April 26, 2011

Chernobyl: Lessons Learned

(Ivanhoe Newswire) -- It has been 25 years since the Chernobyl nuclear disaster. Now, researchers say investigating that incident may help us better understand health consequences of nuclear accidents in the past, present, and future.

Radioactive elements with a long half-life (the time it takes for half the sample to decay), especially caesium and strontium, will be prevalent in the environment for decades to come. Radioactive iodine, despite having a half-life of just eight days, can cause damage by being absorbed into the body through food, where it is stored in the thyroid gland. A three- to eight-times increased risk of childhood thyroid cancer was seen among those with the highest exposures after the Chernobyl. This has led to recommendations to distribute potassium iodine tablets to children and adolescents in the most contaminated areas following a nuclear power plant accident. Unfortunately, no chemoprotective interventions are available for radiation exposure to caesium or strontium.

"Aggressive efforts will be needed to limit exposure to radioactive iodine and caesium and to isolate contaminated areas," the authors were quoted as saying. "In particular, children and young adults are at highest risk because of past data showing that exposure at young ages increases the risk of adverse health effects such as thyroid cancer."

They also discuss the potential harmful effect of radiation for girls in puberty. Evidence from the Japanese Life Span Study (that looked at radiation-related risk factors following the atomic bombs in World War II) suggested that the highest excess risk for breast cancer was for women who were in puberty at the time of the atomic bombing. "Another sensitive time-point is lactation at the time of the accident, when the likelihood of radionuclide absorption to the mammary tissue is high," the authors said.

Documented cancer consequences of the Chernobyl accident were restricted to thyroid cancer in children and were much lower than first expected. Due to the many issues associated with studying Chernobyl health effects, results from new studies focusing on the Fukushima incident might uncover more accurate estimates of the aftermath of nuclear power plant as well as provide useful information for the public health management of future events.

SOURCE: Lancet Oncology, published online April 25, 2011