Uranium-238 in the breastmilk of lactating mothers in several districts of Bihar

• A recent study has revealed the presence of Uranium-238 (U-238) in the breastmilk of lactating mothers in several districts of Bihar.
• The study has raised serious concerns about infant health risks linked to uranium exposure.
  • The research was conducted by scientists from multiple institutions, including AIIMS Delhi.
• The study analysed breastmilk samples from 40 lactating mothers in Bihar.
• The researchers found U-238 in all 40 breastmilk samples, indicating widespread exposure.
• The uranium levels detected were 0–5.25 µg/L, which are below global permissible limits.
• The study concludes that actual health impact is likely low, despite potential risk indicators.
• The study will be expanded to other Indian states to test for heavy metals in breastmilk.
• India has already reported the presence of arsenic, lead, and mercury in breastmilk in earlier studies.

District-Wise Contamination

• The highest average uranium contamination was observed in Khagaria district.
• The highest individual uranium value was recorded in Katihar district.

Infant Health Risks

• The study found that 70% of infants showed potential non-carcinogenic health risks based on Hazard Quotient (HQ > 1).
  • Hazard Quotient (HQ) is a measure used to estimate non-cancer health risk from exposure to a contaminant.
• Infants are particularly vulnerable because they have a limited ability to eliminate uranium from the body.
• Long-term uranium exposure may affect kidney development and may also affect neurological development in infants.
• Long-term uranium exposure may further impact cognitive functions, including IQ levels.

Breastfeeding Recommendations

• The study notes that breastfeeding should not be discontinued, as it remains the most beneficial source of infant nutrition.
• Most uranium absorbed by the mother is excreted through urine, not concentrated in breastmilk.
• The researchers recommend continuing breastfeeding unless a clinical reason suggests otherwise.

Need for Environmental Monitoring

• The researchers highlight the need for continued biomonitoring of toxic contaminants, including pesticides.
• The study emphasises the need to track environmental pollutants that may enter the human food chain.

About Uranium-238 (U-238)

• Uranium-238 is identified as a naturally occurring radioactive element found in the environment.
• U-238 is the most abundant uranium isotope, forming 99.3% of natural uranium.
• U-238 occurs naturally in soil, rocks, and groundwater.

Sources of U-238 Contamination

• U-238 contamination can enter groundwater through natural geological processes.
• Groundwater can also become contaminated through human activities, such as mining.
• Other anthropogenic sources include coal burning and nuclear industry emissions.
• Phosphate fertilisers are another potential source of uranium contamination in groundwater.

Global and National Standards

• The WHO sets a provisional safe limit of 30 µg/L for uranium in drinking water.
• Some countries, such as Germany, follow a stricter limit of 10 µg/L.

Toxicity Characteristics

• Uranium exposure poses greater chemical toxicity risk, as a heavy metal, than radioactive risk.
• The primary chemical toxicity of U-238 affects the kidneys, which are sensitive to heavy metals.

Extent of Uranium Contamination in India and Globally

• In India, uranium contamination has been reported in 151 districts across 18 states.
  • In Bihar, 1.7% of groundwater sources are affected by uranium contamination.
• Elevated uranium levels have been reported globally in Canada, the U.S., Finland, Sweden, Switzerland, and the UK.
• Elevated levels are also reported in Bangladesh, China, Korea, Mongolia, Pakistan, and the Mekong Delta region.
• Despite global contamination, clear clinical symptoms have not been consistently documented.
• The current study stresses the urgent need to monitor U-238 in Bihar to protect maternal and infant health.