“Our biggest concern right now is if some of the other isotopes such as strontium 90 which tend to be more mobile, get through these sediments in the ground water. They are entering the oceans at levels that then will accumulate in seafood and will cause new health concerns.”
Japan’s nuclear watchdog has said the crippled Fukushima nuclear plant is facing a new “emergency” caused by a build-up of radioactive groundwater.
Its operator, Tokyo Electric Power Company (Tepco), has been criticised heavily for its lack of transparency over the leaks.
Tepco’s “sense of crisis is weak,” Shinji Kinjo, the head of a Nuclear Regulatory Authority task force said. “This is why you can’t just leave it up to Tepco alone”.
Strontium-90 is formed as a by-product of nuclear fission. Tests showed that levels of strontium in groundwater at the Fukushima plant had increased 100-fold since the end of last year, Toshihiko Fukuda, a Tepco official, told media.
“When we look at the impact that is having on the ocean, the levels seem to be within past trends and so we don’t believe it’s having an effect.”
Pacific Bluefin tuna caught off the coast of California have been found to have radioactive contamination from last year’s Fukushima nuclear accident. The fish would have picked up the pollution while swimming in Japanese waters, before then moving to the far side of the ocean.
Scientists stress that the fish are still perfectly safe to eat.
Fukushima pollution is potentially a very useful tool to trace the origin and timing of animal movements.
Health experts have said debris arriving on the West Coast is unlikely to be radioactive after having crossed thousands of miles of ocean. Tsunami waves swamped a nuclear power plant and swept debris into the ocean. The debris field, which once could be spotted from satellite and aerial photos, has dispersed.
“There is a view out there that says if it’s more than a few thousand feet deep we don’t really care … just go ahead and dump all that waste. There is an opposite view that says no, that is not sustainable water management policy”
Modern mining for the radioactive ore inevitably pollutes water.
To avoid digging big holes in the ground, operators inject a mixture of sodium bicarbonate, hydrogen peroxide and oxygen into the rock to separate out the minerals and bond to the uranium. Then, they vacuum out the uranium-laden fluids to make a fine powder called yellowcake. The process leaves a toxic mix of heavy metals and radioactive ions floating in the groundwater and generates millions of gallons of waste that need to be dumped deeper underground.