Chronic consumption of groundwater arsenic is a well-known risk factor for many cancers, notably lung, bladder, kidney and skin cancers, and is recognized as such in many countries, notably India. Indeed, increasing cancer incidence and mortality in India has been ascribed to such exposure. Notwithstanding this, there has hitherto been a dearth of quantitative data on the magnitude and spatial distribution of groundwater arsenic attributable cancer mortality in India. Here, we combined random forest model-derived data on the spatial distribution of groundwater arsenic in India with India census data on populations and groundwater usage and recently published dose–response relationships to address this knowledge gap through a population attributable fraction (PAF) approach. We show that around 1.4% (95% CI; ±1.8%) of all lung cancer mortality in India can plausibly be attributable to exposure to groundwater arsenic. Whilst this is a substantial range of values, it is too small to sensibly indicate any plausibility of the narrative of groundwater arsenic exposure being primarily responsible for the increased cancer incidence and mortality in India over the last few decades. Nevertheless, the modeled spatial distribution of groundwater arsenic exposure PAF of lung cancer mortality in India may inform public policy aimed at reducing environment-related detrimental health outcomes.
Wu et al. (2026) studied this question.