The Chernobyl Aftermath
:
Resetting an Ecosystem
By Rinaldi Gotama
李嘉德
Did you know
Major radioactive substances released at Chernobyl included
iodine-131, caesium-137, strontium-90 and plutonium-241. While iodine-131
decays rapidly with a half-life of about 8 days, caesium-137 and strontium-90
approximately require 30 decades to be completely gone from the environment.
April
26, 1986 was a relatively typical day for the citizens of Pripyat, a town specifically
created to house nuclear experts and workers of the Chernobyl Nuclear Power Plant located
in, what is now, Ukraine. Due to a flawed reactor design as well as human error, Chernobyl’s
reactor number four exploded, setting a record as the worst nuclear disaster in history. To put
this into perspective, the accident released 400 times more radiation than the Hiroshima atomic
bomb did in 1945. People in the immediate vicinity received an estimated 350 millisieverts (mSv)
of radiation before being evacuated from the city. This is equivalent to 3500 chest X-rays in a
short period of time, and around 17 times the fatal dose [1]. Although an emergency concrete
sarcophagus was erected around the offending reactor to curb the release of radiation, the
impact of the explosion to the surrounding ecosystem and community is perennial.
More than five million people of Belarus, Russia and Ukraine were affected as a result of the
radioactive explosion that contaminated the surrounding environment and led to the relocation
of almost 300,000 people to safer areas [2]. In a 10-year Chernobyl aftermath report, it was found
that the release of short-lived radioiodines (iodine-131 has a half-life of 8 days) into produce
caused a significant increase in the number of cases of thyroid cancer, particularly among
children who consumed contaminated milk. Radiocaesium destroyed agricultural grounds
and forests in the first few weeks of the explosion and an increase in birth defects among
farm animals was reported. However, the same investigation indicated that aside from thyroid
cancer, no long term health impact from the explosion was detected. In fact, any detrimental
environmental impacts were also largely transient [1].
On the contrary, damage from the radioactive expulsion has been observed to be on a
scale much smaller than originally projected, given the enormity of the accident. A quarter of
a century in the aftermath, species in the vicinity of what is known as the Chernobyl exclusion
zone have astonishingly flourished. The purpose of this zone is to inhibit access to severely
radiologically contaminated areas for safety reasons. Yet, the diversity of these species has
increased to a record number. It is likely that the removal of their biggest predators, humans,
have led to this observation [2]. As people left, activities that harm biodiversity, such as
agriculture and industry, vanished with them – allowing plants and animals to naturally
expand their habitats.
What does this say about the effect of the nuclear accident on wildlife? According to
Jim Smith at the University of Portsmouth in the U.K., “This doesn’t mean radiation is good
for wildlife, just that the effects of human habitation, including hunting, farming, and
forestry, are a lot worse” [3]. While wildlife has apparently burgeoned healthily in the
years following the accident, it does not suggest that the Chernobyl exclusion zone is
safe for prolonged human exposure or that the area has returned to ‘normal’. It would
also be worthwhile to investigate genetic mutations over generations of species that
may have been engendered by the lasting radiation in contaminated areas.
