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BACKGROUND: Heavy metals have been reported to affect liver function. However, there is currently little and inconsistent knowledge about the effects of combined and individual urinary metals on specific parameters of liver function in the general population. Therefore, this study aimed to investigate their associations. METHODS: This study involved 807 general population from the China National Human Biomonitoring of Zhejiang Province 2017-2018. Concentrations of urinary metals, including Chromium (Cr), Cobalt (Co), Nickle (Ni), Arsenic (As), Selenium (Se), Molybdenum (Mo), Cadmium (Cd), Thallium (Tl) and Lead (Pb) were measured. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein (TP), albumin (ALB), direct bilirubin (DBIL), total bilirubin (TBIL) as liver function biomarkers. Multivariable linear regression and weighted quantile sum (WQS) regression were employed to explore the associations of urinary metals with liver function biomarkers. Subgroup analysis stratified by gender and age, excluding smokers and drinkers for sensitivity analysis. RESULTS: Both statistical models indicated that urinary metals were positively associated with ALT and AST, while negatively with TP, ALB, DBIL and TBIL. In the WQS analysis, each quartile increase in the ln-transformed levels of metal mixtures was associated with 4.11 IU/L (95% CI: 1.07, 7.15) higher ALT and 3.00 IU/L (95% CI: 1.75, 4.25) higher AST, as well as, with 0.67 g/L (95% CI: 1.24, -0.11) lower TP, 0.74 g/L (95% CI: 1.09, -0.39) lower ALB, 0.38 µmol/L (95% CI: 0.67, -0.09) lower DBIL, and 1.56 µmol/L (95% CI: 2.22, -0.90) lower TBIL. The association between urinary metals and ALT was primarily driven by Cd (55.8%), Cr contributed the most to the association with AST (20.2%) and TBIL (45.2%), while the association with TP was primarily driven by Ni (38.2%), the association with ALB was primarily driven by As (32.8%), and the association with DBIL was primarily driven by Pb (30.9%). The associations between urinary metals and liver function might differ by sex and age. CONCLUSION: Urinary metals were significantly associated with liver function parameters. Further studies are required to clarify the relationship between heavy metals and liver function.
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The long-term impacts of MnO2 on performance, sludge characteristics and microbial community of biogranule-based anaerobic ammonium oxidation (anammox) process were evaluated in an up-flow anaerobic sludge blanket reactor. It was found that the total nitrogen removal efficiency of reactor was fluctuated between 90%-93% at 1-200mgL-1 MnO2. Notably, the specific anammox activity was increased to maximum value of 657.3±10.6mgTNg-1VSSd-1 at 50mgL-1 MnO2 and then slightly decreased, but still higher than that achieved at 0-15mgL-1 MnO2, which had similar variation trends to the content of heme c and extracellular polymeric substances in anammox granules. High throughput sequencing indicated that MnO2 could improve the microbial richness and diversity of anammox granules and Candidatus Kuenenia was always the dominant species, and its abundance continued to increase to 21.3% at the end of operational experiment. Therefore, MnO2 could be applied to enhance the anammox process and the optimal influent MnO2 concentration was lower than 50mgL-1 in view of the reactor performance and cost issues.
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The stability and resilience of an anaerobic ammonium oxidation (anammox) system under transient nanoscale Zero-Valent Iron (nZVI) (50, 75 and 100â¯mgâ¯L-1), hydraulic shock (2-fold increase in flow rate) and their combination were studied in an up-flow anaerobic sludge blanket reactor. The response to the shock loads can be divided into three phases i.e. shock, inertial and recovery periods. The effects of the shock loads were directly proportional to the shock intensity. The effluent quality was gradually deteriorated after exposure to high nZVI level (100â¯mgâ¯L-1) for 2â¯h. The higher effluent sensitivity index and response caused by unit intensity of shock was observed under hydraulic and combined shocks. Notably, the specific anammox activity and the content of heme c were considerably reduced during the shock phase and the maximum loss rates were about 30.5% and 24.8%, respectively. Nevertheless, the extracellular polymeric substance amount in the shock phase was enhanced in varying degrees and variation tendency was disparate at all the tested shock loads. These results suggested that robustness of the anammox system was dependent on the magnitude shocks applied and the reactor resistance can be improved by reducing hydraulic retention time with the increase of nZVI concentration under these circumstances.
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Hierro/química , Aguas Residuales , Reactores Biológicos , Aguas del Alcantarillado , Purificación del AguaRESUMEN
The short- and long-term effects of Mn2+ on the performance of anaerobic ammonium oxidation (anammox) granules were investigated in the present study. Anammox activity was determined at various Mn2+ concentrations in batch assays, and the 50% inhibition concentration value was determined to be 7.33mgL-1. However, no obvious deterioration of reactor performance was observed during the 150-day continuous-flow operation, and the nitrogen removal efficiency of the test reactor (R1) fluctuated between 91% and 92% as the Mn2+ concentration was increased from 1 to 200mgL-1. Additionally, the specific anammox activity, heme c content and the amounts of extracellular polymeric substances in the anammox biomass increased and then subsequently decreased. The results demonstrated that short-term exposure to Mn2+ has a negative effect on anammox biomass, but the biomass could tolerate Mn2+ stress after acclimation to a high concentration of 200mgL-1 at the end of the continuous-flow experiment.
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Compuestos de Amonio , Reactores Biológicos , Biomasa , Nitrógeno , Oxidación-Reducción , Compuestos de Amonio Cuaternario , Aguas del Alcantarillado , TiempoRESUMEN
The increasing application of engineered nanoparticles (NPs) has posed an emerging challenge to wastewater treatment processes. The short-term impacts of CuNPs, CuONPs, ZnONPs and AgNPs on anaerobic ammonium oxidation (anammox) process were investigated firstly in this study. CuONPs, ZnONPs and AgNPs up to 50mgg-1 suspended solid (SS) did not affect anammox activity, reactive oxygen species (ROS) production or cell membrane integrity. However, 1.25mgg-1SS CuNPs significantly inhibited the anammox activity and the loads that caused 50% inhibition were 4.64±1.24 and 3.27±0.79mgg-1SS for anammox granules and flocs, respectively. 5mgg-1SS CuNPs caused serious accumulation of the toxic intermediate N2H4. Furthermore, CuNPs interacted with extracellular polymeric substances by specifically bonding to tyrosine or tryptophan-containing groups, C-O-C in polysaccharides and -OH in polymeric compounds. Therefore, this study calls for more attention to the risks of NPs to the anammox-based processes.
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Aguas del Alcantarillado , Aguas Residuales , Nanopartículas del MetalRESUMEN
Previous studies investigating the risk of engineered nanoparticles (NPs) to biological wastewater treatment have primarily tested NPs individually; however, limited data are available on the impact of NPs on the anaerobic ammonium oxidation (anammox) process. In this study, the toxicity of CuNPs on anammox granules was investigated individually and in combination with CuONPs or ZnONPs. Exposure to CuNPs at 5mgg-1 suspended solids (SS) decreased the anammox activity to 47.1±8.5%, increased the lactate dehydrogenase level to 110.5±3.4% and increased the extracellular N2H4 concentration by 16-fold but did not cause oxidative stress. The presence of CuONPs or ZnONPs at 5mgg-1 SS did not significantly aggravate or alleviate the toxicity of the CuNPs; however, the introduction of EDTA or S2- could attenuate the adverse effects of the CuNPs, CuONPs and ZnONPs on the anammox granules. EDTA captured Cu ions, whereas S2- shielded and deactivated Cu ions and passivated CuNPs. Therefore, our results indicated that the toxicity of NPs was dependent on the amount of active metal reaching the anammox cells. Overall, the results of this study have filled knowledge gaps and provided insights into the combined toxicity of NPs on anammox biomass.
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Amoníaco/química , Cobre/toxicidad , Ácido Edético/química , Nanopartículas del Metal/toxicidad , Azufre/química , Aguas Residuales/química , Purificación del Agua/métodos , Cobre/química , L-Lactato Deshidrogenasa/análisis , Nanopartículas del Metal/química , Estrés OxidativoRESUMEN
The short- and long-term effects of inorganic phosphate on property of anaerobic ammonium oxidation (anammox) granule were investigated in this study. Acute exposure to high-level phosphate (⩾50 mM) induced the cytoplasm leakage. During a 195-day continuous-flow operation, the gradually increasing phosphate (up to 500 mgP L(-1)) slightly affected the specific anammox activity, hardly impacted the heme c content, remarkably decreased the extracellular polymeric substances production and significantly stimulated the dehydrogenase activity of anammox granules. Microbial community analysis showed no shift in the dominant anammox strain and higher population but lower relative abundance of anaerobic ammonium-oxidizing bacteria compared to the control granules. Interestingly, novel anammox granules with a hydroxyapatite core were cultivated, which possessed excellent settleability, huge granule diameter and superior mechanical strength. This study supported the application of granule-based anammox process as a pre-processing treatment in phosphate-containing and ammonia-rich wastewaters.
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Bacterias Anaerobias/metabolismo , Reactores Biológicos/microbiología , Fosfatos/metabolismo , Eliminación de Residuos Líquidos/métodos , Amoníaco/metabolismo , Tiempo , Eliminación de Residuos Líquidos/instrumentación , Aguas ResidualesRESUMEN
This study evaluated the interactive effect of Cu(II) and Zn(II) on anaerobic ammonium oxidation (anammox) activity using response surface methodology with a central composite design. A regression model equation was developed and validated to predict the normalized anammox activity (NAA) of anammox granules exposed to various heavy metal concentrations. The joint inhibitory effect tended to exacerbate initially and reversed as the concentrations increased and then moderated again. The most severe inhibition, resulting in a NAA of 20.1%, occurred at Cu(II) and Zn(II) concentrations of 16.3 and 20.0mgL(-1), respectively. Notably, the cumulative toxicity was mitigated with the aid of intermittent exposure acclimatization. Additionally, pre-exposure to Cu(II) in the absence of substrates strongly inhibited anammox activity. However, the presence of NO2(-) significantly enhanced Cu(II) inhibition. Therefore, such conditions should be avoided to minimize the disturbance of the anammox process.