Constructed wetlands are an environmentally friendly and economically efficient sewage treatment technology, with fillers playing an important role in treatment processes. However, traditional wetland fillers (e.g. zeolite) are known to be imperfect because of their low adsorption capacity. In this paper, the adsorbent sodium titanate nano fillers (T3-F) was synthesized as an alternative to traditional filler with sodium titanate nanofibers (T3) as the raw material, epoxy adhesive as the adhesive agent and NH₄HCO₃ as the pore-making agent. The properties of T3-F were characterized by powder X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), porosity. The effect of different parameters such as pH, co-existing ions, contact time, initial metal ion concentrations and temperature was investigated for heavy metal adsorption. The results showed that the adsorption of heavy metal by T3-F followed the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacities for Cu²⁺, Pb²⁺, Zn²⁺, Cd²⁺ were about 1.5–1.98 mmol/g, which were 4–5 times that of zeolite, the traditional commonly used filler. Moreover, T3-F could entrap toxic ions irreversibly and maintain structural stability in the adsorption process, which solved the issue of secondary pollution. In the presence of competing ions, the adsorption efficiency for Pb²⁺ was not reduced significantly. Adsorption was strongest at high pH. From the results and characterization, an adsorption mechanism was suggested. This study lays a foundation for the practical application of T3-F as a constructed wetland filler in the future.

Climate change and pharmaceuticals contamination constitute two of the most relevant stressors on the aquatic ecosystems, however, there is a huge lack of information regarding the interactive effects of both stressors. For that, a mesocosm experiment was implemented where adult zebrafish were exposed to combined temperature and the progestin levonorgestrel (LNG) for 21 days. Considering that the liver is one of the organs where there is a greater metabolization and accumulation of toxicants, the main objective of this work was to assess the effects of both stressors on the female zebrafish hepatocytes morphology and functioning, through stereological and immunohistochemical techniques.Our results revealed an increase of coefficient of variation of the number distribution of hepatocytes volume (CVN(υ)) for individuals exposed to LNG, which denotes an increase of the hepatocytes size variability and is suggestive of functional impacts. This was corroborated by the signs of increased glycogen content with the exposure to increased LNG concentrations and temperature, indicating modified hepatocyte glycogen metabolism. Such disturbances can be considered indicators that the fish had to deal with impacts caused by the stress factors.Regarding the immunoreactivity, from the four proteins selected (catalase, CYP1A, HSP90 and Vtg), just in two of them (catalase and Vtg) were observed some responses to both stressors. For catalase there was a hormetic response, in which exposure to lower LNG concentrations caused a significant higher positive immunostaining than under higher LNG concentrations. While, for Vtg, significant effects of temperature and LNG existed, in which a decline in Vtg immunostaining was observed with exposure to higher temperature and lower LNG concentrations. These results should be seen as a warning sign about fine impacts of multiple stressors, such as temperature and progestogens, on the structure and functioning of zebrafish liver and potentially in other aquatic organisms, and on their health implications.

Metals are released from biochar (BC) in either the free or dissolved organic carbon (DOC)-combined form. The complexation of metals with DOC influences their toxicity and bioavailability in the environment. The endogenous release of metal species with heterogeneous DOC from BC is very complex; this process has been neglected and remains unaddressed in the literature to date. In this study, the yield and chemical properties of labile DOC from BC were characterized, and the release of endogenous metal/metalloid elements (K, Mg, Mn, Fe, Al, Cu, and Si) and their species from BC with various pyrolysis temperatures and particle sizes were systematically investigated under various solution chemistries. The results showed that pyrolysis temperature of BC significantly influenced the yield and composition of DOC and DOC-metal/metalloid complexes, while particle size had lower impact. The yield of BC-derived DOC significantly decreased and the components gradually changed from low-molecular weight and low-aromaticity hydrophilic humic acid-like substances to complex high-molecular weight and high-aromaticity hydrophobic substances as pyrolysis temperature increased from 200 to 700 °C. The release of total dissolved metals decreased with increasing pyrolysis temperature, while the highest total dissolved Si was released from BC with the moderate pyrolysis temperature (500 °C). The metal elements were mainly released in the DOC-combined form, while the released Si was mainly in the free form in the neutral water environment. The release of DOC increased while that of dissolved metals decreased with increasing solution pH. The release of total dissolved metals/metalloids increased but the ratio of the DOC-combined metals/metalloids decreased with increasing solution ionic strength. These results provide new insight into the understanding of endogenous metal/metalloid release from BC in the natural environment.

Aerosol particulate matter with dynamic diameter smaller than 2.5 μm (PM₂.₅) is the main cause for haze pollution in China. As a dominant precursor of PM₂.₅, SO₂ emitted from industrial process is now strictly controlled by using limestone/gypsum Wet Flue Gas Desulfurization (WFGD) system in China. However, a phenomenon that fine particle derived from WFGD is recently addressed, and is suggested to be a potential source of primary PM₂.₅. Herein, a first investigation into the particle generation mechanism in WFGD system is conducted with a novel droplet (containing particles) drying and breakage model. The proposed model considers a random and porous crust instead of the previous regular crust assumption, and is verified by comparing the modeling results with measurements. An orthogonal test with four factors and three levels is carried out through modeling calculation, and flue gas temperature (Tg) in the inlet is found to be a governing parameter for PM₂.₅ yields in WFGD. With Tg in range of 120–160 °C, PM₂.₅ yields in desulfurizing tower can reach a maximum value at ∼2 × 10⁸ cm⁻³ under typical WFGD condition. To avoid this situation and reduce the PM₂.₅ generation, Tg is suggested to be lower than 120 °C. Additionally, a new insight of the elimination effect of gas-gas heater (GGH) on “gypsum rain” in WFGD system is provided.

Epidemiological studies have demonstrated association between the total mass of fine particulate matter (PM2.5) exposures and inflammation. There are few studies exploring the associations between PM2.5 constituents and the biomarkers of inflammation in older adults and the underlying biological mechanisms are not exact. In this study, we examined the associations between PM2.5 and its constituents (organic carbon (OC), elemental carbon (EC), total carbon (TC), polycyclic aromatic hydrocarbons (PAHs) and complement three factor (C3), an important biomarker of inflammation in a repeated panel of 175 older adults in Beijing, China. We have constructed three different linear mixed effect models (single-pollutant model, constituent-PM2.5 joint model, and constituent-residual model) to evaluate the association of PM2.5 and its constituents and complement C3, controlling for concentration of high sensitive C-reactive protein (hs-CRP), day of week, mean temperature, relative humidity, location and potential individual confounders. We found robust positive associations of OC, EC, TC, PAHs and PM2.5 mass concentration with complement C3 at different lag patterns. The cumulative effects of pollutants increased across average of 2–5 days. Individuals aged 65 and above, or with diabetes, or BMI ≥30, or with no-cardiopathy, or with hypertension also exhibited positive associations between PM2.5 and complement C3. The results revealed that short-term exposure to PM2.5 and its constituents could result in a significant increase in serum level of complement C3. These findings suggested a possible involvement of complement C3 in the effect of PM2.5 on inflammatory reaction.

Disinfection byproducts (DBPs) generated by ballast water treatment have become a concern worldwide because of their potential threat to the marine environment. Predicting the relative DBP concentrations after disinfection could enable better control of DBP formation. However, there is no appropriate method of evaluating DBP formation in a full-scale ballast water treatment system (BWTS). In this study, multiple regression models were developed for predicting the dibromochloromethane (DBCM) and bromoform (TBM) concentrations produced by an emergency BWTS using field experimental data from ballast water treatments conducted at Dalian Port, China. Six combinations of independent variables [including several water parameters and/or the total residual oxidant (TRO) concentration] were evaluated to construct mathematical prediction formulas based on a polynomial linear model and logarithmic regression model. Further, statistical analyses were performed to verify and determine the appropriate mathematical models for DBCM and TBM formation, which were ultimately validated using additional field experimental data. The polynomial linear model with four variables (temperature, salinity, chlorophyll, and TRO) and the logarithmic regression model with seven variables (temperature, salinity, dissolved oxygen, pH, turbidity, chlorophyll, and TRO) exhibited good reproducibility and could be used to predict the DBCM and TBM concentrations, respectively. The validation results indicated that the developed models could accurately predict DBP concentrations, with no significant statistical difference from the measured values. The results of this work could provide a theoretical basis and data reference for ballast water treatment control in engineering applications of emergency BWTSs.

Baseline emission values of greenhouse gases were not well established for commercial poultry barns in cold regions, including Canada, due to a lack of well-designed field studies. Emission factors of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), were acquired for a commercial broiler barn and cage-layer barn in the Canadian Prairies climate. Between March 2015 and February 2016, monthly measurements throughout the year for the layer barn and over 6 flocks for the broiler barn, and diurnal measurements in the mild, warm, and cold seasons for both barns were conducted, respectively. The ventilation rate was estimated based on a CO₂ mass balance method; thus CO₂ emissions were quantified by the CIGR (2002) models. The CH₄ and N₂O emissions present at low levels from global perspective for both barns; the cold climate proved to be a major reason for the lower CH₄ emission from the layer barn. Considerable seasonal effect was observed only for N₂O emissions from the broiler barn, and for CH₄ and N₂O emissions from the layer barn, both with higher emissions in the mild and warm seasons than in the cold season. The big diurnal variations of CO₂ emissions for the layer barn demonstrated the uncertainty of the seasonal results by snapshot measurements and correction factors (from −20.9% to −22.5%) were obtained. Besides, the difference of CH₄ and N₂O concentrations and emissions as well as CO₂ concentrations between best-case (the first day after manure removal) and worst-case conditions (the last day before manure removal) was not obvious for the layer barn. Additionally, changes of temperature and ventilation rate were likely to have more impact on N₂O emission for the broiler barn and more impact on CH₄ emission for the layer barn than on the other two gas emissions, both with positive correlations.

This study developed a novel Hg(II) immobilization strategy by firstly incubating algal cells in high-phosphate cultures for surface modification, followed by obtaining the P-rich biomass as adsorbents for enhanced Hg(II) removal and then charring the Hg-loaded biomass to prevent leaching of phosphate and to immobilize Hg(II). For algal surface modification, Scenedesmus obtusus XJ-15 were cultivated under different P concentrations and obtained the highest sites concentration of surface phosphoryl functional groups in 80 mg L⁻¹ P cultures. For Hg(II) adsorption, biomass from 80 mg L⁻¹ P cultures (B-80) achieved the highest saturated sorption capacity of 95 mg g⁻¹ fitting to Langmuir isotherm model under the optimum pH of 5.0. For charring stabilization, the Hg-loaded B-80 was calcinated under different temperatures, and the product obtained from 300 °C charring showed the lowest Hg(II) leaching rate without P release. Moreover, FT-IR and XPS analysis indicate that the surge of surface phosphoryl functional groups dominated the enhancement of Hg(II) sorption and also Hg(II) charring immobilization. The above results suggested that the developed strategy is promising for both phosphate and mercury removal from water and for co-immobilization of P and Hg(II) to prevent leaching.

Microplastic (MP) pollution is potentially a major threat to many aquatic organisms. Yet we currently know very little about the mechanisms responsible for the effects of small MPs on phenotypes, and the extent to which effects of MPs are modified by genetic and environmental factors. Using a multivariate approach, we studied the effects of 500 nm polystyrene microspheres on the life history and immunity of eight clones of the freshwater cladoceran Daphnia magna reared at two temperatures (18 °C/24 °C). MP exposure altered multivariate phenotypes in half of the clones we studied but had no effect on others. In the clones that were affected, individuals exposed to MPs had smaller offspring at both temperatures, and more offspring at high temperature. Differences in response to MP exposure were unrelated to differences in particle uptake, but were instead linked to an upregulation of haemocytes, particularly at high temperature. The clone-specific, context-dependent nature of our results demonstrates the importance of incorporating genetic variation and environmental context into assessments of the impact of plastic particle exposure. Our results identify immunity as an important mechanism underpinning genetically variable responses to MP pollution and may have major implications for predicting consequences of MP pollution.

Climatic stressors and chemicals should not be treated as isolated problems since they often occur simultaneously, and their combined effects must be evaluated including their possible interactive effects. In the present study we subjected springtails (Folsomia candida) to combined exposure to phenanthrene and dynamic heat cycles in a full factorial experiment. In a microcosm experiment, we studied the population growth of springtails subjected to a range of sub-lethal concentrations of phenanthrene. During the 28-day experiment we further subjected microcosms to varying numbers of repeated dynamic heat cycles (0–5 cycles) simulating repeated heat waves. We found a synergistic interaction between the effects of phenanthrene and the number of heat waves on both body mass of adults and juvenile production of F. candida showing that the negative effects of phenanthrene were intensified when animals were heat stressed, and/or vice versa. This interaction was not related to internal concentrations of phenanthrene in adult springtails, nor was it due to altered degradation of phenanthrene in soil. We argue that both phenanthrene (by its partitioning into membrane bilayers) and heat have detrimental effects on the physical conditions of cellular membranes in a dose-dependent manner, which, under extreme circumstances, can increase membrane fluidity to a level which is sub-optimal for normal membrane functioning. We discuss the possibility that the synergistic interactions subsequently reduce life-history parameters such as growth and reproduction.