Comprehensive systematic review and meta-analysis of microplastic prevalence and abundance in freshwater fish species: the effect of fish species habitat, feeding behavior, and Fulton’s condition factor

Microplastics are emerging pollutants that cause health problems for aquatic organisms. Fish is one of the important organisms because of its consumption by humankind. The present study examines the abundance and prevalence of microplastics in freshwater fish species through a systematic review study while considering five important factors, i.e. water resources, habitat, feeding behavior, Fulton’s condition factor, and microplastic characteristics. A comprehensive meta-analysis was undertaken to evaluate relevant publications in terms of microplastic abundance. Articles published up to July 30, 2022 were found through Global search engines including, Web of Science, Scopus, and PubMed. In total, 786 articles were found that 53 and 42 articles were used for qualitative review and meta-analysis, respectively. This was carried out by a random-effects model with high heterogeneity (I² = 99.76%). According to the data, the highest attention in microplastic research in body part and water sources are related to gastrointestinal tract (n = 259 (~ 80%)) and rivers (n = 189 (~ 58%)), respectively. According to the results, the average microplastic prevalence range was 5 -100%, and microplastic abundance was within the 0.04–204 items range per individual. The difference between microplastic prevalence and abundance for the key factors for parametric and nonparametric data were analyzed using Analysis of variance (ANOVA) and the Kruskal-Wallis test, respectively. According to the Baujat plot, two studies (ID: 27 and 25) revealed the minimal influence of microplastics abundance. Conclusively, the average microplastics abundance according to the pooled data, varied between 2.23 and 2.48, with a mean of 2.35 items per individual in the studies overall. It is concluded that the amount of ingested microplastics by fish is related only to physiology (height, weight, and body structure) but not feeding behavior, habitat, and surrounding water.