Radioactive Tuna Found Off the California Coast

Traveling across the vast Pacific Ocean, bluefin tuna were found contaminated with radiation originating from the Fukushima nuclear. The devastating accident occurred March 10, 2011. The contaminated tuna highlight the inconvenient truth of broad environmental impacts presenting and yet to reveal themselves. This evidence proves a catastrophic event in one part of the world indeed affects the rest of the planet.

Learn more about the radioactive tuna found off the coast of California.

What is Cesium and Why is It in Tuna?

Cesium is an alkali metal which is liquid at room temperature. Cesium 137 is radioactive and found in nature while cesium 134 is also radioactive but results from human manipulation. After the Fukushima event, bluefin tuna found off San Diego’s coast presented with cesium 134. While these levels of cesium 134 measured in today’s tuna are 10 times higher than earlier years, they are still far below safe-to-eat levels set by US and Japanese governments. However, it is still a concern to see the effects of Fukushima halfway across the globe traveling faster than expectations of water and wind transport.

The Radioactive Tuna Teach a Lesson

“It’s a lesson to us in how interconnected eco-regions can be, even when they may be separated by thousands of miles,” said Nicholas Fisher, one of the scientist reporting from the Proceedings of the National Academy of Sciences. Five months after Fukushima, Fisher and his team decided to test bluefin tuna caught off the coast of San Diego. Their report concludes that the higher cesium levels found in 15 Bluefin tuna must have come from Fukushima.

How Tuna Became Radioactive

Bluefin tuna absorbed radioactive cesium from swimming in contaminated waters and feeding on contaminated prey such as krill and squid, the scientists said. As the predators made the journey east, they shed some of the radiation through metabolism as they grew larger. Even so, they weren’t able to completely flush contamination from their systems. “That’s a big ocean. To swim across it and keep these radionuclides is pretty amazing,” Fisher said. Fisher and his team plan to repeat the study this summer on a larger number of bluefin tuna to better understand how radioactivity affects tuna. Scientists have also expressed interest in studying other migratory species including sea turtles, sharks, and seabirds.

Things to Consider About Tuna

The Environmental Working Group offers a helpful calculator for figuring safe levels of tuna consumption based on gender and weight. While this focuses on mercury contamination, it puts tuna on a list of seafood to eat less often. Regardless of species, people who eat tuna should follow these safety guidelines and indulge sparingly. While scientist report levels are within government-set standards for safety, they would not report whether they personally felt tuna was safe to eat. Daniel Madigan of Stanford University’s Hopkins Marine Station said, “I wouldn’t tell anyone what’s safe to eat or what’s not safe to eat.” It becomes a personal decision based on emerging data. Most important is the relevance this situation offers from a global perspective. We must acknowledge how human activities have a direct and traceable impact on the environment even when preception of results are believed safe.

[CC Image by Caneles via Flickr]

{source: Reuters}

Do you enjoy eating bluefin tuna, most often prepared as sushi? Will this report change how often you eat it or have you already given up fish?