Tiny fish caught off the coast of Japan caused a big splash of fear this week as testing revealed that some contained levels of radioactive material above the government’s safety threshold.

Two samples of fish collected about 26 miles from Fukishima’s leaking nuclear power plant last Friday were found to have up to 4,080 bequerels per kilogram of iodine-131, over twice the allowed limit of 2,000 bequerels per kilogram. Cesium-137 was reported at 526 bequerels per kilogram, slightly over its 500 bq/kg limit, the Japanese government reported Tuesday.

Following the release of these results, some regulatory agencies upped their precautionary measures regarding Japanese seafood. India banned food imports for the next 3 months, and the European Union announced it will increase the rigor of its radiation controls for Japanese food imports.

The U.S. Food and Drug Administration (FDA) stated that seafood imported from Japan would be diverted for testing.

The presence of radiation in fish adds seafood to the list of contaminated Japanese edibles. Produce including broccoli, cauliflower, turnips and some leafy greens, all grown in areas surrounding the plant, have been found to contain high levels of radioactive elements, as has milk.

Japan established limits for radiation in seafood for the first time the day after the fish testing results were revealed. At that time, Tokyo Electric Power Co. (TEPCO) was in the process of releasing 11,500 tons of contaminated water from the crippled Fukushima nuclear power plant into the ocean to make room in containment vessels for more highly contaminated water. This dumping process raised concerns that levels of radiation in seafood would spike to even higher levels.

Indeed, after the contaminated water was released, testing around the plant revealed a concentration of iodine-131 that was up to 7.5 million times the legal limit at its highest point, according to CNN

Still, according to experts, seafood lovers need not fret. Radiation released from the plant is expected to be significantly diluted by surrounding water. The concentrations of both cesium and iodine in water surrounding Fukushima have already dropped dramatically since Tuesday, according to data from the International Atomic energy agency.

Amounts of radiation found in fish before the dumping, although above safety levels, pose no danger to humans, according to Dr. Richard Morin, professor of Radilogic Physics at the Mayo Clinic and Chairman of the American College of Radiology’s Safety Committee.

“That amount of radiation is extremely low,” he said in an interview with Food Safety News.

And even after the dumping, taking into account the amount of radiation that TEPCO estimates will be added to seafood and seaweed, Morin says there’s no need for alarm. 

“If someone were to eat seafood or seaweed within one kilometer from the discharge point for a year, they would get the equivalent of 1/10 of their normal background radiation,” he says.


Morin stresses that while the numbers sound scary, they’re really not dangerous when put in perspective.

He says the bequerel, the unit used to measure radioactive elements, is “a very, very small unit,” so small that it’s usually measured in millions. In medical studies, he says, doctors typically give patients anywhere from 370 to 740 million bequerels/kg of radiation, with no biological effect. That’s compared to the 4,080 Bq/kg of iodine found in Japanese fish.

“I think the key here is that detection doesn’t mean harm,” he says. “We can detect things all the time that don’t mean they’re harmful.  For instance, if we’re changing propane gas for a grill, we will be able to smell it, but that doesn’t mean it’s harmful.”

However, others raise concerns that Japanese seafood imports should be treated with caution until the extent of the damage is determined and more testing is conducted.

“We would like to see a lot more data being collected trying to get a handle on what area of the water is impacted, because it may be a longer-term problem than iodine,” said Patty Lovera, Assistant Director of Food and Water Watch in an interview with Food Safety News. “Cesium can last a lot longer.”

While iodine-131 has a half-life of 8 days, meaning that it diminishes to half its original amount in that time, cesium takes 30 years to halve.

Lovera says Food and Water Watch would like to see FDA ban Japanese seafood imports until the potential damage from cesium has been fully assessed.

“FDA is saying, ‘We’ll put things aside and we’ll screen them,’ but FDA gets overwhelmed with imports. They don’t have the ability or the resources to look at everything.”

Since FDA is normally tests only 2 percent of seafood entering the country, Food and Water Watch is concerned that the agency won’t be equipped to properly test all Japanese seafood.

For now, however, consumers shouldn’t worry too much about the safety of Japanese seafood, as it will be in short supply. The country’s fishing industry was staggered by the massive earthquake and subsequent tsunami of last month, and is still struggling to resume operations.

Nevertheless, many restaurants are taking precautionary measures of their own and opting for fish from other countries. A shift in demand away from Japan has already been noticeable. Australian and Southeast Asian seafood companies have reported increased demand since the Japanese nuclear crisis, reported the Wall Street Journal.

Steering clear of Japanese seafood won’t be much of a change for the U.S.. Last year, only 1.7 percent of U.S spending on seafood was spent on products from Japan.

And for anyone worried that radiated fish will swim through cracks in regulatory agencies  and onto their plate, Japan is allaying fears by taking preemptive measures to test exports for radiation before they leave the country.

Says Morin, “The fact that they’re taking that forward step is a good thing. That means the appropriate authorities in Japan are doing the right thing.”