Urbanization and Agriculture as Drivers of River Pollution: A Case Study from the Arkavathi River Basin

A small seasonal river, the Arkavathi River, which passes through the Silicon Valley of India, Bengaluru city, in southern India, is chosen for this study. This river provides for the drinking water needs of 14 million people of Bengaluru city and is home to vibrant aquatic ecosystems along its course (Review, 2025). A detailed seasonal study (post- and pre-monsoon) was conducted throughout the river to monitor certain physicochemical parameters, major ions, and heavy metals. The heavy metal pollution index confirmed that the water was fit for consumption when the samples were collected. Principal Component Analysis and land use maps confirmed that the river receives pollutants from industrial, urban, and agricultural wastewater discharge. Major ions were primarily sourced from the weathering of rocks. Their order abundance of anions Cl ⁻ >SO ₄ ²⁻ >F ⁻ >NO ₃ ⁻ and cations Na ⁺ >K ⁺ >Mg ²⁺ >K ⁺ . Domestic and industrial effluents are also suspected of pumping excess chloride into the river. We discuss the prevalence of heavy metals in the study area and identify whether agricultural regions impact water quality and environmental health. We also discuss the impact of pest infestation during 2016–2018 on river water quality. Statistical tools have been used to check whether urban or agricultural locations have a greater impact on water quality.This study highlights the importance of continuous water quality monitoring and can serve as baseline data for policymakers to develop effective management strategies. The results would also prompt policy interventions to preserve the ecological integrity of the Arkavathi River.