Increasing contamination of polycyclic aromatic hydrocarbons in Chinese soils.

China is facing a serious threat PAHs contaminated soil. To better understand the current state of soil PAH pollution in China and contribute to the development of feasible prevention and control measures and policies in the future. This study examines the spatiotemporal distributions of soil Polycyclic Aromatic Hydrocarbons (PAHs) pollution in China since 2000, and investigates the key factors influencing changes in levels of soil PAHs. The results of the survey on soil PAHs concentration levels in 716 areas were analyzed by visualization of ArcGIS pro data, correlation analysis and linear regression analysis, it was found that the increase in soil PAH pollution in China is concerning. The analysis indicates significant regional disparities, with pollution levels in the north being higher than in the south. Over the 20-year period, the median level of PAHs in soil increased by 476.8 µg/kg. Construction land areas that heavily rely on fossil fuels and industrial activities exhibit significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) compared to other land use types. The study identifies key socio-economic factors linked to rising PAH levels, including energy consumption (notably coal and oil), industrial and domestic waste production. Coal consumption is highlighted as the leading factor in PAH concentration changes in 18 provinces, followed by industrial waste in 6 provinces. Future projections up to 2030 suggest continued influence of these factors on soil PAH levels. The research emphasizes the urgent necessity for comprehensive soil management policies to address the growing PAH pollution, offering insights into its dynamics and contributing factors in China.

Ecological role of reed belts in lakeside zone: Impacts on nutrient retention and bacterial community assembly during Hydrilla verticillata decomposition.

Reed belts acting as basic nutrient filters are important parts of lake buffer riparian zones. However, little is known about their impacts on nutrient release and bacterial community during plant litter decomposition. In this study, a field experiment was conducted in west-lake Taihu to monitor the changes in nutrients, bacterial enzymatic activities, and bacterial community in plant debris during Hydrilla verticillata (H. verticillata) decomposition in open water (HvC) and reed belts (HvL) area for 126 days. We found that there was lower temperature but higher nutrient concentrations in overlying water in HvL than HvC. Partial least squares path modeling revealed that environmental parameters in overlying water had important impacts on bacterial activities and nutrient release (such as alkaline phosphatase, cellulase, and soluble sugar) and therefore affected dissolved organic matter components in plant debris. According to Illumina sequencing, 46,003 OTUs from 10 dominant phyla were obtained and Shannon index was higher in HvL than HvC at the same sampling time. Neutral community model explained 49% of bacterial community variance and immigration rate by the estimate of dispersal in HvC (Nm: 27,154) and HvL (Nm: 25,765), respectively. Null model showed stochastic factors governed the bacterial community assembly in HvC (66.67%) and HvL (87.28%). TP and pH were key factors affecting the bacterial community structure at the phylum level. More hubs and complex interactions among bacteria were observed in HvL than HvC. Function analysis showed bacterial community had important role in carbon, organic phosphorus, and nitrogen removal but phosphorus-starvation was detected in debris of H. verticillata. This study provides useful information for understanding the changes in nutrients and bacterial community in litter during H. verticillata decomposition and highlights the role of reed belts on retained plant litter to protect lake from pollution.

Vallisneria natans decreased CH4 fluxes in wetlands: Interactions among plant physiological status, nutrients and epiphytic bacterial community.

Submerged macrophytes provide niches for epiphytic microbes (including aerobic methanotrophs) growth. However, little is known about the impacts of submerged macrophytes growth status and nutrients loadings on methanotroph community and methane release in wetlands. In the present study, methane fluxes, bacterial and methanotroph community in epiphytic biofilm, and environmental parameters were investigated during Vallisneria natans senescence in wetlands under low (VnL) and high (VnH) nutrients for seven weeks. Relative conductivity and concentration of H2O2, total chlorophyll and malondialdehyde were higher in leaves of V. natans in VnH than VnL at the same sampling time. Nutrients loading increased methane fluxes in treatments with or without (Control) macrophytes, while healthy V. natans plants reduced the methane flux and nutrients concentration in water columns. CH4 fluxes were positively correlated to temperature and COD (p < 0.05). Methane oxidation rates were 3.04-31.68 µmol methane mg-1 fresh weight of V. natans leaves - epiphytic biofilm within 1 h. Proteobacteria, Cyanobacteria, Bacteroidetes, Verrucomicrobia, Planctomycetes, Actinobacteria and Acidobacteria were dominant phylum in all epiphytic biofilms. The mean abundances of pmoA/16S rRNA were higher in VnL than VnH. According to Illumina sequencing results of pmoA gene, γ-proteobacteria and α-proteobacteria were the dominant methanotroph class in epiphytic biofilm from VnH and VnL, respectively. Among seven detected methanotrophic genera, Methylomonas was significantly higher in VnH than VnL. Network analysis revealed that there were much closer relationships between the environmental parameters and epiphytic bacterial community in VnH than in VnL. COD and MDA were negatively correlated with Methyloglobulus, Methylosarcina, Methylobacter and Methylocystis, but positively correlated with Methylomonas and Methylosinus. This study highlights that methanotrophs in epiphytic biofilm play important roles in methane-oxidizing, which can be affected by plant physiological status and environmental parameters.

Reed restoration decreased nutrients in wetlands with dredged sediments: Microbial community assembly and function in rhizosphere.

Using dredged sediments as substrate for aquatic plants is a low-cost and ecological friendly way for in situ aquatic ecological restoration. However, the limited information available about how aquatic plant restoration affects the microbial ecology and nutrients in dredged sediments. In this study, nutrient contents, enzyme activities, and bacterial and archaeal communities in vertical sediment layers were determined in bulk and reed zones of wetlands constructed with dredged sediments in west Lake Taihu for three years. Reed restoration significantly decreased total nitrogen, total phosphorus, and organic carbon contents and increased alkaline phosphatase, urease, and sucrase activities compared to bulk area. Bacterial communities in vertical sediment layers had higher similarity in reed zone in comparison to bulk zone, and many bacterial and archaeal genera were only detected in reed rhizosphere zones. Compared with the bulk zone, the reed restoration area has a higher abundance of phylum Actinobacteriota, Hydrothermarchaeota, and class α-proteobacteria. The assembly process of the bacterial and archaeal communities was primarily shaped by dispersal limitation (67.03% and 32.97%, respectively), and stochastic processes were enhanced in the reed recovery area. Network analysis show that there were more complicated interactions among bacteria and archaea and low-abundance taxa were crucial in maintaining the microbial community stability in rhizosphere of reed zone. PICRUST2 analysis demonstrate that reed restoration promotes metabolic pathways related to C and N cycle in dredged sediments. These data highlight that using dredged sediments as substrates for aquatic plants can transform waste material into a valuable resource, enhancing the benefits to the environment.

Oligotriarylamine-Extended Organoboranes with Tunable Electron-Donating Strength by Changing the Number of Donor Units.

Triarylborane (Ar3B) and triarylamine (Ar3N) have been widely employed to construct electronically different donor-acceptor (D-A) systems. Herein, we describe a series of A-D-A-type luminescent organoboranes L-B2Nn (n = 1, 3, 5) that show an increased number of Ar3N units as electron donors and two terminal Ar3B as acceptors. When the Ar3N moieties were extended from one to five units, their electron-donating strength was gradually enhanced and the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy gaps could also be tuned, which was further reflected in the red-shifted emissions from blue (λem = 458 nm) to orange (λem = 595 nm) with a decrease in Egap(elect) from 3.19 to 2.61 eV. L-B2N5 showed a huge Stokes shift (∼14 057 cm-1) and a considerably bright emission with an enhanced solid-state quantum efficiency (ΦS = 98%) compared with the other members. L-B2N3 and L-B2N5 exhibited aggregation-induced emissions (AIEs), and an apparent solvatochromic shift was also observed in the emission spectra as the solvent was changed from hexane to tetrahydrofuran (THF) (430 → 595 nm). In addition, the donor-acceptor charge-transfer character in these organoboranes caused a thermally responsive emission over a broad range.

Effects of lead pollution on bacterial communities in biofilm attached to submerged plants.

Submerged plants and biofilms have significant advantages in hydro-ecology rehabilitation, but their tolerance and physiological responses to heavy metal stress have thus far been under-investigated. This study investigated the influence of lead on physiological and biochemical responses, as well as variation in bacterial communities and functional characteristics of submerged plant biofilms. The results showed that chlorophyll a content of two submerged plants decreased with increased lead concentration. The concentration of malondialdehyde of both submerged plants was higher under high lead concentrations than under low lead concentrations, and the concentrations of malondialdehyde and hydrogen peroxide in Vallisneria natans were more stable. The antioxidant enzyme systems of the two plants played protective roles against lead stress. High lead concentration can inhibit the bacterial community and lead to decreased diversity. The most abundant bacterial phyla were Proteobacteria (40.9%), Cyanobacteria (21.5%), and Bacteroidetes (14.3%). Proteobacteria abundance decreased with increased lead concentration, while Cyanobacteria abundance increased. The lead concentration in plants (19.7%, P < 0.01) and the lead concentration in aquatic environment (17.7%, P < 0.01) were significantly correlated with variation in bacterial communities. High lead concentration inhibits the activity of these bacteria related to the conversion of nitrogen and sulfur.

Pillar[5]arene-Based Dual Chiral Organoboranes with Allowed Host-Guest Chemistry and Circularly Polarized Luminescence.

We first describe two examples of highly luminescent organoboranes (NP5BN1 and NP5BN2) with dual chirality that were achieved by molecular functionalization of planar chiral pillar[5]arenes with naphthyls. Sufficiently strong steric effects are imposed by triarylamine (Ar3N) and triarylborane (Ar3B) moieties and further enhanced by the proximity of the chiral building blocks, leading to the isolation of multiple enantiomers via chiral high-performance liquid chromatography. The intramolecular charge transfer from N-donor to B-acceptor across both chiral subunits enabled the circularly polarized luminescence and thermally robust colorimetric responses in their emissions. Furthermore, their remarkable host-guest chemistry was allowed at no expense in the pursuit of advanced chiroptical properties using pillar[5]arene-based supramolecular scaffolds.

Profiles of ARGs and their relationships with antibiotics, metals and environmental parameters in vertical sediment layers of three lakes in China.

Antibiotic resistance is a global health problem, and the role of antibiotics and metal pollution in antibiotic resistance in sediment biocenosis is limited. The occurrence and relationship between antibiotic resistance genes (ARGs), antibiotics, metals and environmental parameters were investigated in vertical layers of sediments in rural and urban lakes. Generally, the total concentrations of seven antibiotics were significantly higher in the rural lake (Lake Taihu = 96%) than in the urban lakes (Xuanwu = 0.3%, Wulongtan = 3%), while similar concentrations were observed for metals (Taihu (34%), Xuanwu (33%) and Wulongtan (33%)). The concentration of metals and antibiotics were mostly higher in the surface sediment layers than the deeper ones (for antibiotics; surface layers = 89%, deeper layer = 11%, for metals; surface = 65%, deep = 35%). The ARGs showed no significant difference between surface and deeper sediments (surface = 48%, deep = 52%, p < 0.05). The potential ecological risk index of Ni, Cu, Zn, Cr, Mn, As, Cd, and Pb contamination showed that Lake Taihu and Wulongtan had moderate ecological risks while Lake Xuanwu had a low ecological risk. Pearson coefficient and network analysis showed that direct and indirect relationship existed among antibiotics, metals, environmental parameters, and ARGs, and the relationship was linked by key environmental components. tetA, blaTEM, SDZ, TOC, OFL, Cd, OTC, NOR, Ni, sulA, AUR, TC, DOX and TN were the major factors that influence the distribution of resistance genes, forming a complex network mechanism of antibiotic resistance. Our study revealed that antibiotics and heavy metals are widely distributed in the surficial sediments and the proliferation of ARGs are influenced by some key environmental components.

Nitrate application decreased microbial biodiversity but stimulated denitrifiers in epiphytic biofilms on Ceratophyllum demersum.

Among nitrogen species, nitrate is more stable than ammonium and nitrite, and it is an important nitrogenous pollutant in surface water. However, little is known about the characterization of epiphytic microbial communities on submersed macrophytes under nitrate loading. In this study, we investigated the co-occurring pattern and response of bacteria and microeukaryotes in epiphytic biofilms under nitrate loading. Nitrate loading significantly affected bacterial and eukaryotic communities, and turnover played greater contribution to the total dissimilarity than nestedness by partitioning beta-diversity analysis. Cyanobacteria, α-proteobacteria, ß-proteobacteria, Actinobacteria, Planctomycetes, Bacteroidetes, and γ-proteobacteria were dominant bacterial phyla/classes. Metazoan (phylum Arthropoda, Rotifera, Gastrotricha, Annelida, and Nematoda) and algae (phylum Bacillariophyta, Chlorophyta, and Streptophyta) were dominated in eukaryotic communities. The abundances of denitrifying bacteria (Rhodobacter, Acinetobacter, Bacillus, Flavobacterium, and Pseudomonas) and genes (nirS, cnorB, and nosZ) increased with nitrate loading. The network analysis showed there were complex interactions among photosynthetic microbes, metazoan, and bacteria (including denitrifiers) that they were potentially interrelated via photosynthesis, predation or feeding. This study provides new perspectives into understanding the factors affecting nitrate removal mechanisms in wetlands with submersed macrophytes.

Bacterial succession in epiphytic biofilms and deciduous layer sediments during Hydrilla verticillata decay: A field investigation.

Submersed macrophytes decay is an important natural process and has important role in mass and energy flow in aquatic ecosystems. However, little is known about the dynamical changes in nutrients release and bacterial community during submersed macrophyte decay in natural environment. In this study, a field observation was conducted in a wetland dominated with Hydrilla verticillata for 36 days. Increase of H2O2 and malondialdehyde (MDA) content and decrease of soluble proteins concentration were detected in leaves during H. verticillata decay. Meanwhile, ammonium-N, soluble microbial products (SMP) and TOC concentration increased in overlying water. According to bacterial 16S rRNA Illumina sequencing analysis, the Shannon values were lower in epiphytic biofilms than deciduous layer sediments. The relative abundances of Proteobacteria, Cyanobacteria and Actinobacteria were higher in epiphytic biofilms than in deciduous layer sediments (P < 0.05). Co-occurrence network analyses showed that a total of 578 and 845 pairs of correlations (|r| > 0.6) were identified from 122 and 112 genera in epiphytic biofilms and deciduous layer sediments, respectively. According to co-occurrence patterns, eight hubs were mainly from phyla Proteobacteria, Acidobacteria and Parcubacteria in epiphytic biofilms; while 37 hubs from the 14 phyla (Proteobacteria, Bacteroidetes, Acidobacteria, Chloroflexi, et al.) were detected in deciduous layer sediments. Our results indicate that bacterial community in deciduous layer sediments was more susceptible than in epiphytic biofilms during decay process. These data highlight the role of microbial community in deciduous layer sediments on nutrients removal during H. verticillata decay and will provide useful information for wetland management.

Planar Chiral Organoboranes with Thermoresponsive Emission and Circularly Polarized Luminescence: Integration of Pillar[5]arenes with Boron Chemistry.

Enantiopure molecules based on macrocyclic architecture are unique for applications in enantioselective host-guest recognition, chiral sensing and asymmetric catalysis. Taking advantage of the chiral transfer from the intrinsically planar chirality of pillar[5]arenes, we herein present an efficient and straightforward approach to achieve early examples of highly luminescent chiral systems (P5NN and P5BN). The optical resolution of their enantiomers has been carried out via preparative chiral HPLC, which was ascribed to the molecular functionalization of pillar[5]arenes with π-conjugated, sterically bulky triarylamine (Ar3 N) as an electron donor and triarylborane (Ar3 B) as an acceptor. This crucial design enabled investigations of the chiroptical properties, including circular dichroism (CD) and circularly polarized luminescence (CPL) in the solid state. The intramolecular charge transfer (ICT) nature in P5BN afforded an interesting thermochromic shift of the emission over a wide temperature range.

Distribution and relationship between antimicrobial resistance genes and heavy metals in surface sediments of Taihu Lake, China.

Heavy metals, pharmaceuticals, and other wastes released into the environment can significantly influence environmental antibiotic resistance. We investigated the occurrence of 22 antimicrobial resistance genes (ARGs) and 10 heavy metal concentrations, and the relationship between ARGs and heavy metals in surface sediment from seven sites of Lake Taihu. The results showed significant correlations (p < 0.05) between sediment ARG levels, especially for tetracycline and sulfonamides (e.g., tet(A), tet(D), tet(E), tet(O), sul1, sul2 and int-1) and specific heavy metals (Fe, Mn, Cr, Cu, Zn, among others) in the Lake. In the surface sediments, heavy metals showed an interaction with resistance genes, but the strength of interaction was diminished with increasing depth. For most of the heavy metals, the concentration of elements in the top sediments was higher than that in other depths. Tetracycline resistance genes (tet(A), tet(B), tet(D), tet(E) and tet(O), ß-lactam resistance genes (SHV, TEM, CTX, OXA and OXY) and sulfonamide resistance genes (sulA, sul1, sul2, sul3 and int-1) were detected. They showed a trend which inferred a statistically significant increase followed by decreases in the relative abundance of these ARGs (normalized to 16S rRNA genes) with increasing depth. This study revealed that tet(A), tet(O), TEM, OXY, int-1, sul1 and sul3 were widespread in surface sediments with high abundance, indicating that these genes deserve more attention in future work.

Occurrence, risk assessment and source apportionment of perfluoroalkyl acids in the river of a hill-plain intersection region: The impacts of land use and river network structure.

Studying the impacts of land use and river network structure on perfluoroalkyl acids (PFAAs) footprint in rivers is crucial for predicting the fate of PFAAs in aquatic environments. This study investigated the distribution, ecological risks, sources and influence factors of 17 PFAAs in water and sediments of rivers from hills to plain areas. The results showed that the detection frequencies were higher for short-chain PFAAs than long-chain PFAAs in water, whereas an opposite pattern was found in sediments. The concentration of ∑PFAAs ranged from 59.2 to 414 ng/L in water and from 1.4 to 60.1 ng/g in sediments. Perfluorohexanoic acid and perfluorooctanoic acid were identified as the main pollutants in the river. The average concentrations of PFAAs were higher in the aquaculture areas (water: 309.8 ng/L; sediments: 43.27 ng/g) than in residential areas (water: 206.03 ng/L; sediments: 11.7 ng/g) and farmland areas (water: 123.12 ng/L; sediments: 9.4 ng/g). Environmental risk assessment showed that PFAAs were mainly low risk or no risk in water, but were moderate risk and even high risk in sediments, especially for perfluorooctane sulfonate. Source apportionment found that PFAA sources were mostly from industry, wastewater discharge, and surface runoff. Dissolved oxygen, chemical oxygen demand, water system circularity, network connectivity and organic matter were significantly correlated to PFAA concentration, indicating that the physicochemical properties and river network might directly influence the environmental behavior of PFAAs. The built-up area was positively correlated with PFAAs. These findings indicated that a comprehensive understanding of the influences of land use and river network structure on PFAAs in rivers is essential for managers to formulate effective PFAA control strategies.

Fate and removal of fluoroquinolone antibiotics in mesocosmic wetlands: Impact on wetland performance, resistance genes and microbial communities.

The fate of fluoroquinolone antibiotics norfloxacin and ofloxacin were investigated in mesocosmic wetlands, along with their effects on nutrients removal, antibiotic resistance genes (ARGs) and epiphytic microbial communities on Hydrilla verticillate using bionic plants as control groups. Approximately 99% of norfloxacin and ofloxacin were removed from overlaying water, and H. verticillate inhibited fluoroquinolones accumulation in surface sediments compared to bionic plants. Partial least squares path modeling showed that antibiotics significantly inhibited the nutrient removal capacity (0.55) but had no direct effect on plant physiology. Ofloxacin impaired wetland performance more strongly than norfloxacin and more impacted the primary microbial phyla, whereas substrates played the most decisive role on microbial diversities. High antibiotics concentration shifted the most dominant phyla from Proteobacteria to Bacteroidetes and inhibited the Xenobiotics biodegradation function, contributing to the aggravation in wetland performance. Dechloromonas and Pseudomonas were regarded as the key microorganisms for antibiotics degradation. Co-occurrence network analysis excavated that microorganisms degrade antibiotics mainly through co-metabolism, and more complexity and facilitation/reciprocity between microbes attached to submerged plants compared to bionic plants. Furthermore, environmental factors influenced ARGs mainly by altering the community dynamics of differential bacteria. This study offers new insights into antibiotic removal and regulation of ARGs accumulation in wetlands with submerged macrophyte.

Interactions between water quality and microbes in epiphytic biofilm and superficial sediment of lake in trophic agriculture area.

Epiphytic and superficial sediment biofilm-dwelling microbial communities play a pivotal role in water quality regulation and biogeochemical cycling in shallow lakes. However, the interactions are far from clear between water physicochemical parameters and microbial community on aquatic plants and in surface sediments of lake in trophic agriculture area. This study employed Illumina sequencing, Partial Least Squares Path Modeling (PLS-PM), and physico-chemical analytical methods to explore the interactions between water quality and microbes (bacteria and eukaryotes) in three substrates of trophic shallow Lake Cyohoha North, Rwanda. The Lake Cyohoha was significantly polluted with total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3-N), and ammonia nitrogen (NH3-N) in the wet season compared to the dry season. PLS-PM revealed a strong positive correlation (+0.9301) between land use types and physico-chemical variables in the rainy season. In three substrates of the trophic lake, Proteobacteria, Cyanobacteria, Firmicutes, and Actinobacteria were dominant phyla in the bacterial communities, and Rotifers, Platyhelminthes, Gastrotricha, and Ascomycota dominated in microeukaryotic communities. As revealed by null and neutral models, stochastic processes predominantly governed the assembly of bacterial and microeukaryotic communities in biofilms and surface sediments. Network analysis revealed that the microbial interconnections in Ceratophyllum demersum were more stable and complex compared to those in Eichhornia crassipes and sediments. Co-occurrence network analysis (|r| > 0.7, p < 0.05) revealed that there were complex interactions among physicochemical parameters and microbes in epiphytic and sediment biofilms, and many keystone microbes on three substrates played important role in nutrients removal, food web and microbial community stable. These findings emphasize that eutrophic water influence the structure, composition, and interactions of microbes in epiphytic and surface sediment biofilms, and provided new insights into the interconnections between water quality and microbial community in presentative substrates in tropical lacustrine ecosystems in agriculturally polluted areas. The study provides useful information for water quality protection and aquatic plants restoration for policy making and catchment management.

Glufosinate-ammonium increased nitrogen and phosphorus content in water and shaped microbial community in epiphytic biofilm of Hydrilla verticillata.

Glufosinate-ammonium (GLAM) can be released into adjacent water bodies with rainfall runoff and return water from farmland irrigation. However, impacts of GLAM on aquatic organisms remain unclear. In this study, changes in water quality, plant physiological parameters and epiphytic microbial community were investigated in wetlands with Hydrilla verticillata exposed to GLAM for 24 days. We found GLAM addition damaged cell and reduced chlorophyll a content in Hydrilla verticillata leaves, and increased ammonium and phosphorus in water (p < 0.001). The α-diversity increased in bacterial community but decreased in eukaryotic community with GLAM exposure. Neutral community models explained 62.3 % and 55.0 % of the variance in bacterial and eukaryotic communities, respectively. Many GLAM micro-biomarkers were obtained, including some clades from Proteobacteria, Bacteroidete, Actinobacteriota, Phragmoplastophyta, Annelida and Arthropoda. Redundancy analysis revealed that GLAM concentration was positively correlated to Flavobacterium, Gomphonema and Closterium but negatively to Methyloglobulus and Methylocystis. Network analysis revealed that 15 mg/L GLAM disturbed the interactions among phytoplankton, protozoa, metazoan and bacteria and reduced the stability of the microbial communities compared to 8 mg/L GLAM. GLAM shaped the nitrogen and phosphorus cycle related bacterial genes. This study highlights that herbicides are non-neglectable factors affecting the efficiency of aquatic ecological restoration in agricultural areas to control agricultural non-point source pollution.

Microplastic contamination in Chinese topsoil from 1980 to 2050.

China's soil is experiencing significant microplastic contamination. We developed a machine-learning model to assess microplastic pollution from 1980 to 2050. Our results showed that the average abundance of microplastics in topsoil increased from 45 items per kilogram of soil in 1980 to 1156 items by 2018, primarily due to industrial growth (39 %), agricultural film usage (30 %), tire wear (17 %), and domestic waste (14 %). During the same period, microplastic levels in cropland rose from 98 to 2401 items per kilogram of soil, and exposure levels for the Chinese population increased from 808 to 3168 items per kilogram. By 2050, a reduction in the use of agricultural films is expected to decrease cropland contamination by half. However, overall levels are anticipated to remain steady due to other persistent sources, indicating a continued spread of microplastics into subterranean environments, water bodies, and human systems. This study highlights China's microplastic challenges and suggests potential global trends, emphasizing the need for increased awareness and intervention worldwide.

Characterization of antibiotic-resistance genes in antibiotic resistance Escherichia coli isolates from a lake.

The spread of antibiotic-resistance bacteria and antibiotic-resistance genes (ARGs) has been of concern worldwide. In this study, 114 Escherichia coli isolates were isolated from surface water samples of a lake to identify their susceptibility to antibiotics, including tetracycline (TC), gentamicin (GN), ampicillin (AMP), streptomycin (ST), oxytetracycline (OC), levofloxacin (LEV), nalidixic acid (NA), and sulfamethoxazole/trimethoprim (SFT). Isolates showing resistance to TC, GN, AMP, ST, OC, LEV, NA, and SFT occurred in 50, 76, 68, 71, 55, 32, 82, and 85 % of the total isolates, respectively. Thirty-seven different resistance patterns were identified, and the most abundant resistance profile (28 of 104) was TC/GN/AMP/ST/OC/LEV/NA/SFT. The occurrence of 29 ARGs were detected in their corresponding resistance clones, and 88 % of TC-resistance, 94 % of SFT-resistance, 90 % of AMP-resistance, 78 % of ST-resistance, and 72 % of quinolone-resistance clones can be described by their corresponding ARGs. It should be noted that most of these antibiotic-resistance clones harbored at least two corresponding ARGs, indicating that high frequencies of combined ARGs occurred in these isolates. In addition, 9 new types of DNA sequence of qnr(B) gene were obtained and were clustered into the same group as showed by phylogenetic trees analysis. These results suggest that the development of antibiotic resistance can be ascribed to the high frequency in the recombination of ARGs through horizontal gene transfer.

A decennial study of the trend of antibiotic studies in China.

Antibiotics are one of the greatest inventions in human history and are used worldwide on an enormous scale. Besides its extensive usage in medical and veterinary arenas to treat and prevent the infection, its application is very prominent in other fields, including agriculture, aquaculture, and horticulture. In recent decades, the increased consumption of antibiotics in China saw a vast increase in its production and disposal in various environments. However, in this post-antibiotic era, the abuse and misuse of these valuable compounds could lead to the unreversible consequence of drug resistance. In China, antibiotics are given a broad discussion in various fields to reveal their impact on both human/animals health and the environment. To our knowledge, we are the first paper to look back at the development trend of antibiotic-related studies in China with qualitative and quantitative bibliometric analysis from the past decades. Our study identified and analyzed 5559 papers from its inception (1991) to December 6, 2021, from the Web of Science Core Collection database. However, with few authors and institutions focusing on long-term studies, we found the quality of contributions was uneven. Studies mainly focused on areas such as food science, clinical research, and environmental studies, including molecular biology, genetics and environmental, ecotoxicology, and nutrition, which indicate possible primary future trends. Our study reports on including potentially new keywords, studies' milestones, and their contribution to antibiotic research. We offer potential topics that may be important in upcoming years that could help guide future research.

Eichhornia crassipes-rhizospheric biofilms contribute to nutrients removal and methane oxidization in wastewater stabilization ponds receiving simulative sewage treatment plants effluents.

Wastewater stabilization ponds (WSPs) have been used in treating sewage treatment plants (STPs) effluents. However, little is known about the role of rhizospheric biofilms on methane release in WSPs with floating plants. In the present study, the nutrient removal, CH4 fluxes, CH4 oxidization potential and rhizospheric bacterial community were investigated in WSPs with Eichhornia crassipes under simulate STPs effluents for 31 days. At the end of the experiment, E. crassipes biomass was 5.60-8.81 times of initial weight and increased with increasing nutrients concentration. E. crassipes effectively reduced methane release and nutrients. Compared to control, E. crassipes reduced 52.30%-83.21% of CH4 fluxes at water-atmosphere interface and had better inhibition effect on CH4 fluxes in treatments with high nutrients. However, methane oxidization rates of E. crassipes roots were higher in low nutrients (0.83 ± 0.046 mg CH4 (kg fresh plant)-1 day-1) than high nutrients (0.12 ± 0.04 mg CH4 (kg fresh plant)-1 day-1). Structural equation modeling revealed that biomass of E. crassipes has negative effect on CH4 fluxes (-0.453, p = 0.000). Proteobacteria, Bacteroidetes, Planctomycetes, Chloroflexi and Actinobacteria were the predominant phyla in the rhizospheric biofilm of E. crassipes and contributed to nutrients removal. Aerobic methanotrophs and pomA abundances were higher in rhizospheric biofilm exposed to high nutrients than low nutrients and aerobic methanotrophs had close interactions with other microorganisms and participated in the carbon and nitrogen cycle, demonstrating that many bacteria harboring pmoA gene did not fully involve in methane oxidization. These data highlight plants E. crassipes have an important role in both reducing methane release and nutrients removal.