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This study addresses the previously unknown effects of algae blooms on the dynamics of phosphorus (P), iron (Fe) and sulfur (S) across a lacustrine sediment-water interface (SWI). A mesocosm experiment was conducted in-situ to investigate these effects based on two recently-developed diffusive gradients in thin-films techniques (DGT). Soluble P, Fe(II), and S(-II) exhibited similar changing trends in a water column subject to the algae addition. Peak concentrations appeared on day 7 of the 16-day experiment. The lowest Eh occurred at the experiment’s midway point indicating a strong algae degradation. A maximum increase in DGT-labile S appeared on day 8 near the SWI, while the DGT-labile P and Fe exhibited persistent increases almost to the end of experiment. Significantly positive correlations of labile P were observed switching from between labile Fe and labile S in sediments, suggesting a significant change in original Fe-coupled dynamics of P under algae decomposition. Apparent fluxes were calculated based on DGT profiles where a simultaneous release of P and S occurred from degraded algae, resulting in bidirectional diffusion fluxes from sediment to overlying water. In contrast, sediment acted as a major source of labile Fe due to added depth and apparently positive fluxes. [ABSTRACT FROM AUTHOR]

Abstract: Polychlorinated biphenyls (PCBs) possessed much potential hazard to environment because of its chemical stability and biological toxicity. Here, we identified the binding mode of a representative compound, PCB153, to human serum albumin (HSA) using fluorescence and molecular dynamics simulation methods. The fluorescence study showed that the intrinsic fluorescence of HSA was quenched by addition of PCB153 through a static quenching mechanism. The thermodynamic analysis proved the binding behavior was mainly governed by hydrophobic force. Furthermore, as evidenced by site marker displacement experiments using two probe compounds, it revealed that PCB153 acted exactly on subdomain IIIA (site II) of HSA. On the other hand, the molecular dynamics studies as well as free energy calculations made another important contribution to understand the conformational changes of HSA and the stability of HSA-PCB153 system. Molecular docking revealed PCB153 can bind in a large hydrophobic activity of subdomain IIIA by the hydrophobic interaction and hydrogen bond interactions between chlorine atoms and residue ASN391. The present work provided reasonable models helping us further understand the transporting, distribution and toxicity effect of PCBs when it spread into human blood serum. [Copyright &y& Elsevier]

The prevalence of antibiotic resistance genes (ARGs) in municipal wastewater treatment plants (MWTPs) has emerged as a significant environmental concern. Despite advanced treatment processes, high levels of ARGs persist in the secondary effluent from MWTPs, posing ongoing environmental risks. This study explores the potential of gamma-ray irradiation as a novel approach for sterilizing antibiotic-resistant bacteria (ARB) and reducing ARGs in MWTP secondary effluent. Our findings reveal that gamma-ray irradiation at an absorbed dose of 1.6 kGy effectively deactivates all culturable bacteria, with no subsequent revival observed after exposure to 6.4 kGy and a 96-h incubation in darkness at room temperature. The removal efficiencies for a range of ARGs, including tetO , tetA , bla TEM-1 , sulI , sulII , and tetW , were up to 90.5% with a 25.6 kGy absorbed dose. No resurgence of ARGs was detected after irradiation. Additionally, this study demonstrates a considerable reduction in the abundances of extracellular ARGs, with the transformation efficiencies of extracellular tetracycline and sulfadiazine resistance genes decreasing by 56.3–81.8% after 25.6 kGy irradiation. These results highlight the effectiveness of gamma-ray irradiation as an advanced and promising method for ARB sterilization and ARG reduction in the secondary effluent of MWTPs, offering a potential pathway to mitigate environmental risks associated with antibiotic resistance. [Display omitted] • Gamma-ray irradiation reduced the abundances of ARGs by 1.69-3.69 logs. • Over 99% of VBNC bacteria were removed by Gamma-ray irradiation. • Gamma-ray irradiation reduced the transformation ability of released eARGs. • Direct action of irradiation was the major contributor to ARGs degradation. • Gamma-ray irradiation treatment improved the effluent quality. [ABSTRACT FROM AUTHOR]

Important biogeochemical processes occur in sediments at fine scales. Sampling techniques capable of yielding information with high resolution are therefore needed to investigate chemical distributions and fluxes and to elucidate key processes affecting chemical fates. In this study, a high-resolution diffusive gradients in thin-films (DGT) technique was systematically developed and tested in a controlled sediment system to measure organic contaminants, antibiotics, for the first time. The DGT probe was used to resolve compound distributions at the mm scale. It also reflected the fluxes from the sediment pore-water and remobilization from the solid phase, providing more dynamic information. Through the fine scale detection, a reduction of re-supply was observed over time, which was concentration and location dependent. Compared to the Rhizon sampling method, antibiotic concentrations obtained by DGT probes were less than the pore-water concentrations, as DGT measures the labile fraction of the compounds. The DGT probe was also tested on an intact sediment core sampled from a lake in China and used to measure the distribution of labile antibiotics with depth in the core at the mm scale. The abuse of antibiotics and widespread of their residues influences the ecosystem, induces the generation of super-bacteria, and finally poses threat to human health. Sediments adsorbs pollutants from the aquatic environment, while may also release them back to the environment. We systematically developed DGT probe approach for measuring antibiotics in sediment in situ in high resolving power, it provides information at fine scale to help us investigate biogeochemical processes take place in sediment and sediment-water interface. [Display omitted] • Developed a new in situ high resolution sampling probe for studying antibiotics. • Resolving power reached the mm scale, better than conventional methods. • Vertical distribution of antibiotics in sediments and their transport were determined. • Antibiotics were detected in an intact sediment core using DGT probe. [ABSTRACT FROM AUTHOR]

In order to gain a profound understanding of the fate of pollutants in advanced oxidation processes (AOPs), this study analyzed the electron contribution of pollutants qualitatively and quantitatively which rarely reported before. The rich electron transfer system was constructed by mesoporous carbon nitride (MCN) coupling with persulfate (PS) driven by visible light and the sulfanilamide antibiotics (SULs) were used as target contaminants. Firstly, the qualitative analysis of electron transfer in the system was confirmed systematically. The electron flow direction tested by i-t curves indicated that PS absorbed electrons, while SULs released electrons. The flow rate of electrons was also accelerated after the addition of SULs. The fitting curve between the kinetics and the peak potential difference tested by CV curve showed that the larger potential difference, the slower rate of oxidative degradation. Secondly, the quantification of electron transfer was achieved through theoretical calculations to simulate the interactions of the 'catalyst-oxidant-antibiotic' system. After the addition of SULs, the adsorption energy of the 'catalyst-oxidant-antibiotic' system was enhanced and the bond length of the peroxide bond was stretched. Notably, the electron transfer analysis results showed that the charge of SULs was around 0.032–0.056 e , indicating that SULs pollutants played the role of electron contributors in the system. The oxidative degradation pathway included the direct cracking of S-N bond, shedding of marginal groups, ring-opening and hydroxyl addition reaction. This study clarified the electronic contribution of SULs in the oxidation system, providing necessary theoretical supplement for the analysis of the transformation of pollutants in AOPs. [Display omitted] • Pollutants could directly join the oxidation reaction by contributing electrons. • The electron contribution of SULs was analyzed qualitatively and quantitatively. • The addition of SULs changed the electron flow and accelerated the electron transfer. • The SULs contributed approximately 0.032–0.056 e to the MCN/PS system. • The 'catalyst-oxidant-pollutant' system was constructed in theoretical calculations. [ABSTRACT FROM AUTHOR]

A new method for the determination of 26 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in marine sediment pore water was developed using online solid phase extraction coupled with liquid chromatography-tandem mass spectrometry. The proposed method requires only about 1 mL of pore water samples. Satisfactory recoveries of most target PFASs (83.55–125.30 %) were achieved, with good precision (RSD of 1.09–16.53 %), linearity (R 2 ≥ 0.990), and sensitivity (MDLs: 0.05 ng/L–5.00 ng/L for most PFASs). Subsequently, the method was applied to determine PFASs in the sediment pore water of five mariculture bays in the Bohai and Yellow Seas of China for the first time. Fifteen PFASs were detected with total concentrations ranging from 150.23 ng/L to 1838.48 ng/L (mean = 636.80 ng/L). The ∑PFASs and PFOA concentrations in sediment pore water were remarkably higher than those in surface seawater (tens of ng/L), indicating that the potential toxic effect of PFASs on benthic organisms may be underestimated. PFPeA was mainly distributed in pore water, and the partition of PFHpA (50.99 %) and PFOA (49.01 %) was almost equal in the solid and liquid phases. The proportions of all other PFASs partitioned in marine sediments were significantly higher than those in pore water. [Display omitted] • A convenient method for the detection of PFASs in marine sediment pore water was developed. • Only about 1 mL of actual sediment pore water is needed to determine various PFASs. • High levels of PFASs were detected in pore water from five mariculture bays of China. • Different PFASs exhibit varying partitioning behaviors at the sediment–pore water interface. • Great attention should be paid to PFASs in the sediment pore water of mariculture areas. [ABSTRACT FROM AUTHOR]

This study investigates the co-precipitation of calcium and barium ions in hypersaline wastewater under the action of Bacillus licheniformis using microbially induced carbonate precipitation (MICP) technology, as well as the bactericidal properties of the biomineralized product vaterite. The changes in carbonic anhydrase activity, pH, carbonate and bicarbonate concentrations in different biomineralization systems were negatively correlated with variations in metal ion concentrations, while the changes in polysaccharides and protein contents in bacterial extracellular polymers were positively correlated with variations in barium concentrations. In the mixed calcium and barium systems, the harvested minerals were vaterite containing barium. The increasing concentrations of calcium promoted the incorporation and adsorption of barium onto vaterite. The presence of barium significantly increased the contents of O-C O, N-C O, and Ba-O in vaterite. Calcium promoted barium precipitation, but barium inhibited calcium precipitation. After being treated by immobilized bacteria, the concentrations of calcium and barium ions decreased from 400 and 274 to 1.72 and 0 mg/L (GB/T15454–2009 and GB8978–1996). Intracellular minerals were also vaterite containing barium. Extracellular vaterite exhibited bactericidal properties. This research presents a promising technique for simultaneously removing and recycling hazardous heavy metals and calcium in hypersaline wastewater. [Display omitted] • Probiotic B. licheniformis simultaneously removed Ba2+ and Ca2+ in hypersaline fluid. • Ca2+ promoted Ba2+ precipitation, but Ba2+ inhibited Ca2+ precipitation. • Hydrochemical index and EPS components changed greatly in Ba2+-Ca2+ fluid. • Intracelluar vaterite containing Ba was also beneficial to the Ba2+ and Ca2+ removal. • Ba-vaterite exhibited bactericidal activity against E.coli. [ABSTRACT FROM AUTHOR]

Abstract: TATB (1,3,5-triamino-2,4,6-trinitrobenzene) explosives were safely irradiated with microwave and showed no visible change according to XPS and XRD spectra. Temperature of TATB sample increased quickly at the beginning and gently during sequent continuous irradiation with temperature less than 140°C after 60min, 480W irradiation, and increased more quickly in 300g at 480W than in 150g at 480W, both implied that heat dissipation was in the majority of microwave energy. Two major risk factors in microwave irradiation were concerned including overheating which should be avoidable with temperature monitor and microwave discharge which should be controllable experimentally though dielectric breakdown mechanism was not elucidated theoretically yet. [Copyright &y& Elsevier]