Radioactive water from the crippled Fukushima nuclear power plant in Japan could reach the west coast of the United States by April, scientists monitoring the situation, have warned.
At that time, radioactive cesium could be contaminating beaches along the Pacific coast. The announcement was made at a meeting of the American Geophysical Union, held in Honolulu.
Reports of the toxic material already present on the west coast of the United States have been denied by health officials. Some websites are stating such waste has been showing up in the U.S. for over a month.
The Fukushima nuclear power plant was struck by a powerful earthquake and tsunami on 10 March 2011. Since that time, the facility has suffered numerous additional programs. Many of these led to the discharge of radioactive material into the environment, including the Pacific Ocean.
Researchers are testing water collected from 16 sites in California, Washington and Hawaii. Ordinary people are encouraged to recover coastal water for testing. Samples are being sent to the Woods Hole Laboratory.
Two forms of cesium are of serious concern for scientists testing the water. The first of these, cesium-137, decays slowly. It takes 30 years for half a sample to break apart. Cesium-134 has a half-life of just two years. Much of the cesium-137 created in atomic tests decades ago are still present in ocean water. When cesium-134 is detected in Pacific waters, it has to come from Fukushima. Both forms of the element have been recorded by detectors in northwest Canada, but cesium-134 has yet to reach the United States.
Using the differences in half-lives, "we can 'fingerprint' the contamination from Fukushima and estimate how much was released into the Pacific," researchers wrote on the project website.
Researchers are currently debating how models of ocean currents could affect the amount of radioactive materials received in North America. The strongest of these currents is the Kuroshio, which cuts almost directly across the Pacific, passing near Hawaii.
No official monitoring program is established in the United States to monitor incoming contamination from Fukushima. The researchers are raising private funds to monitor the ocean, releasing findings on OurRadioActiveOcean.org.
In the United States, cesium-137 is allowed in drinking water, up to levels of 28 Becquerels, or radioactive decay events per second. Ordinary oceans usually measure cesium-137 levels of a few Becquerels. Samples from the U.S. Pacific coast are currently far below that level.
By the middle of 2015, radioactive contamination on the Pacific coast should reach a maximum. Even then, health officials insist the levels will be far below those considered dangerous.
