Impacts Of Nuclear Disaster Over The World

1.How long will the radiation be in the reactor area after it is finally contained? Will the radiation spread across the globe via air or sea?

Any releases of radioactivity would tend to be carried to the east across the Pacific, although day-to-day weather could spread it over considerable parts of Japan. Scientists are already forecasting the path of long-range transport through the atmosphere, as they have long practiced in order to track releases from nuclear testing and major accidents. The Chernobyl nuclear power plant accident in the Soviet Union sent radioactive dust particles hundreds and even thousands of kilometers away, with health effects occurring close in. The breadth of the Pacific would seem to be sufficient protection from detectable health effects.

2. Would it be possible to build underground emergency tsunami shelters that would be insulated from the earthquakes that would surely precede the wave?

This is technically possible but probably not a good idea. It would be psychologically difficult to persuade people to go underground to avoid a tsunami. Debris could pile up around or on top of any entrance. And, as in this case, coastal areas hit by a tsunami can remain flooded for several days, a situation aggravated in some areas by ground subsidence.

3.  What is the probability of a magnitude-7 or higher aftershock in Japan? Could the Japan quake lead to other quakes across the globe? Are we having more earthquakes than before? Why are we seeing such a dramatic increase in seismic activity globally?

From past quakes, an estimate of the likely largest aftershock can be made. A magnitude 7—far, far smaller than a 9—sounds reasonably likely. In recent years, seismologists have realized that the biggest quakes can trigger more quakes thousands of kilometers away, but these are typically small and often located at hot springs or volcanic areas already prone to small quakes. Global seismicity has not been going up in the long term; high-profile events like Haiti and Japan make it look as if it is. Quakes can trigger eruptions from nearby volcanoes; nothing from this one so far.

Globally, seismic energy has been released over the years at a fairly constant rate, with the inevitable random fluctuations. Part of the reason we have a sense of greater seismic activity is the notoriety of recent quakes. Haiti was not a big deal seismically speaking, but because of its location, it killed hundreds of thousands and captured world attention. There is a record of quakes in historical and geologic times preserved in sediments on faults or deposited by tsunamis, but it is not complete enough to address global seismicity trends.

4 .Although the safety of the people of Japan is our main priority, what ramifications has the catastrophe in Japan had on wildlife? Especially due to the numerous cars and debris polluting the waters, are there certain Japan-exclusive or endangered species of plants or animals that could see a collapse in population, possibly extinction?

Scientist M. Sanjayan of The Nature Conservancy in Arlington, Virginia, says that the tsunami’s biggest impact on wildlife will be on coastal birds nesting on small islands rather than on the Japanese mainland where they could easily fly away. Indeed, the U.S. Fish and Wildlife Service is reporting that tens of thousands of birds were buried alive by the waves. (The famed Midway Atoll albatrosses will survive as a species, although their numbers took a beating.) The fate of some other endangered species, such as monk seals, is currently unknown. But although many large mammal casualties will certainly be seen, Sanjayan guesses that most of them were able to ride the waves out with minimal fatalities.

Impacts on wildlife from pollution and radiation leaks are a separate issue, however, and one that is continuing to unfold. Sanjayan says that while species will certainly be harmed by this pollution in the short term, history from Chernobyl and the Bikini Atoll shows that once an area is placed off-limits to human activity, wildlife has a way of rebounding within a few decades.

5. What is the highest intensity of radiation measured so far? What affect will the radiation have on the people of Japan? How many people could it kill?
Keep in mind that news outlets have been reporting the levels in two units: millisieverts (mSv), which is one thousandth of a sievert, and microsieverts (μSv), which is one millionth of a sievert. (All numbers that have been reported are per hour.) So if you’ve been seeing numbers in the thousands, check the units. 3000 μSv/h is equal to 3 mSv/h—equivalent to about 300 chest x-rays, or one head CT scan—which levels at the plant gates have reached at times during this disaster. This New York Times graphic shows how radiation levels around the plant have changed over the past few days with the various explosions that have occurred. The Japanese Atomic Industrial Forum, a nongovernmental organization for nuclear energy, is publishing several updates a day on the plant’s status. The most recent update reiterates that levels peaked at 400 mSv next to unit 3 on Tuesday.

The people most at risk from radiation at the Fukushima Daiichi plant are the workers trying to keep things under control. That’s because the effect on one’s health depends on how near one is to the radioactive sources at the power plant and how long one stays there. Peak radiation levels at the plant were around 400 mSv per hour right in the thick of things, between reactors 2 and 3. According to Peter Burns, former chief executive officer of the Australian Radiation Protection and Nuclear Safety Agency, the limit recommended by the international community for workers dealing with accidents is 100 mSv—so a worker would reach the limit in just 15 minutes. While health effects may not be immediate, that person would also have an increased risk of developing cancer later in life.

Limiting workers’ exposure is extremely important; if exposed to that peak radiation for 2½ hours (1000 mSv total dose) a person would start to feel sick. If the person stayed there for 15 hours, they would likely die within a month. But as one goes farther away from a radiation source, the dose one receives per unit time falls off exponentially, which is why the Japanese government has evacuated the area around the plant. Within the 20-kilometer perimeter that has been evacuated, levels peaked at 0.33 mSv per hour, equivalent to three chest x-rays per hour—or about 30 days worth of exposure to background radiation. If one stayed there a day, one’s total dose would be about the same as a full body CT scan.

6.Since it seems the radiation will mainly head out to sea, what will its effects be on ocean life?

Effects on marine life should be minimal if the plume is blown over the ocean. Radioactive isotopes are most dangerous when animals’ bodies absorb them, thinking they’re something else. For instance, cesium-137 mimics potassium and is absorbed by muscles, while strontium-90 mimics calcium and is taken up by bones. Since ocean water is full of potassium and calcium in the form of salts, this lowers the chance of an animal’s body taking up radioactive particles by mistake.

Furthermore, since the Pacific is so massive, radioactivity will be diluted to levels far too low to be toxic to aquatic life. A much bigger concern is the plume blowing over land and contaminating plant life or the freshwater supply, which would affect animals (including humans) further up the food chain.

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