Not long ago I read on the Smithsonian website that it wasn’t just people, animals and trees that were affected by radiation exposure at Chernobyl, but also the decomposers: insects, microbes, and fungi. Smithsonian writes:
Birds around Chernobyl have significantly smaller brains that those living in non-radiation poisoned areas; trees there grow slower; and fewer spiders and insects—including bees, butterflies and grasshoppers—live there. Additionally, game animals such as wild boar caught outside of the exclusion zone—including some bagged as far away as Germany—continue to show abnormal and dangerous levels of radiation.
However, there are even more fundamental issues going on in the environment. According to a new study published in Oecologia, decomposers—organisms such as microbes, fungi and some types of insects that drive the process of decay—have also suffered from the contamination. These creatures are responsible for an essential component of any ecosystem: recycling organic matter back into the soil. Issues with such a basic-level process, the authors of the study think, could have compounding effects for the entire ecosystem.
But after more recent studies this turns out NOT to be the case. A new study published in the journal Functional Ecological has found evidence that wild animals in the zone are adapting to the ionizing radiation, with some even showing increased levels of antioxidants and reduced to almost NO DNA damage.
Scientist has previously found that humans and other animals can adapt to radiation over prolonged exposure at low doses, but this adaptation has never before been seen in wold populations.
The study, led by Dr Ismael Galván of the Spanish National Research Council, focused on eight sites in and around the 30km-wide exclusion zone since the 1990s, capturing 152 birds from 16 different species.
Chernobyl 28 Years After the Disaster
We all think we know what happened on April 26, 1986, were its said that the world experienced the worst nuclear disaster in history. The explosion at Chernobyl nuclear power plant in Ukraine killed 31 and spread radioactive particles throughout USSR and Western Europe the effects of which are still not completely understood. The fallout has created a haunting landscape around the surrounding areas, but for the animals that survived, there’s been an unintended yet interesting effect. And in the many of the 28 years that have passed, birds have learned to not only survive, but to thrive on the radioactive land. Though long-term radiation exposure usually damages cells with free radicals, researchers have found that birds in the Chernobyl exclusion zone were in much better condition than expected.
“Previous studies of wildlife at Chernobyl showed that chronic radiation exposure depleted antioxidants and increased oxidative damage. We found the opposite — that antioxidant levels increased and oxidative stress decreased with increasing background radiation,” lead author Ismael Galván said.
Why this is important: Theoretically, prolonged exposure to radiation can force humans and other organisms to adapt and even build resistance to larger, heavier doses. But this idea has only been tested in laboratory settings until now.
Chernobyl’s unprecedented disaster has accidentally created an ecological laboratory where scientists can see the real-world effects of radiation exposure. For this study, researchers took blood and feather samples from 152 birds from 16 different species at eight sites around the Chernobyl exclusion zone something that could never be replicated in a confined laboratory.
What the researchers discovered can prove to be key in understanding the effects of radiation exposure on living organisms. For instance, they found that birds with more melanin in their feathers were in poorer health. The production of pheomelanin, a type of melanin, was using up all the antioxidants in the birds’ bodies, which should have been used to fight ionizing radiation.
While the two species that produce a lot of pink pigment in their feathers — the great tit (Parus major) and the barn swallow (Hirundo rustica) — failed to adapt well to their surroundings, the other 14 species did not waste their antioxidants on melanin and evolved to absorb and fight radiation in a more effective way.
And as this wasn’t enough birds are far from the only animals that have survived in the Chernobyl exclusion zone. The post-nuclear area is teeming again with wildlife, with animals reclaiming the territory that has been abandoned by humans. Wolves are at the top of the food chain, and they have become a key indicator of the health of the ecosystem: If wolves are doing well, then so must their prey populations. In tests done by scientists lately, it was found out that wolves were not affected by any radiation at all? How is this possible at all in the worlds worst nuclear disaster ever?
These kinds of studies help us understand not only what happened at these specific disaster sites, but also what can happen in similar situations in the future. By increasing our understanding of radiation exposure, we can be better equipped and prepared for potential disasters like Chernobyl and Fukushima.
How has the environment really been affected by the Chernobyl accident?
For the first 10 days following the April 26 explosion, the ruptured Chernobyl reactor continued to release major quantities of radioactive substances, amounting to a total of about 14 EBq. The most significant radioisotopes released were iodine-131, caesium-137, strontium-90 and plutonium radioisotopes (see table on radioisotopes released).
More than 200 000 km2 of Europe were contaminated above the level of 37 kBq/m2 of caesium-137 1 . Over 70 % of this area lies in the three most affected countries, Belarus, Russia and Ukraine though the radioactive material was distributed unevenly. For example, radioactive deposits were larger in areas where it was raining when the contaminated air masses passed. Also, because radioactive strontium and plutonium particles are heavier than many other radioactive particles, they were deposited within 100 km of the destroyed reactor.
The half-life of radioactive material is the time taken for half the amount initially present to decay. Because many of the most significant radioisotopes have short half-lives in the range of hours or days, most have decayed away by now. For the decades to come, the most important pollutant will be caesium-137 followed by strontium-90. Plutonium and its decay products (in particular americium-241) will remain in the environment over a longer term of hundreds to thousands of years though at low levels.
To what extent have urban areas been contaminated?
Substantial amounts of radioactive materials were deposited in the urban areas near the power plant. However, their residents were evacuated quickly so that they avoided being exposed to high levels of external radiation. Other urban areas have received different levels of deposition, and their residents have received, and are still receiving, some amount of external radiation.
After the accident, radioactive materials were deposited mostly on open surfaces such as lawns, parks, roads, and building roofs, for instance by contaminated rain. Since then, the surface contamination in urban areas has decreased because of the effects of wind, rain, traffic, street washing and cleanup. However, this has caused the secondary contamination of sewage systems and sludge storage.