Iodine-129 in human thyroids and seaweed in China

Area of Science:

• Environmental Science
• Nuclear Chemistry
• Human Health

Background:

• Iodine-129 (129I) is a long-lived radionuclide and a potential environmental contaminant.
• Understanding global fallout distribution is crucial for assessing human exposure.
• Baseline levels of 129I in human tissues and marine life provide insights into environmental contamination.

Purpose of the Study:

• To quantify 129I concentrations and 129I/127I ratios in human thyroids and seaweed from China.
• To compare these levels with pre-nuclear and post-nuclear era data from other global regions.
• To determine if 129I levels in China are influenced by local nuclear sources or global fallout.

Main Methods:

• Neutron activation analysis was employed to measure 129I and 127I.
• Samples of normal human thyroids from Tianjin, China, were analyzed.
• Seaweed samples from the Chinese coast were collected and analyzed.

Main Results:

• The mean 129I/127I ratio in Chinese thyroids was 1.13 x 10(-9), higher than pre-nuclear levels but lower than European post-nuclear levels.
• No significant difference was observed in 129I/127I ratios between Chinese thyroids and those from other regions not directly exposed to nuclear emissions.
• The mean 129I/127I ratio in Chinese seaweed was 2.35 x 10(-10), comparable to global fallout levels.

Conclusions:

• Iodine-129 levels in China are consistent with global fallout background.
• Human thyroids and seaweed in China do not show evidence of direct contamination from nuclear sources.
• The study contributes to understanding the geographical distribution of 129I.