The trade winds appear to be protecting Costa Rica from even tiny amounts of radioactivity produced by the March 11 Japanese earthquake and subsequent damage to the Fukushima Daichi nuclear power plant.
Data from the German Federal Institute for Geosciences and Natural Resources and the Vienna, Austria,-based Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization.
The Preparatory Commission was set up in 1996 to monitor compliance with a nuclear test ban treaty. It has 63 stations around the world that monitor radiation.
Based on reports from these stations, the commission said that radioactivity from Japanhas spread nearly all over the Northern Hemisphere but has not entered the Southern Hemisphere. The German institute has produced a map that shows negligible radiation has passed over Costa Rica.
Costa Rica has a monitoring station in Abangares linked to the commission, but it does not detect radiation. The nearest station that does is in Panamá. The Abangares station is designed to detect seismic shocks of nuclear bomb blasts. There also are radiation detection stations in Guadelupe and Melbourne, Florida.
The commission said that radiation from Japan spread all over the hemisphere within 15 days after the earthquake. The German institute’s mapshows that radiation in the latitudes where Costa Rica is located appear to be going in a circle in the Pacific. The trade winds blow from the northeast over Costa Rica and appear to cause radioactive material to spin clockwise before it reaches the country.
The commission said that the stations that detect radioactivity are so sensitive that they can detect a concentration of one-tenth of a gram of radioactive xenon evenly distributed within the entire atmosphere. The sensor in Vienna sometimes registers traces of the 1986 Chernobyl disaster.
Although constructed to monitor the Comprehensive Nuclear-Test-Ban Treaty, the stations are now used to provide seismic and underwater data to tsunami warning centers, the commission said. Japan received data March 11, and the commission said this contributed to rapid evacuations that saved many lives when the tsunami hit.
The tsunami flooded the nuclear power plants and led to the malfunctions, explosions and release of radioactive gases.
Said the commission:
” . . . the levels detected at stations outside Japan up until April 7 have been far below levels that could cause harm to humans and the environment. The levels are comparable to natural background radiation such as cosmic radiation and radiation from the environment on earth and lower than from manmade sources such as medical applications or nuclear power plants (under normal operations) or isotope production facilities.”