Distinguishing Microplastics from Microplastic-like particles: a Case study of Fish from the Marine Waters of Qatar

Microplastic (MP) pollution poses a significant threat to marine ecosystems. In this study, MP accumulation in the gastrointestinal tracts of 170 samples of four commercially important fish species in Qatar has been assessed along with their level of risk. MP-like particles were extracted via chemical digestion and density separation, and were analysed using stereomicroscopy method. Fibers were the dominant MP shape, with blue being the most common colour. The polymer composition of MP-like particles was further analysed using µ-Raman spectroscopy, and the results confirmed only 7 particles (4.12% of the total 170 fish samples) as MPs (> 70% match with polymer library databases). Polymer analysis confirmed the presence of polyethylene (PE) and polypropylene (PP) in the fish digestive tracts. The mean abundance of 0.070 ± 0.090 MPs/g of fish gut is relatively low, compared to the results reported in other regions of the Gulf and also globally. The herbivorous Siganus canaliculatus ingested more MPs than the other three carnivorous species, but this difference was not statistically significant (p > 0.05).