Read the article, Chernobyl’s effects linger on (http://news.bbc.co.uk/hi/english/sci/tech/newsid_743000/743879.stm) and answer these questions.
1. When was this article published?
This article was published May 10, 2000.
2. Why will restrictions on some food continue in the United Kingdom and former Soviet Union for another 50 years? Restrictions will last that long because “They found that the environment is not cleaning itself as fast as previously thought, and that radioactivity can be released to the soil again after it has been absorbed.” --article
3. Where have high levels of radioactive caesium been measured?
High levels of radioactive caesium have been found in Norway and Cumbria.
4. What happened to the levels of radioactive caesium during the first five years after the Chernobyl accident? The levels of radioactive caesium decreased by a factor of ten during the first five years after the Chernobyl accident.
5. Describe why levels of radioactive cesium are not decreasing anymore.
Levels of radioactive cesium are not decreasing anymore because “With many chemical processes there can be a back reaction, when the contamination diffuses out. Here the rate of absorption is slowing, and it's being matched by diffusion.”--Dr.Smith
6. Why is diffusion of radioactive cesium back into the environment occurring? Explain the physical principle behind this diffusion. The diffusion of the release of radioactive cesium back into the environment occurs because of a concentration gradient which causes a balance in radioactivity and in the soil.
7. How long will the United Kingdom have to continue restrictions on sheep from the Cumbria region as a food item for humans? The restriction on sheep will last from 10 to 15 years.
8. How long will forest berries, fungi, and fish from parts of the former Soviet Union remain restricted? The forest berries, fungi, and fish from parts of the former Soviet Union will remain restricted for another half-century.
All rights reserved. Science NetLinks Student Sheets may be reproduced for educational purposes.Chernobyl’s Effects – E-Sheet Questions
Lesson Title: The Chernobyl Disaster Page 2 of 2
Now read Chernobyl Children Show DNA Changes http://news.bbc.co.uk/hi/english/sci/tech/newsid_1319000/1319386.st and answer these questions.
1. Who are the children that this article is about? To whom were they born?
The children that this article is about are children born after the 1986 Chernobyl disaster and they were born to the parents who had cleaned up the reactor (a.k.a liquidator families.)
2. What are “liquidators”?
Liquidators are members of the clean up team sent in after the reactor exploded.
3. Why are scientists studying the children?
Scientists are studying the children because “there is evidence that low radiation doses can cause multiple changes in human DNA, that are passed on to future generations.”--article
4. What are the controls in this study?
The controls are the siblings of the children in the study.
5. Describe what scientists discovered about the children’s DNA.
Scientists discovered " that the origin of the changes is somatic mutation in the children conceived after parental exposure.”--article
6. Describe the factors that may be linked to the number of DNA changes observed in children. The factors that the passage of time between exposure and conception, and also the duration of the liquidators' work in the contaminated area.
Read Nuclear Energy Agency: Health Impact http://www.nea.fr/html/rp/chernobyl/c05.html and answer these questions.
1. Describe what happens to DNA, cells, and organs after low and high doses of radiation.
“If the damage to DNA is slight and the rate of damage production is not rapid, i.e. at low dose rate, the cell may be able to repair most of the damage. If the damage is irreparable and severe enough to interfere with cellular function, the cell may die either immediately or after several divisions.”--article
“At low doses, cell death can be accommodated by the normal mechanisms that regulate cellular regeneration. However, at high doses and dose rates, repair and regeneration may be inadequate, so that a large number of cells may be destroyed leading to impaired organ function.”--article
2. Describe the acute health effects of the Chernobyl disaster.
“Lower doses and dose rates do not produce these acute early effects, because the available cellular repair mechanisms are able to compensate for the damage. However, this repair may be incomplete or defective, in which case the cell may be altered so that it may develop into a cancerous cell, perhaps many years into the future, or its transformation may lead to inheritable defects in the long term. “--article
3. Describe the chronic or late health effects of the Chernobyl disaster.
“These late effects, cancer induction and hereditary defects, are known as "stochastic effects" and are those effects whose frequency, not severity, is dose dependent. Moreover, they are not radiation-specific and, therefore, cannot be directly attributed to a given radiation exposure.”--article