By Jay T. Cullen
Previously unpublished data results from research expeditions in 2014 and 2015 are summarized here. Overall the data indicate that:
- Fukushima derived radiocesium was first detected 1500 km west of British Columbia Canada in June 2012
- Contamination was detected on the continental shelf (near coastal waters) in June 2013
- By February 2014 Fukushima radiocesium was present at levels similar to preexisting weapons testing derived 137Cs
- The timing of the arrival and levels of radiocesium in the contaminated plume are in reasonable agreement with existing ocean circulation model predictions
- 134Cs, a unique indicator of Fukushima impact given its ~ 2 year half life, increased in 2014 and 2015 relative to previous years indicating that peak concentrations are likely to arrive in 2016
- Maximum combined radiocesium activities (137Cs + 134Cs) offshore as of summer 2015 are 11 Bq m-3 of seawater are about 8-10 fold less than maximum activities measured in the 1960’s due to weapons testing fallout. Current levels do not represent a significant risk to ecosystem or public health
By Jonathan Kellogg and Jay T. Cullen
Results from surface water samples collected in August 2014 during three oceanic research cruises are now available. These seawater samples were analyzed to characterize the distribution of Fukushima derived radionuclides 137-Cesium (137Cs half life ~30 years), and 134-Cesium (134Cs half life ~2 years). Based on the distribution of 134Cs, the Fukushima plume was not consistently present yet on the BC coast. It is likely that peak concentrations of radiocesium will be present offshore in the next year.
The purpose of this short post is to update readers on the activities of the Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) project. This post is the most recent in a series documenting scientific research into the impact of the Fukushima Dai-ichi disaster on environmental and public health. Surface seawater samples were collected from the icebreaker CCGS Sir Wilfrid Laurier as it traveled between Victoria BC to Dutch Harbor Alaska during July 2015. These seawater samples will be analyzed to characterize the distribution of Fukushima derived radionuclides 137-Cesium (137Cs half life ~30 years), and 134-Cesium (134Cs half life ~2 years). As in previous years this information will help to determine how well model predictions of the activities and progression of ocean borne contamination across the Pacific Ocean match with observations. Understanding the spread of this contamination provides important information on the impact of the Fukushima Dai-ichi disaster on the health of the Pacific ecosystem and the North American public. The evolution of the contaminant plume in time and space also helps the scientific community to better understand ocean mixing which is a key parameter toward understanding the oceans role in mitigating atmospheric greenhouse gas increases and climate change.
Continue reading Update: Sampling for Fukushima Derived Radionuclides in the Northeast Pacific and Arctic 2015