A recent study has revealed that the radioactive particles leaked by the crippled Fukushima nuclear plant into the Pacific Ocean, will reach the U.S. coastline within the three years of the incident.
The study showed while atmospheric radiation was detected on the U.S. west coast within days of the incident, the radioactive particles in the ocean plume take considerably longer to travel the same distance.
However, it is likely to be harmless according to the new paper in the journal Deep-Sea Research 1.
The researchers from the Centre of Excellence for Climate System Science have identified the travel path of the contaminated ocean plume through the world's oceans for the next 10 years.
They have claimed that the concentration of radioactive material will quickly drop below World Health Organisation (WHO) safety levels as soon as it leaves Japanese waters.
The study revealed that two energetic currents off the Japanese coast, the Kuroshio Current and the Kurushio Extension, were primarily responsible for accelerating the dilution of the radioactive material, taking it well below WHO safety levels within four months.
Later, eddies, giant whirlpools and other currents in the open ocean were continuing this dilution process and direct the radioactive particles to different areas along the U.S. west coast.
Dr. Vincent Rossi said that there were some uncertainties around the total amount released and the likely concentrations that would be observed, but the contact with the north-west American coasts will not be identical everywhere.
The great majority of the radioactive material will stay in the North Pacific, with very little crossing south of the Equator in the first decade.
Only a measurable, but otherwise harmless, signature of the radiation will spread into other ocean basins, particularly the Indian and South Pacific oceans.
The researchers have also developed a website, adrift.org.au, to track the path of the radiation.
