Tag Archives: 131-I

Updated – No Fukushima radiation found in 2016 Alaskan fish

Alaska Department of Environmental ConservationNo Fukushima contamination was found in any of the 14 fish Alaskan fish samples that were collected between February and September 2016, according to the Alaska Department of Environmental Conservation. The results, released on the Alaksa DEC website, show that the sampled herring, cod, and pollock, halibut, and salmon did not have any detectable levels of 131I, 134Cs (the Fukushima fingerprint radionuclide with a half-life of ~2 years) or 137Cs in the tissues.  These samples were from across Alaskan waters from Southeast to Bristol Bay and the Aleutian archipelago and the Bering Sea. Results from 2016 are similar to their results from 2015 and are part of the network of institutions monitoring for Fukushima radiation in marine waters and seafoods.

The average minimum detectable concentrations for these Alaskan samples on this gamma spectrometer were 63.7 Bq kg-1, 2.1 Bq kg-1, and 1.9 Bq kg-1 respectively for 131I 137Cs,  and 134Cs. While InFORM does not analyze for 131I, those detection thresholds for cesium are 2-3 times higher than are typical for our biotic monitoring program. This may be due to either a smaller sample size or a shorter time in the gamma spectrometer for the Alaskan samples, but the result remains that levels are well below those where intervention is needed (intervention levels for 131I = 170 Bq kg-1 and 134Cs + 137Cs = 1200 Bq kg-1 according to the US Food and Drug Administration). InFORM monitoring in 2016 found 9 salmon (out of 123) from BC and Yukon rivers with detectable levels (where the minimum detectable concentrations were less than 1 Bq kg-1) of  137Cs after a six hour detector run. These nine samples are currently being freeze-dried for an extended, 2 week long, detection run. Results from this additional analysis are expected probably mid-late spring 2017.

An interesting aspect of these 2016 Alaskan samples is that this was the first time a field-deployable gamma spectrometer has been sent by the US Food and Drug Administration to a site for local analyses of samples. Data from the spectrometer were then electronically sent to FDA scientists for analysis. The thought is that this model could be used in the event of nuclear emergency to allow for more rapid analyses of environmental samples.

Alaska DEC will continue monitoring fish samples for Fukushima radiation for at least 2017 and possibly beyond.

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No Fukushima radiation found in 2016 Alaskan fish

Alaska Department of Environmental ConservationNo Fukushima contamination was found in any of the 7 fish Alaskan fish samples that were collected during February and March of 2016. The results, released on the Department of Environmental Conservation website, show that the herring, cod, and pollock sampled did not have any detectable levels of 131I, 134Cs (the Fukushima fingerprint radionuclide with a half-life of ~2 years) or 137Cs in the tissues.  These samples follow on their similar results from 2015 and are part of the network of institutions monitoring for Fukushima radiation in marine waters and seafoods. Continue reading No Fukushima radiation found in 2016 Alaskan fish

No Fukushima Contamination in 2015 Alaskan Fish

Alaska Department of Environmental ConservationThe 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.

Read the full article.

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.

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

Status of the Spent Fuel At Fukushima Dai-ichi: How much was released to the environment?

By Jay T. Cullen

The purpose of this post is to answer the question posed in the title by summarizing a recently published peer reviewed study in the journal Nuclear Engineering and Design. The diary is part of an ongoing effort to communicate results from scientific studies aimed at understanding the impact of the Fukushima Dai-ichi meltdowns on the environment. The paper by Jäckel compares measured and predicted activities of reactor products 134-Cesium (134Cs half life ~2 years) and 137-Cs (137Cs half life ~30 years) in the reactor cores and spent fuel to measurements in the spent fuel pools (SFPs) of Units 1, 2, 3 and 4 at the site to determine how much spent fuel radiocesium was released after the accident. The comparison indicates that only very minor damage to the spent fuel occurred during the accident and subsequent clearing work such that at most about 1% of the Cs inventory from a single bundle (in Unit 2 SFP) was released to the cooling water. The short answer to the question is that not very much of the spent fuel was released at all and the bulk of releases originated from the reactor fuel in Units 1, 2 and 3 at the time of the accident. This is consistent with the results of measurements made of Fukushima derived radionuclides in air, soil and water worldwide since March 2011. Continue reading Status of the Spent Fuel At Fukushima Dai-ichi: How much was released to the environment?