March 11 will mark the five-year anniversary of the Fukushima Daiichi disaster, a series of nuclear meltdowns, triggered by a devastating earthquake-induced tsunami, that released massive amounts of radioactive material and resulted in the largest nuclear disaster since Chernobyl. Since then, the plant’s damaged drainage system has continued to leak radioactive water into the environment, and one of the biggest enduring public concerns has been the safety of fish caught in the area’s surrounding waters.
The purpose of this post is to report on a newly published, peer-reviewed study in the open access journal Scientific Reports that uses field observations to determine how intertidal species abundance and diversity were affected by the 2011 earthquake, tsunami and Fukushima Dai-ichi Nuclear Power Plant (FDNPP) disaster. This post is part of an ongoing series dedicated to summarizing the results of scientific studies aimed at understanding the impact of the FDNPP disaster on ecosystem and public health. Horiguchi and colleagues surveyed intertidal marine organisms and made measurements of artificial radionuclides in specimens in 2011, 2012 and 2013. They found that in 2012 the number of intertidal organisms was lower closer to the FDNPP than farther away and that the sea snail (Thais clavigera) was absent from sampling locations <30 km from the FDNPP. Because sea snails were found in other rocky habitats affected by the tsunami in 2011 the absence of these organisms in 2012 near the plant might be related to the FDNPP disaster. In 2013 both the numbers of organisms and diversity of species were found to be lower at sites within several kilometers south of the FDNPP site. While, according to the authors, there is no clear explanation for the findings at present it is clear that the intertidal biota has been impacted close to the FDNPP since the disaster. The authors conclude that:
it is unlikely that the tsunami was solely responsible for changes in the intertidal communities given the distribution of sea snails
other causes might include acute or sub-acute toxicities from the largest leaks from the FDNPP site in March-April 2011 containing artificial radionuclides, boric acid and hydrazine (and other chemicals)
most significant impacts to the intertidal community occurred along the coast south and proximal to FDNPP which likely reflects predominant local water currents
The changes noted by Horiguchi and colleagues in the intertidal community contrast with the lack of significant changes in benthic organisms along the Japanese coast by Sohtome and colleagues that was summarized here.
The Seattle Times is reporting no contamination in any of the 24 Alaskan salmon, halibut, pollock, cod, or sablefish that were sampled from 4 different regions in 2015 for the Alaskan Department of Environmental Conservation.
See the results from the Department of Environmental Conservation.
Presently, InFORM members at Health Canada are running the ~160 salmon samples from over 15 different major BC fisheries collected in 2015 and we will report the results as soon as they become available.
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→
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→