Japan’s tsunami debris posing 10-year threat to North Pacific

Debris sucked from the shoreline of Japan by the March 11 tsunami has embarked on a 10-year circuit of the North Pacific, posing an enduring threat to shipping and wildlife, a French green group says.

The nine-magnitude earthquake and tsunami created an estimated 25 million tonnes of waste, “countless quantities” of which swept out to sea when the wave receded, Robin des Bois (Robin Hood) said.

The debris includes dense forms as diverse as planes, ships, cars and chemical tanks, which after sinking will become an inshore hazard for trawlers and the environment by leaking oil, fuel and industrial fluids, it said.

Thick mats of floating wood and plastic will take between one and two years to cross the Pacific and then split into two large patches, the group said in a report dated May 31.

One will head northwards parallel to the eastern Pacific coast, drifting on the Alaskan Current.

The other will head southwards, floating on the California Current.

Part of this southerly debris will split off, joining a gentle vortex of well-documented waste in the eastern Pacific that is called the Eastern Garbage Patch.

The rest of the southern branch will then head back across the Pacific under the North Equatorial Current, which will take it to the so-called Western Garbage Patch.

“The entire voyage around the North Pacific could take around 10 years,” Robin des Bois said.

It pointed to many hazards for the environment, including the breakup of plastic into tiny particles called “plastic plankton” which accumulates in the food chain.

In March, a computer model devised by researchers at the International Pacific Research Centre at the University of Hawaii predicted Hawaiian beaches would see the first pieces of debris washing up around a year after the disaster.

Meanwhile, Japanese parents living near the tsunami-hit Fukushima nuclear plant issued an “emergency petition”, demanding the government do more to protect their children from radiation exposure.

A coalition of six citizens’ and environmental groups called for the evacuation of children and pregnant women from radiation hotspots, stricter monitoring and the early closure of schools for summer holidays.

They voiced concern that authorities had focused on testing for radiation in the environment and not on people’s internal exposure through inhaling or ingesting radioactive isotopes through dust, food and drinks.

“Since atmospheric radiation levels show no sign of abating, the inhabitants of heavily contaminated areas will continue to endure high radiation doses, both externally and internally,” they said in the petition.

“To minimise such exposure, residents should be evacuated promptly to areas where radiation is less severe. Top priority must be given to infants, children and expectant mothers – all highly susceptible to radiation effects.”

Japan has struggled to bring the Fukushima plant under control since it was hit by a tsunami that knocked out cooling systems, leading to three reactor meltdowns, explosions and radiation leaks into the air, soil and sea.

Following the March 11 disaster, Japan has raised the exposure limit for adults and children from one to 20 millisieverts per year, matching the maximum exposure level for nuclear industry workers in many countries.

The move has stoked anger and fear among many in Fukushima prefecture towns outside the 20-kilometre evacuation zone around the plant that have been exposed to lower levels of radiation for more than three months.