Sooner than the experts had predicted.
From UK's Guardian (5/1/2012):
Japan tsunami debris moves towards US and Canada
Wreckage including lumber, footballs, parts of roofs and factories, and even bikes will soon start coming ashore in North America
Debris from the Japan tsunami pictured floating in the Pacific. Experts say debris will start coming ashore in North America sooner than thought. Photograph: Ho New / Reuters/REUTERS
Wreckage from Japan's tsunami – fishing gear and furniture, footballs and ships – has swept across the Pacific far faster than expected, with thousands of tonnes projected to land on North American shores this year.
Scientists believe lighter objects such as buoys and oil drums began reaching land last November or December. The rest is spread over thousands of miles of ocean between the Midway atoll and the northern islands of Hawaii.
About 95% will probably never come ashore and is destined for that massive swirl of floating plastic known as the north Pacific garbage patch. The remaining fraction is due to reach the west coast of the US and Canada in October.
No one expects to wake up one morning to a tsunami of rubbish. "It is not like you are going to be standing on the beach looking at the horizon and see a wall of debris come in," said Nicholas Mallos, a marine debris expert at the Ocean Conservancy.
A more definitive picture of the debris is unlikely to emerge before June or July when two privately-funded expeditions are due to travel into the north Pacific. But the latest computer models from the Japanese government and Noaa suggest most of the wreckage that will make landfall will begin washing up this October and continue into late 2013.
Washington, Oregon, British Columbia and Alaska will get much of the debris, while most of California will be protected by currents pushing objects back out to sea. Hawaii, however, is in line for several deposits of tsunami trash.
"It's going to bounce off the western shore of North America, swing back south and come back towards Hawaii and enter that big circular area called the North Pacific Garbage Patch," said Bill Francis, board president of the Algalita Marine Research Foundation in Long Beach, California, which will be leading one expedition. "I heard someone say it's like a big toilet that never flushes. Anything that floats is going to stay out there and stay out there."
The US navy and coastguard will be tracking accumulations of debris which could pose a danger to shipping.
The tsunami swept as much debris into the ocean in one day as is usually dumped in a year, threatening wildlife and the Pacific's ecology, conservationists said. Coral is smothered by plastic, fish get trapped in drifting nets. Birds die from eating plastic.
"It is clearly already an ocean problem. We know that all of these hundreds of tonnes of debris are in the ocean. We know that actually all of the plastic debris contains a lot of toxins, and we know there are other types of toxins that would have got into the ocean from the tsunami and so all of this debris represents a hazard to navigation and a terrible distress to the ocean ecosystem," said Mary Crowley, founder of the Ocean Voyages Institute, which will also be leading an expedition.
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First, the tsunami created debris over a large stretch of coastal Japan, while the leak from the damaged Fukushima reactor occurred in one place. Therefore, the vast majority of the debris was many miles away from the reactor, precluding any contact with the radioactive leak.
Second, the leak of contaminated water from the reactor into the sea started days to weeks after the debris was washed out to sea. By the time the radioactive water leak developed, the debris was already in the ocean, miles away from the reactor, and moving farther offshore by currents and wind. Exposure to contaminated water, which also moves by currents, was unlikely to occur.
Finally, vessels coming into the United States from Japan were monitored for radiation, and readings were below the level of concern. In the one instance where debris from the Fukushima region was found – a small boat picked up by the research vessel STS Pallada – it was tested for radiation and the levels were normal.
80% of radioactive materials dispersed into the atmosphere from Fukushima I Nuclear Power Plant went to the Pacific Ocean, according to the experts. No one exactly knows when the leak of highly contaminated water from the plant (near Reactor 2 water intake) started, though it is most likely after March 21, 2011 when there was a sudden jump in radioactivity in seawater at the plant. NOAA seems to account for the latter in their talking points but not the former, which may turn out to be bigger than the latter in terms of the total amount of radioactive materials.