The phosphates (Pi) are nowadays recognized as pollutants. We studied the effect of Pi (0.625–12.500 mM KH₂PO₄) in the culture medium on in vitro grown 2-month-old Populus alba trees. The levels of sugar phosphates and vacuolar and cytoplasmic Pi in cell compartments of roots and stems were determined using ³¹P NMR, while tissue-specific micro- and macroelements mapping on stem cross-sections were performed using synchrotron-based X-ray microfluorescence. Plants grown on 0.625 mM Pi (MS/2 medium) showed a survival rate of 70%. With the increase in Pi concentrations up to 6.250 mM, plant growth and survival increased, without changes in total P content per mass or in the levels of cytoplasmic and vacuolar phosphates, in both stems and roots, while the levels of Fe, Cu, Zn, Ca and Mn in stems increased. Further increase in Pi to 9.375 and 12.500 mM in the medium resulted in inhibited growth comparable with plants grown on MS/2, with the increase in total P content per mass up to 50%, in both stems and roots, but with no changes in cytoplasmic and vacuolar phosphates; 12.500 mM Pi affected even plant survival (70%) and thus might be considered as mildly toxic. ³¹P NMR results indicate that the high tolerance of P. alba to increased Pi could result from its ability to maintain an intracellular P homeostasis, despite P accumulation up to 50%, in both stems and roots, indicating P. alba as a promising wood species for dendroremediation.

The problem of haze pollution in China is still serious, and it is an important issue how to measure and improve environmental regulation efficiency of haze control (EREHC) in China. To explore the spatial evolution characteristics and influencing factors of EREHC in each province in China, this paper builds an evaluation system for EREHC in China and calculates EREHC values in 30 provinces, autonomous regions, and municipalities in China from 2003 to 2015 through the super-efficiency slacks-based measure (SE-SBM) model. Moreover, the influencing factors and the driving mechanism of EREHC in China are examined by using the Theil index, Moran’s I index, and the geographically and temporally weighted regression (GTWR) model. The results are as follows. (1) During the sample period, EREHC in each province in China is mostly favorable, and the average efficiency value is approximately 0.5. EREHC has been declining only in some regions in China. (2) EREHC in eastern China is the best, followed by western China, and EREHC in central China is the lowest. The inter-regional difference in EREHC has been declining over time. (3) EREHC is positively correlated with economic level, the industrial upgrading, and the opening to the outside world, but negatively correlated with energy mix and labor force quality. The positive and negative effects of the level of scientific and technological input are different among the three economic regions. The results indicate that EREHC in China is generally at low level, which presents the spatial difference characteristic of “High East and Low West.” It will help improve regional EREHC to raise the level of regional economic development, deepen industrial upgrading, and open to the outside world.

A scheme of selective removal of metal ions from chromium-containing synthetic solutions with the following chemical composition, Cr (VI)-Fe (III), Cr (VI)-Fe (III)-Ni (II), Cr (VI)-Fe (III)-Ni (II)-Zn (II), and Cr (VI)-Fe (III)-Ni (II)-Zn (II)-Cu (II)) by Shewanella xiamenensis biofilm immobilized on a zeolite support, was proposed. Three biological processes, biosorption, bioaccumulation, and longtime bioreduction, were applied for metal removal. The process of Zn (II), Ni (II), and Cu (II) showed to be pH dependent. The maximum removal of Ni (II) was achieved during a 1-hour biosorption process at pH 5.0–6.0, of Zn (II) at pH 5.0, and of Cu (II) at pH 3.0. Chromium (VI) and Fe (III) ions were more efficiently removed by bioaccumulation. Chromium (VI) removal in the studied systems varied from 16.4% to 34.8 and of iron from 55.8 to 94.6%. In a long-term bioreduction experiment, it was possible to achieve complete reduction of Cr (VI) to Cr (III) ions by Shewanella xiamenensis in 42 days and by Shewanella xiamenensis biofilm on zeolite in 35 days. Shewanella oneidensis can be effectively used to remove metal ions from chemically complex effluents.

Cigarette smoke is a known risk factor for urothelial carcinoma (UC). However, there is limited information about the distributions and effects of volatile organic compounds (VOCs) on smoking-related UC risk. With this hospital-based case-control study, we explored the associations between urinary levels of cotinine and VOC metabolites (acrylamide, 1,3-butadiene, and benzene) and the risk of UC. Urological examinations and pathological verifications were used to confirm the diagnoses of UC. All study participants provided smoking-related information via questionnaires and face-to-face interviews; they also provided urine samples for the measurement of VOC metabolites, cotinine, and 8-hydroxydeoxyguanosine (8-OHdG), which was used as an indicator of oxidative stress. We applied multiple logistic regression analysis to estimate the risk of UC, and we found that levels of urinary cotinine and 8-OHdG were higher in the UC group than in the control group. Furthermore, urinary levels of VOC metabolites, including N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA), N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine, N-acetyl-S-(4-hydroxy-2-buten-1-yl)-L-cysteine-3, trans,trans-muconic acid (t,t-MA), and S-phenylmercapturic acid (SPMA), increased with increasing levels of urinary cotinine. After adjusting for potential risk factors, dose–response relationships were observed between UC risk and urinary levels of AAMA, t,t-MA, SPMA, and 8-OHdG. Participants with high urinary levels of cotinine, AAMA, t,t-MA, SPMA, and 8-OHdG had risks of UC that were 3.5- to 6-fold higher than those of participants with lower levels. Future, large-scale investigations of the risks of UC should be explored, and repeated measurement of VOC metabolites should be assessed.

Dyes are widely used in many industrial sectors, many contain harmful substances to human health, and their release into the environment entails several environmental problems, generating a major worldwide concern as water resources are increasingly limited. The development of cheap and efficient biosorbents that remove these pollutants is of utmost importance. In this study, powdered seeds of the araticum fruit (Annona crassiflora) were used in the biosorption of crystal violet (CV) dye from aqueous solutions and simulated textile effluents. Through the characterization techniques, it can be observed that the material presented an amorphous structure, containing an irregular surface composed mainly by groups containing carbon, hydrogen, and oxygen. CV biosorption was favored at the natural pH of the solution (7.5) for a dosage of 0.7 g L⁻¹ of araticum seed powder. The pseudo-second-order model was the most suitable to represent the biosorption kinetics in the removal of the CV. Biosorption capacity reached equilibrium in the first minutes at the lowest concentrations, and, at the highest, after 120 min. The equilibrium data were well represented by the Langmuir model, with a maximum biosorption capacity of 300.96 mg g⁻¹ at 328 K. Biosorption had a spontaneous and endothermic nature. In the treatment of a simulated effluent, the biosorbent removed 87.8% of the color, proving to be efficient. Therefore, the araticum seeds powder (ASP) can be used as a low-cost material for the treatment of colored effluents containing the crystal violet (CV) dye.

Climate change is considered the major environmental challenge for the world. Cement and lime production is a highly energy-consuming, heavily polluting process, and the CO₂ emissions are very substantial. Alkaline environment, high temperature, and long processing time lead the researchers to work on alternative soil improvements. Microbially induced calcite precipitation (MICP) has been introduced as a technique for modification of geotechnical properties of sand. The main purpose of the present study was to focus on the efficiency and environmental impact of conventional and microbial grouting. Samples were treated with three chemical stabilizers, namely Portland cement, lime, and cement and lime. The stabilizers were injected with flow gravity and constant head which are almost the same as microbial grouting. Then, the results of conventional grouting were compared with the results of biocement samples which were gathered from previous studies to discuss the efficiency and environmental impacts. The results for treated samples were discussed and compared based on 1 m³ of soil and a final target of 700 kPa. It was found that in order to obtain the same compressive strength, the cost and calcium carbonate consumption of the cement injection method were 2.5 times more than those of the microbial method. Biocementation has some advantages over existing technologies, such as less calcium usage in the same unconfined compressive strength (UCS).

In this study, the toxic effects of potassium bromate (KBrO₃) were tested on Allium cepa L. meristematic cells. In order to determine the toxic effect and dose relationship, KBrO₃ toxicity was investigated at doses of 25, 50, and 100 mg/L. The toxic effects were evaluated by using cytogenetic, biochemical, anatomical, and physiological parameters, and serious damages were observed depending on the dose. Significant reductions in germination percentage, weight gain, and radicle length were observed in all KBrO₃-treated groups compared with the control. Mitotic activity decreased in meristematic cells after KBrO₃ application. and mitotic index was decreased by 1.8 times in 100 mg/L KBrO₃-treated group compared with the control group. The frequencies of micronucleus and chromosomal abnormalities tested as cytogenetic parameters were significantly higher in the group treated with 100 mg/L KBrO₃ than those in the control group. Fragment and sticky chromosome were the most common types of chromosomal abnormalities. Lipid peroxidation measured in terms of MDA content increased with increasing doses of KBrO₃. The activities of catalase and superoxide dismutase as antioxidant enzymes were importantly changed in KBrO₃-treated groups. Anatomical changes such as cell deformation, substance accumulation, cell wall thickening, and flattened nucleus were determined after KBrO₃ application, and it was observed that these changes reached a maximum level at 100 mg/L dose of KBrO₃. As a result, KBrO₃ treatments were been found to cause physiological, biochemical, cytogenetic, and anatomically toxic effects in meristematic cells of A. cepa, a eukaryotic model organism. The versatile toxicity induced by KBrO₃ increased depending on the dose and reached a maximum level at 100 mg/L.

A novel ZnO-CeO₂-rGO (ZCG) ternary nanocomposite with varying ZnO/CeO₂ weight proportions was synthesized by a hydrothermal process for photoelectrochemical water splitting and photocatalytic application. XRD diffraction peaks of ZCG nanocomposites displayed the patterns of ZnO and CeO₂ nanoparticles, and SEM revealed irregular flake-like particles, which were uniformly decorated on the rGO matrix. Increase in the intensity ratio of D and G bands from Raman spectra revealed changes in oxygen bonding in the ZnO-rGO (ZG) and ZCG nanocomposites. The shift in the band edge positions and the decrease in the band gap with increase in the cerium oxide content in ZCG composites were observed from UV-Vis and Mott-Schottky plots. XPS results showed that Ce³⁺ fraction increased with an increase in the cerium oxide content in ZCG nanocomposites. The ZCG3 (85:15) nanocomposite exhibited decreased electron-hole recombination rate as evidenced from the photoluminescence and electrochemical impedance spectroscopy Nyquist plots. The characteristic frequency in Bode’s plot shifted to a lower frequency for the ZCG3 electrode demonstrating low interfacial charge transfer resistance, and ZCG3 photoelectrode displayed a higher photocurrent density of 0.69 mA/cm² at 1.5 V compared with other photoelectrode. The optimized and highly efficient ZCG3 nanocomposite exhibited improved photocatalytic degradation of methylene blue (MB) with a reaction rate constant of 0.0201 min⁻¹. Combination of defects in the form of Ce³⁺ ion and surface oxygen vacancies coupled with rGO as the electron acceptor improved the charge carrier density and carrier transport in addition to the formation Schottky-type junction and the presence of an internal electric field.

The presence of nanoplastics (NPs) in various products and from the weathering of released plastic materials are of concern for the environment’s safety. The purpose of this study was to examine the biophysical effects of polystyrene NPs on freshwater mussels. Mussels were exposed to a range of concentrations of NPs (0.1, 0.5, 1, and 5 mg/L) for 24 h and allowed to depurate for 12 h in clean aquarium water. The digestive gland was isolated and analyzed for NPs, lipids, viscosity, protein aggregation, anisotropic changes (liquid crystals: LCs), and the oscillatory modulation in viscosity during the formation of self-organizing enzyme complex of fumarase, malate dehydrogenase, and citrate synthase. The results revealed that mussels accumulated NPs in the digestive gland and their levels were significantly correlated with lipids levels, LCs, the increase in the malate dehydrogenase/citrate synthase activity ratio, and oscillations in viscosity. Protein aggregation was also found to be correlated with lipid levels. The data suggests that the presence of NPs in the digestive gland involves changes in lipid content and LC formation and perturbs the normal oscillations in viscosity during sequential enzyme reactions of the above enzymes. It is concluded that the uptake of NPs in cells could disrupt the internal organization of cells which can interfere with the normal association of enzymes involved in energy metabolism.

In this work, we used TiO₂ nanobelts and P25 particles as titanium sources to combine with β-Bi₂O₃ to form β-Bi₂O₃/TiO₂ and β-Bi₂O₃/P25 composites. The prepared samples were characterized by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), and UV-vis absorbance spectroscopy and fluorescence spectroscopy. The structure and performance of two composites were comparatively investigated, and the β-Bi₂O₃ molar ratios in them were optimized and their roles in them were studied. The results showed that the TiO₂ nanobelts and commercial TiO₂ (P25) particles combined with β-Bi₂O₃ nanosheets. The optimal molar ratios of Bi to Ti element in two kinds of composites are 1:1. The β-Bi₂O₃ in P25/β-Bi₂O₃ makes more contribution to the improvement of photocatalytic activity of them than that in β-Bi₂O₃/TiO₂ because P25 particles are distributed on β-Bi₂O₃ nanosheet more uniformly. The photocatalytic activities of β-Bi₂O₃/TiO₂ (0.02275 min⁻¹) and β-Bi₂O₃/P25 (0.02382 min⁻¹) are 3.72 times and 3.90 times than that of pure β-Bi₂O₃ (0.0061 min⁻¹) for EE2 removal. The enhanced photocatalytic activities of two kinds of composites are ascribed to photo-induced interfacial charge transfer on the heterojunction between β-Bi₂O₃ and TiO₂ or P25. From the economic view, β-Bi₂O₃/P25 composites are better than β-Bi₂O₃/TiO₂ because TiO₂ nanobelts in the β-Bi₂O₃/TiO₂ composite are obtained from P25 via extra hydrothermal treatment in strong alkaline environment. The free radical capture experiment indicated that the dominant reactive species are h⁺ and •O⁻₂ for EE2 removal by TiO₂/β-Bi₂O₃ and P25/β-Bi₂O₃ composites.