NEW DELHI: Leaves collected one year after the Fukushima nuclear disaster from surrounding regions had sufficient radioactive toxins on them to cause butterflies to die earlier and have deformed offspring. This is the dire conclusion of a study conducted by scientists of the Universities of Rukyus (Okinawa) and Nagasaki. The study is published in the open access journal BMC Evolutionary Biology.
Researchers fed groups of pale blue grass butterflies (Zizeeria maha) leaves from six different areas at varying distance from the disaster site. They found that even in comparatively low levels of radiation, there was an observable difference in the butterflies' lifespan, depending on the dose of caesium radiation in their food, which ranged from 0.2 to 161bq/kg. Leaves were collected from six locations situated 59 km to 1760 km from the nuclear disaster site.
For comparison, leaves collected in the months after the disaster around 20km from the site had radiation in the thousands of Bq/kg. Butterflies fed leaves with higher cesium radiation doses were also smaller and some had morphological abnormalities such as unusually shaped wings.
Professor Joji Otaki, University of Rukyus, says: ""Wildlife has probably been damaged even at relatively low doses of radiation, and our research showed that sensitivity varies among individuals within a species.""
They also found that feeding offspring the same contaminated leaves as their parents magnified the effects of the radiation. But offspring fed uncontaminated leaves were mostly like normal butterflies, and the authors say this shows that decontaminating the food source can save the next generation.
In a previous study, the group found that eating leaves with high levels of radiation seriously affected the pale grass blue butterfly.
The offspring fed an uncontaminated diet had a similar lifespan, irrespective of the amount of radiation their parents had been exposed to. The only effect seemed to be that those whose parents had been exposed to higher caesium diets had smaller forewings. But those fed the same contaminated diet as their parents showed magnified effects.
The authors say that this shows that the effects of eating contaminated food can be significant, and that they can be passed on, but are minimized if the next generation have an unaffected diet.
Professor Otaki says: ""Our study demonstrated that eating contaminated foods could cause serious negative effects on organisms. Such negative effects may be passed down the generations. On the bright side, eating non-contaminated food improves the negative effects, even in the next generation.""
Source : The Times of India,23 September 2014