Identification of Heavy Metal Pollution Source Due to Idol Immersion Activity Across the Cauvery River Basin, Tamil Nadu, South India

Idol immersion activities alter the hydrological parameters of an aquatic body. However, relevant research in the Cauvery river basin in terms of idol immersion activity has been limited. In the present study, a total of 29 water and topsoil samples were collected from the Cauvery basin before and after idol immersion, and evaluated for the presence of metals. The experimental results showed elevated Cd and Pb levels in water and sediment samples of both Cauvery and Kollidam rivers. Strong statistical significance was observed for all the elements studied in the soil samples collected before and after idol immersion (P < 0.01). Industrial effluents, textile waste, untreated sewage, municipal waste and agricultural activities are the most common causes of elevated levels of heavy metals in the study area. Further, geo-accumulation index and pollution load index studies showed lesser impact of idol immersion on metal distribution compared to other sites reported from India. However, strict regulatory policies of the concerned authorities help maintain the quality of the Cauvery basin.