[en] Highlights: • Present review focuses on roles of biochar, AMF and their combination in soil quality improvement. • Functionality and dynamics of biochar and AMF in soil has been decoded. • Combined application of biochar and AMF (BC + AMF) could open a promising way of soil rejuvenation. • Above mentioned soil amendments play crucial roles in environmental management. Conservation of soil health and crop productivity is the central theme for sustainable agriculture practices. It is unrealistic to expect that the burgeoning crop production demands will be met by a soil ecosystem that is increasingly unhealthy and constrained. Therefore, the present review is focused on soil amendment techniques, using biochar in combination with arbuscular mycorrhizal fungi (AMF), which is an indispensable biotic component that maintains plant-soil continuum. Globally significant progress has been made in elucidating the physical and chemical properties of biochar; along with its role in carbon sequestration. Similarly, research advances on AMF include its evolutionary background, functions, and vital roles in the soil ecosystem. The present review deliberates on the premise that biochar and AMF have the potential to become cardinal to management of agro-ecosystems. The wider perspectives of various agronomical and environmental backgrounds are discussed. The present state of knowledge, different aspects and limitations of combined biochar and AMF applications (BC + AMF), mechanisms of interaction between biochar and AMF, effects on plant growth, challenges and future opportunities of BC + AMF applications are critically reviewed. Given the severely constrained nature of soil health, the roles of BC + AMF in agriculture, bioremediation and ecology have also been examined. In spite of the potential benefits, the functionality and dynamics of BC + AMF in soil are far from being fully elucidated.

[en] Highlights: • Potential pathogens in marine environments increase with anthropogenic activities. • Anthropogenically-impacted coastal microbiomes are different from less impacted microbiomes. • Antimicrobial resistance genes were enriched in the anthropogenic-impacted microbiota. Anthropogenic activities in coastal marine ecosystems can lead to an increase in the abundance of potentially harmful microorganisms in the marine environment. To understand anthropogenic impacts on the marine microbiome, we first used publicly available microbial phylogenetic and functional data to establish a dataset of bacterial genera potentially related to pathogens that cause diseases (BGPRD) in marine organisms. Representatives of low-, medium- and highly impacted marine coastal environments were selected, and the abundance and composition of their microbial communities were determined by quantitative PCR and 16 S rRNA gene sequencing. In total, 72 BGPRD were cataloged, and 11, 36 and 37 BGPRD were found in low-, medium- and highly human-impacted ecosystems, respectively. The absolute abundance of BGPRD and the co-occurrence of antibiotic resistance genes (AGR) increased with the degree of anthropogenic perturbation in these ecosystems. Anthropogenically impacted coastal microbiomes were compositionally and functionally distinct from those of less impacted sites, presenting features that may contribute to adverse outcomes for marine macrobiota in the Anthropocene era.

[en] Highlights: • The rise of temperature and Cd exposure level increased Cd accumulation in leaves. • High temperature and Cd exposure have negative effects on physiological traits. • The lowest leaf number and length occurred at high temperature × high Cd exposure. • Temperature rise would aggravate Cd toxicity on Myriophyllum aquaticum. • The seedlings from seeds have no advantage to cope with Cd over the propagules. Due to a close contact with water column, submerged macrophytes are easily disturbed by environment change in freshwater ecosystems, especially at the seedling stage. In recent decades, freshwater ecosystems have been subject to severe cadmium (Cd) pollution, which can cause toxic effects on the growth of submerged macrophytes. Moreover, the temperature rise resulting from climate warming and water level decline may further aggravate such effect, especially in shallow lakes. Here, we investigated the independent and interaction effects of Cd exposure levels (0, 0.5, 1, and 2.5 mg L⁻¹) and temperature (15, 25, and 30 °C) on morphological and physiological traits of Myriophyllum aquaticum (Vell.) Verd. Seedlings generated from propagules and seeds. The temperature rise and Cd exposure generally resulted in a significant increase of Cd concentrations and antioxidant enzyme activities in leaves, as well as a decrease of chlorophyll a and b concentrations. The number and length of leaves generated from propagules always show a downward trend with the increase of Cd exposure, regardless of the temperature. Moreover, the lowest leaf number and length always occurred at high temperature (i.e. 30 °C) when the Cd exposure level increased to 1 and 2.5 mg L⁻¹. For the seedlings generated from seeds, the temperature rise caused an increase of leaf emergence rate under low Cd exposure levels, but resulted in a significant decrease with the Cd exposure level. This study indicates the negative effects of Cd exposure and temperature rise on submerged macrophytes at the seedling stage, and highlights that temperature rise would enhance Cd toxicity.

[en] Highlights: • Physical process controls aggregation mechanism of MPs. • Brownian motion and structural layer force play a dominant role in aggregation behavior of NPs. • The concentration, valence and hydrated ability of cations jointly affect aggregation rate and aggregate structure of NPs. • Anion species play a role in the reaction-controlled regime. • NPs preferentially aggregate in eutrophication, high hardness areas and sea water. In recent years, microplastics (MPs) and nanoplastics (NPs) have attracted worldwide attention because of the potential risks they pose to aquatic environments, but there are few studies on the difference of aggregation mechanism between MPs and NPs. In this study, 100 nm and 1 μm polystyrene plastics were selected as models to explore the aggregation mechanism of MPs/NPs under different aquatic environments. The influence of ion species and concentrations on the aggregation behaviors and kinetics were systematically investigated to predict the effects of water quality on the occurrence form of MPs and NPs based on DLVO theory and revised modified Smoluchowski theory. Results showed concentration, valence and hydrated ability of cations jointly affected the aggregation behavior of NPs. The critical coagulation concentration ratio of cations were consistent with Schulze-Hardy rules. But the different aggregation rate coefficients of same valent cations were ascribed to the structural layer force. Anion species played a role in the reaction-controlled regime by producing hydrogen ions to neutralize negative charges on NPs surfaces. Due to the strong Brownian motion and structural layer force, NPs would be stable in freshwater but preferentially aggregated when transport through brackish water, estuaries, eutrophication and high hardness areas and sea water, forming the accumulation hot spots of NPs in the sediment. While for MPs, physical process controlled the aggregation mechanism of them, leading to high stability in natural water and eventually transporting into marine environments. This study provided a theoretical foundation for assessing the transport, distribution, fate and ecological risks of MPs and NPs in realistic aquatic environments.

[en] Highlights: • PM_2.5 pollution and O₃ pollution often occur simultaneously during summer. • Opposite relationship between boundary layer height and pollution was found in Shanghai. • Dominant polluted synoptic patterns and their impacts in Beijing and Shanghai were elucidated. The rapid development in the economy during past decades has caused serious air pollution issues in China with high concentrations of PM_2.5 and O₃, particularly in the densely populous cities. To integrate PM_2.5 and O₃ controls, it is necessary to understand the impacts of meteorology on both pollutants. Thereby, the complex linkages between planetary boundary layer (PBL), synoptic forcing, regional transport, and heavy pollution in Beijing and Shanghai during summer were investigated using long-term measurements, simulations, and reanalysis. Influenced by the unfavorable meteorological conditions, PM_2.5 pollution and O₃ pollution often simultaneously occurred. In Beijing, the heavy concurring pollutions usually happened on the days with shallow afternoon PBL and southerly/southwesterly prevailing winds. Within the PBL, the pollutants emitted from the southern plains can be transported to Beijing and accumulated on the windward side of the mountains. At the top of PBL, the synoptic southerly warm advections can strengthen the elevated thermal inversion layer and suppress the development of PBL, leading to worse pollution. Contrarily, the heavy pollutions in Shanghai usually occurred on the days with deep afternoon PBL and southwesterly warm advections within the PBL. Although the warm advections were more favorable to the PBL development than the movements of cool marine air mass, the input of pollutants from the southwest can overweigh this advantage, resulting in poor air quality in Shanghai. The occurrence of heavy pollution or clean condition in Shanghai was primarily determined by the synoptic forcing rather than the local PBL structure. This comparative study indicates that the relationship between PBL height and pollution level is changeable and complicated, which needs to be elucidated from the synoptic perspective.

[en] Highlights: • Iminodiacetic functionalized magnetic peanut husk (PN–Fe₃O₄-IDA) was synthesized. • PN-Fe₃O₄-IDA was used as an adsorbent for the removal of Cu and Pb in solution. • Coordination and electrostatic attraction are main mechanisms for the adsorption. • High removal efficiency and operational convenience with the use of PN-Fe₃O₄-IDA. • Excellent features of PN-Fe₃O₄-IDA promotes its practical applications. The presence of higher concentrations of heavy metals in water affects its quality with a concomitant adverse effect on its users thus their removal is paramount. A novel adsorbent, PN-Fe₃O₄-IDA derived from the chemical modification of peanut husk (a low-cost agricultural biomass produced in significant quantities globally) using magnetic nanoparticles (Fe₃O₄) and iminodiacetic acid was utilized for the remediation of heavy metals in aqueous solution. Analytical techniques vis-à-vis the Fourier-Transform Infrared, Scanning Electron Microscope, Brunauer–Emmett–Teller, X-ray photoelectron spectroscopy and X-ray Diffraction were applied for the characterization of PN-Fe₃O₄-IDA. Results from the characterization studies showed that PN-Fe₃O₄-IDA possessed a mesoporous structure, a heterogeneous surface and functional groups such as carboxylic acid and a tertiary nitrogen atom which enhanced its adsorption capacities as well as magnetic properties which ensured its easy removal from the solution using a magnet. The maximum uptake of Pb and Cu onto PN-Fe₃O₄-IDA was 0.36 and 0.75 mmol g⁻¹ (at 318 K) respectively with the chemisorption process being the major reaction pathway for the processes. The synthesized adsorbent exhibits significant adsorption capacity for the selected pollutants as well as some unique features which promotes its use as an adsorbent for wastewater remediation processes.

[en] Highlights: • Two ecotypes of Sedum alfrdii showed different root cell wall (RCW) thickness in response to Cd. • The methylation degree of pectin had opposite trend in NHE and HE S. alfredii. • RCW thickened due to the increased content of cellulose and lignin under Cd stress. • Cd induced the same spatial distribution of thickened cell wall and methylated pectin. • Pectinous RCW thickening contributed more Cd bonded tightly in the NHE than in the HE. Root cell wall (RCW) modification is a widespread important defense strategy of plant to cope with trace metals. However, mechanisms underlying its remolding in cadmium (Cd) accumulation are still lacking in hyperaccumulators. In this study, changes of RCW structures and components between nonhyperaccumulating ecotype (NHE) and hyperaccumulating ecotype (HE) of Sedum alfredii were investigated simultaneously. Under 25 μM Cd treatment, RCW thickness of NHE is nearly 2 folds than that of HE and the thickened cell wall of NHE was enriched in low-methylated pectin, leading to more Cd trapped in roots tightly. In the opposite, large amounts of high-methylated pectin were assembled around RCW of HE with Cd supply, in this way, HE S. alfredii decreased its root fixation of Cd and enhanced Cd migration into xylem. TEM and AFM results further confirmed that thickened cell wall was caused by the increased amounts of cellulose and lignin while root tip lignification was resulted from variations of sinapyl (S) and guaiacyl (G) monomers. Overall, thickened cell wall and methylated pectin have synchronicity in spatial location of roots, and their coordination contributed to Cd accumulation in S. alfredii.

[en] Highlights: • Positive matrix factorization was used to obtain potentially toxic elements sources. • Exposure risk model was used to calculate health risk of potentially toxic elements. • Geostatistics was applied to determine hazardous area with health risk. • Significant human influence was identified on all 9 potentially toxic elements. • Non-carcinogenic risk of potentially toxic elements was found for children. Quantifying source apportionment of potentially toxic elements (PTEs) in soils and associated human health risk (HHR) is essential for soil environment regulation and pollution risk mitigation. For this purpose, an integrated method was proposed, and applied to a dataset consisting of As, Cd, Cr, Cu, Hg, Ni, Pb, Se, and Zn in 273 soil surface samples. Positive matrix factorization (PMF) was used to quantitatively examine sources contributions of PTEs in soils; and the HHR arising from the identified source was determined by combining source profiles and health risk assessment; at last, sequential Gaussian simulation (SGS) was used to identify the areas with high HHR. Four sources were identified by PMF. Natural and agricultural sources affected all 9 PTEs contents with contributions ranging from 19.2% to 62.9%. 41.9% of Cd, 40.8% of Pb, 58.6% of Se, and 29.8% of Zn were controlled by industrial and traffic emissions. Metals smelting and mining explained 35.5%, 30.5%, and 24.9% of Cr, Cu, and Ni variations, respectively. Hg was dominated by atmospheric deposition from coal combustion and coking (58.7%). The mean values of the total non-carcinogenic risks of PTEs were 1.55 × 10⁻¹ and 9.40 × 10⁻¹ for adults and children, and the total carcinogenic risk of PTEs had an average value of 8.86 × 10⁻⁵. Based on source-oriented HHR calculation, natural and agricultural sources were the most important factor influencing HHR, explaining 51.0% and 49.1% of non-carcinogenic risks for children and adults, and 44.2% of carcinogenic risk. SGS indicated that 1.1% of the total area was identified as hazardous areas with non-carcinogens risk for children.

[en] Highlights: • Biological and environmental factors controlling concentration of halocarbons in the YS and the ECS were investigated. • Bromoperoxidase (BrPO) activities in the YS and ECS during winter were measured for the first time. • The production mechanism of halocarbons was identified through incubation experiments in BrPO-treated seawater. • The influences of specific factors on the production of halocarbons in the enzyme-mediated reaction. Volatile brominated compounds are important trace gases for stratospheric ozone chemistry. In this study, the spatial variations of dibromomethane (CH₂Br₂), bromodichloromethane (CHBrCl₂), dibromochloromethane (CHBr₂Cl) and bromoform (CHBr₃) in the seawater and overlying atmosphere were measured in the Yellow Sea (YS) and the East China Sea (ECS) in winter. The air-sea fluxes of CH₂Br₂, CHBrCl₂, CHBr₂Cl and CHBr₃ ranged from −11.46 to 25.33, −4.68 to 7.91, −8.60 to 4.08 and −88.57 to 8.84 nmol m⁻²·d⁻¹, respectively. In order to understand the mechanism of halocarbons production, we measured bromoperoxidase (BrPO) activity (39.18–186.74 μU·L⁻¹) in the YS and ECS for the first time using an aminophenyl fluorescein (APF) method and performed in-situ incubation experiments in BrPO-treated seawater. The production rates of CH₂Br₂, CHBrCl₂, CHBr₂Cl and CHBr₃ ranged from 14.21 to 94.74, 0.00 to 19.74, 0.00 to 30.62 and 6.18–72.75 pmol L⁻¹·h⁻¹, respectively, in BrPO-treated seawater. There were significantly higher production rates in coastal waters compared with the open sea (P = 0.016) because of higher DOC levels near the coast. Moreover, the production rates of halocarbons increased with BrPO activity and H₂O₂ concentration. The results showed that enzyme-mediated reaction was an important source for the production of halocarbons in seawater. The present research is of great significance for understanding the production mechanisms of halocarbons in seawater and global oceanic halocarbons emissions.

[en] Highlights: • Birds exposed to Deepwater Horizon crude oil had lower body weights and increased liver mass. • Oil exposure increased reticulocytes and mean corpuscular hemoglobin concentration. • Light and electron microscopy revealed no evidence of Heinz bodies in zebra finches exposed to oil. Exposure to crude oil during spill events causes a variety of pathologic effects in birds, including oxidative injury to erythrocytes, which is characterized in some species by the formation of Heinz bodies and subsequent anemia. However, not all species appear to develop Heinz bodies or anemia when exposed to oil, and there are limited controlled experiments that use both light and electron microscopy to evaluate structural changes within erythrocytes following oil exposure. In this study, we orally dosed zebra finches (Taeniopygia guttata) with 3.3 or 10 mL/kg of artificially weathered Deepwater Horizon crude oil or 10 mL/kg of peanut oil (vehicle control) daily for 15 days. We found that birds receiving the highest dosage experienced a significant increase in reticulocyte percentage, mean corpuscular hemoglobin concentration, and liver mass, as well as inflammation of the gastrointestinal tract and lymphocyte proliferation in the spleen. However, we found no evidence of Heinz body formation based on both light and transmission electron microscopy. Although there was a tendency for packed cell volume and hemoglobin to decrease in birds from the high dose group compared to control and low dose groups, the changes were not statistically significant. Our results indicate that additional experimental dosing studies are needed to understand factors (e.g., dose- and species-specific sensitivity) and confounding variables (e.g., dispersants) that contribute to the presence and severity of anemia resulting from oil exposure in birds.