The headlines and photos on the website Before It's News are alarming.

``Your Days of Eating Pacific Ocean Fish Are Over at the Very Least,'' reads the headline of a post accompanied by photos of people suffering from radiation poisoning, as well as a deformed infant, and an article that suggests the Pacific is off limits as a food source. This comes after other posts raised health concerns about Pacific tuna caught off the California coast that were tainted by radiation that probably came from the crippled Fukushima reactor in Japan, which was destroyed by the March 2011 earthquake and tsunami.

Are there reasons to be concerned? Yes, but not quite to an extent that should keep you from enjoying a tuna sushi roll.

First of all, put the amount of radiation detected in the tuna in context. Tuna are a pelagic fish and swim throughout the Pacific Ocean. There is no doubt some have come in contact with the radioactive isotopes cesium-137 and cesium-134, which are associated with nuclear fission, whether from a power plant or a bomb.

Before freaking out, though, consider just how much radiation was detected in the tuna. As more than one writer has observed, you would get a dose of radiation that's 20-fold greater from eating a banana, which has a naturally occurring potassium isotope. You don't hear much about how we all need to start monitoring exposure to a daily banana equivalent dose of radiation. Nor is anyone in a panic about potatoes, kidney beans, sunflower seeds or a host of other foods that have naturally occurring radioactive elements. And don't even mention Brazil nuts, which have five times the radioactivity of bananas.

A National Academy of Sciences study of the Pacific fish concluded that normal consumption would expose a person to doses that ``are comparable to, or less than, the dose all humans routinely obtain from naturally occurring radionuclides in many food items, medical treatments, air travel, or other background sources.''

What's more, even if the tuna were exposed to an elevated level of cesium off the coast of Japan, most of the radioactivity will have dissipated by the time they reach North American coastal waters, according to Ken Buesseler, a researcher at the Woods Hole Oceanographic Institution. In fact, tuna contain a different and naturally occurring isotope, polonium-210, at a level that's 1,000 times greater than the amount of cesium picked up from Fukushima. Even this is much less than a person receives in a routine dental X-ray.

John LaForge, who writes for Nukewatch, correctly notes that there is no "safe" level of exposure to radioactivity. But this is almost like saying that traveling in a car at a speed that's fast enough to result in a fatal accident isn’t ``safe.'' This surely doesn’t mean we should stop driving.

The reality is we live is a world surrounded by much greater sources of radiation than Pacific tuna. If lowering the cumulative exposure to radiation is the goal, there's probably more to be gained by not walking around with a mobile phone glued to your ear than skipping a meal of tuna.

And yet, it's easy to see how a collection of facts -- some unrelated, others misrepresented, intentionally or otherwise -- can get blown out of proportion.

Take a look at a map that accompanies the Before It's News post -- and posted elsewhere on the Internet -- that purports to illustrate the spread of radioactive pollution in the Pacific. It's frightening at first glance, since it seems to show the entire ocean glowing with contamination. The problem is that this is a map issued by the National Oceanic and Atmospheric Administration showing the spread and impact of the giant tsunami unleashed by the earthquake, not the dispersion of radiation in the Pacific.

As for tuna, there is a real and bigger concern -- mercury, which has been tied to brain damage in kids and infants. The heavy metal tends to get concentrated in the flesh of top-line predators -- particularly some types of tuna. We can thank coal-fired power plants for much of the mercury in our food.

This isn't to minimize the disaster that is Fukushima. As the New York Times and others have reported, at least 300 tons of radiation-laced water have leaked from the plant, and some may have seeped into the Pacific. And the plant operators and government seem to be blundering from one miscalculation to the next. If the scale of the leak increases, or large quantities of more persistent radioactive elements such as strontium-90 get into the food chain, there might be cause for greater concern. So far, that doesn't seem to have happened.

Maybe there's a reason the death of the Pacific isn't news yet.

(James Greiff is a member of Bloomberg View's editorial board. Follow him on Twitter.)