An overview of microplastic research in marine and freshwater habitats using topic modeling

Microplastics are considered the major pollutant of the Anthropocene. This study presents a retrospective examination of the literature to characterize microplastic research in marine and freshwater habitats and to explore the interconnections among the topics uncovered. After automated text mining, topic modeling was carried out to track the evolution of research topics in peer-reviewed articles on microplastics published from January 2010 to May 2021. The literature analysis suggested a total of 15 topics. The most representative terms in topics related exclusively to marine habitats were similar and differed from those in the topics related to both marine and freshwater habitats. The observed patterns in the popularity of the topics uncovered suggest that several topics have tended to increase in prevalence over time. However, no topic had high popularity, and only two topics were considered "cold," i.e., there was a drop in prevalence over time. The topics that had the largest research gaps on average across all topics were also among the most specific, those describing the key themes of certain manuscripts. This type of literature analysis is increasingly necessary so that the scientific knowledge available can be useful in the search for solutions to the environmental problems of today's society.