Umbrella Review on Micro and Nanoplastics: Mapping the Scientific Landscape

Area of Science:

• Environmental Science
• Ecotoxicology
• Materials Science

Background:

• Micro- and nanoplastics (MNPs) are pervasive emerging contaminants with potential ecological and human health risks.
• The rapid growth of review literature necessitates a comprehensive synthesis of current research trends and knowledge gaps.

Purpose of the Study:

• To conduct an umbrella review of MNP research using scientometric mapping and thematic synthesis.
• To evaluate research trends, methodological patterns, evidence convergence, and identify knowledge gaps in MNP studies.

Main Methods:

• Analysis of 7,349 review articles from Web of Science Core Collection up to June 2025.
• Integration of manual refinement, automated text-mining, and CiteSpace network analyses.
• Thematic synthesis to identify research concentrations and knowledge gaps.

Main Results:

• Strong focus on aquatic ecosystems, fish models, contamination, and adverse effects of common polymers (PE, PS, PP, PET).
• Consensus on MNP occurrence, oxidative stress, inflammation, cytotoxicity, and bioaccumulation.
• Identified methodological heterogeneity, limited taxonomic diversity, and underrepresentation of terrestrial/atmospheric systems and less common polymers.

Conclusions:

• Despite research consolidation, significant limitations exist in evidence integration, methodological standardization, and ecological representativeness.
• Urgent need for integrative, standardized, and ecologically relevant approaches to improve MNP risk assessment.
• Further research should focus on environmental transport, degradation, microorganism interactions, and realistic exposure scenarios.