Pharmaceutically active compounds are carried into aquatic bodies along with domestic sewage, industrial and agricultural wastewater discharges. Psychotropic drugs, which can be toxic to the biota, have been detected in natural waters in different parts of the world. Conventional water treatments, such as activated sludge, do not properly remove these recalcitrant substances, so the development of processes able to eliminate these compounds becomes very important. Advanced oxidation processes are considered clean technologies, capable of achieving high rates of organic compounds degradation, and can be an efficient alternative to conventional treatments. In this study, the degradation of alprazolam, clonazepam, diazepam, lorazepam, and carbamazepine was evaluated through TiO₂/UV-A, H₂O₂/UV-A, and TiO₂/H₂O₂/UV-A, using sunlight and artificial irradiation. While using TiO₂ in suspension, best results were found at [TiO₂] = 0.1 g L⁻¹. H₂O₂/UV-A displayed better results under acidic conditions, achieving from 60 to 80% of removal. When WWTP was used, degradation decreased around 50% for both processes, TiO₂/UV-A and H₂O₂/UV-A, indicating a strong matrix effect. The combination of both processes was shown to be an adequate approach, since removal increased up to 90%. H₂O₂/UV-A was used for disinfecting the aqueous matrices, while mineralization was obtained by TiO₂-photocatalysis.

Polychlorinated diphenyl ethers (PCDEs) are a class of potential persistent organic contaminants, which have been widely detected in aquatic environment. In the present study, the effects of 3,4,4′-tri-CDE and its two possible metabolites (2-MeO-3′,4,4′-tri-CDE and 2-HO-3′,4,4′-tri-CDE) on oxidative stress biomarkers in liver of Carassius auratus were evaluated. The fish were treated with these three compounds at different doses (0.1, 1, and 10 μg/L) via semi-static water exposure. The liver samples were individually taken at 3, 7, and 21 days for analysis of oxidative stress indicators, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), and malondialdehyde (MDA). Compare to the control group, the hepatic antioxidant enzyme activity and GSH contents showed significant decreases (p < 0.05) at high-dose treatment (10 μg/L) and prolonged exposure time (21 days) in most of the toxicant-treated groups, indicating the occurrence of oxidative stress in fish liver. However, no consistent trend of the variations of antioxidant parameters was observed at low doses (0.1 and 1 μg/L). Meanwhile, the lipid peroxidation was significantly induced with extending exposure time and increasing dose. In addition, the toxicity order of three compounds was discussed using the integrated biomarker response (IBR) index. Notably, 2-HO-3′,4,4′-tri-CDE was indicated to cause the most severe hepatic oxidative stress.

Nitrogen removal by anammox process has been recognized as efficient, cost-effective, and low-energy alternative removal. The longer start-up periods of anammox process hindered the widespread application of anammox-based technology. In this study, four identical unplanted subsurface-flow constructed wetlands (USFCWs) were built up to investigate the effects of electron acceptors (Fe³⁺, Mn⁴⁺, SO₄²⁻) on the start-up of anammox process. Results indicated that the start-up time of anammox process was shortened to 105 days in R1 (with Fe³⁺ addition) and 110 days in R2 (with Mn⁴⁺ addition) with nitrogen removal efficiencies of above 75%, compared with 148 days in R0 (control). The addition of SO₄²⁻ had no significant effect on start-up process. High-throughput sequencing results demonstrated that Shannon index increased significantly from 2.87 (R0) to 5.08 (R1) and 5.00 (R2), and the relative abundance of Candidatus Anammoxoglobus rose from 3.6 to 5.3% in R1. Denitratisoma increased significantly in R2 under addition of Mn⁴⁺, which was beneficial for the occurrence of anammox process. The functional genes that related to signal transduction mechanisms and secondary metabolite biosynthesis, transport, and catabolism were upregulated after addition of electron acceptors. These results demonstrated that adding electron acceptors Fe³⁺ or Mn⁴⁺ could be an effective way to accelerate the start-up of anammox process. Graphical abstract ᅟ

Fluorene-9-bisphenol (BHPF), a new derivative of bisphenol A (BPA), has been introduced for treatment with estrogen-related tumors, such as endometrial cancer. This study investigated the potential mechanism underlying the action of BHPF against endometrial cancer in vitro. We used the cell counting kit-8 (CCK8) method on Ishikawa cells to screen sub-lethal doses of BHPF and established the optimal concentration at which BHPF influenced the proliferation of Ishikawa cells. Effect of BHPF on cell migration and invasion was investigated by cell scratch assay and transwell assay, respectively. Expression levels of epithelial-mesenchymal transition (EMT)–related proteins were detected by Western blot analysis. BHPF was found to inhibit the proliferation of Ishikawa cells, whose migration and invasion abilities were also reduced. Western blot indicated that BHPF can significantly inhibit the EMT process of Ishikawa cells by blocking transforming growth factor-β (TGF-β) signaling pathway. This is the first report of the effect of BHPF on the biological behavior of endometrial cancer cells and its inhibition of endometrial cancer progression by repressing both endometrial cell proliferation and epithelial-mesenchymal transition, hence suggesting it as a novel anti-cancer drug. Graphical abstract Schematic representation of the molecular basis underlying BHPF treatment. BHPF repressed the EMT process by regulating EMT-related genes, such as E-cadherin, N-cadherin, and vimentin as well as the TGF-β signaling pathway–related genes, including p-Smad2/3 and slug, in a BHPF-dependent manner.

The reduction of wet desulfurization wastewater is one of the important tasks of coal-fired power plants, and it is important for achieving “zero emissions.” Evaporation and concentration (E&C) with waste heat is an effective way to reduce wastewater. Here, two typical types of industrial desulfurization wastewater are used to study the change rule of pH and total dissolved solids during wastewater concentration in a circulating evaporation tower. The results indicate that with the increase of concentration ratio, the pH of desulfurization wastewater is decreased rapidly and then is gradually stabilized at 2–3 when SO₂ or SO₃ is contained in flue gas, and the increase in conductivity is less for wastewater with higher SO₄²⁻ content. The characteristics of various ions are also analyzed, and the composition and microscopic morphology of the precipitates are characterized during concentration. The growth pattern of Ca²⁺ concentration is dependent on the ratio of Ca²⁺ and SO₄²⁻ in raw wastewater. When the concentration ratio is 7.21, the insoluble and slightly soluble substances undergo precipitation and the solid content is approximately 20%, which can help realize the concentration and reduction of desulfurization wastewater.

Removal of petroleum products from contaminated soil is a long-term process requiring attention and constant monitoring. The aim of this study was to determine the effect of Fyre-Zyme enzyme preparation and/or calcium carbonate on microbiological changes and conversion of n-aliphatic hydrocarbons in soil contaminated of petroleum-derived substances. The material for testing was soil contaminated with petroleum substances. The total concentration of n-alkanes with a C8–C40 chain length was 420.1 mg·kg⁻¹ DM. The pot tests were carried out by introducing stimulators. As a decomposition promoter for n-alkanes in contaminated soil, a 6% water solution of Fyre-Zyme and/or 1% sterile CaCO₃ was used. The pots were incubated at 25 °C for 21 days. The dynamics of changes in the microbiota and concentration of n-alkanes were controlled for 21 days, every 7 days taking soil for testing. Microbiological tests included determining the total number of bacteria and fungi. Chemical analysis was performed by chromatographic method. Stimulating of soil bioremediation of contaminated hydrocarbons with calcium carbonate increased the number of bacteria, and stimulation with Fyre-Zyme and calcium carbonate—the number of filamentous fungi. There was no significant correlation between the concentration of n-alkanes in the soil and the total number of bacteria and fungi but stimulating of soil bioremediation with calcium carbonate increased the number of bacteria, and stimulation with Fyre-Zyme and calcium carbonate—the number of filamentous fungi. The observed correlations indicate that the concentration of n-alkanes in the contaminated soil increases with the addition of Fyre-Zyme.

In a rapid urbanization context, socio-economic development has caused large increases in carbon emissions. In this study, various techniques such as cointegration analysis, vector autoregression, and decoupling elastic function methods are applied to analyze the sequential collaborative relationship between economic development and carbon emissions in the process of urbanization in terms of the time-series lag relationship and the decoupling relationship. The main findings are as follows: (1) urbanization and carbon emissions displayed a temporal correlation relation with a lag of order 4, according to stability tests, and (2) the development of urbanization, economic growth, and changes in land use may be responsible for the time lag in carbon emissions. Furthermore, the mechanisms behind the effect of urbanization on carbon emissions are investigated to assist future carbon emissions reduction efforts. (3) From 1990 to 2014, carbon emissions and economic development showed a temporal evolution trend of “weak decoupling–expansionary coupling–weak decoupling” in the Pearl River Delta region, and there was an overall weak decoupling state: carbon emissions increased with growth in economic development, but the emissions growth rate was lower than the speed of economic development. (4) From 1990 to 2014, economic development showed a trend of sustained growth in the Pearl River Delta region, and differences were detected in the decoupling status between carbon emissions and economic development at different times. The overall decoupling status of the nine cities in the region was one of weak decoupling; however, the decoupling index, carbon emissions, and economic development levels displayed differences, whereby cities with high carbon emissions and high economic development levels were not necessarily the cities in which environmental pressures from economic development were the most severe. Our results have important theoretical and practical significance as they clarify the impact of economic development on carbon emissions in the process of urbanization, as well as the carbon emissions reduction work that must be undertaken in urban systems.

Energy cooperation has been emphasized strongly in the Belt and Road (B&R) initiative. Therefore, the energy efficiency of China has attracted much attention from experts. However, relevant studies are still insufficient. This paper analyzes the total factor energy efficiency (TFEE) and its influencing factors of 17 B&R key regions from 2005 to 2015. We use the ratio of target energy input and actual energy input to calculate the regional TFEE under environmental constraints. The Malmquist index and the Tobit model are applied to investigate the internal and external influences of TFEE. Measurement analysis shows that the TFEE of the B&R key regions has not improved in recent years and it is unbalanced during the study period. Regions in the east area have the highest TFEE; regions in the west area have the second high TFEE; and regions in the north area have the lowest TFEE. Regression analysis shows that for the B&R key regions, technical changes, coal consumption, research and development, and environmental pollution have mainly negative effects on TFEE; pure efficiency changes, scale efficiency changes, economic structure, opening up, and government finance have mainly positive effects on TFEE. Finally, precise policy implications are proposed.

To investigate the emission characteristics of the dissolved N₂O in distilled water and activated sludge mixture, the total volume mass transfer coefficients of N₂O in distilled water and activated sludge mixture were determined by batch experiments. The results indicated a difference between emission processes of N₂O in distilled water and activated sludge mixture. At different initial N₂O concentrations, the total volume mass transfer coefficients of N₂O in distilled water were relatively stable, while the total volume mass transfer coefficients of N₂O in activated sludge mixture increased with increasing initial N₂O concentrations, due to endogenous denitrification by microorganisms in the mixture. Since N₂O was reduced and consumed by heterotrophic bacteria in activated sludge, biochemical reactions were involved in the transfer process of N₂O escaping from the mixture to the atmosphere. Therefore, use of distilled water was suggested to determine the total volume mass transfer coefficient in experiments calculating N₂O emission rates for biological nitrogen removal processes.

This article identifies environmental factors that explain most of the dynamic year-to-year changes in mercury concentrations of young-of-year (YOY) yellow perch (Perca flavescens) in study reservoirs. Mercury concentrations in fish, collected each fall, were measured for 9 years in four reservoirs in northeastern Minnesota. Three to 4 years of data were also obtained for two natural lakes and one other reservoir. Average annual concentrations varied considerably from year to year with a mean change of 39% between consecutive years across all lakes. Those averages show a similar time trend for each lake over the years and suggest that important factors influencing mercury bioaccumulation change annually and are also experienced in common over the study region. Three factors satisfying that description are precipitation depth, water level, and average air temperature. This article reveals that all three have statistically significant correlations with observed mercury concentrations. Moreover, multiple regressions indicate that maximum water levels and average air temperatures explain most of the observed variations. Regressions employing precipitation depth and temperature are less significant.