Tag Archives: Japan

Fukushima residents exposed to far less radiation than thought

by Katherine Kornei
Published in Science
23 Jan 2017

Citizen science usually isn’t this personal. In 2011, roughly 65,000 Japanese citizens living near the crippled Fukushima Daiichi Nuclear Power Plant started measuring their own radiation exposure in the wake of the Tōhoku earthquake and tsunami. That’s because no one, not even experts, knew how accurate the traditional method of estimating dosage—taking readings from aircraft hundreds of meters above the ground—really was. Now, in a first-of-its-kind study, scientists analyzing the thousands of citizen readings have come to a surprising conclusion: The airborne observations in this region of Japan overestimated the true radiation level by a factor of four.

Continue reading Fukushima residents exposed to far less radiation than thought

Advertisements

Aftershock rattles Japan’s Fukushima region

A Mw 6.9 aftershock shook the Iwaki region of the coast of Japan on November 22, 2016. Considered an aftershock, since it was within 2 rupture lengths of the  2011 Great East Japan earthquake that itself ruptured a 300 km stretch of seafloor, this is just the latest shaker of the hundreds of quakes >Mw 4 that have occurred since March 11th, 5 years ago. While on the human timescale, there has been enough time for many structures to be rebuilt and life to return to normal for many, geologically speaking the M9 quake is still reasonably fresh. While aftershocks DO get more spaced out in time since the main shock, they do not necessarily become weaker and so this is unlikely to be the last tremor of this magnitude in the area. Continue reading Aftershock rattles Japan’s Fukushima region

External ionizing radiation doses of high school students in Japan, France, Poland and Belarus

By Jay T. Cullen

Third-year science students H. Onodera and R. Suzuki, both 18, and second-year students M. Saito, Y. Fujiwara, both 17, and S. Anzai, 16 and their supervising teacher T. Hara, 57, took part in compiling the study.  They used citizen science deployed dosimeters to compare external radiation dose experience by students in different countries.
The purpose of this post to report on a peer-reviewed, open access study published in the Journal of Radiological Protection where high-school aged citizen scientists measured and compared the external ionizing radiation doses experienced by students in Japan, Belarus, France, and Poland. Adachi and colleagues equipped 216 high-school students in Japan (inside and outside Fukushima Prefecture), Belarus, France and Poland with an electronic dosimeter to estimate and compare annual external ionizing radiation doses in 2014.  The distribution of doses experienced in each region overlapped with each other indicating that personal external ionizing radiation exposure in Fukushima Prefecture and Belarus are within the range of annual doses from terrestrial background radiation in other locations.

Continue reading External ionizing radiation doses of high school students in Japan, France, Poland and Belarus

Contamination of freshwater fish by the Fukushima Nuclear Accident: Overview of monitoring results

By Jay T. Cullen

Adult Oncorhynchus mykiss or rainbow trout. One of the species monitored for Fukushima derived radionuclides in the Wada et al. (2015) study.

The purpose of this post is to report the results of a monitoring study looking for Fukushima Dai-ichi Nuclear Power Plant (FDNPP) derived contamination in freshwater fishes in Japan.  The peer reviewed study by Wada and colleagues was recently published in Journal of Environmental Radioactivity which is unfortunately behind a publisher paywall.  This post continues a series of posts aimed at communicating the results of scientific investigations of the impact of the FDNPP disaster on public and environmental health.  Wada and colleagues measured the amount of 131-Iodine (131I half life ~ 8 days), 134-Cesium (134Cs half life ~2 years), and 137-Cesium (137Cs half life ~30 years) in freshwater fish species collected from rivers, lakes and aquaculture ponds in Fukushima Prefecture between March 2011 and December 2014.  A total of 16 species and 2692 individual fish were examined.  Between March and June 2011 11 fish were found to have detectable but low activities of 131I (<25 Bq kg-1 wet weight) suggesting that radioactive iodine did not accumulate significantly in fish.  Continue reading Contamination of freshwater fish by the Fukushima Nuclear Accident: Overview of monitoring results

Impact of the Fukushima Nuclear Disaster on Marine Animals Along the Coast of Japan

By Jay T. Cullen

Samurai Crab (Paradorippe sp.)
Samurai Crab (Paradorippe sp.)

The purpose of this diary is to share the results of a recently published, peer reviewed, study that examined the radiological impact of the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) meltdowns on invertebrates living in coastal waters close to the disaster site in Japan.  The paper by Sohtome and colleagues measured the activity of artificial radionuclides 134-Cesium (134Cs half life ~ 2 years) and 137-Cesium (137Cs half life ~ 30 years) in 592 specimens representing 46 different taxonomic families collected in coastal waters in Fukushima Prefecture between July 2011 and August 2013.  The authors found 137Cs in 77% of the samples with highest activities in the organisms near to or south of the FDNPP where highest levels in seawater and marine sediments were found after the large initial releases in 2011.  Levels of 137Cs decreased exponentially with time with differences between the various taxonomic groups.  Continue reading Impact of the Fukushima Nuclear Disaster on Marine Animals Along the Coast of Japan