Animal Populations Affected by Nuclear Meltdown

Emma Morris
March 12, 2018

Submitted as coursework for PH241, Stanford University, Winter 2018


Fig. 1: Scientists Brenda E. Rogers from Texas A&M University (right) with local researcher Julia Gorjanaja in the Slavutich Radioecological Laboratory are studying mice from the contaminated landscape in the vicinity of the Chernobyl Nuclear Power Plant. (Source: Wikimedia Commons)

Many of us know two of the biggest nuclear accidental disasters today as the Chernobyl catastrophe in 1986 and the Fukushima Daiichi incident in 2011. Such tragic events not only impacted the land and lives of many humans and generations to come, but the environments animal and insect species. For instance, humans made the decision to abandon Chernobyl after the tragedy, but this choice wasnt necessarily obvious or even an option for the wildlife that called it home for decades. Indeed, we can look to nuclear disasters in particular to tell the tale of animal evolution years after these disasters occur, and make changes in how we approach nuclear science and engineering so that we can prevent further such accidents.

Devastation and Evolution Concerns: Fukushima and Chernobyl

In the event of an accidental nuclear meltdown, the natural environment responds by showing a complex interaction between radiation dosages of different plants and animals. [1] It takes time for research to be safely conducted, as the area surrounding the meltdown can be highly toxic and radioactive.

In Fukushima, scientists found morphological defects in certain species of animals due to increased mutation in rates in somatic and germ cells. [2] Results show that non-human organisms may have had their genes adapt over time in response to the survival mechanisms employed by these organisms to cope with radiation. [2] One of the species studied, the pale grass blue butterfly, showed decelerated growth, reduced size among the organisms, and even possible evolution in radiation resistance. [2]

While Chernobyl is neither desolate nor crawling with mutated animals, it has experienced sad and severe ecological impacts. 90% of the trees died in the Exclusion Zone, diversity of invertebrate species in heavily contaminated areas did not return to normal levels until ten years later, and embryo fatality rates were elevated when laboratory female mice were mated with captured mice that were exposed to radiation - 2 of 122 captured mice were found sterile (see Fig. 1). [3] Soil fauna such as mice, moles, and insects were hard-hit by the radioactive fallout, heavily impacting these organisms population sizes due to the impact on the affected organisms young. [2]

Responses and Moving Forward

In thinking ahead, we as humans will need to closely monitor where and how we manage our nuclear energy as these events have given us good reason to be protective of our wildlife populations. In the years following the Chernobyl disaster, animal species sustained negative effects due to radiation and changes to their habitats, yet years later, they can now call Chernobyl home. The Chernobyl area has transformed itself into a refuge for the wildlife, allowing them to increase in population and escape human influence. [2] Reports show that numerous adverse effects were observed mainly in high exposure areas within 30 km from the reactor. [1] And we know that such effects included increased mortality of coniferous plants, soil invertebrates, and mammals; reproductive losses in plants and animals; and genetic effects in both plants and animals. However, researchers found that by 1988 (2.5 years after the incident at Chernobyl), the targeted researched populations was comparable to a control species even in the most heavily polluted plot. [4] Knowing what they know now, it will be essential to help the animal populations that continue to survive in these abandoned nuclear wastelands.

© Emma Morris. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] L. Högberg, "Root Causes and Impacts of Severe Accidents at Large Nuclear Power Plants," Ambio 42, 257 (2013).

[2] E. Graue, "Effect of Nuclear Disasters on Animals and Insects," Physics 241, Stanford University, Winter 2017.

[3] C. Goldenstein, "Ecological Consequences of the Chernobyl Disaster," Physics 241, Stanford University, Winter 2012.

[4] D. Krivolutsky and A. Pokarzhevsky, "Effect of Radioactive Fallout on Soil Animal Populations in the 30-km Zone of the Chernobyl Atomic Power Station," Sci. Total Environ. 112, 69 (1992).