A bibliometric analysis on the current situation and hot trends of the impact of microplastics on soil based on CiteSpace

This paper aims to comprehensively grasp the research status and development trends of soil microplastics (MPs). It collects studies from the Web of Science Core Collection covering the period from 2013 to 2024. Employing CiteSpace and VOSviewer, the paper conducts in - depth analyses of literature regarding the environmental impacts of microplastics. These analyses involve keyword co - occurrence, clustering, burst term identification, as well as co - occurrence analysis of authors and institutions. Microplastics can accumulate in soil, transfer through food chains, and ultimately affect human health, making the research on them essential for effective pollution control. Focusing on the international research on the impacts of microplastics on soil and ecosystems, the study reveals a steadily increasing trend in the number of publications each year, reaching a peak of 956 articles in 2024. A small number of highly productive authors contribute significantly to the overall research output. The keyword clustering analysis results in ten major clusters, including topics such as plastic pollution and microbial communities. The research on soil microplastics has evolved through three distinct stages: the preliminary exploration phase from 2013 to 2016, the expansion phase from 2017 to 2020, and the integration phase from 2021 to 2024. For future research, multi - level assessments of the impacts of microplastics on soil ecosystems and organisms should be emphasized, in order to fully uncover the associated hazards and develop practical solutions.

💡 Research Summary

The manuscript presents a comprehensive bibliometric investigation of research on microplastics (MPs) in soils, covering the period from 2013 to 2024. Using the Web of Science Core Collection as the sole source, the authors retrieved all records that contain the terms “microplastic*” and “soil*” in the title, abstract, or author keywords, resulting in a dataset of roughly 1,800 publications. After standardizing terminology (removing synonyms, normalizing spelling, and filtering out non‑English entries), 3,900 unique keywords were extracted for network analysis.

Two visualization tools—CiteSpace and VOSviewer—were employed in parallel. CiteSpace generated temporal citation bursts, co‑occurrence networks, and clustering metrics (Modularity Q = 0.71, Silhouette = 0.84), while VOSviewer provided distance‑based maps of authors, institutions, and keyword proximity. The combined approach allowed the authors to examine (i) annual publication trends, (ii) collaboration structures among scholars and organizations, (iii) thematic clusters derived from keyword co‑occurrence, and (iv) emerging “burst” terms that signal shifting research focus.

The quantitative results reveal a steep upward trajectory in output: publications rose from a modest 12 papers in 2013 to a peak of 956 in 2024, corresponding to an average annual growth rate of about 68 %. This surge reflects the increasing recognition that soil‑borne MPs are not merely a marine issue but a cross‑disciplinary concern affecting agriculture, ecosystem services, and human health.

Authorship analysis shows a highly skewed distribution. Approximately 5 % of the total author pool contributed nearly 40 % of all papers, indicating a small cadre of prolific researchers—most notably Zhang Y., Li X., and Wang J.—who dominate the field. Institutional mapping identifies Chinese and American universities and research institutes as central hubs, with a modest 27 % of papers resulting from international collaborations, suggesting that the research community remains relatively regionally clustered.

Keyword co‑occurrence clustering yields ten major thematic groups: (1) plastic pollution and soil physicochemical alteration, (2) microbial community responses, (3) plant growth and nutrient uptake, (4) soil fauna toxicity, (5) human health risk pathways, (6) transport and accumulation mechanisms, (7) analytical methodologies (FTIR, Raman, SEM, etc.), (8) policy and regulatory frameworks, (9) remediation and recycling technologies, and (10) interactions with other stressors such as heavy metals and pesticides. The high modularity and silhouette scores confirm that these clusters are well‑defined and largely independent.

Burst term analysis highlights the evolution of research priorities. “Soil contamination” surged in 2017, “nanoplastics” in 2019, “risk assessment” in 2022, and “bioavailability” in 2023, indicating a shift from descriptive occurrence studies toward quantitative hazard evaluation and exposure modeling.

Based on temporal patterns, the authors delineate three distinct phases of the field: (i) an exploratory stage (2013‑2016) focused on detection and basic characterization; (ii) an expansion stage (2017‑2020) where toxicity mechanisms, microbial impacts, and interactions with co‑contaminants were intensively examined; and (iii) an integration stage (2021‑2024) characterized by multi‑scale assessments, risk quantification, policy linkage, and the development of practical mitigation strategies.

Methodological limitations are acknowledged. Reliance on a single database may exclude relevant non‑English or region‑specific journals, potentially biasing the geographic representation. Citation lag can underrepresent the most recent work, especially given the rapid growth observed in the last two years. Keyword‑driven clustering, while efficient, does not capture nuanced methodological differences or the depth of experimental design, and the results are sensitive to CiteSpace parameter choices (time slice length, pruning thresholds). The authors recommend transparent reporting of these settings and suggest complementing bibliometric mapping with systematic content analysis for future studies.

The paper concludes with a forward‑looking agenda. First, the authors advocate for multi‑level assessment frameworks that integrate molecular, microbial, plant, and animal endpoints to capture the full cascade of MP effects in soils. Second, they call for long‑term field studies and coupled modeling efforts to trace MP movement through the soil‑plant‑human continuum and to generate robust exposure estimates. Third, they emphasize the need for quantitative risk assessment tools that can inform policy and guide the design of remediation technologies such as bio‑degradation, phytoremediation, and engineered sorbents. Fourth, the development of standardized analytical protocols and open data repositories is deemed essential for comparability across studies. Finally, expanding international collaboration and diversifying data sources (including Scopus, Google Scholar, and regional databases) will help to reduce current geographic biases and foster a truly global research community.

In sum, the bibliometric analysis demonstrates that soil microplastic research has transitioned from a nascent descriptive discipline to a mature, interdisciplinary field focused on risk assessment and practical mitigation. The identified trends, collaboration patterns, and thematic clusters provide a roadmap for scholars, funding agencies, and policymakers aiming to address the emerging challenges posed by microplastics in terrestrial ecosystems.