By David McNeill
3 February 2012
TOKYO – Researchers working around Japan's disabled Fukushima Daiichi nuclear plant say bird populations there have begun to dwindle, in what may be a chilling harbinger of the impact of radioactive fallout on local life.
In the first major study of the impact of the world's worst nuclear crisis in 25 years, the researchers, from Japan, the US and Denmark, said their analysis of 14 species of bird common to Fukushima and Chernobyl, the Ukrainian city which suffered a similar nuclear meltdown, showed the effect on abundance is worse in the Japanese disaster zone.
The study, published next week in the journal Environmental Pollution, suggests that its findings demonstrate "an immediate negative consequence of radiation for birds during the main breeding season [of] March [to] July".
Two of the study's authors have spent years working in the irradiated 2,850 sq kilometre zone around the Chernobyl single-reactor plant, which exploded in 1986 and showered much of Europe with caesium, strontium, plutonium and other radioactive toxins. A quarter of a century later, the region is almost devoid of people.
Timothy Mousseau and Anders Pape Moller say their research uncovered major negative effects among the bird population, including reductions in longevity and in male fertility, and birds with smaller brains.
Many species show "dramatically" elevated DNA mutation rates, developmental abnormalities and extinctions, they add, while insect life has been significantly reduced.
A soon-to-be-released study indicates that bird populations near the Fukushima nuclear disaster have decreased. Studies at Chernobyl found that birds avoided highly radioactive nests but they are not completely sure how the birds can tell. It was found that birds had physical changes after being exposed to radiation. The Chernobyl study indicates that original bird populations dwindle and/or leave but migrating in birds may help keep the population from totally collapsing. They found this instance for other animals where populations go down but migrating populations may move in.
It was found in November 2011 that spiders in Iitate were concentrating cesium and large amounts of radioactive silver. Information released today showed earthworms were concentrating cesium as much as 20,000 bq/kg and that these concentrations could impact other animals that eat the worms.
Professor Bin Mori, the person who discovered the radioactive silver in spiders has found high concentrations of cesium and radioactive silver in lizards. The lizard dung was extremely high in cesium and radioactive silver. Professor Mori also found red dragonflies with considerable radiation contamination and mentions a study of fish crickets and locusts showing contamination.