Chernobyl disaster to residual radioactivity from Chernobyl in the plants they graze on in the wild during the summer. 1,914 sheep needed to be given uncontaminated feed for a period of time before slaughter during 2012, and these sheep were located in just 18 of Norway's municipalities, a decrease of 17 from the 35 municipalities affected animals were located in during 2011 (117 municipalities were affected during 1986). The after-effects of Chernobyl were expected to be seen for a further 100 years, although the severity of the effects would decline over that period. Scientists report this is due to radioactive caesium-137 isotopes
Radiation effects from the Fukushima Daiichi nuclear disaster continue to monitor for long-term mental effects as they may not be present right away. On 24 May 2012, more than a year after the disaster, TEPCO released their estimate of radioactivity releases due to the Fukushima Daiichi Nuclear Disaster. An estimated 538.1 petabecquerels (PBq) of iodine-131, caesium-134 and caesium-137 was released. 520 PBq was released into the atmosphere between 12 and 31 March 2011 and 18.1 PBq into the ocean from 26 March to 30 September 2011. A total of 511 PBq of iodine-131 was released into both the atmosphere and the ocean, 13.5 PBq of caesium-134 and 13.6