Fukushima radioactivity and Pacific biota Nicholas Fisher*, Daniel Madigan**, and Zofia Baumann* *School of Marine and Atmospheric Sciences, State University of New York, Stony Brook **Hopkins Marine Station, Stanford University November, 2012

Fukushima Daiichi Nuclear power plant March 11, 2011

Buesseler et al ES&T Surface ocean concentrations from March 21 to July 31, 2011 Earthquake, Tsunami …and a failed Nuclear Power Plant

SAMPLING & RADIOANALYSIS smaller mixed zooplankton bigger mixed zooplankton and myctophid fish Photos by Ken Kostel Anthropogenic radioisotopes: 134 Cs, 137 Cs, 110m Ag Japan US - Hawaii US – Stony Brook Long Island

131 I: 8-day half-life; after 70 days only 0.1% remaining; after 1 year % remaining 127 I: stable, present at concentrations of ~ 400 nM in seawater I bioconcentrated about 10,000 times out of seawater by brown macroalgae (active uptake), but relatively little bioaccumulation in most other marine organisms Background information on radioactive iodine

137 Cs: 30-year half-life; still detectable in Pacific seawater and trace levels in biota as remnants from nuclear weapons testing in the Pacific, which peaked in the 1960s (fission product) 134 Cs: 2.1-year half-life: neutron activation product, undetectable in Pacific waters and biota prior to Fukushima accident 133 Cs: stable, present at concentrations of ~40 nM in seawater Background information on radioactive cesium

Cesium non-essential for all organisms, generally follows K uptake pathways and tissue distributions shows low uptake in marine phytoplankton (Kds < 100) but much higher in freshwater where there are orders of magnitude lower K, Na concentrations (Kds ~10,000) modest biomagnification in marine food chains (much less than methylmercury)—high assimilation efficiencies (~70%) in fish and daily loss rates of ~2% from excretion; ~2/3 of Cs obtained from diet concentrates in muscle tissue (e.g., filet of fish)

TRACK OF THE CRUISE IN JUNE 2011 Buesseler et al. (PNAS 2012)

134 Cs in surface water 134 Cs in biota 110m Ag in biota Buesseler et al. (PNAS 2012)

137 Cs 134 Cs 110m Ag 40 K Copepods n = CF = CF = Large zooplankton (euphausiids, gelatinous) n = CF = CF = Fish n = CF = CF = 13 bd168 Mean concentrations (Bq kg -1 dry) in biota

1:1 Data from Buesseler et al PNAS CESIUM ISOTOPIC RATIOS IN BIOTA ~1

Natural Anthropogenic RANGES OF RADIOISOTOPES IN BIOTA Data from Buesseler et al PNAS Ratio of mean natural : anthropogenic = 6 : 1 Pre-Fukushima [ 137 Cs] = x Bq dry kg -1 Kaeriyama et al., 2008

Simplified movement patterns for juvenile Pacific bluefin tuna (blue arrows) from Japan to the California and juvenile yellowfin tuna (yellow arrows)

Radionuclide concentrations Bq kg -1 dry mass SL Body mass Age 134 Cs 137 Cs 40 K 134 Cs: 137 Cs Cs cmkg dryyears Bq kg -1 PBFT 2011 n=15 Median Mean SD PBFT 2008 n=5 Median Mean SD YFT 2011 n=5 Median Mean SD Measured 134 Cs, 137 Cs, and the natural 40 K for post-Fukushima bluefin (PBFT 2011), pre-Fukushima bluefin (PBFT 2008), and post-Fukushima yellowfin tuna (YFT 2011)

Simplified movement patterns for juvenile Pacific bluefin tuna (blue arrows) from Japan to the California and juvenile yellowfin tuna (yellow arrows)

Cesium concentrations in post-Fukushima bluefin tuna Japan safety limit: 100 Bq kg -1 wet wt (~410 Bq kg -1 dry wt) 134 Cs: 137 Cs in myctophid fish off Japan = 0.9; in plankton = 1.1; in water = 1.0

NO significant relationship between cesium and fish length

U.S. Washington DC U.K. Japan East Asia Argentina Estonia Portugal

Doses to human consumers (1 Sv = 100 rem = 1 joule kg -1 ) Tuna: from Cs Tuna: from 40 K Banana: from 40 K Dental x- ray 1 flight NY to LA (cosmic rays) Consumption of: 200 g 1 banana Dose (µSv) Top 5% of recreational fishermen in California (µSv y -1 ) = 47 bananas/y Average seafood consumer in US (µSv y -1 ) = 9.3 bananas/y Average seafood consumer in Japan (µSv y -1 ) = 346 bananas/y

Doses to zooplankton and bluefin tuna (nGy h -1 ) (1 Gy = 100 rads = 1 joule kg -1 of tissue) 110m Ag 134 Cs 137 Cs 210 Po 40 K Natural : anthropogenic Zooplankton (near Japan) Tuna (in California) n.a Tuna (near Japan) n.a

Simplified migration patterns of some highly migratory species in the Pacific

Questions going forward 1.What is the radiocesium load of PBFT in 2012 and 2013? 2.What proportion of older, larger fish are CCS residents and what proportion are Japan migrants? 3.Do New Zealand PBFT make round trips to Japanese waters?

Takashi et al What is the Cesium load of PBFT in 2012 and 2013?  Our 2011 data are from fish that spent ~1 month in contaminated waters  This year’s cohort spent their first year in contaminated waters  Values may be much higher Buesseler et al. 2011

Still a work in progress—stay tuned…. Conclusions so far: Cs and 137 Cs accumulate in bluefin tuna in waters off Japan and are retained by tuna during their migration across the Pacific; 2.Yellowfin tuna which are residential species show no evidence of Fukushima radioactivity; 3.Radioactivity clearly detectable in tuna in California coastal waters, but at low concentrations compared to natural radioactivity, and doses to marine biota and to human consumers are low; 4.Cs isotopes may be useful in tracing migration of some fish, mammals, turtles, birds.

Acknowledgements Ken Buesseler (WHOI) S. Zegers, J. George, H. Baumann (Stony Brook) Funding: Moore Foundation

Individual fish SL Body mass Age 137 Cs 134 Cs 40 K cmdry kgyearsBq kg -1 PBFT < Median Mean SD YFT Median Mean SD Concentrations of 134 Cs, 137 Cs, and the naturally occurring radionuclide 40 K for pre-Fukushima bluefin (PBFT 2008) and post-Fukushima yellowfin tuna (YFT 2011)

Bayliff What proportion of older, larger fish are CCS residents and what proportion are Japan migrants?  To what extent does the EPO fishery depend on Japan stocks (versus its own smaller year classes) for its larger fish?  EPO may be fishing out older year classes

Year Catch (×10 3 mt) Muscle biomass (×10 6 kg) Median Mean SD Pacific bluefin Thunnus orientalis catch data in the Eastern Pacific Ocean and total harvested muscle biomass in the EPO Yields mean of 3.6 million Bq (= 1 mCi) of Cs in harvested tuna per year

Sampling method StationSample composition % abundance of dominant species 137 Cs 134 Cs 137 Cs 134 Cs 110m Ag 40 K 134 Cs : 137 Cs 134 Cs : 110m Ag anthropogenic : natural radioactivity ratio Bq kg -1 CFBq kg -1 Bongo nets (300 µm) 2 zooplankton mixedcopepods 500.3bd134bd1.9217bd *bd ** bd bd255bd0.5195bd median mean sd Methot net (4 mm) 25scyphomedusanChrysaora sp euphausiids Euphausia pacifica euphausiids Nematoscelis difficilis fish, shrimps, euphausiids, pyrosomatids mixed nd median† mean† sd† fish Stenobrachius leucopsarus bd1440.7bd fish Cyclothone pseudopallida, Sigmops gracile 40, bd2321.0bd fishS. gracile bd1290.9bd0.24 median bd144 mean bd168 sd bd55

PBFT 2011 SL (cm) Body mass (kg dry) Age (years ) 7 Be 211 Bi 212 PbTotal mBq kg nd2.5nd < < < < < < < < Median Mean SD Measured concentrations of naturally occurring radionuclides 7 Be, 211 Bi, and 212 Pb and for n=15 post-Fukushima Pacific bluefin tuna (PBFT 2011)

sample type 134 Cs 137 Cs 40 K 134 Cs : 137 Cs Bq kg -1 dry mass North - near Sendai macroalgae mean sd mussel South – near Iwaki macroalgae mean sd mussel mean sd Cs: South of Fukushima vs. North macroalgae: 3x higher mussels: 8x higher Fukushima NPP Baumann et al. in prep. RADIOACTIVITY IN COASTAL SAMPLES

3. Do New Zealand PBFT make round trips to Japanese waters?  If so, they likely contribute to spawning stock