Single and combined effects of microplastics and wastewater on kidney of Cyprinus carpio

Abstract

Rapid pace of urbanisation and industrialisation has led to accumulation of different pollutants such as domestic sewage, agricultural runoff and industrial waste in water bodies. Additionally, microplastics (MPs) are problematic due to their toxicity, environmental persistence, abundance and ability to adsorb different contaminants. Among different aquatic organisms, fishes are considered as an exceptional indicator to study water quality and well-being of aquatic ecosystem due to their sensitivity to alterations in environmental conditions. In addition, they are an important protein source; however, toxicants in them could affect health of human beings consuming them. Therefore, the current study was designed to study the combined effects of low-density polyethylene (LDPE) MPs and wastewater on histomorphology of kidney of minor carp Cyprinus carpio. The results showed that significant alterations such as paracellular spaces, damaged hematopoietic tissue, detachment of renal tubule from basal lamina, damaged renal tubules, paracellular spaces, vacuolization, necrosis and exudate were found in kidneys of fingerlings belonging to treated groups. Moreover, Organ index of kidney also indicated significant (p≤0.05) rise in different treatment groups in comparison to control group. Overall, the results concluded that the combination of LDPE MPs and wastewater effects kidneys of C. carpio fingerlings in duration and dose-dependent manner with limited reversibility following exposure.