A recent study revealed that lactating mothers from several parts of Bihar had traces of Uranium (U238) in their breast milk. The researchers analysed milk samples from around 40 mothers from different districts of Bihar and found uranium in all of them.
There is no standard for permissible levels of uranium in breast milk. However, the WHO sets a provisional limit of 30 micrograms per litre (ug/L) for uranium in drinking water. Germany has set a stricter standard of 10 micrograms per litre. The research concluded that overall, the levels of the heavy metals in the milk were far below permissible levels.
Dr Ashok Sharma of AIIMS Delhi, who is a co-author of the study, told ANI, “Our research found uranium in all 40 breast milk samples. While 70% of infants showed potential non-carcinogenic health risks, the overall uranium levels were still below permissible limits. Therefore, the actual health impact on mothers and infants is expected to be minimal.”
The breast milk samples had uranium levels of 0-5.25ug/L/L. "However, based on the observed uranium concentrations in breast milk samples (0-5.25 ug/L), the study still concludes that the actual impact on infant health is likely low, and most uranium absorbed by mothers is excreted primarily through urine, not concentrated in breast milk. Therefore, breastfeeding remains recommended, unless a clinical indication suggests otherwise," Dr Sharma said.
Nuclear scientist Dr Dnesh K Aswal, member of NDMA and former group director of Bhabha Atomic Research Centre, who spoke to NDTV, said that the levels were well within safe limits. "The levels detected are well within safe limits. In fact, the World Health Organisation's permissible threshold in drinking water is nearly six times higher than what has been observed," he said.
The study found that the highest levels were found in samples found in Kathihar district, and the highest average contamination was found in Khagaria.
Why is the uranium still a concern?
Uranium is naturally present in rocks like granite and can seep into groundwater over time. Mining, coal combustion, nuclear industry operations and the use of phosphate fertilisers can increase the presence of the material in the environment.
Infants are more vulnerable as their bodies are not efficient in eliminating the heavy metals.
According to the findings, 70 per cent of the infants had HQ>1, which indicated that they could have non-carcinogenic health risks from uranium exposure through breast milk. Exposure to the material during infancy may affect kidney development, neurological development, and cognitive and mental health outcomes (including low IQ and neurological development delay) if exposure continues.
“Even though some infants had hazard quotient (HQ) values above 1, indicating possible health risks, the actual uranium levels in breast milk ranged from 0 to 5.25 micrograms per litre. Most uranium comes through the mother’s urine, not concentrated in breast milk.” Dr Sharma said.
Why mothers should continue breastfeeding
Despite the finding, the researchers and health experts have concluded that the mothers should continue breastfeeding as it's the best source of nutrition for the infants.
“Unless there is a specific clinical reason, mothers should continue to breastfeed,” Dr Sharma added. “The benefits of breast milk far outweigh the potential risks posed by uranium at the levels we observed.”
Dr Sharma also said that the researchers are planning to conduct more studies to understand the presence of heavy metals and their effects on human health.
Past research has identified arsenic, lead and mercury in breast milk, and future studies will look at pesticides and other environmental contaminants.