The 1,000-square mile exclusion zone surrounding the Chernobyl Nuclear Power Plant has remained virtually free from human intrusion for the last 30 years—ever since the landscape was blanketed in lethal levels of radiation following a catastrophic meltdown. The years since have seen a gradual rewilding of the area, with nature reclaiming the ghost town surrounding the defunct plant, and animals large and small moving into the surrounding forests. Headlines trumpet that the wildlife is “thriving,” “flourishing,” and ruling the landscape.
The real story is vastly more complicated. Animals are present, but they haven’t escaped the effects of radiation, according to the results of 15 years’ worth of studies conducted by Timothy Mousseau, a professor of biology at the University of South Carolina, Columbia, and his colleagues. Theirs is one of the only research groups gathering on-the-ground data to better understand the Chernobyl disaster’s effects on the plants, animals and microbes living there. In 2011, they also branched out to Fukushima, repeating some of their Ukraine studies in the Japanese disaster zone, for comparison.
The insights they’ve gleaned provide us a picture of how early to chronic radiation exposure plays out in real-world natural settings, and overall, the findings do not bode well for wildlife. Although plants, animals and other organisms are often present, Mousseau and his colleagues have found that they are frequently plagued with mutations and genetic damage. As a result, animals tend to occur in lower numbers than in places not affected by radiation, and indeed, all of the major animal groups the researchers have surveyed—including birds, butterflies, dragonflies, bees, grasshoppers, spiders and mammals—are less abundant in more radioactive areas, Mousseau writes.
Animals vary in their ability to live in the most heavily contaminated areas, however, and based on genetic studies, the researchers believe that a species’ natural ability to repair its DNA and susceptibility to genetic damage likely explain differences. Many of the effects observed in animals also parallel those seen in human victims of radiation exposure, Mousseau explains, including atom bomb survivors. Such symptoms range from cataracts to infertility, and from tumors to other developmental malformations. Brain size is also sometimes impacted, with those born in more contaminated places having smaller brains.
Unsurprisingly, the researchers found that the frequency and intensity of those symptoms seems to increase in proportion to doses received by the organism. “We see small effects at low doses and big effects at higher doses,” Mousseau says. Some of the symptoms also occur in animals that were exposed to radiation levels lower than those predicted to cause ill effects, he adds.
Radiation additionally seems to impact animal populations as a whole—not just individuals. While Chernobyl might be hailed as an unexpected boon for wildlife, the benefits are not equally distributed across the landscape. “In many of the populations living in the more radioactive areas we have studied, birth rates are down, life spans are shorter and they have a higher proportion of immigrants than elsewhere,” Mousseau says. “All of which points to these areas as being ‘ecological black holes’ that are only sustained via continuous immigration from adjacent, unaffected areas.”
Few other research groups have tested whether animals and plants in Chernobyl and Fukushima are actually evolving special adaptations to deal with radiation. “The majority of studies that suggest that organisms are adapting do not have a scientific design that allows for such assessments,” Mousseau says, referencing the findings of a recent review article. Others that imply positive or negligible effects are based on computer models alone rather than field data.
Insights based on fieldwork—good or bad—can help us better prepare for possible future incidents in which people or wildlife are exposed. Nuclear power plants continue to be built around the globe, and many of the reactors currently operating in the U.S. are undergoing 20-year life extensions, Mousseau points out. “Given this growth, along with the vast stockpiles of spent fuel that are accumulating, accidents and acts of terrorism seem inevitable,” he says. “To my mind, it would be negligent to not invest in much greater research concerning the health and environmental consequences of nuclear accidents.”
