Scientists disagree over radiation effects
Abnormalities are found in Chernobyl's wildlife 22 years after meltdown.
Thu, May 07, 2009 at 02:55 PM
THE EFFECTS: Abnormalities are shown in barn swallows. (Photo: T.A. Mousseau/Plenty)
By all visual accounts, the area surrounding Ukraine’s Chernobyl nuclear power plant is a 19-mile haven flush with wildlife and greenery. Scientists note moose, boar, wolf, eagle, and river otter sightings, all signs of a thriving ecosystem. So fecund is the infamous and irradiated land, the Ukrainian government designated it a wildlife sanctuary in 2000.
But looks can be deceiving. Since the nuclear reactor meltdown in April 1986 and the area’s immediate evacuation, the Zone of Alienation has been essentially devoid of human activity, except for scientists studying nuclear safety and how 22 years of radiation exposure affects animal and plant life.
“Of all the small mammals out there, the voles are getting the highest internal dose,” says biologist Robert Baker, who studies bank voles (Clethrionomys glareolus) in Chernobyl. “They eat lichens and things that perpetuate the radioactivity, so when they eat it they become ‘screamers’ themselves. That’s our slang for highly radioactive because it makes the Geiger Counter scream.”
While no one disputes the presence of radiation in Zone wildlife, its impact—whether it has genetically altered species and if so, is the change detrimental to the species survival—continues to be a topic of heated debate. Chernobyl is considered the “foremost nuclear catastrophe in human history” by the United Nation’s International Atomic Energy Agency, which in 2005, along with seven other international agencies, released a Chernobyl Forum report (PDF), intended to settle once and for all the disaster’s impact. But in regard to wildlife, the report equivocated over the long term genetic effects.
“Both in the exclusion zone, and beyond, different cytogenetic (chromosomal) anomalies attributable to radiation continue to be reported from experimental studies performed on plants and animals. Whether the observed cytogenetic anomalies in somatic (sex) cells have any detrimental biological significance is not known,” the report concludes.
Behind this ambiguous finding, lie the contradictory study results and animosity between a handful of scientists. Baker and his group at Texas Tech University maintain that they have no definitive results linking genetic changes in bank voles to radiation exposure. Meanwhile, an ongoing study of Chernobyl barn swallows (Hirundo rustica) by two scientists at the University of South Carolina and Universite Pierre et Marie Curie, say they’ve found significant effects.
The study (PDF) of 7,700 barn swallows by biologists Tim Mousseau and Anders Møller published last year concluded there is “an elevated diversity and frequency of abnormalities in barn swallows from Chernobyl compared with control populations in Ukraine and elsewhere.”
They identified abnormalities ranging from albinism, abnormal coloring, tumors, deformed toes, beaks, tail feathers, eyelids, and air sacks occurring more frequently or uniquely as compared to control groups. Most importantly, they concluded these deformities are the result of radiation exposure and are affecting the swallows’ survival.
But ask Baker what he makes of these findings and he’s unwavering. “I think his work is inaccurate, to be blunt,” he says of Møller’s study. “If there are mutations there, they’re not likely from radiation.”
And herein lies the politically charged and many billion dollar question: Does every level of radiation matter? “This is a long-running debate about whether there’s a threshold level below which radiation releases really don’t matter or whether all radiation releases matter. The scientific consensus is that all releases matter to some level. That’s the prevailing, official view of the National Academy of Sciences. It’s not the view of the Nuclear Regulatory Commission,” says Chris Paine, director of the nuclear program for the Natural Resources Defense Council.
Baker’s group, which openly supports nuclear power as a clean, safe source of electricity and receives research funding from the Department of Energy (DOE), says in his most recent bank vole research that while they found as increase in DNA mutations, it is not due to radiation exposure at Chernobyl.
“I will be shocked if there are no consequences to living in the area [Chernobyl],” Baker says, “the problem is to prove it.”
Alternatively Mousseau, who has been unsuccessful in receiving research grants from the DOE, says of the Chernobyl Forum report’s conclusions, “They took the most conservative perspective possible and ignored a great deal of the information that’s out there. They set the bar for the scientific standard so high they missed much of the picture.”
While highest standards are good practice in most situations, Mousseau agrees, in Chernobyl there was a paucity of data to begin with, he says, due to the collapse of the Soviet Union and a lack of funding. “What they [Chernobyl Forum] did that was incorrect was to conclude that because there was no information, there was no effect.”
In a review of Chernobyl research (PDF) Mousseau and Møller say that of 33 studies looking for genetic mutations in wildlife, 25 found an increase in mutations, but note that many of the sample sizes are too small to be statistically significant.
“From our perspective, which is a boarder view, what is most overwhelming is the fact that almost every study on every organism that’s been conducted with any level of rigor has found evidence for significant genetic damage.”
Amid the disputes, however, both camps do agree on one point: There needs to be more research on Chernobyl wildlife to definitively resolve the matter. “This is an important question,” says Baker. “We need to know what are the biological consequences of living in an environment created by a disaster such as Chernobyl. And I don’t think we know the answer.”
Story by Victoria Schlesinger. This article originally appeared in Plenty in May 2008.