Fukushima
Radioactivity Detected Off West Coast
EDITOR’S NOTE: imagine the impact of a similar accident at the Millstone Nuclear Power Plant only 20 west of Charlestown.
Monitoring efforts along the Pacific Coast of the U.S. and Canada
have detected the presence of small amounts of radioactivity from the 2011
Fukushima Dai-ichi Nuclear Power Plant accident 100 miles (150 km) due west of
Eureka, California. Scientists at the Woods Hole Oceanographic Institution
(WHOI) found the trace amounts of telltale radioactive compounds as part of
their ongoing monitoring of natural and human sources of radioactivity in the
ocean.
In the aftermath of the 2011 tsunami off Japan, the Fukushima
Dai-ichi Nuclear Power Plant released cesium-134 and other radioactive elements
into the ocean at unprecedented levels. Since then, the radioactive plume has
traveled west across the Pacific, propelled largely by ocean currents and being
diluted along the way. At their highest near the damaged nuclear power plant in
2011, radioactivity levels peaked at more than 10 million times the levels
recently detected near North America.
"Most people don't realize that there was already
cesium in Pacific waters prior to Fukushima, but only the cesium-137
isotope. Cesium-137 undergoes radioactive decay with a 30-year half-life
and was introduced to the environment during atmospheric weapons testing in the
1950s and '60s. Along with cesium-137, we detected cesium-134 – which
also does not occur naturally in the environment and has a half-life of just
two years. Therefore the only source of this cesium-134 in the Pacific today is
from Fukushima."
The amount of cesium-134 reported in these new offshore data is
less than 2 Becquerels per cubic meter (the number of decay events per second
per 260 gallons of water). This Fukushima-derived cesium is far below where one
might expect any measurable risk to human health or marine life, according to
international health agencies. And it is more than 1000 times lower than
acceptable limits in drinking water set by US EPA.
Continue reading at Woods Hole Oceanographic Institution.