International teams of scientists are working to discover how radioactive particles from the Fukushima Daiichi nuclear power plant disabled five years ago are traveling throughout the ocean.
A massive earthquake and tsunami in March 2011 caused the Fukushima Daiichi nuclear power plant in Japan to melt down, releasing radiation into the surrounding environment.
Some of this radiation was released directly into the ocean, but most of it went into the atmosphere, where it spread and eventually rained into the ocean.
While scientists had a gauge on levels of radiation in the ocean before the Fukushima incident, they weren’t sure what would happen with the additional radiation from the meltdown.
Monitoring the fallout in the oceans can be challenging. The biggest hurdle to testing is the sheer size of the ocean, which makes monitoring and sampling difficult. Another problem is that water is constantly in motion, affected by wind, competing currents and temperature, which can make predictions difficult.
Going with the flow
A review, published in the Annual Review of Marine Science, of the condition of the oceans five years after Fukushima was presented at the Goldschmidt Conference in Japan the week of June 26.
“It’s a really timely review. This particular group … of experts … have produced a really great overview of what has happened … what is likely to happen and what that means for both environmental and public health,” Jay Cullen, chemical oceanographer and head of the Fukushima InFORM project in Canada, told VOA.
Results of the study show radiation levels in the ocean spread much as the models had projected.
The main radiation plume from the disaster surfed along currents and reached western North American shores in June 2013. Radiation levels, steadily rising as the plume travels along the coast, are expected to peak before the end of 2016.
The levels detected, even though they are rising, are very low and do not pose any risk to humans, scientists said.
Swimming in the ocean for eight hours a day for an entire year, even in the highest levels measured, would give you a dose of radiation 1,000 times smaller than what you’d receive during a dental X-ray, Ken Buesseler, oceanographer and lead author of the review, told VOA.
In the U.S., individual states are responsible for monitoring radiation levels in the ocean to ensure the levels are safe for people and marine life. However, the level of monitoring done by states does not meet the level for research.
While the testing methods used by states cannot detect radiation at the low levels quoted in the study, states such as Alaska collaborate with researchers and federal agencies, sharing samples and testing results.
Buesseler’s work at the Woods Hole Oceanographic Institution gave Alaska a much better understanding of the movement of radioactive particles in the ocean, said Marlena Brewer, an environmental program specialist with the state’s Department of Environmental Conservation.
But “we don’t really need to see down to … those levels [of the study], because the established safety levels for foodstuffs is orders of magnitude higher,” Brewer said.
Bob Gerlach, a state veterinarian for Alaska who also runs the state’s fish monitoring program, said understanding radiation transport in the oceans at the levels in the review is important, but it is also a tremendous economic investment. He said that having several agencies and groups work together makes the cost of these types of studies more manageable.
“The collaborative effort shows … the ability of these different agencies to work together to come up with information that’s going to be a benefit to the general public,” Gerlach said.
Five years on, Buesseler said, it’s important to keep monitoring the radiation levels in the oceans.
Buesseler said that even though “radioactive contaminants are getting lower,” studies of radiation levels should continue, both to track ongoing releases and to be better prepared should an incident like Fukushima occur in the future.