Assessing the Mitigation of Uranium and Heavy Toxic Elements with Physicochemical and Hydrogeochemical properties of groundwater in the Malwa Region of Punjab, India

Abstract

The escalating levels of uranium in groundwater present a critical challenge to public health and environmental sustainability in the Malwa region of Punjab, India. This study addresses the dearth of understanding regarding uranium contamination by investigating its hydrogeochemical behavior in the hot, sub-tropical steppe, semi-arid Malwa region. Our research aims to unravel the controlling factors influencing uranium mobility and distribution in groundwater. Ion chromatography was employed for the comprehensive determination of cations (Na+, K+, Li+, Ba+) and anions (F-, Cl-, Br-, NO3-, SO42-, PO4-). Inductive-coupled plasma mass spectrometry was utilized for the quantification of heavy elements including strontium (Sr), cadmium (Cd), lead (Pb), uranium (U), aluminium (Al), chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), cobalt (Co), zinc (Zn), arsenic (As), and selenium (Se) concentrations in groundwater samples. Results indicate alarming uranium levels ranging from 1.13 to 299.40 µg/L with mean of 54.03 µg/L. 73% to 92% of samples surpassing Bureau of Indian Standards (BIS) and World Health Organization (WHO) guidelines. Groundwater is primarily of Mg-HCO3 type which exhibited alkaline characteristics attributed to silicate weathering, ion exchange, and carbonate weathering in semi-arid conditions. Cluster analysis grouped uranium with nitrate, sodium and potassium, emphasizing their interconnected behavior. Spearman correlation analysis revealed a close association between uranium concentrations and various parameters including electrical conductivity, total dissolved solids (TDS), alkalinity, nitrate, sulfate, Na, and K. TDS, nitrate, and alkalinity exhibited high correlations with uranium which indicates that salt-induced competition among ions is the primary cause of uranium mobilization. This is evident in increased uranium levels with mixed water species (Mg-Cl, Na-HCO3). Furthermore, concerning levels of arsenic and selenium exceeding BIS and WHO limits underscore additional health concerns. This research underscores the urgent need for understanding and managing uranium contamination in the Malwa region. The broader implications for public health and environmental sustainability necessitate immediate attention and comprehensive remediation strategies.