Hydrogeochemical characterization and non-carcinogenic health risk assessment of fluoride and nitrate-affected groundwater in northern parts of Tumkur district, Karnataka, India

Abstract

Groundwater contamination from geogenic and anthropogenic sources is a significant concern for the public health across the globe. In India, fluoride and nitrate contamination are the most prevalent contaminants in the groundwater. This study evaluated groundwater quality in four over-exploited sub-districts of Tumkur district in Karnataka by collecting 143 samples from post and pre-monsoon seasons and using different hydrogeochemical, statistical and bivariate graphical approaches. Comparison with Drinking Water Standard guidelines revealed elevated levels of fluoride, nitrate, and total dissolved solids (TDS), rendering the groundwater unsuitable for drinking. According to Chadha’s diagram, the predominant groundwater type is Na-Cl, and Gibbs diagram suggested the influence of rock dissolution and weathering. Bivariate plots indicated that hydrogeochemical characteristics were primarily influenced by silicate weathering of minerals, cation ion exchange processes, and anthropogenic factors. A non-carcinogenic health risk assessment was conducted using two different hazard index (HI) approaches from United States Environmental Protection Agency (USEPA) and Agency for Toxic Substances and Disease Registry (ATSDR). It was found that health risk associated with fluoride is more significant than the health risk from nitrate, with children being the most affected, followed by adolescents and adults. A holistic approach to assess cumulative health risks from fluoride and nitrate contamination in groundwater, as demonstrated in this study, promotes the synergistic advancement of SDG 3: Good health and well-being and SDG 6: Clean water and sanitation.

Keywords:

• fluoride contamination
• nitrate contamination
• non-carcinogenic health risk
• total hazard index
• endpoint specific hazard index

Acknowledgments

The authors thank the Department of Atomic Energy (DAE) – Board of Research in Nuclear Science, (BRNS), Mumbai, for granting the fund to this research under the grant number 36(4)/14/21/2017-BRNS/36198.

Author contributions

MT involved in sampling data collection, data analysis and results interpretation, and manuscript preparation. SP carried out data curation, content review.

Data deposition

Not applicable.

Ethical approval/consent to participate

This work does not contain any studies with human participants or animals performed by any of the authors.

Consent to publish

This work does not involve any personal data of individuals in any form.

Disclosure statement

The authors declare that there are no financial or non-financial interests to disclose.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author PS. The data are not publicly available because this research was funded by - Board of Research in Nuclear Science (BRNS), Department of Atomic Energy (DAE), Govt. of India.

Additional information

Funding

This work was supported by the Department of Atomic Energy (DAE) – Board of Research in Nuclear Science (BRNS), Mumbai, under the project grant number 36(4)/14/21/2017-BRNS/36198 to the Corresponding author Dr. PS