Where is radiation cloud from japan

Non-ionizing radiation includes visible light and radio waves—things that, as the name implies, do not have the ability to form charged ions in other materials. Ionizing radiation, however, does form charged ions and as a result presents a serious health threat because it can alter the atomic structure of living tissue.

Ionizing radiation also comes in several different types, including alpha, beta, and gamma radiation, all with different degrees of concern and health impacts. What is the normal background level of radiation? The normal background level of radiation is different for different places on the planet.

In the ocean, the largest source of radiation comes from naturally occurring substances such as potassium and uranium, which are found at levels 1, to 10, times higher than any sources of radiation caused by humans. The largest human release of radionuclides was the result of atmospheric nuclear weapons tests carried out by the U.

Despite even the high concentration of nuclear fallout in the Pacific caused by U. What is the state of fisheries off Japan and along U. West Coast? Most Japanese fisheries were unaffected by Fukushima, but coastal fisheries nearest the reactors remain closed because of concern over exposure by some species, particularly those that live on or near the seafloor.

There is currently no concern about the levels of cesium and other radionuclides in fish off the West Coast of the U. Are fish such as tuna that might have been exposed to radiation from Fukushima safe to eat? Seawater everywhere contains many naturally occurring radionuclides, the most common being polonium As a result, fish caught in the Pacific and elsewhere already have measurable, but small, quantities of these substances.

Most fish do not migrate far from their spawning grounds, which is why some fisheries off Fukushima remain closed. But some species, such as the Pacific bluefin tuna, swim long distances and could pick up cesium in their feeding grounds off Japan before crossing the Pacific. However, cesium is a salt like potassium, and it will begin to flush out of exposed fish soon after they enter waters with lower contamination from Fukushima.

By the time tuna are caught in the eastern Pacific, cesium levels in their flesh are times lower than when they were off Fukushima.

A study published in in the Proceedings of the National Academy of Sciences PNAS reported finding very low levels of cesium in Pacific bluefin tuna caught by recreational fisherman off the coast of California in August The FDA reviewed this study and determined that the levels of cesium were roughly times lower than levels that would prompt FDA to investigate further to determine if there were a health concern.

Is there concern about other radionuclides, such as strontium? The continued release of radionuclides from groundwater and leaking tanks at Fukushima nuclear power plants site needs to be watched closely, as the character or mix of radionuclides is changing.

One example is the higher levels of strontium contained in groundwater and in storage tanks that are leaking into the ocean. Because strontium mimics calcium in humans and animals, it is taken up by and concentrated in bones, where it remains for long periods of time it has a half-life of 29 years and it is is not replaced as quickly in the body as cesium. What we see is that the levels of cesium in the ocean are decreasing faster than strontium near the Fukushima nuclear power plant site.

However, levels of both are much lower than at their peak in We remain most concerned about the potential of new releases from the thousands of storage tanks on the site, which contain highly radioactive water awaiting processing. Some leaks have been reported, and one reason we continue to monitor strontium is to look for signs of these leaks.

Given that strontium concentrates in bones, this radionuclide could become a larger concern in small fish such as sardines, which are often eaten whole. So far, however, evidence suggests that levels of strontium in fish remain much lower than those of cesium Is it safe to eat seafood from the Pacific?

Except for the vicinity of the reactors, seafood and other products taken from the Pacific should be safe for human consumption. Radiation levels in seafood should continue to be monitored, of course, but radiation in the ocean will very quickly become diluted and is not of concern by the strict standards used in Japan beyond the region closest to Fukushima. The same is true of radiation carried by winds around the globe. However, crops and other vegetation near the reactor site including grass that cows eat to produce milk that receive fallout from the atmosphere build up radioactivity and can remain contaminated even if washed.

When these foods are consumed, a person receives much of this dose internally, often a more severe pathway to receive radiation than by external exposure. Is there an easy way for me to test fish or water at home? Unfortunately there is no simple way to test fish or other seafood at home for radiation contamination. The levels found in most animals are far too low to be detected by a Geiger counter or other readily available detector.

As for water, other than funding and sending us a sample to analyze there are no simple ways to test your home drinking water for cesium. We use 20 liter 5 gallons samples that we filter through a special resin that cesium attaches to. We then place this concentrated sample on an extremely sensitive detector for a day or more to measure the amount of cesium and that it contains.

This is in part because it entered the ocean days before the major radioactive releases began, and many of the most abundant radioactive contaminants do not concentrate on wood, plastics and other floating materials.

It did, however, carry invasive species, which are of concern to coastal ecosystems on the West Coast. How does radiation released from the Japanese reactors compare to the accident at Chernobyl? The Chernobyl accident released higher levels of radioactivity, but this varies depending upon which radioactive contaminants you are talking about. The difference is because Chernobyl was a much more violent event that included a large explosion resulting in a complete breach of the reactor vessel.

The event also started a very hot graphite fire that released large amounts of radioactive material into the atmosphere equivalent to between 3 and 5 percent of the total reactor inventory.

Winds carried the radioactive fallout first to the north and eventually into the Black Sea to the south. Radiation in the Black Sea and Baltic Sea, though elevated, remained well below what was seen in the ocean off Fukushima, because Chernobyl is so much further from the ocean. Although Fukushima included explosive events attributed to the escape and ignition of hydrogen gas, the main reactor vessels were not breached to the extent that occurred in Chernobyl. As a result, releases from Fukushima consisted primarily of gases and those contaminants that, under high temperature, become gases.

Why is the Fukushima accident of interest to oceanographers? In addition to measuring the concentration and spread of radioactivity in the ocean, scientists can also use these radioactive contaminants to learn about ocean properties and processes.

Oceanographers use substances called tracers to study the path and rate of ocean currents and of processes such as mixing that are important parts of the global ocean and climate systems. Some of these substances are natural, but many are the result of human activity, such as the Chernobyl accident or nuclear weapons testing, and now releases at Fukushima. Here are some other links I have passed to others. Our Radioactive Ocean Citizen science campaign aims to collect ocean samples and fund radiation analysis.

The background level of radiation in oceans and seas varies around the globe. Measured in atomic disintegrations per second Becquerels of cesium in a cubic meter of water, this variation becomes readily apparent.

The primary source of cesium has been nuclear weapons testing in the Pacific Ocean, but some regions have experienced additional inputs. The Irish Sea in showed elevated levels compared to large ocean basins as a result of radioactive releases from the Sellafield reprocessing facility at Seacastle, U.

Levels in the Baltic and Black Seas are elevated due to fallout from the explosion and fire at the Chernobyl nuclear reactor. Human sources of radiation released into the atmosphere over the past 60 years, although serious, pale in comparison to the radionuclides already naturally present in the ocean.

One of the most prevalent substances released through nuclear weapons testing, the accidents at Chernobyl and Three Mile Island, and now Fukushima, is cesium Cs. Total releases from Fukushima are currently above those at Three Mile Island, but below Chernobyl levels. Among the dozens of radioactive substances naturally present in seawater of which cesium is one , uranium and potassium are the ones present in the greatest abundance. Note: Ovals are not to scale.

He uses techniques that span isotope geochemistry, next generation DNA sequencing, and satellite tagging to study the ecology of a wide variety of ocean species. He recently discovered that blue sharks use warm water ocean tunnels, or eddies, to dive to the ocean twilight zone, where they forage in nutrient-rich waters hundreds of meters down.

Born in New Zealand, Simon received his B. With much of his work in the South Pacific and Caribbean, Simon has been on many cruises, logging 1, hours of scuba diving and hours in tropical environs. He has been a scientist at Woods Hole Oceanographic Institution since Gregory Skomal is an accomplished marine biologist, underwater explorer, photographer, and author. He has been a fisheries scientist with the Massachusetts Division of Marine Fisheries since and currently heads up the Massachusetts Shark Research Program.

For more than 30 years, Greg has been actively involved in the study of life history, ecology, and physiology of sharks. His shark research has spanned the globe from the frigid waters of the Arctic Circle to coral reefs in the tropical Central Pacific. Much of his current research centers on the use of acoustic telemetry and satellite-based tagging technology to study the ecology and behavior of sharks.

He has written dozens of scientific research papers and has appeared in a number of film and television documentaries, including programs for National Geographic, Discovery Channel, BBC, and numerous television networks. His most recent book, The Shark Handbook, is a must buy for all shark enthusiasts. Robert D. He served in the U. Pictured here are model simulations using dye on the long-term dispersal of Cs released into the Pacific Ocean off Fukushima following the Daiichi nuclear accident, 43 days, days, and day after.

While many of the exposed marine organisms remain around Japan, a number of species are highly migratory and swim across the North Pacific to the West Coast of North America. Two examples of these migratory fish are Pacific bluefin tuna Thunnus orientalis and albacore tuna Thunnus alalunga , and both Cs and Cs have been detected in these species caught in the eastern Pacific.

For public health, the levels of radiation are very low and far below levels that are considered cause for concern.

In a recent study of fifty bluefin tuna sampled off the U. West Coast in , the smaller bluefin recent migrants from Japan had Cs 0. For scientists the Cs and Cs served as a marker indicating migratory pathways. If, for example, a Pacific bluefin tuna had detectable levels of Cs which decays relatively quickly , it indicated that they recently migrated from Japan.

This has provided important insight into the dynamics of tuna migration in the Pacific. By definition, radiation is energy in the form of waves or energized particles.

The two types are:. Radiation has always been a natural part of our environment, with sources in the soil, water, and air. Man-made sources include mining, power generation, nuclear medicine, military applications, and consumer products.

Here, we consider ion production by enhanced gamma rays from radionuclides Fig. The gamma ray enhancement in the atmosphere was actually observed by the radiosonde measurements at Fukushima Fukushima University In the Debye shielding theory Debye and Huckel that uses statistical thermodynamics, an isolated charge will be surrounded by oppositely charged ions unless a strong external force regulates the charge distribution.

Since the re-distribution of ions is strongly bounded by ion-neutral collisions in the atmosphere, we expect some electrostatic polarization with only small increase in the electric current. As the result, the electric field decreases for the same point charges, like a dielectric media or condenser. Such a condenser effect has two timescales: One is regulated by the conduction current large-scale motion , with expected timescale of few tens minutes in the lower atmosphere under normal conditions.

The shielding effect might already appear in the timescale of the PG measurement because of the second effect. All three mechanisms predict the suppression of ground-level PG for the same cloud charges.

The next question is whether the predicted suppression of PG is detectable. Figure 2 shows examples of the PG behavior during rainfall events after the FNPP1 accident March 15, and during a similar event with the rain strength, PG amplitude, and time of year before the accident March 23, The temporal resolution of the rain measurement accumulation method is 10 min.

The PG variation in Fig. Such an effect has never been studied before, either after nuclear tests Harris or the Chernobyl nuclear accident Israelsson and Knudsen ; Tuomi Therefore, it is worth finding any statistical differences in the behavior of PG, particularly the negative peak values and timescale around it, between during the first 50 days after the Fukushima accident when the atmospheric radioactivity increased and the same time in the other years.

This is the purpose of this paper. One-minute averaged values of PG around isolated light rain 0. Horizontal blue lines and vertical blue arrows denote the rain periods and the registration timing of the accumulation rain. We use 1-min resolution PG data from Kakioka from , since the digital data are publicly available from that year.

The insulation was tested and confirmed even during rainfall events as part of maintenance. At Kakioka, the rain data was also measured using the unmanned accumulation method every 10 min at 0. Therefore, light rain of less than 0. For example, continuous rain of 0. Figure 3 shows distribution of PG values for different rain conditions at min resolution at Kakioka from March 13 to April 30 for —, divided into and the other years.

We classified the weather conditions by the min values of the registered rainfall; the figure shows three categories see figure captions. Under these restrictions, Fig. Since the percentage is very low for no rain cases, the unit is changed in the graph right axis. The rain record is obtained by an accumulation method every 10 min see text for detail.

The data are compared between immediately after the FNPP1 accident 13 March—30 April, and the same period 13 March—30 April at different years — Total numbers of min bins are given at the top of each bar. Here, we examined simple distribution of the min PG values to improve the statistical reliability. Ideally, data would be subdivided according to meteorological properties e.

Fortunately, balloon and ground data at Tsukuba 20 km from Kakioka shows that the rain-time wind velocities at ground and cloud altitudes from March 13 to April 30 in were about the average level of the same period of — Figure 4 shows the peak value distributions upper panel and min averages around these peak values lower panel , using 1-min resolution PG values. The occurrence rate of the PG peak values immediately after the FNPP1 accident is generally similar to those for the other years in Fig.

This result also suggests that the ground PG values changed more quickly around the peak values in than the other years. In both panels, red crosses are for , dashed lines are for the other years, and thick line is for the average. To examine how quickly the PG value reaches its negative peak or decays from it, Fig. For , these periods correspond to: before the FNPP1 accident, periods of high radioactivity in the atmosphere, and sufficiently decreased radioactivity, respectively.

To minimize the effect of variance with short timescale, we used the time range when the PG increase or decreased around the peak was monotonic. Therefore, different data points minutes have different numbers of samples, and those with fewer than seven samples are not plotted. When the radioactive particles were floating, immediately after the FNPP1 accident March 14—April 30, , the PG increased toward and decreased from the negative peak faster than in the other years, as shown in Fig.

Relative PG values compared to peak values during 10 min centered at the peak time for different PG peaks values for three different periods of a year. The red-hatched area is range of standard deviation at each point of data. Numbers of data point of each minute are given at the top of each panel with red text for and blue text for the other years. Data point with six samples or more are plotted.

In all panels, red crosses are for , dashed lines are for the other years, and the thick line is for the average. In May, the floating radioactive particles which may have included both new inflow from the FNPP1 area and re-suspensions from other areas decreased significantly while the surface contamination level stayed at the same level Yamauchi et al. The profiles for the normal years are different between May and March—April because of the different weather systems, but the March—April profile is still at the lowest limit of the annual variation for May, and outside the annual variation in Fig.

Also, the average time profiles lie around the upper limit of the standard deviation of for each minute, and hence the anomaly in is most likely real.

For reference, Fig. The change in the offset value in turn reinforces the shortening of the timescale for negative PG in While the difference in PG behavior might simply have come from coincidental difference in the cloud and atmospheric condition as mentioned above, we consider a scenario by increased ionizing radiation.