Bisphenol A (BPA) is an endocrine-disrupting compound that pollutes aquatic habitats via plastic leaching, wastewater discharge, and landfill runoff. It functions as an environmental estrogen, resulting in reproductive anomalies, skewed sex ratios, and physiological damage to fish and other aquatic species. This study investigates the seasonal occurrence of environmental bisphenol A (eBPA) in the coastal region of the River Ganga, focusing on ecological risk assessment. The present study examined the concentrations of eBPA in surface water, soil, and fish at three sites. eBPA was quantified using a highly specific and sensitive ELISA method tailored for aquatic samples. eBPA concentrations ranged from 256.2 to 565.33 ng/L, 245.82 to 446.1 ng/L, and 295.32 to 667.19 ng/L in surface water; from 2145.29 to 2976.11 µg/kg-dw, 2017.8 to 2633.47 µg/kg-dw, and 2502.1 to 3966.46 µg/kg-dw in sediment during the pre-monsoon, monsoon, and post-monsoon periods, respectively; and from 2.63 to 219.27 ng/g-dw in various fish species. Unlike surface water and soil, seasonal variations in eBPA concentration were not apparent at the species level in fish. The feeding zone of biota influenced the concentration of eBPA, demonstrating a trend of pelagic > demersal > benthic > benthopelagic. This research is the pioneering report on the impact of eBPA pollution on aquatic ecosystems, illustrating that fish exposed to eBPA pose health concerns to people. These findings highlight the imperative for additional research on fish contamination by eBPA for human food safety and the protection of the riverine ecosystem in the coastal region of the Ganga River.