhou, South of China. BPA, BPS, and BPAF were widely detected in urine samples, with a median concentration of 0.96, 0.42, and 0.15 µg/L, respectively. Median urinary levels of BPA and BPS were higher in males than females (p > 0.05). In addition, BPA and BPS urinary levels in young adults (15-30 years old) were greater than those in children (0-15 years old) (p > 0.05). Nevertheless, most of the BPs were detected in wastewater samples, of which BPA and BPS were predominant BPs, with a median concentration of 1.0 and 0.29 µg/L. The average per capital mass loads of ΣBPs on the weekdays of mix typed WWTP was much higher than those of the weekends. Nonetheless, the average loads of ΣBPs on the weekdays of domestic WWTP was slightly lower than those of the weekends. This indicated that important sources of BPs might include industrial wastewater and household cleaning products. Urinary BPA, BPS, and BPAF accounted for less than 5% per capital mass loads in wastewater, suggesting that much of the BPA, BPS, and BPAF in municipal wastewater originate non-human excretion. Hence, the wastewater-based epidemiology (WBE) approach based on parent compounds is not available for assessing human exposure to BPs, neither for other industrial chemicals with diverse sources in municipal wastewater. These results contributes to the development of an efficient surveillance system which can provide insight in the trends of human exposure of BPs.

Simultaneous adsorption of Cd2+ and photocatalytic degradation of tris-(2-chloroisopropyl) phosphate (TCPP) by mesoporous TiO2.

In this work, the prepared mesoporous TiO2 was employed to eliminate the environmental risk induced by the combined pollution (tris-(2-chloroisopropyl) phosphate (TCPP) and Cd2+). The prepared material was characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-DRS), Raman imaging spectrometer (Raman), N2 adsorption/desorption isotherm and X-ray photoelectron spectroscopy (XPS). In the combined pollution system, the prepared TiO2 simultaneously exhibited a higher adsorption and photocatalytic activity for Cd2+ and TCPP at neutral condition, respectively. The adsorption of Cd2+ and photo-degradation of TCPP by mesoporous TiO2 followed pseudo-second-order and pseudo-first-order kinetics model, respectively. The removal efficiency of TCPP was improved from 67% to 100% when the concentration of co-existed Cd2+ increased from 0.5 mg L-1 to 2 mg L-1, due to the fact that the adsorbed Cd2+ on the surface of TiO2 scavenged electron and thus inhibited the photo-generated electron-hole pairs recombination. In addition, six degradation intermediates were determined by high resolution mass spectrum (HRMS) and potential transformation pathways of TCPP under the co-existence of Cd2+ were proposed. The results suggested that rapid and high-efficient simultaneous removal of Cd2+ and TCPP was feasible, which laid the basis for the remediation of other combined pollution in the future.

Transcriptome profiling of Pseudomonas aeruginosa YH reveals mechanisms of 2, 2', 4, 4'-tetrabrominated diphenyl ether tolerance and biotransformation.

Aerobic degradation of 2, 2', 4, 4'-tetrabrominated diphenyl ether (BDE-47) by Pseudomonas aeruginosa YH (P. aeruginosa YH) were investigated in this study. BDE-47 degradation was mainly through the biological action of intracellular enzymes, and the metabolites included debrominated metabolites (BDE-28 and BDE-7), hydroxylated metabolites (6-OH-BDE-47, 5-OH-BDE-47, 2'-OH-BDE-28 and 4'-OH-BDE-17), and brominated phenols (2,4-DBP and 4-BP). P. aeruginosa YH also exhibited exceptional ability to degrade intermediates, and the degradation rates of 50 µg/L BDE-28, BDE-7, and 2,4-DBP were 68.4%, 82.3% and 92.7% on the 5th day, separately. Transcriptome sequencing revealed that 991 genes were up-regulated, and 923 genes were down-regulated in P. aeruginosa YH after exposure to 0.5 mg/L BDE-47 (FDR ≤ 0.001, |log2Ratio| ≥ 1). The differentially expressed genes were related to transport, metabolism and stress response. Harf inhibitory concentration (IC50) of BDE-47 decreased from 167.5 mg/L to 68.4 mg/L when multidrug efflux pump was inactivated by 20 mg/L andrographolide, indicating that it helped the bacterial tolerance against BDE-47. Moreover, efflux pump inhibition would accelerate the adsorption of BDE-47. The adsorption rate obtained equilibrium at approximately 70% in 2 days, while 5 days in the control group. Degradation efficiency of 2 mg/L BDE-47 decreased from 26.8% to 13.9% when multidrug efflux was suppressed.

In vitro biotransformation and evaluation of potential transformation products of chlorinated paraffins by high resolution accurate mass spectrometry.

Chlorinated paraffins (CPs) are high production chemicals, which leads to their ubiquitous presence in the environment. To date, few studies have measured CPs in humans and typically at relatively low concentrations, despite indications that exposure may be high compared to various persistent organic pollutants. The aim of this study is to investigate the in vitro biotransformation of CPs by human liver fractions. We determined the changes of the CP concentrations after the enzymatic transformation with human liver microsomes using a two-tiered in vitro approach. CP concentrations decreased with human liver microsomes, with the decreases of 33-94% after incubating with different groups of enzymes for 2 h. The profiles of CP rapidly shifted after the incubation with human liver microsomes. In addition, the concentrations of CPs and the biotransformation products were tentatively measured using high-resolution mass spectrometric analysis, including very short CP (carbon chain length <10), alcohols, ketones, and carboxylic acids. C‒C bond cleavage is a potential transformation pathway for CPs, and ketones are potential products of CP biotransformation, especially for long-chain CPs (C>17). The ketone products may be investigated as CP exposure biomarker in biomonitoring studies.

Insights into the electrochemical degradation of triclosan from human urine: Kinetics, mechanism and toxicity.

Electrochemical degradation of triclosan in human urine was firstly studied by using Ti/SnO2-Sb/PbO2 anode doped with rare-earth elements. The results indicated that the Ti/SnO2-Sb/Gd-PbO2 anode demonstrated the best performance with the degradation rate constants being 0.095 min-1 in fresh urine and 0.045 min-1 in hydrolyzed urine at a current density of 10 mA cm-2. The electrochemical degradation was improved in the presence of phosphate and chloride, while the degradation was obviously inhibited by urea, bicarbonate and ammonia. Degradation mechanism mainly involved ether-bond cleavage, hydroxylation, cyclization, dehydrogenation and carboxylation. Quantitative structure-activity relationship model showed that ecological risks of cyclization products to fish, daphnid and green algae was higher than the parent compound, implying that the potential risks to aquatic organism should not be ignored before triclosan mineralized completely. Energy consumption for 90% triclosan degradation ranged from 4.5 to 47.8 Wh L-1, and the consumption increased along with the hydrolysis of urine. The results indicate that electrochemical oxidation is a feasible and energy-saving technique to effectively remove triclosan from human urine.

Urinary Concentrations of Bisphenols in the Australian Population and Their Association with the Per Capita Mass Loads in Wastewater.

Health concerns and related regulation of bisphenol A (BPA) in some countries have led to an increase in the production and use of unregulated and poorly understood BPA analogues, including bisphenol S (BPS), bisphenol F (BPF), bisphenol B (BPB), and bisphenol AF (BPAF). To assess the temporal trends of human exposure to BPA analogues, urine and wastewater samples were collected from South East Queensland, Australia between 2012 and 2017 and analyzed for five bisphenols using validated isotope dilution liquid chromatography tandem mass spectrometry methods. BPA and BPS were the predominant bisphenols detected in both urine and wastewater samples, with median concentrations of 2.5 and 0.64 µg/L in urine and 0.94 and 1.1 µg/L in wastewater, respectively. BPB, BPF, and BPAF had low detection frequencies in both urine and wastewater samples. Concentrations of BPA in both urine and wastewater decreased over the sampling period, whereas concentrations of BPS increased, suggesting that BPS has become a BPA replacement. The contributions of urinary excretion to wastewater were calculated by the ratio of daily per capita urinary excretion to wastewater-based mass loads of bisphenols. Urinary BPA and BPS contributed to less than 1% of the load found in wastewater, indicating that much of the BPA and BPS originates from other sources.

Removal of sulfamethazine and Cu2+ by Sakaguchia cladiensis A5: Performance and transcriptome analysis.

To reduce the potential risks of contamination of antibiotics and heavy metals to ecological environment and human safety, biological removal of these composite pollutants is the focus of much study. One previously identified isolate, Sakaguchia cladiensis A5, was used to decompose sulfamethazine (SMZ) and adsorb Cu2+. The ability of A5 to remove SMZ was enhanced by pre-induced culture, which reached 49.8% on day 9. The removal of SMZ could be also increased to 37.6% on day 3 in the presence of Cu2+, but only to 12.2% in the system without Cu2+. The biosorption of Cu2+ mainly occurred on the cell walls, while the biodegradation of SMZ was inside the cells. By comparative transcriptome analysis for A5, 1270 and 2220 differentially expressed genes (DEGs) were identified after treating single SMZ and SMZ/Cu2+, respectively. The Gene expression pattern analysis suggested a suppression of transcriptional changes in A5 responding to SMZ/Cu2+ as compared to under the sole stress of SMZ. The DEGs functional enrichment analysis suggested that the antioxidant and sulfate assimilation pathways played a key role on SMZ biodegradation and Cu2+ biosorption. The DEGs of proteins CAT, PRDX5, SAT, and CYSC were up-regulated to facilitate the resistance of A5 against oxidative toxicity of Cu2+. Moreover, the protein MET30 activated by Cu2+ was also overexpressed to promote the transmembrane transport of SMZ, such that A5 could decompose SMZ more effectively in SMZ/Cu2+ system. The results of this study would provide new insights into the mechanism of biodegradation and biosorption of SMZ/Cu2+.

Concentrations of phthalate metabolites in Australian urine samples and their contribution to the per capita loads in wastewater.

Exposure to phthalates is a public health concern. In this study, we collected both urine and wastewater samples from 2012 to 2017 and analysed for 14 phthalate metabolites to assess human exposure to phthalates in Southeast Queensland (SEQ), and for associations between phthalate metabolites in urine and wastewater samples. Twenty-four pooled urine samples were prepared from 2400 individual specimens every two years (stratified by age, gender and collection year). Wastewater samples were collected from the three major wastewater treatment plants (WWTPs) representing locations in the SEQ region including a regional city, part of the state capital city and a third major urban WWTP in the region. Over the period, decreases for most phthalate metabolites, i.e. mono-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), monobenzyl phthalate (MBzP), monocyclohexyl phthalate (MCHP), mono(3-carboxypropyl) phthalate (MCPP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), and monomethyl phthalate (MMP), but an increase in monoethyl phthalate (MEP, particularly in young children) were observed in urine. In general, temporal changes were smaller in urine pools representing older age groups. We also found substantial variation in per capita mass loads of phthalate metabolites between samples from the three WWTPs with generally higher concentrations of most phthalates in the metropolitan areas. Per capita mass loads of most phthalate metabolites in wastewater were higher than would be expected from the per-capita excretion in urine, suggesting there are additional sources contributing to the majority of the observed phthalate metabolites in wastewater. For MEHHP and MEOHP we estimate that the urinary excretion accounts for a substantial fraction (average about 50%) of the mass load observed in the wastewater hence wastewater data may provide useful for monitoring trends in exposure.

Insights into the degradation and detoxication mechanisms of aqueous capecitabine in electrochemical oxidation process.

Electrocatalytic oxidation and detoxication of capecitabine (CAP) in aqueous solution were investigated with Ti/SnO2-Sb/Ce-PbO2 anode. The relative contributions of generated free radicals showed an increase in the pseudo zero order tare constants in the following order: OH (9.4%) < SO4- (24.2%) < O2- (53.3%). The operating parameters and solution matrixes, i.e. applied current densities, initial CAP concentrations, initial Cl- and NO3- concentrations, influencing the CAP degradation efficiency were evaluated. The kinetic rate constant of 0.1404 min-1 was found within 7 min at current density of 10 mA cm-2 and initial CAP concentration of 20 mg L-1, while the mineralization efficiency of 59.5%, mineralization current efficiency of 2.06%, detoxication rate to Escherichia coli of 55.5% were achieved at reaction time 90 min. The major degradation pathways of CAP were oxidation, defluorination and bond cleavage, following with the formation of carboxylic acids, NO3-, NO2-, NH4+ and F-. Electrochemical oxidation process based on Ti/SnO2-Sb/Ce-PbO2 anode is proved to be effective for elimination, mineralization and detoxication of aqueous CAP.

Effects of benzo [a] pyrene (BaP) on the composting and microbial community of sewage sludge.

Benzo [a] pyrene (BaP), the most ubiquitous polycyclic aromatic hydrocarbons (PAHs) found in sludge, can impact the composting processes of sewage sludge as well as the quality of compost produced. In the present study, we investigated the effects of BaP at various concentrations on physicochemical characteristics, heavy metal passivation, and microbial community during the composting processes. The removal efficiency of BaP at 5 and 20 mg kg-1 after composting was 51.1% and 74.2%, respectively. In comparison with the control, the content of residual Cu, Pb, Cr and Ni in 5 mg kg-1 BaP contained system declined dramatically on the second day of composting, while such content in 20 mg kg-1 BaP system significantly decreased on the 8th day. Regardless of the presence of BaP in the sludge, composting process had a positive passivation effect on Cu, Pb, Cr and Ni. A stronger inhibitory effect of BaP at higher concentration was observed on microorganism, which reduced microbial abundance and species in the composting, and influenced microbial diversity. Besides, microbial communities in BaP-containing composting would improve the transformation of silicates and minerals, increase the concentration of humus and extend the passivation time of heavy metals. As these results verified, composting process could remove BaP from the sludge effectively, and BaP had a significant impact on heavy metal passivation and abundance and composition of microbial community during the composting process.