The atmospheric transport of iodine-129 from Fukushima to British Columbia, Canada and its deposition and transport into groundwater

Scientists from Univ. of Ottawa’s Dept. of Earth Science and Environment Canada (Government of Canada), Dec 2015: The atmospheric transport of iodine-129 from Fukushima to British Columbia, Canada and its deposition and transport into groundwater

• The Fukushima-Daiichi nuclear accident (FDNA) released iodine-129 (15.7 million year half-life)… The mean pre-accident 129I concentration in rain was [31,000,000 atoms/L]… following the FDNA, 129I values increased to [211,000,000 atoms/L]… [P]ulses of elevated 129I continued for several months…
• The 129I in shallow… groundwater showed measurable variability through March 2013 with an average of [3,200,000 atoms/L]… coincident with modeled travel times…
• Radionuclides released from the FDNA have been detected across the globe… [R]eleases of 129I and 131I… travel great distances…
• The Abbotsford-Sumas Aquifer… spans the Canada–U.S. border between [B.C., Canada and Washington, US] and supplies ∼120,000 people with drinking water…
• A pulse of 129I in precipitation with maximum concentrations of [211,000,000 atoms/L] in Vancouver and [221,000,000 atoms/L] at Saturna Island was observed 6 days following the FDNA. A value of [311,000,000 atoms/L] was also measured during the first week of July…
• The high 129I concentrations while the FDNA was ongoing are attributed to the rapid trans-Pacific transport of 129I from Fukushima… This response in 129I concentrations shows that radionuclides from Fukushima were transported rapidly from Japan to the west coast of Canada and the US… [Sampling from Washington State], which is a composite of rainfall events spanning 15 March 2011 to 16 April 2011 shows a significantly elevated 129I concentration of [95,000,000 atoms/L]…
• There was a spike in 129I concentration observed in the precipitation sample from the period of 1 July 2011 to 8 July 2011 [which] rose to [311,000,000 atoms/L]… a substantially higher concentration than any other sample… As monitoring at Fukushima detected no pulse of 129I in precipitation in July… this spike is likely due to a… nuclear fuel reprocessing facility. Modeling of the air parcel back trajectories… for the sampling period shows air mass trajectories from Hawaii, north Japan, and Russia…
• The initial increase in 129I concentration at the water table appeared within ∼95 days, with a maximum concentration of [10,500,000 atoms/L]…
• In the model cases, 129I reached the water table very rapidly…
• Groundwater 129I concentrations in two nearby wells showed minor anomalies over the sampling period which could be due to rapid infiltration of the FDNA atmospheric 129I signal… [M]odeling shows that it was possible for a component of the 129I deposited by the FDNA to be conducted rapidly from the ground surface to the water table… We conclude that it is possible that a fraction of 129I from the FDNA is transported conservatively in this aquifer via preferential flow paths to the water table…

See also: Official in Canada advises public not to drink rainwater coming from Fukushima
And: Rain with 20,000,000 particles of Iodine-131 per liter fell on US (VIDEO)http://onlinelibrary.wiley.com/doi/10.1002/2015WR017325/full