Eco toxicological and Spatial risk assessment of estrogenic endocrine disrupting compounds in Middle Ganga

Abstract

Chemical pollution threatens 60% of marine mammals, making it the second most significant threat to marine biodiversity. However, this alarming figure highlights the even greater risks faced by freshwater ecosystems, where biodiversity declines are happening at a faster rate than in marine environments. Freshwater ecosystems are especially vulnerable to the impacts of chemical pollution due to their limited water volume and flow, which reduces the dilution of contaminants. Their close proximity to pollution sources—such as agricultural runoff, industrial discharge, and urban waste intensifies this exposure. Furthermore, restricted natural flushing and water exchange, along with nutrient loading and additional stressors like habitat degradation and invasive species, further amplify the impacts of pollution on freshwater biodiversity. The Middle Ganga Reach (MGR), along the state of Uttar Pradesh, serves as an important habitat for endangered riverine mammals, yet faces intensified challenges to habitat suitability for these species due to various anthropogenic pressures, including EDC pollution from both point and non-point sources. Although research on e-EDCs in the river has progressed over the years, the spatiotemporal data remains incomplete and fragmented, particularly lacking in detailed characterization of point source contamination. This is a significant gap in our understanding of current risks and may result in inadequately informed and insufficient conservation efforts The objective of this thesis research was to investigate (a) the spatiotemporal distribution and load of e-E-EDCs in drains effluents and MGR (b) investigate and assess the estrogenic potential and ecological risk of selected e-EDCs to aquatic life, (c) identify high-risk zones spatially in river, and (d) assess the bioaccumulation potential of e-EEDCs in the prey species of the Gangetic dolphin, quantify the associated ecological risks, and identify suitable biomonitors for evaluating e-EDCs exposure in the MGR. The study also proposes a monitoring framework to provide guidance on monitoring and assessment of chemical contamination in Gangetic dolphin and habitats.