The purpose of this diary is to provide an update with the most recent results of the Integrated Fukushima Ocean Radioactivity Monitoring (InFORM) project. The diary is part of an ongoing effort to communicate scientific research into the impact of the Fukushima Dai-ichi nuclear disaster on environmental and public health. New results from our most northern citizen scientist collected samples demonstrate that as of November of 2014 the contaminated seawater from Fukushima had yet to reach British Columbia's coastal waters. New results of the project will be published as analyses are completed on onshore and offshore seawater samples as well as marine biota.
Ailish Bouwman and Megan Ives collecting a water sample for the InFORM project at the Government Wharf in Sandspit, Haida Gwaii BC Canada.
By Jay T. Cullen
@JayTCullen and @FukushimaInFORM
February 16, 2015
What we found:
The absence of any detectable 134-Cs (an unambiguous fingerprint isotope of Fukushima contamination) in the seawater samples indicates that as of November 2014 these locations covering the length of the British Columbia coast have not be affected by ocean currents carrying Fukushima contamination.
https://docs.google.com/...
FYI The detection limit for 134-Cs averages ~0.2 Bq m-3. So despite the presence of Fukushima contamination in more offshore waters this contamination has yet to arrive on our beaches or in our coastal ecosystem.
Newly added results come from seawater samples collected in collaboration with citizen scientists at the following locations in British Columbia, Canada during November 2014.
- Bamfield
- Masset, Haida Gwaii
- Lax Kw'alaams
Samples were processed and the amount of gamma emitting isotopes determined using a high purity germanium detector. We look primarily for radioisotopes of cesium (134-Cs half life ~2 years and 137-Cs half life ~ 30 years) for the following reasons:
- 134-Cs has a half life that is short enough that all other human sources to the environment have decayed away making it an ideal tracer for Fukushima contamination
- next to the short lived Iodine-131 (half life ~ 8 days), Cs isotopes were released in greatest activity to the environment from Fukushima and would be most likely to represent a radiological health risk given their chemistry and propensity to be taken up by the biota
- other isotopes were released in much lower amounts from Fukushima relative to Cs (see other posts here and search for plutonium and strontium for example) and would therefore be much more difficult to detect
- because they are gamma emitters (unlike Pu isotopes and 90-Sr which emit alpha and beta radiation respectively) they are relatively easy and resource efficient to detect
The absence of detectable 134-Cs indicates that waters near these locations spanning the length of British Columbia have not been contaminated with Fukushima radioactive elements transported across the Pacific by prevailing currents as of Nov 2014. The presence of 137-Cs is due to historical sources of this human made isotope owing to atmospheric nuclear weapons tests in the 20
th century and contamination from the Chernobyl disaster in 1986. You can read about the levels of 137-Cs in the North Pacific pre-Fukushima
here.
More results will be published as they become available.