후쿠시마지역 기형나비
| 원전 사고 日 후쿠시마현 나비, 극심한 기형 나타나 |
| 기사등록 일시 [2012-08-14 11:40:50] |
일본 과학자들은 2011년 후쿠시마 원전 방사성 물질 누출 후 다리나 더듬이 혹은 날개 모양이 기형인 나비들이 증가했고 밝혔다.
과학잡지 '사이언티픽 리포츠'(Scientific Reports)에 게재된 보고서에 따르면 나비들의 기형은 방사성 물질과 관련돼 있는 것으로 실험실 실험을 통해 나타났다.
과학자들은 지난해 3월 후쿠시마 원전 사고 두 달 후 후쿠시마을 포함한 10곳에서 144마리의 남방부전나비를 채집했다.
그 결과 일반적으로 더 많은 양의 방사성 물질에 노출된 나비들이 더 작은 날개 혹은 불규칙적인 눈 모양을 가지고 있었다. 오키나와(沖繩)현 류쿠스 대학의 오타키 조지 교수는 "일반적으로 곤충들은 방사성 물질에 강한 저항력을 갖는 것으로 알려져 왔는데 이는 예상치 못한 결과"라고 말했다.
과학자들은 첫번째 채집 후 6개월 뒤 똑같은 10곳에서 다시 나비들을 채집했다. 그 결과 후쿠시마현에서 잡힌 나비들은 첫번째 채집 때보다 두 배 이상의 돌연변이율을 보였다.
이는 음식을 통해 섭취된 방사성 물질이 체내에 축적된 데다 사고 이전에는 나타나지 않았지만 사고 후 기형으로 변이된 어미 세대의 유전적 물질이 자식 세대로 물려진 때문으로 보인다고 이들은 설명했다.
일본 과학팀의 발견은 향후 방사성 물질이 환경의 어떤 영향을 끼칠지에 대한 중요한 수단으로 이용될것으로 비춰진다.
Exposure to radioactive material released into the environment has caused mutations in butterflies found in Japan, a study suggests.
Scientists found an increase in leg, antennae and wing shape mutations among butterflies collected following the 2011 Fukushima accident.
The link between the mutations and the radioactive material was shown by laboratory experiments, they report.
The work has been published in the journal Scientific Reports.
Two months after the Fukushima Daiichi nuclear power plant accident in March 2011, a team of Japanese researchers collected 144 adult pale grass blue (Zizeeria maha) butterflies from 10 locations in Japan, including the Fukushima area.
When the accident occurred, the adult butterflies would have been overwintering as larvae.
Unexpected results
By comparing mutations found on the butterflies collected from the different sites, the team found that areas with greater amounts of radiation in the environment were home to butterflies with much smaller wings and irregularly developed eyes.
"It has been believed that insects are very resistant to radiation," said lead researcher Joji Otaki from the University of the Ryukyus, Okinawa.
"In that sense, our results were unexpected," he told BBC News.
Prof Otaki's team then bred these butterflies within labs 1,750km (1,090 miles) away from the accident, where artificial radiation could hardly be detected.
It was by breeding these butterflies that they began noticing a suite of abnormalities that hadn't been seen in the previous generation - that collected from Fukushima - such as malformed antennae, which the insects use to explore their environment and seek out mates.
Six months later, they again collected adults from the 10 sites and found that butterflies from the Fukushima area showed a mutation rate more than double that of those found sooner after the accident.
The team concluded that this higher rate of mutation came from eating contaminated food, but also from mutations of the parents' genetic material that was passed on to the next generation, even though these mutations were not evident in the previous generations' adult butterflies.
The team of researchers have been studying that particular species butterfly for more than 10 years.
They were considering using the species as an "environmental indicator" before the Fukushima accident, as previous work had shown it is very sensitive to environmental changes.
"We had reported the real-time field evolution of colour patterns of this butterfly in response to global warming before, and [because] this butterfly is found in artificial environments - such as gardens and public parks - this butterfly can monitor human environments," Prof Otaki said.
The variations in colouration of the butterfly were previously reported by Prof Otaki and his colleagues in the open access journal BMC Evolutionary Biology, as he told BBC News.
"Colour-pattern changes of this butterfly in Aomori, Japan was [previously] observed only in the recent northern range margins during a limited period of time. Most importantly, the range-margin population did not show any 'abnormality' per se," he clarified.
The findings from their new research show that the radionuclides released from the accident had led to novel, severely abnormal development, and that the mutations to the butterflies' genetic material was still affecting the insects, even after the residual radiation in the environment had decayed away.
"This study is important and overwhelming in its implications for both the human and biological communities living in Fukushima," explained University of South Carolina biologist Tim Mousseau, who studies the impacts of radiation on animals and plants in Chernobyl and Fukushima, but was not involved in this research.
"These observations of mutations and morphological abnormalities can only be explained as having resulted from exposure to radioactive contaminants," Dr Mousseau told BBC News.
The findings from the Japanese team are consistent with previous studies that have indicated birds and butterflies are important tools to investigate the long-term impacts of radioactive contaminants in the environment.
