A bibliometric review on microplastic research trends and knowledge gaps in surface and groundwater systems

Microplastics (MPs) have emerged as pervasive contaminants in surface and ground water systems worldwide, making it an increasing threat to ecosystem integrity and human health. Despite a rapid increase in research output, knowledge remains diffuse across environmental compartments and disciplines. This study examines global research trends (2010–2025) concerning MPs in freshwater systems using systematic evaluation, highlighting dominant themes, transport pathways, and policy gaps. Through PRISMA-compliant bibliometric and content analysis of 49,869 records from the Web of Science and Scopus databases, 179 peer-reviewed articles meeting all inclusion criteria were selected for detailed analysis. VOSviewer network visualization indicated a drastic increase in publication after 2020, with China leading the contributions, citations and institutional collaborations. Keyword clustering revealed the key research areas, including environmental distribution, toxicological effects, contaminant interactions and bioaccumulation. The dominant microplastic polymer types were PE, PP, PS, PET, PA, and PVC, while the most frequently reported forms were fibers and fragments. The significant analytical development includes Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, Pyrolysis-Gas Chromatography-Mass Spectrometry (Pyrolysis-GC-MS), and Scanning Electron Microscopy (SEM). However, the absence of standardized sampling strategies and analytical procedures remains a major limitation in this field. MPs also act as vectors for detrimental contaminants, enabling the translocation across soil–water boundaries and potentially threatening drinking water safety. This study highlights the need for standardized methodologies, integrated monitoring networks and interdisciplinary approaches to enhance comprehensive risk evaluation and regulatory responses, while emphasizing the necessity for further validation in real-world wastewater systems.