Impact of Microplastics on Reproductive and Physiological Aspects of Aquatic Inhabitants

Abstract

Environmental changes induced by humans pose a continuous threat for the natural freshwater ecosystems, and all this has a detrimental effect on the biotic communities. Organisms inhabiting freshwater ecosystems are more sensitive to changes in environmental conditions due to the unique conditions of such ecosystems. For the protection and management of ecological diversity, the quality of the water of an area is of remarkable concern as it gets polluted due to the release of various contaminants such as pesticides, disinfectants, heavy metals, microplastics, drugs, chemicals, and oil mixtures. Pollution due to microplastics has gained concern over the last few decades. This existence of microplastics in the aquatic ecosystem poses a significant risk to the aquatic inhabitants and even to the human health as they play a pivotal role in food chains. Multitudinous research has highlighted the accumulation of this xenobiotic compound in the gastrointestinal tract, gills, and hepatopancreas of aquatic inhabitants. The existence of microplastics in an ecosystem is a worldwide problem due to their toxic effects on fish and shellfish. These organisms experience various health issues such as oxidative stress, alterations in the immune system, neurotoxicity, retarded growth, hormonal disruption, behavioral changes, and damage to reproductive organs due to exposure to xenobiotics and other such compounds. In medaka fish, analysis of mRNA sequencing has depicted that bioaccumulation of microplastics alters the expression of genes involved in brain development, metabolic processes, and cell adhesion. With an increase in pollution levels in aquatic systems, these xenobiotics have accumulated in the crustaceans where they disrupt the normal molting process. These chemical residues get amassed in the tissues of living organisms and thus have profound effects on the health of an ecosystem. It is the need of the hour to modulate the existence and distribution of xenobiotics in an aquatic ecosystem. Therefore, the continuous monitoring of the pollutants along with the development of knowledge about the interrelationship between the concentration of xenobiotics and their adverse effects is a requisite for the accurate assessment of such chemicals in the natural ecosystem.