Toxicological assessment of nanoparticles and microplastics

According to National Oceanic and Atmospheric Administration (NOAA), microplastics are small plastic particles of less than 0.2 inches (5 millimeters) long and considered as sesame seeds. The microplastics (MPs) reach the rivers, lakes, and oceans after being flushed into sewers. Nanoparticles (NPs) are colloidal particles within the size range of 1 to 100 nanometers (nm). Secondary NPs occurred naturally by the degradation of macro and microplastic waste materials and are more heterogenous than primary NPs. The damaged biomolecules lead to the occurrence of numerous reactions including inflammatory response, cell death, tissue damage, and DNA damage. Free radical generation (non-enzymatic antioxidants) and antioxidant defenses helps to balance the excess ROS and repair the damaged cells to reduce oxidative stress. NPs and MPs eventually move to the aquatic environment followed by the entrance of NPs and MPs into the bodies of aquatic animals to cause harmful effects. NPs may also dramatically increase the CAT and SOD activities. MPs and NPs are very harmful to the organisms however combined with other chemical components. These components are cause serious harmful to the fish and damage the nervous system of fish. NPs and MPs can also cross the blood brain barriers in the brains of fish.