Scientists said Tuesday they have detected radioactive cesium from the Fukushima No. 1 nuclear plant in plankton collected from all 10 points in the Pacific they checked, with the highest levels at around 25 degrees north latitude and 150 degrees west longitude.
Researchers from the Japan Agency for Marine Earth Science and Technology were among the team members who released a report on the findings at a meeting of the Japan Geoscience Union at the Makuhari Messe international convention center in Chiba Prefecture.
Minoru Kitamura, a marine ecologist and senior researcher at the agency, said plankton are thought to play a key role in the dispersion of the cesium because they are eaten by bigger fish.
Kitamura said his team will continue to study the accumulation of radioactive cesium.
The researchers collected plankton at 10 points in the Pacific from off Hokkaido to Guam between January and February 2012.
They detected cesium-134 in plankton at all 10 points. The density of radioactive cesium was the highest at 8.2 to 10.5 becquerels per kilogram in samples collected from waters around 25 degrees north latitude and 150 degrees east longitude. The lowest concentration at any of the 10 points was 1.9 becquerels per kilogram.
The density of cesium in seawater was highest in waters at around latitude 36 to 40 degrees north, the team said.