Radiation From Fukushima Disaster Reaches Oregon Coast (nypost.com)

An anonymous reader quotes a report from New York Post: Radiation from Japan's 2011 Fukushima nuclear disaster has apparently traveled across the Pacific. Researchers reported that radioactive matter -- in the form of an isotope known as cesium-134 -- was collected in seawater samples from Tillamook Bay and Gold Beach in Oregon. The levels were extremely low, however, and don't pose a threat to humans or the environment. In 2011, a 9.0-magnitude earthquake triggered a wave of tsunamis that caused colossal damage to Japan's Fukushima Daiichi nuclear power plant. The disaster released several radioactive isotopes -- including the dangerous fission products of cesium-137 and iodine-131 -- that contaminated the air and water. The ocean was later contaminated by the radiation. But cesium-134 is the fingerprint of Fukushima due to its short half-life of two years, meaning the level is cut in half every two years. Cesium-137 has a 30-year half-life. Particles from Chernobyl, nuclear weapons tests, and discharge from other nuclear power plants are still detectable -- in small, harmless amounts. While this is the first time cesium-134 has been detected on US shores, Higley said "really tiny quantities" have previously been found in albacore tuna. The Oregon samples were collected by the Woods Hole Oceanographic Institution in January and February. Each sample measured 0.3 becquerels, a unit of radioactivity, per cubic meter of cesium-134 -- significantly lower than the 50 million becquerels per cubic meter measured in Japan after the disaster.

Comments

This is what, the third or fourth time?

[cirby]

We've had warnings about "radiation reaching the west coast of the US" a few times already. We've seen similar stories in 2015 and 2014 (a couple of times in each year).

In those, it was Cesium-137. Now, this group is all about Cesium-134, apparently because people didn't get upset enough about the Cesium-137.

"Possible false positives" may be their excuse, but no, it's not the first time someone made the claim of radiation reaching the west coast.

By the way: they weren't kidding about the amount being very small. It's 0.3 decays per cubic meter per second - which is a really, REALLY small number. The most amazing thing about the story is that we can manage to detect something that's so close to zero in real world terms. Three-tenths of a disintegration per second times (approximately) 30,000,000,000,000,000,000,000,000,000 molecules of water in a cubic meter of seawater...

(Someone check my math on this: it's late, and I'm sleepy...)

For comparison

[Solandri]

1 Bq = 1 radioactive decay per second. It's a tiny, tiny amount. For further reference:

• The amount of K40 and Rb87 in your body gives off about 4600 Bq.
• The K40 (same radioactivity source as in bananas) dissolved in seawater gives off about 12 Bq/L, or about 12,000 Bq per cubic meter. (Cue the alarmists crying that the amount of K40 in your body is static and so we should subtract it. No, you don't subtract it, you divide by it. 0.3 Bq / 4600 = 0.006%. So it's increased the radiation your body normally withstands while staying hale and hearty by 0.006%)
• The Rb87 dissolved in seawater gives off about 0.11 Bq/L, or about 110 Bq per cubic meter.
• The U238 dissolved in seawater gives off about 0.04 Bq/L, or about 40 Bq per cubic meter.
• Heck, the amount of Tritium in seawater gives off about 0.0006 Bq/L, or about 0.6 Bq per cubic meter.
• A granite countertop gives off about 1000 Bq per kg.

If 0.3 Bq / m^3 were dangerous, you'd be dead ten thousand times over just from the natural radioactivity in your own body, a hundred thousand times over from natural radiation from other sources. These measurements of residual radiation from Fukushima are a testament to how good our instruments are at detecting minute quantities of radiation. Not a sign that our oceans are dangerous.

Re:Who's to say?

[Sarten-X]

If it were true that long-term low level radiation were unquestionably harmful, you'd expect to find a clear negative trend.

No, that's not what we'd expect to find at all.

We'd expect to find at the high end a certain level of radiation that is absolutely lethal, and as the dose is reduced, the impact would drop down steadily, until a zone where life expectancy is reduced. However, that life expectancy is more or less on an absolute scale, and must be compared to the life expectancy of the species being exposed. An insect may survive high doses of radiation simply because it wouldn't normally live long enough to exhibit symptoms, while a longer-lived animal like a human will likely survive long enough to get cancer that ultimately causes death.

At a very low dose, the chances of having any noticeable symptom from radiation is unlikely enough that it could equally likely be caused by millions of other factors, so usually nobody cares. There is still a negative trend in survivability, but it's dwarfed by all of the other fatal conditions.

Too little radiation and the species dies due to inability to keep pace with changing environmental conditions.

Radiation isn't the only mechanism for mutation, though. Rather, it's the fast and cheap way to make a lot of mutations really fast, usually in places that cannot possibly contribute to evolution.

In order to change the species, an offspring's DNA must be mutated. That's dependent on a few thousand cells out of the trillions in a human body. Those particular cells are the ones involved in meiosis, splitting and reassembling the DNA that will become half of the offspring. During that reassembly process is where most mutations happen, usually by random chemical processes rather than any radiation. This enzyme doesn't successfully react with that protein, so a gene gets skipped or altered or inserted... It is extremely rare that a gene is altered by radiation during the process.

Once an offspring's development begins, though, the effects of mutations become more pronounced. If radiation mutates a single cell during early stages of growth, that fetus will develop with a cluster of mutated cells. Unless those cells are destined to become a gonad, however, the mutation will die with that generation, and the species will not change.

Similarly, radiation affecting a mature individual is is unlikely to have any positive effect, as the mutation is almost always either destructive or irrelevant. The proper functioning of a human body requires millions of interactions between tens of thousands of proteins, so randomly changing one protein is more likely to break something than to add new functionality. Of course, as before, even breaking something is only going to affect the species if it happens to occur in a cell involved in reproduction.

It is important to remember that evolution is never towards anything. It is away from an inability to reproduce (usually due to death). As an illustration, you must realize that you are the result of an unbroken line of millions of ancestors dating back millions of years, and every single one of those millions of ancestors were fertile and successful in mating. There is no scorecard in evolution. Either you pass on your genes, or you don't. It doesn't matter if your changing environment caused you severe illness or discomfort. As long as you manage to find a mate and make a child, you've won the natural selection game.

In short, radiation is a purely random occurrence with purely random effects, and the odds of any particular radiation-caused mutation being beneficial are so absurdly small that it is absolutely safe to say that overall, there is no safe dose.