90Sr in deciduous teeth from 1950 to 2002: the Swiss experience

Area of Science:

• Environmental Science
• Radiological Health
• Pediatric Health

Background:

• Monitoring of Strontium-90 (90Sr) in human milk teeth in Switzerland began following atmospheric nuclear explosions.
• This monitoring aimed to assess the long-term impact of radioactive fallout on children's health.

Purpose of the Study:

• To analyze trends in 90Sr activity in Swiss children's milk teeth over several decades.
• To determine the apparent half-life of 90Sr in deciduous teeth and investigate regional variations.
• To evaluate the impact of events like the Chernobyl disaster and nuclear power plant operations on 90Sr levels.

Main Methods:

• Analysis of 90Sr activity in milk teeth samples collected from children across different Swiss regions.
• Statistical analysis to identify trends, calculate half-life, and compare regional data.
• Correlation analysis between 90Sr activity and factors like birth year, extraction year, and geographical location.

Main Results:

• 90Sr activity peaked in the early 1960s, coinciding with atmospheric nuclear testing, and subsequently decreased significantly.
• An apparent 90Sr half-life of 9.8 ± 3 years was calculated for milk teeth.
• Regional differences in 90Sr levels were observed, with Zürich county showing 16% less activity than Vaud county, potentially linked to dairy consumption.
• The impact of Chernobyl fallout and Swiss nuclear reactors on milk teeth 90Sr levels was minimal.

Conclusions:

• Atmospheric nuclear testing was the primary source of 90Sr in Swiss children's milk teeth, with levels decreasing substantially post-treaty.
• Dietary factors, such as dairy consumption, may influence regional 90Sr bioaccumulation.
• Accurate measurement of 90Sr requires highly pure chemical separation techniques.