The magnitude 9.0 earthquake and tsunami that killed more than 19,000 people and caused a nuclear meltdown in Japan last year also swept away homes, vehicles, and entire communities into the ocean.

On the earthquake's one-year-anniversary, many in B.C. are wondering when the debris mass will wash up on the coast, and whether it will be radioactive.

Tsunami artifacts have reportedly been showing up on the B.C. coast for several months, but Environment Minister Terry Lake said on Sunday that the bulk of the debris is expected to appear in 2013. He said researchers from Canada and the US have teamed up with all levels of government to monitor the spread of the debris cloud, which is approximately the size of California.

"The heavy debris will sink to the bottom [of the ocean], anything that has flotation value we do expect to see," he said. "Fishing buoys, running shoes, plastic bags—the lighter debris will have a greater chance of making its way over."

Lake stressed the importance of handling the debris carefully, as he expects that items of sentimental value to the people of Japan may also wash up on B.C.'s shores.

The tsunami on March 11, 2011 severely damaged the Fukushima Daiichi nuclear power plant's cooling system, causing radiation to spew out and unleashing the world's worst nuclear crisis in more than two decades. As a result, any debris that reaches B.C. will be tested for radiation risks, said Lake.

"I think the risk of that is extremely low," he said. "We must remember the actual tsunami occurred, and then it wasn't until quite a few days later that the problem at Fukushima happened."

Simon Fraser University physician-scientist Dr. Tim Takaro, who attended a Vancouver conference on Sunday on the health and environmental consequences of the Fukushima nuclear meltdown, also said it is unlikely that tsunami debris will be radioactive.

The real cause for concern is the assumption that the nuclear disaster in Japan is over, he said.

"The reactors are still requiring vast amounts of water—millions of gallons of water to keep them cool," he said. "Much of that water is still escaping into the ocean and is radioactive…That has the potential to affect our food supply."

With files from CTV British Columbia's Penny Daflos