Hepatocyte growth factor is protective in early stage but bone-destructive in late stage of experimental periodontitis.

BACKGROUND AND OBJECTIVE: Clinical studies found high levels of hepatocyte growth factor (HGF) expression in patients with periodontitis. Studies suggest that HGF plays an important role in periodontitis, is involved in inflammation, and modulates alveolar bone integrity in periodontitis. This study aims to investigate the effects and mechanisms of HGF in the progression of experimental periodontitis. METHODS: We used silk thread ligation to induce periodontitis in HGF-overexpressing transgenic (HGF-Tg) and wild-type C57BL/6J mice. The effects of HGF overexpression on alveolar bone destruction were assessed by microcomputed tomography imaging at baseline and on days 7, 14, 21, and 28. We analyzed the cytokines (IL-6 and TNF-α) and lymphocytes in periodontitis tissues by enzyme-linked immunosorbent assay and flow cytometry. The effects of HGF on alveolar bone destruction were further tested by quantifying the systemic bone metabolism markers CTXI and PINP and by RNA sequencing for the signaling pathways involved in bone destruction. Western blotting and immunohistochemistry were performed to further elucidate the involved signaling pathways. RESULTS: We found that experimental periodontitis increased HGF production in periodontitis tissues; however, the effects of HGF overexpression were inconsistent with disease progression. In the early stage of periodontitis, periodontal inflammation and alveolar bone destruction were significantly lower in HGF-Tg mice than in wild-type mice. In the late stage, HGF-Tg mice showed higher inflammatory responses and progressively aggravated bone destruction with continued stimulation of inflammation. We identified the IL-17/RANKL/TRAF6 pathway as a signaling pathway involved in the HGF effects on the progression of periodontitis. CONCLUSION: HGF plays divergent effects in the progression of experimental periodontitis and accelerates osteoclastic activity and bone destruction in the late stage of inflammation.

Association between age, gender, and oral traumatic ulcerative lesions: a retrospective study.

BACKGROUND: Oral traumatic ulcerative lesions (OTUL) are commonly encountered in clinical practice, yet there is limited research on their clinical characteristics and traumatic etiological factors. This retrospective study aimed to analyze the age, gender, clinical characteristics, and traumatic etiological factors in a large cohort of patients with OTUL and provide valuable insights for dental clinicians to optimize patient care and prevention strategies. METHODS: A total of 1543 patients with OTUL were enrolled in this study. Age, gender, medical history, clinical characteristics and traumatic etiological factors were collected and analyzed. Logistic regression analysis was performed to determine the significance of age and gender as factors related to OTUL. RESULTS: The study revealed significant variations in clinical characteristics and traumatic etiological factors among different age groups and between genders. Logistic regression analysis demonstrated that both age and gender were significant factors related to OTUL. CONCLUSION: The clinical characteristics of OTUL and traumatic etiological factors appear to be significantly different according to age and gender. More targeted prevention strategies should be implemented for all age and gender groups.

Migration characteristics of microplastics in riparian soils and groundwater.

Investigations have revealed the presence of microplastics in both soil and groundwater, but the migration characteristics from soil to groundwater remain incompletely understood. In this study, two sampling sections consisting of soil-groundwater-river water were established near Lianxi Bridge and Xilin Bridge along the Jiuxi River in Xiamen. A total of 22 soil samples, 36 groundwater samples, and 18 river water samples were collected. Microplastics were detected in all samples with an abundance range of 392-836 n/kg in soil (mean, 655 ± 177 n/kg), 0.58-2.48 n/L groundwater (mean, 1.23 ± 0.42 n/L), and 0.38-1.80 n/L in river water (mean, 0.86 ± 0.41 n/L). Flakes predominantly constituted the shape of microplastics found in soil, while fibers dominated those present in water. Black, yellow, and red were the dominant color types. Polyamide (PA) and polyethylene (PE) were the main components of microplastics within soils, whereas polyethylene terephthalate (PET), polypropylene (PP), and PA prevailed within water. Microplastic particle sizes ranged from 39 to 2498 µm in soils, mainly from 29 to 3394 µm in water. The upstream section displayed higher abundances of microplastic compared to the downstream, revealing the soil particles having an intercepting effect on microplastics. The distribution and migration of microplastics in soil and groundwater are affected by many factors, including natural and anthropogenic factors, such as soil depth, soil properties, pore structure, hydrodynamics, hydraulic connections between groundwater and surface water, the extensive utilization and disposal of plastics, irrational exploitation of groundwater, and morphology and types of microplastics. These research findings contribute to a better understanding of the pathways, migration capacity, and influencing factors associated with microplastic entry into groundwater, thereby providing valuable technical support for the development of strategies aimed at controlling microplastic pollution.

Magnetic polymer particles as a highly efficient and facile cleanup adsorbent for multi-pesticide residues analysis in aquatic products.

A novel and efficient sample pretreatment procedure using magnetic particles was exploited for the determination of multi-pesticide residues in aquatic products. The magnetic adsorbent was prepared using divinyl benzene and N-vinyl pyrrolidone as functional monomers modified on the Fe3O4 @SiO2. The obtained magnetic adsorbent, octadecylsilane sorbents, and graphitized carbon black were employed as effective adsorbents to remove matrix interferences in aquatic products, and their dosages were optimized. Satisfactory levels of accuracy and precision were procured under optimum conditions. The method limits of quantification ranged from 0.1 to 2.0 µg/kg. The analytical accuracy of the developed method for the analysis of multi-pesticide residues in freshwater and seafood products was validated. It was found to be suitable for the analysis of multi-pesticide residues in different types of aquatic products. Additionally, the method was successfully applied for the analysis of pesticide residues in fish samples obtained from aquaculture plants located in Zhejiang Province, China. The detected concentrations of pesticides ranged from 0.14 to 0.95 µg/kg. In general, this method shows promising application prospects for the rapid determination of multi-pesticide residues in aquatic products.

Evaluation of a Three-Dimensional Printed Guide and a Polyoxymethylene Thermoplastic Regulator for Percutaneous Pedicle Screw Fixation in Patients with Thoracolumbar Fracture.

BACKGROUND This study aimed to evaluate the efficacy of a porous polyoxymethylene thermoplastic regulator combined with a three-dimensional (3D) printed template to guide pedicle needle insertion in patients undergoing percutaneous pedicle screw fixation (PPSF) for thoracolumbar fracture. MATERIAL AND METHODS Forty patients were randomly divided into group A, treated using a porous polyoxymethylene thermoplastic regulator combined with a 3D printed template, and group B, who underwent conventional PPSF. Data recorded included the number of pedicle screws successfully inserted on the first attempt, the number of attempts, the time to successful needle insertion, the total time of fluoroscopy, and the duration of surgery. The Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI) scores one day before surgery, and at day 1, day 7, month 1, and month 3 after surgery were recorded. The postoperative vertebral posterior kyphotic angle (KA) and the rate of change of KA were recorded. RESULTS Group A had a significantly increased total number of successful first insertions compared with group BV (P<0.05). Postoperative VAS and ODI scores of patients in both groups were significantly lower than before surgery (P<0.05), with no significant difference between the two groups at postoperative month 1 and month 3 (P>0.05). The postoperative vertebral posterior KA decreased significantly in both groups after surgery, with no significant difference between the two groups (P>0.05). CONCLUSIONS The use of a porous polyoxymethylene thermoplastic regulator combined with a 3D printed template may improve the success of pedicle insertion in patients undergoing PPSF.

Is oral lichen planus a risk factor for peri-implant diseases? A systematic review and meta-analysis.

BACKGROUND: To evaluate whether oral lichen planus (OLP) is a risk factor for peri-implant diseases (PIDs) with a systematic review and meta-analysis. METHODS: Five electronic databases including Medline, Embase, Web of Science, the Cochrane Library and Scopus were searched. The included studies are observational human studies written in English. The population of interest included those with/without OLP who received dental implant treatment. The follow-up time after implantation was from 1 month to 20 years. The quality of the included articles regarding risk of bias and methodology were assessed with the Newcastle-Ottawa Scale or the Agency for Healthcare Research and Quality. The data involving exposure (OLP), primary outcomes (implants having PIDs) and secondary outcomes (probing depth/PD, bleeding on probing/BOP and bone loss/BL) and potential confounders were extracted. Heterogeneity was assessed by I2 test. Dichotomous data are expressed as the risk ratio (RR) and 95% confidence interval (CI) which were calculated with a fixed effect model. RESULTS: Of the 66 articles, two studies were enrolled and evaluated as high quality, which totally contained 68 participants receiving 222 (OLP vs. non-OLP, 112 vs. 110) implants with 12 to 120-month follow-up time. Proportions of implants with PIDs between OLP and non-OLP groups were as follows: 19.6% (22/112) vs. 22.7% (25/110) for PIM and 17.0% (19/112) vs. 10.9% (12/110) for PI. The meta-analysis revealed no recognizable difference in number of implants with PIDs (PI: RR = 1.49, 95% CI 0.77-2.90, P = 0.24; PIM:RR = 0.88, 95% CI 0.53-1.46, P = 0.61; PIDs: RR = 1.08, 95% CI 0.75-1.55, P = 0.68) or BOP (RR = 0.90, 95% CI: 0.70-1.15, P = 0.40) between OLP and non-OLP groups. CONCLUSIONS: Available articles regarding the effects of OLP on PIDs remains very limited. Existing evidence does not support OLP as a suspected risk factor for PIDs. Large-scale prospective trials are required to validate the findings.

The characterization, pharmacokinetic, and tissue distribution studies of TPGS-modified artesunate liposome in rats.

OBJECTIVE: The objective of this study (ARS-TPGS-Lipo) was to enhance the stability, encapsulation efficiency (EE), improve AUC, circulation time and liver targeting of ARS-TPGS-Lipo. METHODS: ARS-TPGS-Lipo was prepared by thin-film dispersion method and characterized by TEM. The EE, in vitro release and stability of ARS-TPGS-Lipo were detected by HPLC and UV. In addition to the safety evaluation, the pharmacokinetics and tissue distribution studies were also carried out after i.v. administration. RESULTS: The size, PDI, zeta potential, and EE of ARS-TPGS-Lipo were 126.7 ± 9.9 nm, 0.182 ± 0.016, -10.1 ± 1.43 mV, and 78.8 ± 1.89%, respectively. ARS-TPGS-Lipo showed the slow-release effect in vitro release experiments. The AUC of ARS in the ARS-TPGS-Lipo group was 7.51 times higher than in the ARS group after i.v. administration and the circulation time was significantly prolonged. The tissue distribution results showed the components of artesunate and its metabolism DHA of the ARS-TPGS-Lipo group were much higher in liver than the ARS-Lipo group. CONCLUSION: ARS-TPGS-Lipo was prepared successfully, which had the smaller vesicles size with a better PDI, better stability, higher EE, and slow-release. The results of safety evaluation indicated that ARS-TPGS-Lipo had no hematotoxicity and hepatorenal toxicity. The pharmacokinetic studies indicated ARS-TPGS-Lipo had higher AUC, longer circulation time and better liver targeting.

Oral lichen-planus-associated fibroblasts acquire myofibroblast characteristics and secrete pro-inflammatory cytokines in response to Porphyromonas gingivalis lipopolysaccharide stimulation.

BACKGROUND: Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease in which comprehensive inflammation-related cytokines are involved. These cytokines are commonly produced by immune cells and specific nonimmune cells including keratinocytes, endothelial cells and fibroblasts. This raises the question of whether fibroblasts in OLP lesions contribute to the inflammatory process upon inflammatory simulation. METHODS: Primary cultured Oral lichen-planus-associated fibroblasts (OLP AFs, n = 5) and normal buccal mucosal fibroblasts (NFs, n = 5) were examined by immunohistochemistry, Western blotting and reverse transcription-polymerase chain reactions (RT-PCR). Various inflammatory mediators were evaluated with a multiplex assay. Differences among groups were assessed using a Student's test or repeated measures one-way ANOVA, as appropriate. RESULTS: OLP AFs express significantly higher levels of α-smooth muscle actin (α-SMA) than NFs, indicating the presence of myofibroblasts. Myofibroblasts secrete Interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) in response to Porphyromonas gingivalis lipopolysaccharide (pg. LPS). CONCLUSION: OLP AFs demonstrated α-SMA expression and secreted pro-inflammatory cytokines in response to pg. LPS stimulation.

[Tissue distribution of TPGS modified artesunate liposome and its metabolites in rats].

Artesunate, which is a widely used anti-malaria medicine, can be made into liposome to overcome its poor bioactivity. Its tissue distribution in rats may change with different dosage forms, which therefore shall be studied after ARS-TPGS-Lipo was injected. Based on this experiment, ARS-TPGS-Lipo and ARS-Lipo were prepared by thin-film hydration method. LC-MS/MS method was used to simultaneously determine ARS and DHA in rat tissues at different time points. The results showed that this method was suitable for the content analysis of ARS and DHA in biological samples. The distribution of ARS and DHA in ARS-TPGS-Lipo, ARS-Lipo and ARS groups were quite different. The content of ARS-TPGS-Lipo in liver was the highest, with significant differences.ARS and DHA contents in ARS group eliminated rapidly. ARS and DHA contents in ARS-Lipo group were higher in liver and spleen, while those in ARS-TPGS-Lipo group significantly increased only in liver (P<0.05).

Heavy metal contamination along the China coastline: A comprehensive study using Artificial Mussels and native mussels.

A comprehensive study was carried out to assess metal contamination in five cities spanning from temperate to tropical environment along the coastal line of China with different hydrographical conditions. At each of the five cities, Artificial Mussels (AM) were deployed together with a native species of mussel at a control site and a polluted site. High levels of Cr, Cu and Hg were found in Qingdao, high level of Cd, Hg and Pb was found in Shanghai, and high level of Zn was found in Dalian. Furthermore, level of Cu contamination in all the five cities was consistently much higher than those reported in similar studies in other countries (e.g., Australia, Portugal, Scotland, Iceland, Korea, South Africa and Bangladesh). Levels of individual metal species in the AM showed a highly significant correlation with that in the native mussels (except for Zn in Mytilus edulis and Cd in Perna viridis), while no significant difference can be found between the regression relationships of metal in the AM and each of the two native mussel species. The results demonstrated that AM can provide a reliable time-integrated estimate of metal concentration in contrasting environments over large biogeographic areas and different hydrographic conditions, and overcome the shortcomings of monitoring metals in water, sediment and the use of biomonitors.

Adsorption of metals on aged microplastics in intensive mariculture areas: Aggravating the potential ecological risks to marine organisms.

Field determination of the metal adsorption capacity of microplastics (MPs) by using a passive sampler had been done in typical subtropical mariculture area in China. The adsorption of eight metals (Fe, Mn, Cu, Zn, As, Pb, Cr and Cd) by five types of MPs (low-density polyethylene, polypropylene, polystyrene, poly(ethylene terephthalate) and poly(vinyl chloride) (PVC) was compared, including metal types, mariculture types (cage and longline culture), metal residue content in ambient environment, polymer types and particle sizes of MPs. The results showed that Cu, Zn, As, Cd, Pb and Cr in the mariculture environment were contaminated compared with the quality criteria. The concentrations of these six metals adsorbed on five MPs increased linearly with those in seawater. More enriched Cu and As in MPs in marine cage culture than in longline culture, due to the obvious endogenous pollution emissions for the artificial diets, fish medicine and disinfectants. Aged PVC with more cracks and pores showed higher metal adsorption capacity than any other polymers. MPs with a smaller size range of 50-74 µm tended to accumulate higher amounts of metals than those with a larger size range of 74-178 µm, consisting with the surface characteristics of MPs. The significant positive relationship between the concentrations of nutrients in seawater and the adsorption amounts of Cu, Zn and As on MPs implies that the eutrophication would promote their pollution. Based on the ecological risk assessment, the occurrence of MPs could aggravate the potential risk of metals to marine organisms in intensive mariculture areas. This is the first time to reveal the impacts of the adsorption of metals on aged MPs on the potential ecological risks of metals to organisms under the realistic environmental condition.

Rapid and sensitive analytical strategy for multi-class antibiotic residues analysis in aquatic products with amphiphilic magnetic polymer particles as an effective cleanup adsorbent.

Multi-class antibiotic analysis in aquatic products is still challenging owing to the complex matrix and low co-extraction efficiency of various antibiotics. A facile and sensitive sample pretreatment method based on magnetic dispersive solid-phase extraction was thus developed via systematic optimization of extraction and purification procedure. The multi-class antibiotics can simultaneously be extracted by acetonitrile-2 % acetic acid. Amphiphilic magnetic particles and C18 were used as adsorbents to remove matrix interferences, affording significantly reduced matrix effects of analytes. Under the optimum conditions, satisfactory linearity, recovery, precision, and sensitivity were achieved. The method limits of quantification were 0.25-0.5 µg kg-1. Besides, it displayed obvious advantages in operation convenience and efficiency due to the usage of magnetic particles. The developed method was successfully used to analyze antibiotic residues in both freshwater and seafood products, manifesting its suitability for antibiotic residues analysis in aquatic products.

Ecological interception effect of mangroves on microplastics.

As the last barrier preventing river pollutants from entering the ocean, mangroves have strong absorption and purification abilities, and strong tolerance. We collected mangrove surface water and sediment samples from the Xixi Estuary of Xiamen city. The results showed that the abundance of microplastics in seawater ranged from 620 to 13,100 n/m3, the abundance of microplastics in sediment ranged from 143 to 488 n/kg, the distribution of microplastics was uneven, and the abundance of microplastics in the Xixi Estuary mangrove was significantly higher than that in the non-mangrove area. The sediment column sample results also showed that microplastics were detected in each layer of the sediments, indicating that microplastics were trapped in each layer of mangrove sediments. Therefore, we believe that mangrove forests have an ecological interception effect on microplastics. After entering mangroves, microplastics are affected by tidal reciprocating current scouring, river runoff, sunlight, wind erosion and other factors and gradually break into increasingly smaller particles through physical, chemical and biological effects. Microplastics accumulate in the sediments and experience sedimentation, suspension and reprecipitation processes together with the surface sediments. Mangroves should be widely planted in estuaries to reduce microplastic entry into the ocean.

Spatial and temporal distributions of microplastics and their macroscopic relationship with algal blooms in Chaohu Lake, China.

Microplastics are emerging pollutants with sizes less than 5 mm, and they are ubiquitous. The occurrence of algal blooms has become a major problem affecting water quality in Chaohu Lake. To understand the relationship between the microplastic distribution and algal bloom density from a macroscopic point of view in Chaohu Lake, we collected microplastic samples from water and sediments during the wet and dry seasons and collected satellite remote sensing images of the algae density in recent years. The research results showed that the spatial and temporal distributions of microplastics were uneven and varied greatly. The average abundances of microplastics in the water samples were 2133 ± 1534 n•m-3 in the dry season and 1679 ± 1577 n•m-3 in the wet season, and the average abundance of microplastics in sediments was 308 ± 231 n•kg-1. The abundance of microplastics in the estuaries was higher than those in other locations, and it was higher in the western part of the lake than in the eastern part. The microplastics in water and sediments presented different sizes, colors, shapes and compositions. The abundance, distribution and migration of microplastics were mainly affected by population density, rainfall, runoff, hydrodynamic force and wind direction. At a more macroscopic level, the distribution of microplastics was similar to that of algal blooms, TN and TP to some extent, especially in the early stage of algal bloom outbreaks, and the algal density was significantly positively correlated with the flux of microplastics into the lake. Microplastics, as carriers of algae, could promote the growth of algae blooms in the early stage, while in the later stage, microplastics and algal blooms could aggregate and coprecipitate through adsorption or adhesion and then inhibit the growth of algae.

Selective adsorption of antibiotics on aged microplastics originating from mariculture benefits the colonization of opportunistic pathogenic bacteria.

Microplastics and antibiotics widely coexist in the aquatic environment, especially in mariculture regions. However, antibiotics adsorbed on microplastics and their role in the colonization of microorganisms on microplastics are poorly understood. Therefore, in-situ aging experiments were conducted to investigate the impact of antibiotics and microplastics co-occurrence on microorganisms and assess their potential risks to human health. Results showed that antibiotics were adsorbed selectively on microplastics, with 29 investigated antibiotics (n = 40) detected in surrounding water but only 6 investigated antibiotics were adsorbed on microplastics. The concentration of antibiotics accumulated on microplastics was controlled by microplastic types and environmental conditions. For example, aged polypropylene (PP) had more developed pore structures resulting in higher adsorption of antibiotics than other microplastic types. High-throughput sequencing showed higher diversity and distinct composition of microorganisms attached to the microplastics than the surrounding water. Opportunistic pathogenic bacteria such as Mycobacterium possessed positive relationships with tetracycline and doxycycline on aged microplastics, which showed adsorbed antibiotics on aged microplastics could benefit some specific pathogens colonized on the microplastics and spread into unaffected ecosystems, marine organisms even humans. The health risk quotient (HQ) implied the potential human health risk of consuming commercial seafood polluted by antibiotics and microplastic loaded with antibiotics. This study revealed the interaction of antibiotics and microorganisms with aged microplastics in aquaculture systems, providing a novel insight into their synergistic effects on ecological and human health.

Combined effects of micro-/nano-plastics and oxytetracycline on the intestinal histopathology and microbiome in zebrafish (Danio rerio).

Accumulated evidence has demonstrated that microplastics and oxytetracycline (OTC) affect organisms, but few studies have investigated their combined effects on aquatic organisms. In this study, adult zebrafish (Danio rerio) were exposed to single and binary-combined contamination of micro-, nano-sized polystyrene plastics and OTC for 30 days, and the intestinal histopathology, gut microbiota and antibiotic resistance genes (ARGs) of zebrafish were measured. The results showed that the intestinal epithelial damage increase with the decrease of plastic sizes. Nano-sized plastics, OTC and their combined exposure caused intestinal epithelial damage, and co-exposure with micro-sized plastics reduced the intestinal damage caused by single OTC exposure. The gut microbial communities were affected by the combined exposure to microplastics and OTC. Compared with the blank control, the relative abundance of Fusobacteria increased 12.7 % and 21.1 % in OTC combined with 45-85 µm micro-plastics (MOTC) and 40-54 nm nano-plastics (NOTC), respectively, and that of Bacteroidetes increased 26.2 % and 18.6 % in the MOTC and NOTC treatments, respectively. The effects of MOTC and NOTC on the biodiversity of the zebrafish gut microbiome were different; MOTC increased the biodiversity by 11.3 % compared with the blank control, whereas NOTC decreased the biodiversity by 8.8 % compared with the blank control. Furthermore, the abundance of ARGs in 40-54 nm nano-plastics, MOTC and NOTC treatments was increased 96.9 %, 96.6 % and 68.8 % compared with the control group, respectively. Additionally, significant differences were observed in ARGs characteristics between the micro- and nano-plastics treated groups whether combined with OTC or not. These results are essential to further understand the combined ecotoxicological effects of micro- or nano-plastics and antibiotics on aquatic organisms.

Vertical distribution and river-sea transport of microplastics with tidal fluctuation in a subtropical estuary, China.

The river-sea transport of microplastic with complex environmental conditions and diverse driving factors has received growing attention in the estuary. This research investigated the vertical distribution of microplastics in the water column and surface sediments and explored the effect of tidal variation on the transport of microplastics in Jiulong Estuary and Xiamen Bay, China. Results show that the microplastics in the estuary (630 ± 515 µm) was significantly larger than that in the bay (344 ± 420 µm, p < 0.01). Low-density microplastics are present in the whole water column, while high-density microplastics was apt to accumulate in the bottom water and surface sediment suggesting biofouling and material density of microplastics synergistic affect its vertical distribution. Every 1-2 h high-frequency samples collected in a whole tide found the increase of fine size (45-300 µm) and decrease of large size (>300 µm) in the flood tide, which implied fine microplastics were easily driven into the estuary from the bay at flood tide than large microplastics. The abundance of microplastics in the sediments decreased in the fast-rising and fast-falling period implies the tide influences the fragmentation and resuspension of microplastics in the estuary. Finally, the flux of microplastics entering Xiamen Bay was 53.5 t/month in the moderate flow month were estimated based on the abundance of different water layers instead of floating microplastics in the surface water.

[Environmental Process, Effects and Risks of Emerging Contaminants in the Estuary-Coastal Environment].

Human activities and global climate change have contributed substantially to the input of land-sourced pollutants into the aquatic environment, especially for emerging or newly identified contaminants, such as microplastics, emerging persistent organic pollutants, pharmaceuticals, and personal care products. The prevalence and toxicity of these emerging pollutants has raised continued concern for the health and safety of the public worldwide. A review of sources, distribution, interfacial transport processes of microplastics, per-and polyfluorinated compounds, antibiotics, and endocrine-disrupting chemicals and factors that influence their environmental behavior in the estuary-coastal environment have been included. The adverse ecological effects and health risks of these emerging contaminants to humans were also reviewed. Lastly, the direction of future research was provided regarding the environmental behavior of multiple emerging pollutants in the coastal environment and the health risks resulting from their interactions, supporting the prevention and control of marine pollution and the healthy development of the marine economy.

[Pollution Characteristics of Microplastics in Sediments of Xiamen Bay Beach].

Microplastics widely exist in various environmental media and have become a global environmental problem. To investigate the pollution characteristics, deposition patterns, and influencing factors of microplastics in the sediments of bay beach, five typical beaches were selected in Xiamen Bay. According to the tidal variation, 0-10 cm, 10-20 cm, and 20-30 cm sediment column samples were collected in layers at the high tide line, middle tide line, and low tide line at the same time, and the characteristics of the horizontal and vertical distribution of microplastics in the beach sediments were studied. The results showed that the abundance of microplastics in 45 sediment samples in Xiamen Bay beach ranged from 39 to 260 n·kg-1, with an average abundance of (114±26) n·kg-1. The shapes of microplastics were mainly fibers, fragments, granules, and foams, with fibers making up the largest proportion. The main components were polyethylene terephthalate (PET), cellophane, and polyethylene (PE). The colors of microplastics included transparent, yellow, blue, black, white, etc. The average abundance of microplastics showed a certain pattern depending on the beach location, intertidal zone, and sampling depth. Moreover, the abundance and distribution of microplastics on the beach were affected by various natural and human factors such as waves, tides, shoreline shape, the number of tourists, and the cleaning of marine floating debris. These results aid the understanding of the distribution characteristics and sources of microplastics in beach sediments, provide a basis for the transport of microplastics from land to sea, and provide data support for the collection of sea floating garbage and shoreline garbage.

Assessment of seasonal variability of input of microplastics from the Northern Dvina River to the Arctic Ocean.

Northern Dvina River is one of the largest rivers in the European Arctic flowing into the White Sea through the populated regions with developed industry. Floating plastics include microplastics (0.5-5 mm) and mesoplastics (5-25 mm) were observed on seasonal variations in the Northern Dvina River mouth. The samples were collected every month from September to November 2019 and from May to October 2020 with a Neuston net that was togged 3 nautical miles in the Korbel'nyy Branch of the River delta. Chemical composition of the plastic particles was determined using a Fourier transmission infrared spectrometer. The majority of the microplastics were identified as polyethylene 52.6%, followed by polypropylene 36.8%. After estimating the export fluxes of microplastics from the Northern Dvina River to the Arctic, there is no significant seasonal variation of the river export of microplastics. The microplastics export rate during the spring flood period in May turned out to be maximum, 58 items/s, while the minimum discharge was in September with a value of 9 items/s. The average weight concentration of microplastics was 18.5 µg/m3, which is higher than it was found in the Barents Sea - 12.5 µg/m3 and several times higher than in the Eurasian Arctic on average - 3.7 µg/m3. These results indicate that the Northern Dvina River is being one of the main sources of microplastic pollution of the White and the Barents Seas.