This study reports on the geochemistry of surface-and groundwaters along the Subarnarekha River system (northeastern India). Multi-isotopic approaches (Sr, O, H) have been applied for tracing the water origin and pathways and investigate how far pollutants released by mining, ore processing and metallurgical activities can migrate at the catchment scale. Results of the Sr isotope systematics did not provide any evidence of mining processes-derived minerals impacts on the water. Pollution from mining activities entering the river are transported to the estuary as non-impacting fine fractions.