Assessment of groundwater quality of CKDu affected Uddanam region in Srikakulam district and across Andhra Pradesh, India

Uddanam region in Srikakulam district of Andhra Pradesh, India, is a chronic kidney disease (CKD) hotspot with high prevalence of CKD of unknown etiology (CKDu). Several investigators have suggested that groundwater contamination could be one of the factors contributing to the high prevalence of CKDu in this region. This study focused on the monitoring and assessment of groundwater quality of Uddanam with a major objective of identifying etiological factors of CKDu linked to drinking water. Composite groundwater sampling was carried out in 40 selected villages in Uddanam and 100 villages of other nine districts in Andhra Pradesh during August 2018-May 2019. About 35% of villages in the study area had acidic groundwater (pH < 6.5) while only 3% villages in other districts had acidic groundwater. Moreover, groundwater had elevated silica (SiO2) concentration (similar to 45 mg/l) during the monsoon (wet) season while high lead (Pb) concentration (0.023 mg/l) was measured during pre-monsoon (dry) season. The lead concentration in the groundwater samples were found to be above the Bureau of Indian Standards (BIS) permissible limit (0.01 mg/l) in 55% of villages during dry season as compared to 10% during wet season. Fluoride (F) concentration in groundwater was found well below the BIS permissible limit (1.5 mg/l) in 95% of villages of study area with mean concentration (0.54 mg/l, SD = 0.40). Synergic effects on kidney function of lead, fluoride, silica and water hardness in acidic water need to be explored. In this study, analysis of organic contaminants such as pesticides and phthalates in groundwater samples of the study area were also carried out. Pesticides were not found in any groundwater samples, however, phthalates were detected in all water samples. Groundwater treated with reverse osmosis (RO) process is recommended for drinking and cooking as a preventive measure for CKDu in Uddanam.