A multi-institutional scientific investigation has uncovered alarming levels of uranium in the breast milk of women from six districts in Bihar, signalling a serious public health concern for infants who rely exclusively on maternal milk during early development. The study was jointly conducted by Mahavir Cancer Sansthan & Research Centre in Patna, Lovely Professional University in Punjab’s Phagwara, the National Institute of Pharmaceutical Education and Research (NIPER) in Hajipur, and the All India Institute of Medical Sciences (AIIMS), New Delhi.

The research team collected breast milk samples between October 2021 and July 2024 from 40 lactating mothers aged 17 to 35 years across Bhojpur, Samastipur, Begusarai, Khagaria, Katihar and Nalanda districts. The analysis detected uranium in every sample, with concentrations reaching up to 5.25 microgrammes per litre (µg/L). Since there is no globally accepted or nationally prescribed permissible limit for uranium in breast milk, the presence of the radioactive heavy metal in all samples raises significant concern.

To determine the uranium content, samples were analysed using the Agilent 7850 LC-ICP-MS analytical system at NIPER-Hajipur. The institutions also jointly carried out a detailed carcinogenic and non-carcinogenic risk assessment for mothers and infants. Although no carcinogenic risk was observed, infants were found to be significantly more vulnerable to non-carcinogenic impacts due to their rapid physiological development and the way uranium is processed and eliminated in early life.

The findings point to widespread exposure in the surveyed districts. The highest concentration of uranium was recorded in Katihar at 5.2 µg/L, while the lowest mean value—2.35 µg/L—was found in Nalanda. Khagaria recorded the highest mean concentration at 4.035 µg/L. Based on hazard quotient calculations, approximately 70% of the infants represented in the study were potentially susceptible to non-carcinogenic health effects due to uranium intake through breast milk.

This new evidence adds to growing concerns over environmental contamination in the State. In previous years, independent studies had identified arsenic and lead in breast milk samples from various parts of Bihar, indicating a cascade of exposures linked to chronic contamination of water and soil. The detection of uranium now extends this pattern, underscoring the seriousness of environmental health risks faced by vulnerable populations.

The organizations involved in the research identified drinking water and food grown in contaminated soils as the likely sources of uranium entering the human body. Bihar relies heavily on groundwater for drinking and domestic use, and several assessments have reported unsafe uranium levels in many parts of the State. Nationwide, groundwater uranium contamination has been documented in 151 districts across 18 states. In Bihar alone, earlier studies have highlighted contamination in at least 11 districts, including Patna, Vaishali, Nalanda, Katihar and Bhagalpur.

The latest findings highlight an urgent need for targeted interventions. Ensuring access to safe drinking water, identifying contamination hotspots, introducing low-uranium water sources, and conducting routine monitoring in affected districts could play a critical role in reducing exposure. Equally important is the need for public health screening and follow-up for infants and mothers in high-risk areas, along with environmental management strategies to reduce the long-term build-up of uranium in local ecosystems.

The participation of several national and regional scientific institutions indicates growing awareness of the health risks posed by groundwater contamination. However, the study also points to gaps in regulatory frameworks, particularly the absence of guidelines on acceptable uranium levels in breast milk. As uranium contamination moves from groundwater into the biological realm, the findings underscore the need for urgent policy attention and coordinated action.

The report, Discovery of uranium content in breast milk and assessment of associated health risks for mothers and infants in Bihar, India, published in the journal Nature, is expected to catalyse further research on uranium exposure pathways and the long-term health implications for communities in the affected regions.