NEW DELHI: The study was carried out by Mahavir Cancer Sansthan, Patna, under the leadership of Dr Arun Kumar and Prof Ashok Ghosh, in collaboration with AIIMS, New Delhi, led by Dr Ashok Sharma from the department of biochemistry.Conducted between October 2021 and July 2024, the research analysed breast milk from 40 mothers aged 17-35 in Bhojpur, Samastipur, Begusarai, Khagaria, Katihar and Nalanda. Uranium (U238) was detected in all samples, with concentrations ranging from 0 to 5.25 g/L. There is no permissible limit for uranium in breast milk.Khagaria recorded the highest average contamination, Nalanda the lowest, while Katihar showed the single-highest reading. Nearly 70% of infants faced exposure levels associated with potential non-carcinogenic health risks.Co-author Dr Ashok Sharma of AIIMS said the source of contamination remains unclear. “We do not yet know the source of the uranium; the Geological Survey of India is also trying to find out. Unfortunately, uranium comes into the food chain and causes cancer, neurological disorders and affects the growth of children – which is a very serious concern,” Dr Sharma said.Bihar’s environmental conditions have compounded the issue. The state’s heavy dependence on groundwater for drinking and irrigation, discharge of untreated industrial effluents and long-term use of chemical fertilisers and pesticides have already led to contamination with arsenic, lead and mercury in biological samples. The detection of uranium in breast milk signals the contamination has reached the most vulnerable population – infants.Infants are especially vulnerable to uranium because their organs are still developing, they absorb toxic metals more readily and their low body weight amplifies exposure. Uranium can cause kidney damage, neurological impairment, cognitive delays and increase the risk of cancer later in life.Globally, elevated uranium in groundwater has been reported in Canada, the US, Finland, Sweden, Switzerland, the UK, Bangladesh, China, Korea, Mongolia, Pakistan and the Mekong delta. But its presence in breast milk in Bihar takes the problem to a new level.Despite the alarming results, the researchers strongly emphasised that breastfeeding should continue. It remains irreplaceable for immunity and early development, and should be discontinued only on medical advice. With uranium from contaminated groundwater being traced in the most essential nutrition an infant receives, the study calls for urgent biomonitoring, rigorous water-quality testing and immediate public-health intervention.Considering the threat it poses to the most vulnerable of humankind, the research is a call for action.