Since our first post about the impacts of Japan’s nuclear crisis on the oceans, a lot has happened, but many questions remain and the situation is constantly changing.
As the cooling systems for the injured reactors at the Fukushima Daiichi nuclear power station remain offline, the method used to avoid a fire and full-blown meltdown of the reactors has been the continuous pumping of seawater onto the fuel rods.
Much of the seawater is evaporated, but thousands of tons of radiated water runoff have filled the nuclear plant. Tokyo Electric, who runs the facility, has shown extreme difficulties handling the growing amounts of radiated water.
They began pumping over 10,000 tons of seawater with lower levels of radiation out into the ocean, to make room for more contaminated water. Shortly afterwards a large crack was discovered last Saturday in a pit next to the seawater intake pipes at the No. 2 reactor which began leaking drastically higher levels of radiation directly into the Pacific.
During the leak, Tokyo Electric reported that seawater near the plant contained radioactive iodine-131 that was 5 million times the legal limit, and cesium-137 levels at 1.1 million times the legal limit.
As water gushed from the crack at the rate of seven tons of highly radioactive water each hour, safety officials attempted to clog the leak for days using methods that stirred images of the failed attempts to control the BP oil spill. The materials used to clog the leak were; 120 pounds of sawdust, three garbage bags of shredded newspaper and about nine pounds of a polymeric powder that absorbs water (See: golf balls and rubber tires in BP’s ‘Junk Shot’). They appeared to have clogged the leak on Tuesday using sodium silicate acting as a cement and the radiation levels in the surrounding waters are dropping off.
Currently, the most concerning element in the runoff is the high concentration of cesium-137 which has a half-life of 30 years, and can persist in the oceans for decades to a century. Cesium-137 can be absorbed by the base of the food web in phytoplankton, zooplankton and kelp, which can then build up in fish, marine mammals, and humans.
Other radioactive elements including plutonium have also been detected outside the plant and could threaten marine life. Previous releases of nuclear materials have shown that radioactive material can travel with ocean currents, become deposited in marine sediments, and travel up the marine food web in some animals like seals, but it is unclear if there were any negative impacts in marine life or humans from these events.
The extent to which the radioactive materials are distributed and how long-term the impacts persist will depend largely on the sinking speed of the particles, as well as their solubility. At this time, no one really has any idea if there will only be localized impacts, or if they will be more widespread.A lot depends on what Tokyo Electric is able to do to end all contaminated water from entering the sea, and what they do to dispose of the radioactive water remaining onsite.
Japan has imposed a temporary fishing and shipping ban within 30 km (18.6 miles) around the leak area. Japanese officials have created standards for levels of safe radiation in seafood, but the current drop in prices at Japanese seafood markets shows that people may not desire any radiation in their fish or are simply frightened by the very idea of radiation in their fish, even where there isn’t any.
As the first anniversary of the BP oil spill approaches (April 20), the ‘Tokyo Electric Nuclear Spill’ reminds us that leaks of any hazardous material are hard to manage and outdated facilities are dangerous. Our current energy choices are causing tragic losses of human life, and threats to marine ecosystems, fishing and food supply. As you continue to monitor the nuclear crisis in Japan, think back to the last time you heard about a dangerous leak of offshore wind energy?
Matt Huelsenbeck is a climate change science intern at Oceana.