Nuclear tuna on the menu

Sometimes, problems that seem like they're a world away can end up right on your dinner plate.

Take the nuclear disaster in Fukushima, Japan. You know it's bad news for the Japanese... and maybe you've even heard about some of the contaminated food they've had to deal with over there.

Well, now some of those foods are turning up here, specifically Pacific bluefin tuna with higher-than-normal levels of radiation that have been caught off my home territory -- the coast of California.

Despite the radiation, these fish can be sold to consumers since the levels are still below the safety limits set by the U.S. government. But those levels are also 10 times higher than what was seen in tuna caught before the March 2011 nuclear crisis.

In fact, the 15 samples of tuna tested all contained higher-than-expected levels of two radioactive substances: ceisum-134 and cesium-137.

The researchers also tested tuna from other parts of the Pacific -- tuna that never passed through Japanese waters as well as tuna that migrated from waters near Japan before the nuclear crisis.

They found no sign at all of cesium-134 and only the expected background levels of cesium-137 (those levels themselves are remnants of 1960s nuclear weapons testing in the Pacific, which should tell you how long this stuff can linger).

In other words, the higher levels of radiation found in the current crop of tuna coming from Japanese waters are without a doubt a result of the disaster -- and the news gets worse from here.

These fish spent only about a month in waters contaminated with radiation. The next batch coming through will have spent much more time there.

The researchers plan more tests when they arrive. Keep an eye out for more information.