The purpose of this post is to provide readers with a brief update on our citizen science sampling program that is monitoring seawater concentrations of contamination derived from Fukushima Daiichi Nuclear Power Plant (FDNPP) meltdowns. This post is part of an ongoing effort to provide scientifically sound information regarding the environmental and public health impact of the disaster and to combat misinformation commonly found online. Coastal sampling is carried out by our volunteers at 16 locations up and down the coast of British Columbia to complement offshore sampling in the north Pacific and Arctic Oceans by scientists working from research vessels. Results of samples collected up until May 2018 indicate the following:
Levels inshore continue to increase as the bulk of contamination released from FDNPP in March-April 2011 arrive at the coast Seawater contamination levels are ~8-10-fold lower than those measured here at the height of atmospheric nuclear weapons testing between 1958-1963 last century Levels measured now do not approach levels known to represent a significant health risk to marine organisms or human beings Given that release rates of radiologically significant isotopes from the FDNPP site are very small compared to rates at the height of the disaster in March-April 2011, levels of contamination and risk are unlikely to increase in the futureSince 2014 the Integrated Fukushima Ocean Radionuclide Monitoring (InFORM) project has been monitoring levels of radioactive contamination in seawater and marine organisms to conduct a thorough assessment of the risk presented by the FDNPP disaster for the marine and public health in Canada. An important part of this project is the work of citizen scientist volunteers that collect seawater (20 liters or ~5 gallons) for us each month at various locations along the British Columbia coast and send it back to our labs for analysis. You can read about how these samples are collected and analyzed here. Samples are analyzed for Cesium-137 (137Cs, half-life ~30 years), and Cesium-134 (134Cs, half-life ~2 years). These isotopes are useful because they are relatively easy to measure, were released in relatively large quantities from the FDNPP, and because the short half life of 134Cs serves as a fingerprint of the disaster as all other human sources of this artificial isotope have decayed away from the environment.
Locations where samples are collected are indicated on the map below:
The following figures summarize our most recent results and compare the concentration of 137Cs in coastal versus offshore seawater over the last number of years.
Contamination levels continue to show a significant amount of regional variability where communities on the west coast of Vancouver Island and on Haida Gwaii in the North with more exposure to the open ocean having relatively higher 137Cs levels compared with communities nearer the mainland in the Salish Sea. This is consistent with the contaminated water arriving in the northeast Pacific due to transport by the North Pacific Current and spreading toward the coast. The general trend along the coast is that 137Cs is increasing over time which is to be expected as the plume of contaminated water arrives. On the right panel above you can see that while offshore contamination levels have stabilized and started to drop the coastal waters are increasing toward the maximum values seen offshore. These levels (<10 Bq cubic meter of seawater) offshore and at the coast are so low as to be an insignificant threat to the health of marine organisms or human beings who rely on the ocean for food and recreation. Indeed, this contamination is so small relative to the ionizing radiation emitted by naturally occurring isotopes that are always present in seawater, that without incredibly sensitive equipment these levels are not measurable (e.g. with a geiger counter). Given that levels offshore have reached a peak that is well below levels known to cause harm to living things we do not expect any measurable risk along the coast of British Columbia in the future.
The InFORM program is funded to continue our monitoring efforts into 2019 and I will continue to report these results as they become available.
