More than a year after a tsunami in Japan flooded the Fukushima Dai-ichi nuclear power plant, researchers from Stanford and Stony Brook Universities report discovering trace amounts of radioactive material in bluefin tuna caught off California's coast in August of 2011.
The Fukushima plant, which contained six reactors, experienced a series of system failures and meltdowns following the tsunami and the resulting flood, ultimately releasing radioactive materials into the surrounding ocean. The researchers think the material found in the tuna came from the Fukushima plant.
The initial idea for the study was "kind of a shot in the dark," according Daniel Madigan, a Stanford Ph.D. student at the Hopkins Marine Station in Pacific Grove, Calif., and the lead author of the report, which was published in the Proceedings of the National Academy of Sciences.
"Our expectations were pretty low," he said.
Their expectations were so low, in fact, that the team initially sampled only 15 fish, a limited sample size, Madigan said.
Their hypothesis was based on previous knowledge of bluefin tuna migration. Since young tuna typically travel from Japan eastward toward California, Madigan and his team suspected that if there were any trace elements from the Fukushima plant, they would be found in those fish.
And it seems they were right.
There were heightened levels of both cesium 134 and 137 in the local tuna population, though the team reported that these levels were not toxic for human consumption and have not harmed the fish. Cesium 134, however, can only be created by human activities, such as in nuclear power plants and weapon manufacturing. The team concluded that any cesium 134 found in the tuna was from the Fukushima plant.
But the importance of this research goes beyond the lives of migratory tuna. Madigan and his team hope to continue the study, observing cesium levels in other migratory animals such as sea turtles, whales and sharks in an attempt to further understand the true extent of the Fukushima plant's impact.
There is also the question of how the levels of radioactive material have changed in air-breathing animals, such as sea birds, Madigan said.
"We want to know what proportion of the contamination comes from gills versus food," he said, noting that it is most likely an animal's meal that passes along the radioactive cesium.
Though the study of 15 tuna has grown into a full-scale research project, it began as a bit of a fluke.
"This was actually a side project of what I'm doing," said Madigan, who primarily studies predatory fish in the pelagic, or open water, ecosystems. "Our observations turned into something much bigger."
In order to expand the research as far as Madigan and his team want to, he said they need to find some new sources of funding.
The initial study was funded through the Gordon and Betty Moore Foundation, an organization dedicated to environmental conservation both in the Bay Area and around the world, which gave Woods Hole Oceanographic Institute $3.7 million to fund research relating to the Fukushima plant. A portion of those funds were given to Madigan and his team to conduct their study, but it is unclear how much.
It is difficult to get an estimate for how much funding the team would need, stated Dan Strober, the Academic and Research News Contact at the Stanford News Service, in an email.
"The costs are hard to pinpoint because it's mostly personnel time and costs associated with acquiring samples," Strober stated in an email.
But what is clear is that further research will require additional funds, he stated.
"We have no funding going forward," Madigan said. There are, however, some potential funds "in the works" that he was not at liberty to discuss.
As far as Madigan can tell, no government agency has taken on the responsibility to sponsor this kind of research and so he and his team will have to rely on private funding to continue their work.
"It is definitely not the end," Madigan said about his team's research. "If anything, this is just the beginning."