[audio] Small risk of major fish contamination from Fukushima leak via abc radio

Japanese authorities estimate that 300 tonnes of radioactive water from the Fukushima nuclear plant has been pouring into the Pacific Ocean every day for up to two years.

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BUESSELER: Well, you say it’s not under control and they also wouldn’t admit to what was very obvious to us, to the Japanese, and several lines of evidence that the were continued sources from that site. What’s also changing to is that the character of what’s coming out, the different isotopes that are radioactive are shifting from being predominantly a caesium concern early on to what might be different isotopes, including strontium 90, if you know something about these isotopes, they accumulate differently in fish and in parts of our bodies, so strontium is called the bone seeking isotope, because it looks like there’s calcium in the fish and in our bone, so it has a more long term affect and potentially different health affect to the caesium that’s been released earlier.

EWART: What about the likely effects on marine life and fish, in particular. We’re talking about the livelihoods of many people here. Is there a genuine concern that there could be a long term seriously damaging affect?

BUESSELER: Well, when you say affect, we’re not talking about a direct causing cancer either in humans or fish in those waters, but a concern to our consumption of this seafood that have low levels that overtime if you kept eating levels above that, you would have concerns with your intake and therefore the health risks from eating the seafood. Now it’s localised to Japan, because the source greater at the coast, the contaminated fisheries that are closed are exclusively off Fukushima. Fortunately at least for caesium, the isotope levels go down quite rapidly as the fish move across the Pacific, so we’ve heard of Bluefin Tuna off Santiago being contaminated, but at much, much lower levels than off Japan and therefore no longer of health concerns. So the health concerns I would have are restricted to consumers of seafood products near Japan and for that reason, they’ve kept those fisheries closed.

EWART: But when we talk about 300 tonnes of radioactive water pouring into the Pacific everyday. It sounds quite dramatic. But obviously we’re talking about a vast expanse of water. So what happens to this radioactive water once it starts to merge with the sea water as it were. I mean is it effectively watered down, are we talking about a tiny, tiny amount here?

BUESSELER: Exactly. What happens within even a few kilometres, you get 10 or 100 times less. You go out several 100 kilometres offshore, the concentrations are lower.

We can detect very minute amounts of these isotopes. They were there before this accident, from some of the weapons testings fallout in the 60’s, at very low concentration. Now we saw an elevation, particularly in March and April of 2011. This is still a lingering source I recall, but much smaller source and so it’s direct contribution across the Pacific would be quite small, compared to what was released two years ago. But lingering concentrations coming into coastal waters could affect coastal Japan fisheries and different isotopes such as strontium 90 as I said before could have different uptake and longer retention in the fish.