Animals and insects in the vicinity of the Fukushima No. 1 plant contain high concentrations of radioactive cesium, providing a clue to how radioactivity accumulates in the food chain, a study has shown.
More than 6,700 becquerels per kilogram of cesium 137 were detected in a frog captured in Nihonmatsu, Fukushima Prefecture, 40 km west of the crippled nuclear facility, according to a survey published Saturday by Tokyo University of Agriculture and Technology and Hokkaido University.
The finding suggests animals relatively high up the food chain tend to accumulate more radioactive substances, the team of scientists said. There has been little research data on radioactive contamination of wildlife so far other than a few birds and animals caught by hunters.
The study also found 2,843 becquerels per kilogram of cesium 137 in a freshwater crab. As for insects, a reading in excess of 4,313 becquerels was detected in a camel cricket while 957 becquerels were recorded in a beetle, it said.
In Midori, Gunma Prefecture, around 180 km southwest of the Fukushima No. 1 plant, up to 903 becquerels were detected in frogs and 403 becquerels in a camel cricket.
Concentration levels appear to vary depending on how animals ingest food contaminated with radioactive materials, and geographical traits may also cause differences in how contamination occurs, the team concluded.