2011 Fukushima Fall Out: Aerial Deposition On To Sea Ice Scenario And Wildlife Health Implications To Ice-Associated Seals

FROM: ALASKA MARINE SCIENCE SYMPOSIUM

Bering Sea - Mammals

2011 Fukushima Fall Out: Aerial Deposition On To Sea Ice Scenario And Wildlife
Health Implications To Ice-Associated Seals

Dr.Doug Dasher, ddasher@alaska.edu
John Kelley, jjkelley@alaska.edu
Gay Sheffield, ggsheffield@alaska.edu
Raphaela Stimmelmayr, raphaela.stimmelmayr@north-slope.org

On March 11, 2011 off Japan’s west coast, an earthquake-generated tsunami struck the
Fukushima Daiichi nuclear power plant resulting in a major nuclear accident that
included a large release of airborne radionuclides into the environment. Within five days
of the accident atmospheric air masses carrying Fukushima radiation were transiting into
the northern Bering and Chukchi seas. During summer 2011 it became evident to coastal
communities and wildlife management agencies that there was a novel disease outbreak
occurring in several species of Arctic ice-associated seals. Gross symptoms associated
with the disease included lethargy, no new hair growth, and skin lesions, with the
majority of the outbreak reports occurring between the Nome and Barrow region. NOAA
and USFWS declared an Alaska Northern Pinnipeds Usual Mortality Event (UME) in late
winter of 2011. The ongoing Alaska 2011 Northern Pinnipeds UME investigation
continues to explore a mix of potential etiologies (infectious, endocrine, toxins, nutritious
etc.), including radioactivity. Currently, the underlying etiology remains undetermined.
We present results on gamma analysis (cesium 134 and 137) of muscle tissue from
control and diseased seals, and discuss wildlife health implications from different
possible routes of exposure to Fukushima fallout to ice seals. Since the Fukushima fallout
period occurred during the annual sea ice cover period from Nome to Barrow, a sea ice
based fallout scenario in addition to a marine food web based one is of particular
relevance for the Fukushima accident. Under a proposed sea ice fallout deposition
scenario, radionuclides would have been settled onto sea ice. Sea ice and snow would
have acted as a temporary refuge for deposited radionuclides; thus radionuclides would
have only become available for migration during the melting season and would not have
entered the regional food web in any appreciable manner until breakup (pulsed release).
The cumulative on-ice exposure for ice seals would have occurred through external,
inhalation, and non-equilibrium dietary pathways during the ice-based seasonal spring
haulout period for molting/pupping/breeding activities. Additionally, ice seals would
have been under dietary/metabolic constraints and experiencing hormonal changes
associated with reproduction and molting.

LINK TO ORIGINAL REPORT  (Page 222)