Fishmeal is a fundamental ingredient of feedstuffs and is used globally in aquaculture. However, there are few data on the antibiotic resistance genes (ARGs) and human pathogenic bacteria in fishmeal and little understanding of the potential risks of fishmeal application in mariculture systems. Here, we investigated the high-throughput profiles of ARGs and human potential pathogenic bacteria (HPPB) in representative fishmeals (n = 5) and the potential impact of fishmeal on mariculture sediments. ARGs were quantified with microbial DNA quantitative PCR arrays and HPPB were analyzed with Illumina sequencing of 16S rRNA genes. The impact of the fishmeal on the aquaculture sediments was assessed in a microcosm study. Twenty-four unique ARGs (3–14 per sample) and 25 HPPB species were detected in the fishmeal samples. The most prevalent ARGs were fluoroquinolone resistance genes. The overall abundance of HPPB was 5.0–25.5%, and the HPPB species were dominated by Vibrio parahaemolyticus, Clostridium novyi, and Escherichia coli. In the mariculture microcosm sediment, fishmeal significantly increased the normalized abundance of the class I integrase gene (25.4-fold), which plays an important role in the dissemination of ARGs. Dosing with fishmeal also contributed to increases in a resident sulfanilamide resistance gene (sulI gene) and the emergence of a macrolide resistance gene (ermB gene) in the sediment. These findings demonstrated that fishmeal itself is an underestimated reservoir and source of ARGs and HPPBs, and that the application of fishmeal facilitates the dissemination of ARGs in aquaculture sediments. Our results extend our knowledge of the ARGs and HPPB within fishmeal and may provide a feasible and effective approach to the detection of ARGs and HPPB in fishmeal during food safety inspection. Graphical abstract ᅟ

The photochemical role of Fe(III)-citrate complex is significant in natural waters due to its ubiquitous existence and excellent photoreactivity at near neutral pH. Although there are many reports on the photoinduced degradation of pollutants in the Fe(III)-citrate system, the optimum pH for its photoreactivity is yet not clearly understood. Here, for the first time, we demonstrated that the optimum pH was 5.5 for the photoproduction of •OH in the Fe(III)-citrate system via kinetics modeling based on the steady-state approximation. According to the experimental results, the •OH photoproduction increased with increasing pH until 5.5 and then decreased in Fe(III)-citrate solution, which agreed well with the prediction trend of kinetic modeling. The effect of the common ligand oxalate on the photoreactivity of Fe(III)-citrate system was also investigated. The addition of oxalate promoted the photoproduction of •OH in Fe(III)-citrate solutions, and the measured [•OH]ₛₛ increased with oxalate concentration under a fixed Fe(III)-to-citrate ratio. Little synergistic effect exists in Fe(III)-citrate-oxalate system at pH 4.0–5.5. In contrast, an appreciable synergistic effect was observed at near neutral pH (6.0–8.0). Higher oxalate-to-citrate ratio facilitated the synergistic effect. Furthermore, antifungal drug fluconazole could be removed efficiently in the Fe(III)-citrate-oxalate system. The photodegradation kinetics also verified the optimum pH of Fe(III)-citrate system and synergistic effect of oxalate. By LC-ESI-MS/MS analyses, the photoproducts of fluconazole in the Fe(III)-citrate-oxalate system were identified and the reaction mechanism involving hydroxylation substitution and subsequent cleavage of heterocyclic amine was proposed. These findings suggest that Fe(III)-citrate exhibits best photoreactivity at pH 5.5, and the coexistence of reactive ligands will enhance its photoreactivity at circumneutral pH, indicating potential application in wastewater treatment via addition of appropriate citrate and co-ligands.

The immunostimulating and therapeutic properties of Ginkgo biloba (GB) have always been the focus of traditional medicine over thousands of years. During last decade, special attentions were paid to use of GB in aquaculture to enhance fish health and survival. In the present study, we investigated for the first time the immunogenic effects of dietary GB against oxidative and toxicity induced by organophosphate pesticide, diazinon. In non-diazinon-exposed fish, the plasma total immunoglobulin, lysozyme activity, and peroxidase activity significantly elevated after 60-day experiment in fish supplemented with 1 and 2 g GB/kg diet (p < 0.05). The respiratory burst activity and complement activity significantly increased only in groups supplemented with 0.5 g GB/kg diet (p < 0.05). Furthermore, the peroxidase activity, total immunoglobulin, and lysozyme activity significantly declined in groups supplemented with 4 g GB/kg diet during feeding trial (p < 0.05). There were no significant differences in expression of interleukin 1 beta (IL-1β) and transforming growth factor beta 1 (TGF-β1) genes in kidney between control group (non-GB-supplemented fish) and GB-supplemented fish (p > 0.05). In diazinon-exposed fish, all immunity components significantly decreased during exposure in control and those fed 0.5 and 4 g GB/kg diet (p < 0.05). In fish fed 1 and 2 g GB/kg diet, no alternations were found in immunity components during exposure period (p > 0.05). In addition, diazinon induced the expression of IL-1β and TGF-β1 genes in control and fish fed 0.5 and 4 g GB/kg diet (p < 0.05). No significant changes were observed in expression of IL-1β and TGF-β1 genes in fish supplemented with 1 and 2 g GB/kg (p > 0.05). In conclusion, the results of the present study suggest an immunogenic role for dietary GB at optimum dietary levels (1–2 g GB/kg diet) against toxicity induced by diazinon. Nevertheless, GB at high dietary levels (4 g GB/kg diet) showed immunosuppressive effects, which makes it necessary to optimize its levels in diet.

Water level and wind speed have important influences on radon release in particle-packing emanation media. Based on radon migration theory in porous media under three water level conditions, an experimental setup was designed to measure the surface radon exhalation rate of uranium tailings from heap leaching uranium mine at different water levels and wind speeds. When the water level was at 0.3 m (overlying depth 0.05 m), radon transfer velocities at the gas–liquid interface were also measured at different wind speeds. Results show that when the water level was equal to or lower than the surface of the sample, the radon exhalation rate increased with increasing wind speed and decreased with increasing water level. When the water level was higher than the surface of the sample, radon exhalation rate of the water surface increased with increasing surface wind speed. The wind speed, however, was less influential on the radon exhalation rate as the depth of the overlying water increased, with a dramatic decrease in radon release. That said, at different wind speeds, radon transfer velocities at the gas–liquid interface were consistent with literature. On the other hand, changes in wind speed had significant influences on the radon transfer velocity at the gas–liquid interface, with the effect less pronounced at higher wind speeds.

This study aims to investigate the validity of pollution haven hypothesis for the period from 1982 to 2013 in ten newly industrialized countries. For this purpose, we examine the relationship between real income, foreign direct investment, energy consumption, and ecological footprint using second-generation panel data methodology to take into account the cross-sectional dependence among newly industrialized countries. In doing so, the possible nonlinear relationship between foreign direct investment and environmental degradation is also searched. The results show that increased energy consumption and economic growth lead to increase in ecological footprint. Moreover, the U-shaped relationship between foreign direct investment and ecological footprint is confirmed in newly industrialized countries.

In this study, we focused on the rate of adsorption of phosphate on to the surface of magnetite in the presence of coexisting anions, organic matters and heavy metals. Magnetite particles were prepared using a co-precipitation method. Iron (II) sulfate heptahydrate and iron (III) chloride hexahydrate were mixed and then a sodium hydroxide solution was added drop-wise in the mixed iron solution. Coexisting anions were found to have no effect on the decrease in phosphate adsorption. However, phosphate adsorbed on to magnetite surface decreased with increasing total organic carbon (TOC) concentration of natural organic matter (NOM) such as citric, oxalic, and humic acid. The amount of phosphate adsorbed rapidly decreased with the increase of NOM concentration; therefore, it can be noted that NOM concentration considerably affects the adsorption of phosphate due to the negative charge exiting on the surface of NOMs. Glucose and ethanol, meanwhile, were found to have no effect on the phosphate adsorption. The amount of phosphate adsorbed did not change in the presence of heavy metals, namely, Pb and Cd, under acidic conditions. However, under alkaline conditions, the amount of phosphate adsorbed decreased with increasing concentrations of Pb and Cd. In the case of coexisting As(III), the amount of phosphate adsorbed decreased at all pH levels with increasing As(III) concentrations.

Gas sparging is used as a traditional way to control membrane fouling in submerged membrane bioreactors (MBRs) in wastewater treatment. However, the gas sparging accounts for the largest fraction in operational cost to run the MBR systems. In this study, membrane fouling was controlled by integrating scouring media with gas sparging to reduce fouling rate at relatively low operational energy. Comparative study was performed using a fluidized membrane reactor treating synthetic feed solutions between polyethylene terephthalate (PET) scouring media (SM) fluidized by gas sparging (GS), liquid recirculation (LR), and combination of them to control membrane fouling. Addition of PET scouring media reduced the gas flow rate by 67% more with 30% less in fouling rate than gas sparing only. Combined usage of gas sparging and liquid recirculation to fluidize the PET scouring media (LR + GS + SM) showed 37% lower in fouling rate than that obtained by the scouring media fluidized by liquid recirculation (LR + SM) only through the reactor. The LR + GS + SM configuration reduced energy consumption by 90% more than that required by gas sparging alone. Mechanical cleaning driven by fluidizing PET scouring media could reduce membrane fouling due to removing deposit of inorganic particles from membrane surface effectively. However, the PET scouring media was not very effective to reduce membrane fouling caused by organic colloids which are expected to contribute pore fouling significantly.

We report an arrangement on the effect of anthropogenic litter on marine and estuarine reptiles, checking for evidence about different types of impact (ingestion vs. entanglement) and pressure (three size-based categories). From 1976 to 2018, we obtained a “blacklist” of 11 species impacted by marine litter (about 13% of 85 species of marine and estuarine reptiles), belonging to three orders (Testudines, Squamata, and Crocodilia). We obtained only occasional evidence of an impact for Squamata (Hidrophis elegans, Disteira major) and Crocodilia (Crocodylus porosus). Regarding the different types of pressure, the highest number of evidence has been obtained for macro-litter (10 species) and the lowest for micro-litter (4 species, all Chelonidae). Among Testudines, Lepidochelys kempii and Natator depressus evidenced a lack of data for micro-plastic. In Squamata, information is lacking for micro-plastic with only occasional references for meso-plastic (in Hydrophis elegans) and macro-plastic (Disteira major and Crocodylus porosus). We obtained a direct correlation between the research effort and the number of citations regarding different types of pressure and impact of marine litter: therefore, our blacklist of impacted species could be increased, carrying out further research focused on other poorly studied marine and estuarine reptiles. We suggest the use of a standardized nomenclature to reduce the amount of lost information.

Climate change seriously affects habitat suitability for coldwater fish. Amur whitefish (Coregonus ussuriensis) is a commercially important coldwater fish species found in northeast China that is particularly sensitive to water temperature. We use water temperature models for Songhua (Harbin to Yilan) and Mayi rivers to predict habitat suitability for Amur whitefish and other coldwater fish species during the months of July and August in 2014 and 2100—2 months during which river temperatures can reach extremes. The predict-results showed that fish habitat was to deteriorate over time, and to be less suitable for survival of coldwater fish species in 2100 than that in 2014. Under scenario RCP4.5 (Representative Concentration Pathway 4.5), the time period during which habitat for Amur whitefish was unsuitable increased continually; under scenario RCP8.5 (Representative Concentration Pathway 8.5), Amur whitefish might even disappear from the river basin. A significant increase in river water temperature will compromise coldwater fish survival and possibly lead to their disappearance. Practical measures to control greenhouse gas emissions and reduce the impact of global warming on aquatic ecosystems must be taken.

High retention membrane bioreactors (HR-MBR) combine a high retention membrane separation process such as membrane distillation, forward osmosis, or nanofiltration with a conventional activated sludge (CAS) process. Depending on the physicochemical properties of the trace organic contaminants (TrOCs) as well as the selected high retention membrane process, HR-MBR can achieve effective removal (80–99%) of a broad spectrum of TrOCs. An in-depth assessment of the available literature on HR-MBR performance suggests that compared to CAS and conventional MBRs (using micro- or ultra-filtration membrane), aqueous phase removal of TrOCs in HR-MBR is significantly better. Conceptually, longer retention time may significantly improve TrOC biodegradation, but there are insufficient data in the literature to evaluate the extent of TrOC biodegradation improvement by HR-MBR. The accumulation of hardly biodegradable TrOCs within the bioreactor of an HR-MBR system may complicate further treatment and beneficial reuse of sludge. In addition to TrOCs, accumulation of salts gradually increases the salinity in bioreactor and can adversely affect microbial activities. Strategies to mitigate these limitations are discussed. A qualitative framework is proposed to predict the contribution of the different key mechanisms of TrOC removal (i.e., membrane retention, biodegradation, and sorption) in HR-MBR.