“Eco-Toxicological Risk Assessment Of Mixed Pesticides On Freshwater Fish: A Case Study From The Ganga Basin”

Abstract

The present study investigates the eco-toxicological risk assessment of mixed pesticide contamination on freshwater fish in the Ganga River at Ghazipur district, with a focus on and other Indian major carps as bioindicators. Water and sediment samples collected from upstream, midstream, and downstream sites were analyzed using GC-MS and HPLC, revealing the presence of organochlorine (DDT, aldrin), organophosphate (chlorpyrifos, malathion), and pyrethroid (cypermethrin) pesticides at concentrations exceeding WHO/FAO permissible limits. Tissue analysis of fishes demonstrated significant bioaccumulation, with the highest residues recorded in liver, followed by kidney, gills, and muscle. Hematological parameters showed reduced hemoglobin and RBC counts, while WBC counts, glucose levels, and enzymatic disruptions (AChE, LDH) indicated physiological stress. Histopathological examination revealed severe tissue alterations, including gill lamellar fusion, hepatic degeneration, and renal tubular necrosis. Ecological risk assessment based on Risk Quotient (RQ) analysis classified DDT and chlorpyrifos as “very high risk,” while aldrin, malathion, and cypermethrin posed “high risk” to aquatic life. These findings highlight that pesticide mixtures exert synergistic toxic effects, threatening both aquatic biodiversity and food chain safety. The study emphasizes the urgent need for stricter pesticide regulation, sustainable agricultural practices, and integrated monitoring to safeguard river ecosystems and human health.