The 26th of April 1986 saw one of the worst nuclear power plant disasters unfolded. When one of Chernobyl’s four reactors exploded releasing un-paralleled levels of radioactivity into the atmosphere, which would end up scattered over parts of the Ukraine, Belarus, Russia and even as far as Wales (radioactive sheep I kid you not!) 1,2. This single event would be the catalyst for a staggering rise in thyroid disorders propelling them to become one of the most common health problems in areas affected by the Chernobyl radioactive fallout (3)
To put this into perspective, the explosion at Chernobyl was 400 times stronger than the Hiroshima atomic bomb (1) releasing close to 2EBq (2000000000000000000 Bq) worth of radioactivity into the air. By comparison the maximum therapeutic dose of iodine -131 used in cancer treatment clinics is 7.4 GBq (7400000000 Bq) Chernobyl released 270000000 times the therapeutic cancer dose.
During the explosion three main radioactive elements were released into the atmosphere each with its own half-life (the time it takes for half of the element to disintegrate) and ability to affect the body.
Iodine-131: Half-life of 8 days – known to lead to thyroid problems
Strontium-137: Half-life of 29 years, can cause leukemia
Cesium-90: Half-life of 30 years can harm the entire body especially the liver and spleen.
How Radioactive Iodine effects the thyroid
Iodine (I-131) a byproduct of energy production in a nuclear reactor was absorbed into humans and animals via inhalation, the consumption of contaminated foods (vegetables and meats) and drinking contaminated milk from animals grazing on contaminated grass. (6)
Up to 1/3 of all radioactive iodine in the body will be up-taken into the thyroid gland. As the radioactive iodine decays, it emits radiation affecting not only the thyroid itself but the surrounding and nearby tissue in doing so capillaries carrying oxygenated blood are prevented from reaching the area. The result of so many dying cells is sudden chronic inflammation. Consequentially the immune cells congregate at the thyroid to clear away the dead cells among which they find the debris of TPO and Tg cells which will be stored in the immune memory as a pathogenic invader of years to come. (7,8)
Despite the fact that I-131 has a short half-life the damaged nuclear reactor continued to emit I-131 for about 40 days after the incident. It took roughly seven months of the emitted I-131 to decay to a safe level thus those exposed over this time would passively absorb enough I-131 to cause thyroid and other health issues for years to come (2).
Following the Chernobyl disaster, a significant increase in underactive thyroid cases would be reported in people living in the most affected areas of the Ukraine, Belarus and Russia with a notably large increase in the number of childhood and adult thyroid cancer cases. (4,9 – 12).
References
- International Atomic Agency. Frequently Asked Chernobyl Questions, 2005
- Nuclear Energy agency. Chernobyl: Assessment of Radiological and Health Impact 2002 Update of Chernobyl: Ten Years On, 2002
- Detours V, et al. Genome-wide gene expression profiling suggests distinct radiation susceptibilities in sporadic and post-Chernobyl papillary thyroid cancers, 2007
- Williams D. Twenty years’ experience with post-Chernobyl thyroid cancer, 2008
- Yama N, et al. A retrospective study on the transition of radiation dose rate and iodine distribution in patients with I-131-treated well-differentiated thyroid cancer to improve bed control shorten isolation periods, 201
- Braverman ER, et al. Managing terrorism or accidental nuclear errors, preparing for iodine-131 emergencies: a comprehensive review, 2014
- Yahyapour R, et al. Radiation-induced inflammation and autoimmune diseases, 2017
- Yoshida S, et al. Guidelines for iodine prophylaxis as a protective measure: information for physicians, 2014
- Pacini F, et al. Thyroid consequences of the Chernobyl nuclear accident, 1999
- IAEA 1991. International Chernobyl Project: Technical Report: Assessment of Radiological Consequences and Evaluation of Protective Measures, 2006
- UNSCEAR. United Nations Scientific Committee on the Effects of Atomic Radiation, United Nations, 1988
- Cardis E, et al. The Chernobyl accident — an epidemiological perspective, 2012