Novel approach to nitrate and macro-elements: carcino-spectrum of human health risk projections

Groundwater is a vital yet increasingly vulnerable resource, with nitrate contamination posing a significant risk to human beings and the ecosystem. The present study offers an integrated, sustainability-focused assessment of groundwater quality in India's eastern littoral state, based on groundwater quality data from 422 sampling locations. In 2024, nitrate concentrations peaked at 387 ppm, with an average of over 37 ppm; notably, more than 20% and 17% of samples exceeded the Bureau of Indian Standards and World Health Organization guidelines, respectively. Both non-carcinogenic and carcinogenic health risks were assessed, revealing that nitrate poses risks through oral and dermal exposure, while nitrite contributes to cancer risk through ingestion. Principal component analysis multiple linear regression highlighted strong correlations among nitrate and macro-elements such as sodium, chloride, calcium, magnesium, and potassium, indicating common anthropogenic sources such as fertilizer runoff and wastewater infiltration. Multivariate analysis showed that nitrate is the dominant contaminant influencing groundwater quality shifts from 2020 to 2024, largely driven by agricultural intensification and sewage disposal contributions. These findings underscore the critical importance of adopting strategic intervention policies and promoting resilient groundwater governance frameworks across national and international scales.