ハチの繁殖能力、現在のチェルノブイリレベルの放射線被ばくで低下　研究

【パリＡＦＰ＝時事】1986年に史上最悪の原発事故が起きたチェルノブイリの立ち入り禁止区域内と、同じレベルの放射線にさらされたマルハナバチの繁殖能力が30～45％低下したとの研究結果が21日、発表された。研究者らは、これまで考えられてきた原子力の環境リスクの見積もりを再考するよう促している。（写真は資料写真）
　英学術専門誌「英国王立協会紀要」に掲載された研究は、電離放射線が昆虫に与える影響について調べた。昆虫は他の種に比べ、電離放射線に耐性があると考えられてきた。
　スコットランドとドイツの研究者らは、チェルノブイリの立ち入り禁止区域と同じ放射線レベルを実験室で再現、複数のハチのコロニーを被ばくさせた。この結果、コロニーの繁殖能力が、これまで昆虫には影響を与えないとされてきた放射線量だったにもかかわらず、３０～４５％低下したことが分かった。
　論文の筆頭著者で、英スターリング大学で環境汚染の講師を務めるキャサリン・レインズ氏はＡＦＰに対しメールで、「チェルノブイリで検出される放射線レベルにさらされると、コロニーで生まれる女王バチの数が著しく減少するとともに、コロニーの成長に遅れがみられた」と説明した。
　また、研究者らは「汚染地域における授粉と生態系サービスに影響が出る可能性があると予測している」という。【翻訳編集ＡＦＰＢＢＮｅｗｓ】

〔ＡＦＰ＝時事〕（2020/10/26-12:46）

Bumblebees exposed to levels of radiation found within the Chernobyl exclusion zone suffered a significant drop in reproduction, in new research published Wednesday that scientists say should prompt a rethink of international calculations of nuclear environmental risk.
The study, published in the journal Proceedings of the Royal Society B, set out to discover how ionising radiation affects insects, which are often thought to be more resilient than other species.
Researchers in Scotland and Germany exposed bee colonies in a laboratory setting to a range of radiation levels found in areas of the exclusion zone around the ruined Chernobyl site, where a reactor exploded in 1986 in the world's worst nuclear disaster.
They found that colony reproduction reduced by 30 to 45 percent at doses previously considered too low to impact insects.
We found that at radiation levels detectable in Chernobyl, the number of new queen bees produced from the colony was significantly reduced and colony growth was delayed -- meaning colonies reached their peak weight at a week later, said the paper's lead author Katherine Raines.
The lecturer in environmental pollution at the University of Stirling told AFP by email that researchers anticipate that this may have an effect on pollination/ecosystem services in contaminated areas.
The authors said they chose bumblebees both because of a lack of lab-based research into bees and because of their crucial role in pollination.
Ionising radiation can occur either from nuclear sites or medical procedures, although the levels tested were higher than those that would likely be found in the environment from normal releases, Raines said.
But she added that the researchers were very surprised that we could detect effects as low as we did.
Our research suggests insects living in the most contaminated areas at Chernobyl may suffer adverse effects, with subsequent consequences for ecosystem services such as pollination, she added.
The authors said if their findings could be generalised they suggest insects suffer significant negative consequences at dose rates previously thought safe and called revisions to the international framework for radiological protection of the environment.
People are not allowed to live near the Chernobyl power station and the abandoned settlements within the exclusion zone are surrounded by forests hosting birds, wolves, elks and lynxes.
A giant protective dome was put in place over the destroyed fourth reactor in 2016.