skip to main |
skip to sidebar
Radiation from Fukushima is probably in your sushi, but it isn’t going to kill you (??)
March 2015 – FUKUSHIMA, Japan - There’s
a steady, low, background level of radioactivity we encounter in
everyday life. Some of it is human-made but very diffused, born out of
the atomic and nuclear testing of the mid-20th century. Some of it is
created naturally: radon gas seeping from marble floors, for instance,
or the increased dose of cosmic rays that airline passengers get during a
flight. Few people think about these exposures. But since Japan’s
Fukushima Daiichi nuclear power plant disaster in March 2011, there’s
been worldwide concern that the plant contaminated Pacific Ocean seafood
enough to affect human health. During the disaster, explosions in
reactor containment buildings sent clouds of radioactive steam into the
atmosphere, which drifted over land and sea. In the months and years
since the original explosion, leaks of radioactive water from the site
have flowed into the ocean as well.
Now
a newly published study suggests that there is nothing—much—to worry
about. To comprehensively assess the region’s seafood, Pavel Povinec of
Comenius University in Slovakia and Katsumi Hirose of Sophia University
in Japan collected and analyzed information from samplings of the
region’s seawater, fish, shellfish, and seaweed collected since the
Fukushima Daiichi disaster. They found that the average annual
consumption of all seafoods combined would result in radiation exposure
of anywhere from 0.2 to 1.0 millisieverts (mSv) a year, while exposure
from fish alone would account for 0.02 to 0.12 mSv a year. By
comparison, a woman is exposed to about 0.4 mSv of radiation when she
has a mammogram and around 0.03 mSv during a 10-hour airline flight,
according to the American Cancer Society. The average American is
exposed to around 3 mSv of background radiation a year, according to the
organization.
“What
they’re doing is mostly compiling these thousands of data that have
been collected to try and interpret what the trends are,” said Ken
Buesseler, a senior scientist at the Woods Hole Oceanographic
Institution who has studied radiation levels in seawater since the
Fukushima Daiichi disaster. “It’s very useful for someone to pull them
together to see what’s in the fish over time.” The team found that
levels of cesium 134 and cesium 137, substances that can increase a
person’s cancer risk if the exposure is high enough, spiked in the weeks
immediately after the disaster but began to fall sharply by May 2011
thanks to the region’s strong ocean currents. According to the data,
levels of radio-cesium are well below the health risk threshold—even
when combined with naturally occurring radioactive elements in
seafood—and are slowly continuing to fall.
The
researchers also looked at data collected on strontium 90, a
radioactive substance that when consumed is absorbed by bone. Those
levels turned out to be present at low levels in coastal seafood since
the nuclear disaster, but they have not subsided much over time.
Strontium 90 levels in the region’s seafood spiked twice more since
March 2011, they found. Each incident followed a leak of radioactive
water from the power plant site. Buesseler said that strontium 90 levels
in the region’s seafood should get more attention because there are
holding tanks on the Fukushima Daiichi site containing roughly 150
million gallons of wastewater with “more than 100 times the total
strontium 90 released in 2011….There’s potential for additional
contamination.”
Buesseler
noted that the strontium 90 data Povinec and Hirose worked with came
from fewer than two dozen fish. “What they did is correct; it’s all they
had to go on,” he said. “But it’s of concern that there are so few data
of strontium 90 in seafood because over time it’s becoming more
significant and it’s of greater health concern.” –Take Part
0 comments:
Post a Comment