Human exposure to uranium in groundwater.

Area of Science:

• Environmental Science
• Toxicology
• Public Health

Background:

• High concentrations of naturally occurring uranium were found in private well water in a residential community.
• Uranium contamination exceeded drinking water standards, necessitating alternative water sources for residents.
• The source of uranium was identified as natural geological deposits.

Purpose of the Study:

• To assess the long-term impact of uranium exposure from drinking water on human health.
• To investigate the persistence of uranium in the body after cessation of exposure.
• To correlate water uranium levels with urine uranium levels in affected residents.

Main Methods:

• Water samples from private wells were analyzed for uranium concentration and isotopic composition.
• Urine samples were collected from residents at two time points after they stopped drinking well water.
• Uranium concentrations in urine were measured and compared to a national reference population.

Main Results:

• Elevated uranium levels were detected in residents' urine, with 85% exceeding the 95th percentile of the reference population.
• Urine uranium concentrations were positively correlated with water uranium concentrations.
• Uranium levels in urine decreased over six months but remained elevated, with 87% still exceeding the reference population's 95th percentile.

Conclusions:

• Long-term ingestion of uranium in drinking water leads to detectable elevated uranium concentrations in urine for up to 10 months after exposure stops.
• Even after reducing exposure, uranium can persist in the body, highlighting the importance of monitoring environmental contamination.
• This study underscores the public health risks associated with naturally occurring radioactive elements in drinking water sources.