Occurrence, distribution and characteristics of microplastics in gastrointestinal tract and gills of commercial marine fish from Malaysia

Microplastics are tiny plastic particles with size below 5 mm, prevalence in marine environments and the occurrence have been reported in commercial marine fish worldwide. Microplastics' abilities to absorb various marine contaminants raised considerable concern on their role as a vector to spread harmful pollutants to the alienated environment. This study focussed on the occurrence of microplastics in gastrointestinal tract (GIT) and gills of 158 fishes across 16 species from two locations in Malaysia coastal waters. Microplastics were detected approximately 86% in the GIT and 92% in the gills of examined fish. High incident of microplastics was detected in fishes from the area that is close to an urban area with average microplastics incident reaching up to 9.88 plastics items/individuals. Meanwhile, only 5.17 microplastics per individual were recorded in fishes from a less urbanised area. Isolated microplastics comprised 80.2% of fibres, 17.7% of fragments and the remaining was derived from filaments (3.1%). Infrared and Raman spectroscopy analysis of selected microplastics revealed the chemical composition of microplastics which comprised of polyethene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS) and polyethylene terephthalates (PET). FESEM images indicate, different surface characteristics of microplastics as a result of environmental exposure. Further, elemental analysis using EDX for green PE fragments showed the uneven distribution of chromium (Cr) and iron (Fe) on the surface, suggesting the adherence of heavy metals on the surface of microplastics. Overall findings indicate the widespread distribution of microplastics in commercial marine fishes from Malaysia waters and could potentially lead to human exposure through fish consumption.