The purpose of this post is to report the most recent results of Kelp Watch 2015 , a program dedicated to monitoring for the presence of Fukushima contamination off our Pacific Coast. This post is the latest in a series dedicated to the public dissemination of information about the impacts of the Fukushima Dai-ichi disaster on the health of the North Pacific Ocean ecosystem and health of North American residents. New results from the third sampling period (January through March 2015) of Kelp Watch 2015 were released on April 6, 2015 and can be found here. As with previously reported results here, here and here no radioactive isotopes from Fukushima were detected in kelp growing at sampling sites spread along our Pacific coast. The absence of 134Cs in kelp suggests that ocean transport of Fukushima contamination had yet to reach North American coastal water. As the contaminated water reaches the shoreline in the coming months Kelp Watch 2015 will help to track the arrival of the plume in time and space.
A review of the goals and approach of Kelp Watch 2015 can be found at their project website.
Samples were collected January to March of 2015 at various sampling locations along the Pacific Coast .
Owing to its relatively short half life of ~2 years radioactive 134Cs serves as a useful tracer of Fukushima impact because it was released in significant quantities into the environment after the disaster in March 2011. All other sources of the man made isotope have occurred far enough in the past that any 134Cs detected in the environment serves to unequivocally identify Fukushima impact. Similar to previous work by this program all samples of kelp collected from the Pacific by Kelp Watch 2015 during the first quarter of 2015 had no detectable (detection limit ~ 0.04 Bq kg-1 dry weight of kelp) levels of 134Cs indicating that isotopes from Fukushima are not significantly affecting radioisotope activities in these organisms to date.
Note that the Tofino British Columbia kelp sample was collected on Jan. 10, 2015 in close proximity to Ucluelet BC where the first seawater sample with Fukushima contamination was collected on Feb. 19, 2015. The fact that the kelp was devoid of 134Cs reflects that later arrival time of the plume and lack of exposure time to allow the kelp to accumulate the signal from coastal seawater. The coming months will be most important for characterizing the arrival of the contaminated plume in time and space.
Ongoing monitoring of seawater and marine organism activity concentrations of radioisotopes from Fukushima will help to determine the likely impacts on the ecosystem and public health along North America’s Pacific coast resulting from the disaster. As new results are generated by this great, citizen scientists driven project, I will report them here.