Environmental Research 203 (2022) 111791 Available online 29 July 2021 0013-9351/© 2021 Elsevier Inc. All rights reserved. Mobilization and health risk assessment of fertilizer induced uranium in coastal groundwater Mahalakshmi Mathivanan a , Chidambaram Sabarathinam b, c , Prasanna Mohan Viswanathan d, * , Venkatramanan Senapathi e , Devaraj Nadesan c , Gunarani Gunaseelan Indrani a , Gnanasekar Malaimegu f , Sahoo Sunil Kumar g a Center for Bioenergy, School of Civil Engineering, SASTRA Deemed University, Thanjavur, 613401, India b Water Research Centre, Kuwait Institute for Scientifc Research, P.O. Box 24885, 13109, Safat, Kuwait c Department of Earth Sciences, Annamalai University, Annamalai Nagar, Tamilnadu, India d Department of Applied Geology, Faculty of Engineering and Science, Curtin University, Malaysia, CDT 250, 98009, Miri, Sarawak, Malaysia e Department of Disaster Management, Alagappa University, Karaikudi, 630003, Tamil Nadu, India f Research Scholar, SASTRA Deemed University, Thanjavur, 613401, India g Health Physics Division, BARC, Mumbai, India A R T I C L E INFO Keywords: Uranium Redox Agriculture Lithology Landuse Health hazards ABSTRACT Uranium (U) in groundwater is hazardous to human health, especially if it is present in drinking water. The semiarid regions of southern India chiefy depend on groundwater for drinking purposes. In this regard, a comprehensive sampling strategy was adopted to collect groundwater representing different lithologies of the region. The samples were collected in two different seasons and analysed for major and minor ions along with total U in the groundwater. Two samples during pre monsoon (PRM) and seven samples during post monsoon (POM) had U > 30 μgL 1 , which is above the World Health Organization’s provisional guideline value. The high concentration of U (188 μgL 1 ) was observed in the alluvial formation though a few samples showed the release of U near the pink granite (39 μgL 1 ) and the concentration was low in the lateritic formation (10 μgL 1 ). The uranyl carbonato complexes UO 2 (CO 3 ) 2 2 and UO 2 (CO 3 ) 3 4 were associated with high pH which facilitated the transport of U into groundwater especially during POM. U 3 O 8 is the major form observed in groundwater compared to either UO 2 or UO 3 in the both seasons. The uranium oxides were observed to be more prevalent at the neutral pH. Though U concentration increases with pH, it is mainly governed by the redox conditions. The principal component analysis (PCA) analysis also suggested redox conditions in groundwater to be the major process facilitating the U release mechanism regardless of the season. The POM season has an additional source of U in groundwater due to the application of nitrogenous fertilizers in the alluvium region. Furthermore, redox mobilization factor was predominantly observed near the coastal region and in the agricultural regions. The process of infltration of the fertilizer-induced U was enhanced by the agricultural runoff into the surface water bodies in the region. Health risk assessment was also carried out by determining annual effective dose rate, cancer mortality risk, lifetime average daily dose and hazard quotient to assess the portability of groundwater in the study area. Artifcial recharge technique and reducing the usage of chemical based fertilizers for irrigation are suggested as sustainable plans to safeguard the vulnerable water resource in this region. 1. Introduction Apart from dissolution of geogenic sources, U in groundwater could be enhanced by agricultural NO 3  and PO 4 3 fertilizers (Barringer et al., 2013). But, contamination of groundwater with increased concentration of NO 3  and Cl  may indicate the presence of fertilizer or leakage from unlined cesspools (Barringer et al., 2012). U is a radioactive compound that is highly reactive and generally not available in the elemental forms in the ambient conditions. The decay of U its reaction by-products are of serious concern to health hazard. A study near the mining and the * Corresponding author. E-mail addresses: mahalakshmi@civil.sastra.edu (M. Mathivanan), sabarathinam.chidambaram@gmail.com (C. Sabarathinam), prasanna@curtin.edu.my (P. Mohan Viswanathan), venkatramanansenapathi@gmail.com (V. Senapathi), devarajndr@gmail.com (D. Nadesan). Contents lists available at ScienceDirect Environmental Research journal homepage: www.elsevier.com/locate/envres https://doi.org/10.1016/j.envres.2021.111791 Received 9 January 2021; Received in revised form 24 July 2021; Accepted 26 July 2021