Ingestion and the toxicological effects of virgin polyethylene (PE) and polyvinylchloride (PVC) microplastics in commercial freshwater fish, tilapia (Oreochromis niloticus)

Microplastics (MPs), which are tiny particles measuring less than 5 mm, have emerged as a notable environmental issue due to their widespread presence in aquatic environments and their potential to harm aquatic organisms. In this study, the diet of tilapia (Oreochromis niloticus) exposed them to two types of MP materials: PE and PVC fragments. The fish were exposed for three weeks (21 days), and various behavioural changes and mortality were noticed. Moreover, microplastics can impact the growth, reproduction, and survival of tilapia, as evidenced by reduced growth rates and observed behavioural changes in exposed fish. Such modifications might have important effects on the general condition and population dynamics of aquatic environments. In both the gill and gastrointestinal tract (GIT), the MP fragments were accumulated. The GIT of tilapia fish revealed 4.8 ±2.7 items/individual from the collected PVC pieces; gills included 6.6±2.07 items/individual. Similarly, PE fragment accumulation in the GI tract of fish showed 5.6±2.6 items/individual, and the gills showed 5.8±0.84 items/individual. A dietary intake of microplastics led to increasing inflammatory alterations in the liver and intestines. This study assessed the levels of oxidative enzymes in exposed groups of fish (control, PVC, and PE fragments). The MP-exposed tilapia fish exhibited remarkable changes in the enzyme level and the nutritional values, which were compared to control groups. All things considered, microplastics seriously compromise the health and ecological processes of freshwater fish, including tilapia. More study is required to completely understand these effects as well as develop feasible strategies for reducing the microplastics' hazard in freshwater habitats.