Presentation from Safecast: The Next Three Years symposium, March 15, 2014

1. Fukushima – a view from the ocean
Ken Buesseler, Senior Scientist
Woods Hole Oceanographic Institution
http://cafethorium.whoi.edu
Yokohama June 2011 Daisan Kaiyu Maru
Sept 2013

2.  Natural sources are larger than
man‐made sources
 Fukushima total still poorly
known
 We can measure less than 1 Bq
 In the ocean (and human body)
different radionuclides have
different fate and toxicity
 Cesium is soluble in seawater
 137Cs half‐life = 30 years
134Cs half‐life = 2 years
Ken Buesseler
WHOI
We live in a radioactive world (and ocean)
1 Bq = 1 Becquerel = one radioactive decay per second
1 PBq = peta‐Becquerel = one million billion Bq
1015 Bq = 1,000,000,000,000,000 Bq

3. What are levels of cesium‐137 in ocean prior to Fukushima?
 Range from <1 to >60 Bq m‐3
 Higher in Baltic and Black Seas due to Chernobyl & Irish Sea due to Sellafield

4. Sources of Fukushima radionuclides to the ocean
Atmospheric
deposition
１
Mid‐March
2011
Direct discharge２
Early April 2011 peak
now small and continues
Through river runoff３
Through underground
water flow
４
small and continues
small and continues Y. Masumoto
JAMSTEC

5. One year history of cesium‐137 in ocean off Fukushima
Levels prior
to March 11
At nuclear power plant
Ocean Cs levels peak on April 6th
‐ possible reproductive effects
and mortality for marine biota
Levels of
concern
for
seafood
Highest
ocean levels
post
Chernobyl
US drinking
water limit
 Fukushima is an
unprecedented
event for the ocean
 levels highest in
2011, then leveled
off
 reactor site remains
a source
 levels now safe for
marine biota &
human exposure
 still concern for
seafood?
one banana
April 1 June 1 Aug 1 Oct 1 Dec 1 Feb 1
‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ 2011 ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐2012‐‐‐
Data from TEPCO Buesseler et al., 2012
Japan
regulatory limit

6.  134Cs varies by 3 orders of magnitude‐ up to 4000 Bq m‐3
 134Cs seen from 30 km out 600 km off shore
 Highest values associated with near shore eddy
 Kuroshio acts as barrier (if air deposition to south, not very much)
Buesseler et al. PNAS April 2012‐ data available on line
134Cs in ocean‐ June 2011
134Cs t1/2 = 2 yr
>99.5% soluble

7. 10
100
1,000
10,000
100,000
1,000,000
10,000,000
100,000,000
3/18/11 10/4/11 4/21/12 11/7/12 5/26/13 12/12/13
137Cs(Bq/m3)
Cesium source continues at Fukushima Dai‐ichi
Evidence includes
 TEPCO reporting
 Independent ocean studies
 Seafood monitoring

8. What about surface ocean cesium‐134 in May 2013
 134Cs indicates continued
source at NPP
 Highest Cs closest to
shore, associated with
locations of higher
groundwater input
 Lower overall in Sept.
than May 2013
• but 150 Bq m‐3 at 1 km
(WHOI)
• >1‐2,000 Bq m‐3 at coast
(TEPCO)
Max =
45 Bq m‐3
Buesseler, Yoshida et al, unpublished

9. What about Fish and cesium accumulation?
information page from Japanese Ministry of Agriculture, Forestry and Fisheries (MAFF)
 Cesium uptake and
loss from fish is
rapid
 50% loss in 50 days

10. Data from Japan Fisheries
Figure adapted from
Buesseler, Science, 2012
Fisheries closed off
Fukushima
Elevated Cs consistent
with continued sources

11. Tbq = 1012 Bq
adapted from J. Kanda

12. How big is NPP source today?
For cesium isotopes
 Total today = 0.3 TBq/mo (1 TBq = 1012 Bq)
 Source in March/April 2011 = 10‐30,000 TBq/mo
For strontium‐90
 Total today = 0.1 TBq/mo?
 Source in March/April 2011 = 100 TBq/mo
At NPP, Cs is actively being removed from cooling water, and
naturally sorbed to sediments, while 90Sr and tritium are not
 w/diversion of groundwater, salt water intrusion could lead to Cs
remobilization
 w/leaking tanks, large potential 90Sr source
Each tank= 300 tons x 40 x 106 Bq/L = 12 TBq

13. Predicted surface ocean 137Cs
April
2012
April
2014
Arrival
N. US Coast
& Hawaii
Seattle
San Diego
How long until cesium reaches US west coast?
2014
 Arrives 2013‐2014 (after debris)
 Predicted 137Cs off US varies from 1‐2 to 30 Bq m‐3
 Levels are low for exposure & fisheries
 US public concern but no government monitoring
Rossi et al., DSRI, 2013

14. In response, launched citizen scientist crowd funding site
Jan. 14, 2014
url‐ http://ourradioactiveocean.org
email‐ ourradioactiveocean@whoi.edu

15. First 2 month’s success
stories
 Public attention high
 >55,000 views
 30 sampling sites in progress
 >215 donors
 $28K raised
 No 134Cs YET along US west
coast

16. Our Radioactive Ocean
SUPPORTERS
Alaska Ocean Observing System
Bamfield Marine Science Centre
David Suzuki Foundation
Deerbrook Charitable Trust
Gordon and Betty Moore Foundation
Gwaii Haanas National Park Reserve,
Parks Canada
Humboldt State University, Marine Lab
KUSP Santa Cruz
Mothers for Peace of San Luis Obispo
Onset Computer
Pacific Blue Foundation
Point Blue Conservation Science
Prince William Sound Science Center
Santa Barbara Channel Keeper
Say Yes! to Life Swims LLC
Scripps Institution of Oceanography
Topanga Wildlife Youth Project
University of California Davis, Marine
Pollution Studies Lab
University of Guam Sea Grant
University of Hawaii
Woods Hole Oceanographic Institution
& thanks to more than 160 concerned
citizens who have made donations!