This study focused on assessing the impact of pollutants discharged from the Fuxin Meng Wastewater Treatment Plant (FMWWTP) on the microbial communities in the Xi River; specific comparison between upstream and downstream regions was made. Water samples were obtained by mixing morning, midday, and evening sampling at two points: one upstream and one downstream, each 500 m from the FMWWTP outfall. Utilizing metagenomic sequencing in conjunction with measured conventional physical and chemical properties, the research aimed to elucidate differences in microbial community structure, metabolic functions, potential biological contamination, and antibiotic resistance gene prevalence. The findings indicated a notable decrease in microbial diversity downstream compared to upstream; this was influenced primarily by the effluent from FMWWTP. This disparity in microbial diversity was evident at various taxonomic levels, with downstream samples showing higher diversity at the phylum level than at the genus level. Furthermore, downstream microbial populations demonstrated a broader range of metabolic and functional genetic diversity. Interestingly, the abundance of metabolic systems was generally greater downstream, with the notable exception of energy metabolism. This could be attributed to the stress imposed on downstream microorganisms by organic chemicals discharged from the treatment plant, and this prompts an enhanced metabolic decomposition function. The study also uncovered significant levels of potential biological contamination and antibiotic resistance gene pollution. This was more pronounced downstream of FMWWTP. In conclusion, discharge from FMWWTP has a substantial impact on the microbial communities of the Xi River, and this underscores the urgent need to optimize wastewater treatment processes to better comply with environmental quality standards.

Microplastics are persistent and complex contaminants and have been recognized as a global concern. Recently, increasing efforts have been devoted to studying the influence of microplastics on soils. However, the complexity of microplastics and the diversity of extraction methods result in a lack of systematic analysis and comprehensive review in this field. In this paper, we used CiteSpace software to summarize the development of this field. Then, we visualized and analyzed the knowledge structure, research hotspots, and trend directions of this field. We found that the number of publications escalated dramatically, and 281 institutions in 69 countries have published articles in this field. Among them, China was the most productive contributor. However, according to the scientific collaboration analysis, we found that more than 90% of the authors who contributed to the field had no close connection. In co-occurrence analysis for subject categories, we found that the research in this field covered environmental science, engineering, ecology, and agriculture. Additionally, the effect of soil microplastics on agriculture was the most important problem in scientific research. The keyword co-occurrence cluster analysis revealed a total of 6 clusters, including “Identification” (#0), “Microbial community” (#1), “Oxidative stress” (#2), “Adsorption” (#3), “Porous media” (#4), and “Abundance” (#5). We discussed several aspects in detail, including detection methods, characteristics, environmental effects, adsorption capacity, removal and degradation, and toxicity. According to these results, we summarized the current research hotspots and evaluated future research trends in soil microplastics. This study is the first to specifically visualize the research field, and these results provide a reference for future research in the field of soil microplastics.