Researchers say high concentrations of radioactive caesium have been detected in plankton in the Pacific Ocean off the shattered Fukushima nuclear plant.
The Fukushima nuclear plant was badly damaged in the March earthquake and tsunami that struck Japan, and has been leaking radiation ever since.
It is feared more radiation could now enter the food chain.
Researchers from Tokyo University collected plankton from the sea south of the Fukushima nuclear plant, discovering nearly 700 becquerels per kilogram of caesium in plankton close to the shore.
Research leader professor Takashi Ishimaru told Japan’s NHK network sea currents had carried contaminated water south from the nuclear plant, heavily contaminating the plankton.
A wide range of fish and other marine species feed on the plankton, leading to fears it could have a serious impact on the food chain.
