Impact of water-particle interactions on molybdenum budget in humid tropical rivers and estuaries: insights from Nethravati, Gurupur and Mandovi river systems

The study presents the seasonal and inter-annual monitoring of molybdenum (Mo) distribution and variability in humid tropical riverine and estuarine systems (Nethravati, Gurupur and Mandovi estuaries) of west coast of India. The study investigates the geochemical behaviour of Mo in the river and estuaries, and their ultimate fluxes into the ocean. The riverine flux of dissolved Mo (DMo) to the Nethravati, Gurupur and Mandovi estuaries are 1800molyr−1 (4.88molday−1), 195molyr−1 (0.53molday−1) and 10.5×103molyr−1 (28molday−1) respectively, and the riverine particulate Mo (PMo) flux to Nethravati estuary is 10.8×103molyr−1. The DMo in river (~30 to 40%) is scavenged onto particles under oxidized acidic river water conditions and subsequently released in the estuary, impacting the solute budget of Mo to the sea.