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Radioactive tuna from Japan found near California, safe to eat for now scientists say

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XiaNaphryz

LATIN, MATRIPEDICABUS, DO YOU SPEAK IT
Japan's radiation found in California bluefin tuna:

For the first time, scientists have detected radioactivity in fish that have migrated into California waters from the ocean off Japan, where radiation contaminated the sea after explosions tore through the Fukushima nuclear reactors last year.

Radioactive cesium was detected in samples of highly prized Pacific bluefin tuna, but it is well below levels considered unsafe for humans, the scientists say.

The evidence is "unequivocal" that the tuna - caught off San Diego a year ago - were contaminated with radiation from Japan's nuclear disaster, the researchers said.

Virtually all bluefin tuna on the market in the United States is either farmed or caught far from the Fukushima area, so American consumers should not be affected by radiation contamination in their fish, seafood distributors say. The migratory bluefin studied by the researchers were all caught by sport fishermen and were not headed for the market.

Daniel J. Madigan, a marine ecologist at Stanford's Hopkins Marine Station in Pacific Grove (Monterey County), Nicholas Fisher, a marine scientist internationally known as a specialist in radiation hazards at Stony Brook University on Long Island, and Zophia Baumann, a staff scientist in Fisher's laboratory, reported their discovery Monday in the early online edition of the Proceedings of the National Academy of Sciences.
Unexpected discovery

The finding was wholly unexpected, Madigan said. It came about when he was researching the migratory patterns of bluefin tuna as part of a broader study of Pacific fish migration.

Madigan had collected samples of muscle tissue from 15 2-year-old tuna given to him by San Diego fishermen in August, and when tests detected radioactivity in one sample he sent all 15 samples to Fisher in Long Island, he said.

The young tuna, averaging about 13 pounds apiece, were found to be contaminated with two radioactive forms of the element cesium. Isotopes called cesium-134 and cesium-137 do not exist in nature but are produced only in nuclear explosions such as the weapons tests of the Cold War era.

Before the Fukushima earthquake and tsunami, low levels of the radioactive cesium-137, which decays to harmlessness only over thousands of years, had been measured in Japanese waters, while the shorter-lived cesium-134 was undetectable, the scientists said. That difference, they said, was crucial in concluding that the radioactive contamination was linked to the Fukushima disaster.

Increased concentrations of radioactivity contaminated nearly 60,000 square miles of the ocean off Japan after workers at Fukushima pumped thousands of tons of seawater over reactors last year to prevent a complete meltdown of the reactor cores.

Fisher said there is one unanticipated benefit from Madigan's discovery of radioactivity in the bluefin tuna. If the cesium isotopes are also detected in other migratory ocean species like turtles, sharks, seals and seabirds, that information should prove valuable as "tracers" that would add fresh details of migratory patterns to what is now gathered by widespread tagging programs, he said.
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More thorough investigation is needed:

A new study planned

Meanwhile, Madigan said, he is preparing to collect samples from a new group of bluefin tuna that have recently migrated to the waters off San Diego in order to determine their levels of radioactive cesium.

They will have lived in Fukushima's contaminated ocean for a full year longer than the first fish he collected, and the scientists will seek to know whether radiation levels in the tunas' bodies have increased or decreased, he said.

"We don't think there will be any public health concern from the results of the new tests," Fisher said, "but if we do see any higher concentrations of cesium, we will certainly alert public health agencies again."

In Japan the fatty muscle in the tuna is particularly prized as a delicacy, sliced and eaten raw as sushi. It is very pricey, and early this year a nearly 600-pound Pacific bluefin sold in a Japanese wholesale market for the equivalent of $736,000 - $1,238 a pound.
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T

toxicgonzo

Taxes?! Isn't this the line for Metallica?
Resturants in the U.S. are now changing their menu's from tuna melts to tuna meltdowns.
 
P

POWERSPHERE

Banned
blinky.jpeg


SOON
 
D

Drkirby

Corporate Apologist
Well, the Half life of Cesium-137 is about 70 days, so it should mostly be gone in a few years. If it poses little health risk now, it shouldn't ever pose any health risk from my view, but I'm no authority on these sorts of things.
 
E

Enco

Member
Enjoy it California guys.

Fuck the scientists calling it safe. If the tuna in my area had some radioactive shit inside it I would ditch it for good.
 
C

CiSTM

Banned
Enco said:
Enjoy it California guys.

Fuck the scientists calling it safe. If the tuna in my area had some radioactive shit inside it I would ditch it for good.
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I think there are plenty of food products that contain radioactive shit.
 
X

XiaNaphryz

LATIN, MATRIPEDICABUS, DO YOU SPEAK IT
AAequal said:
I doubt this is more bad for you then the high mercury levels of tuna. Also we understand radiation and it's effects on people well so there really isn't need to stop eating tuna ;)
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Gator's in Florida IIRC, so wouldn't most of his seafood would be from the gulf or Atlantic anyway?
 
F

Famassu

Member
AAequal said:
there really isn't need to stop eating tuna ;)
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Except the fact that many (most?) tuna species are highly endangered species and it won't take long (as in, < 5-10 years, even) if things continue like now before they are extinct.

But hey, whatevs, plenty of other fish species that aren't yet quite as endangered as tuna.
 
D

Dynamite Shikoku

Congratulations, you really deserve it!
Drkirby said:
Well, the Half life of Cesium-137 is about 70 days, so it should mostly be gone in a few years. If it poses little health risk now, it shouldn't ever pose any health risk from my view, but I'm no authority on these sorts of things.
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I believe the half-life is about 30 years actually
 
T

Tzeentch

Member
Drkirby said:
Well, the Half life of Cesium-137 is about 70 days, so it should mostly be gone in a few years. If it poses little health risk now, it shouldn't ever pose any health risk from my view, but I'm no authority on these sorts of things.
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-- LOL. The half-life of Cesium-137 is about 30 YEARS. It's also one of the most dangerous radioactive isotopes as it emits gamma radiation (non-Hulk producing) and has a long environmental half life due to its high bioaccumulation potential (it is chemically similar to potassium).

-- That said, the article is not clear what tissues were sampled or what the activity levels are. The media tends to blow things WAY out of proportion so I understand their reticence, but some specifics (Bq/kg) would be useful. Please read the actual source article as it is FAR clearer what is going on: http://www.pnas.org/content/early/2...html?sid=b14126bb-a727-4d3c-8113-644f9d7cacf8

-- Activity levels were c. 6.3 Bq/kg in white tissue. That's actually very low. Safe limits in the US are 1000 Bq/kg (or 0.27 pCi/g) and activity level does not translate directly to radiation exposure - but eating fish is a good transport mechanism. Note that the grass in your local neighborhood may have a higher activity level than these fish (albeit you don't usually eat the grass).

-- They don't state the activity levels of tuna sampled around Japan (as they didn't sample there) but warning bells went off when they state "we back-calculated radiocesium concentrations in muscle" because characterization of Cesium-137 in the environment is VERY poor (it's what my Masters is all about, actually). They basically made a huge assumption and then didn't qualify their prediction accuracy (I don't really blame them, but I would be VERY leery of taking anything they say regarding predictions too seriously). However, the Japanese reported activity levels of Cesium 134 + 137 of 61-168 Bq kg-1

TLDR the actual reported levels of Cesium-137 activity levels are still quite low. Characterizing actual risk from that activity level is very difficult. Tuna caught around Japan has higher activity levels, but are still well below safe levels. Yes, you should probably avoid eating hundreds of kilograms of tuna meat within short periods of time to avoid accumulating radiactive material in your body.
 
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