¹²⁹I in rainwater across Argentina

Area of Science:

• Environmental Science
• Radiochemistry
• Atmospheric Chemistry

Background:

• Iodine-129 (129I) is a long-lived radioactive isotope with anthropogenic sources.
• Understanding 129I distribution is crucial for assessing global radioactive contamination.
• The Southern Hemisphere has fewer direct 129I sources, making atmospheric transport a key factor.

Purpose of the Study:

• To measure 129I concentrations in rainwater across Argentina.
• To investigate the distribution patterns of 129I in the Southern Hemisphere.
• To identify potential sources of observed 129I levels.

Main Methods:

• Rainwater sampling at multiple stations across Argentina (25° S to 55° S).
• Analysis of iodine-127 (127I) and 129I concentrations using advanced analytical techniques.
• Comparison of measured 129I levels with natural background and nuclear weapons test data.

Main Results:

• Measured 129I concentrations were significantly higher than background levels.
• Levels exceeded those attributable to historical atmospheric nuclear weapons tests.
• The observed 129I distribution suggests a source outside the Southern Hemisphere.

Conclusions:

• Atmospheric transport of 129I from Northern Hemisphere nuclear fuel reprocessing plants is the likely source.
• This study confirms long-range atmospheric transport of anthropogenic radionuclides to the Southern Hemisphere.
• Monitoring 129I in precipitation is vital for tracking global radionuclide dispersal.