Groundwater usage characterization in a tribal stretch infected with chronic kidney disease of unknown etiology (CKDu).

Chronic kidney disease of unknown etiology (CKDu) is a recent discovery in this part of the world in central India in a tribal stretch. About 100 people have already died and more than 300 compulsively hospitalized from a single village, Supebeda, that consists of only 1200 people in the state of Chhattisgarh. Media reports since 2018 and public outcry nationally compelled many Government agencies to visit the area and investigate the malady to find a solution. Although medical teams ascribed the menace to CKDu (Chowdhary et al., 2020), common people still believe that groundwater is the real culprit (Rathore et al., 2022). The entire village historically relies on this precious resource for all their water use. Two of the present authors visited the area in 2020 and made a quick appraisal of its groundwater quality (Dewangan and Verma, 2022). Since no serious quality deterioration could be detected, Herojeet et al. (2023) made an in-depth analysis of the collected data and found that the area indeed suffers from nitrate (NO₃^–) and fluoride (F^–) contamination. They did make a deterministic and probabilistic modeling of the human health risk assessment due to these contaminants, but a wholesome picture of the groundwater quality from usage perspective could not be brought out. Hence the present investigation.

Literatures on CKDu reveal that agricultural workers are mostly the victims of this enigmatic disease throughout the world (Bradley et al., 2024; Fiseha et al., 2024). While Hettithanthri et al. (2021) define the characteristics of the affected population as low-income agricultural workers aged 30–60 years, Nayak et al. (2023a) directly link farming and water sources to the origin of CKDu based on 25 case studies from around the globe. This study was, therefore, extended from drinking water appraisal to deciphering groundwater quality for agricultural purposes so that some important evidences on the genesis of CKDu could be discerned. Besides, since the economy of this region depends on agriculture, it is imperative that the quality of groundwater is examined from its irrigational suitability perspective. Till date, researchers have mainly focused on studies related to several multifactorial features, such as hydrogeochemical investigations, source apportionment of chemicals, heat stress, agrochemicals, genetic predisposition, nonsteroidal anti-inflammatory drugs, infectious diseases (leptospirosis), and other nephrotoxic medications while working on CKDu (Gifford et al., 2017; Jolly and Thomas, 2022; Hettithanthri et al., 2021; Redmon et al., 2021). Very limited work has so far been done on the suitability of groundwater resources for various water uses, such as for drinking, agriculture, and industry, in a CKDu area. This work fulfils this gap in knowledge in the quest for finding a solution to the infection by CKDu.

Chhattisgarh State is rapidly implementing the Government of India’s ambitious “National Jal Jeevan Mission” in which “Har Ghar Jal (water in every home)” is the popular slogan (Press Information Bureau, 2024). This scheme aims to provide every household in the country with access to piped water connections to ensure a clean drinking water supply, thus improving public health and sanitation (Sustainable Development Goal 6). To alleviate apprehension of CKDu infection due to water usage in Supebeda, the State Government is in the process of prioritizing implementation of this scheme in this region. But then since the modus operandi of the scheme shall involve pipelines and many other fixtures made up of metals for storing and transporting groundwater from high-yielding borewells, it is essential that the corrosiveness of the water is examined to ensure safety and efficient performance of these materials. Moreover, because this study area lies in a ‘naxal-prone’ zone affected by the Left Wing Extremism (Press Information Bureau, 2019), the Indian Government has a long-term plan to industrialize the region to enhance employability of the people and engage them in the rightful way. Since industrialization shall involve heavy machinery and use of various kinds of materials, it is vitally important that groundwater is evaluated adequately for its corrosiveness and affinity to scaling.

Supebeda has been constantly drawing the Government’s attention recently because of the public sufferings due to CKDu, and it is likely that this area shall be prioritized for early implementation of all Government’s schemes. Therefore, the primary objective of this study is to characterize the groundwater resources of this village from various usage perspectives, such as for drinking, agricultural and industrial purposes, using multi-indexing techniques and statistical analyses, keeping an eye on any possible breakthrough on the genesis of CKDu for the greater good of humanity. The study answers the following five essential hypothetical questions: (1) Whether groundwater is potable? (2) Whether there is a link between drinking water and CKDu? (3) Whether groundwater is suitable for agricultural purposes? (4) Whether groundwater quality will hinder the Government’s endeavors for piped water supply to the villages? (5) How good groundwater is for industrial usage?

Chronic kidney disease (CKD) is the third fastest growing malady infecting about 850 million people globally (Nature, 2024). It’s predicted to become the fifth highest cause of years of life lost by 2040 from a rank of sixteenth in 2016 (Foreman et al., 2018) and twelfth in 2017 (Global Burden of Disease – Chronic Kidney Disease Collaboration, 2020). It causes the highest economic burden of any disease group in the low-and lower-middle-income countries (Essue et al., 2017; Levin et al., 2023), such as Sri Lanka (Abeysekera et al., 1996), Central American nations (Trabanino et al., 2002), Tunisia (Abid et al., 2003), Egypt (Minshawy, 2011), and India (Rajapurkar et al., 2012). What is intriguing is its unknown etiology (CKDu) primarily affecting the economically weaker sections of society, such as farming communities (Hettithanthri et al., 2021; Bradley et al., 2024; Fiseha et al., 2024). While groundwater is considered the root cause of CKDu in Sri Lanka (Imbulana and Oguma, 2021; Zeng et al., 2022; Shi et al., 2023; Chandrajith et al., 2024), this hypothesis is supported by many other workers world-wide, such as by Khandare et al. (2015), Lal et al. (2020), Tatapudi et al. (2019), and Mascarenhas et al. (2017) in India, Campese (2017) in central America and most recently by Nayak et al. (2023a) globally. In India, it is reported in the States of Andhra Pradesh (Ramesh et al., 2011; Ganguli, 2016), Goa (Mascarenhas et al., 2017), Delhi (Ghosh et al., 2017), Tamil Nadu (Parameswaran et al., 2020), Odisha (Mohanty et al., 2020), Maharashtra (Mogal, 2020), and Chhattisgarh (Chowdhary et al., 2020), a part of which forms the present study area of Supebeda. The fact that about one-fourth of the Supebeda’s population suffers from CKDu, the economic turmoil on the families of this village can very well be visualized.

The village Supebeda is important because it is for the first time that CKDu infection of such a greater magnitude (100+ deaths and 300+ hospitalizations) has occurred in India. And it is the second time in the history of CKDu investigations that groundwater is being studied in detail from a utilization perspective. The first such study was carried by Hu et al. (2024) in Sri Lanka for drinking and industrial purposes, but their appraisal in terms of groundwater potability is of limited scope due to adoption of three indices that give contrasting results. Moreover, they do not identify any violating parameter(s) that could possibly be playing a role in the etiology of CKDu. The present analysis is unique in the sense that it evaluates the groundwater resources of a CKDu region not only for drinking but also for agricultural and industrial purposes by using all conventional techniques prevalent in literature. It answers many pertinent questions the public in such areas have been asking the medical professionals and authorities for quite some time. Besides, it identifies many violating parameters that are members of the Hofmeinster ion series, strongly hypothesized as a dominant factor for the onset of CKDu (Rajkumar et al., 2025a). The outcome of this study will, therefore, not only help the people of Supebeda but also the millions of people suffering from CKDu around the globe.