Phytoplankton

Zooplankton

Polychaete sp.1

Polychaete sp.2

Blue mussel

Pacific oyster

Amphipod

Mysid shrimp

Dungeness crab

Crangon shrimp

Shiner surfperch

Pacific herring

Walleye pollock

Northern anchovyDove sole

Chum salmon

Gonatid squidCoho salmon

Lingcod

Sablefish

Halibut

Chinook salmon

Killer whale ()Killer whale ()

0.0001

0.001

0.01

0.1

1

10

100

1000

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000

137 C

s (B

q/kg

wet

wei

ght)

Time (days)

137Cs-Japan Consumption Guideline (100 Bq/kg)

137Cs-Canada Consumption Action Level (1000 Bq/kg)

Model Parameterization and Theory

Figure 4. Simulations showing predictions of the accumulation of 137Cs activities in organisms of the food web over time: A)

current scenario with seawater activity (CW) = 5.0 x 10-4 Bq/L; sediment activity (CS) = 0.05 Bq/kg dw; and, B) future scenario

with (CW) = 0.01 Bq/L; (CS) =1.0 Bq/kg dw (B). The simulations include the nuclear decay rate (kN = 6.33 x 10-5 d-1) for 137Cs.

The red solid line represents the Canadian Action Level for Consumption following a Nuclear Emergency of 1000 Bqkg-1; the

red dashed line represents the limit for radiocesium contamination in food (100 Bqkg-1) used currently in Japan.

While current 137Cs activities do not indicate a health concern for the consumption of fish products by human populations in the west coast of Canada, 137Cs activities may achieve levels in upper trophic levels that may pose health risks in wildlife species. A rigorous monitoring program would also support the further development of the model and improve the ability to forecast 137Cs activities in marine organisms and uptake in human populations that consume sea products.

A MARINE FOOD WEB BIOACCUMULATION MODEL FOR CESIUM 137 IN THE PACIFIC NORTHWEST

Juan Jos Alava & Frank A.P.C. Gobas 1 School of Resource and Environmental Management, Faculty of Environment, Simon Fraser University, Burnaby, BC, Canada (E-mail: jalavasa@sfu.ca) November, 2014

Model Outcomes: Simulations

The area selected for the bioaccumulation modeling work is the resident killer whales outer coast habitat (i.e. offshore) in the Pacific Northwest coast (i.e. a region of the western coast of USA and Canada; Figs. 1-2).

A simplified oceanic food web, including Chinook salmon (Oncorhynchus tshawytscha) and killer whales, were constructed for the modeling work (Fig. 3).

Most of the data on feeding ecology, diet and trophic levels for fish and other aquatic biota were retrieved from Alava et al. (2012)

137Cs seawater activity data were obtained from Smith et al. (2013) to simulate current conditions (i.e. using 5.0 x 10-4 Bq/L), and from Rosi et al. (2013) for a future scenario over the 2014-2020 time period (i.e. 0.01 Bq/L).

137Cs sediment activity data are scarce for the study region, thus assumed activities were used as inputs in the model (Current scenario: 0.05 Bq/kg dw; Future scenario: 1.0 Bq/kg dw).

137Cs activities in the atmospheric air inhaled by air breathing organisms (i.e. killer whales) were assumed to be negligible in Pacific Northwest waters off the coast of Canada.

The Fukushima nuclear accident on 11 March 2011 emerged as a looming threat to the marine biodiversity in the Pacific Ocean and human health in coastal communities. Assessment of the long term consequences of radiocesium 137 (137Cs) releases from the Fukushima plant should consider the extent of ecological magnification in food-webs in addition to ocean dilution.

Pacific salmon are the major diet item of British Columbia resident killer whales (Orcinus orca), and therefore contribute to the accumulation of contaminants (e.g., POPs) found in this species (Fig. 1; Cullon et al., 2009).

137Cs cannot be ruled out as a potential bioaccumulative pollutant in regional food-webs, including the resident killer whale food-web in BC waters (Figs. 1 & 2).

Background Study Areas, Food web construction & Diet composition

Figure 2. Transport, fate and partitioning of 137Cs in a multi-media marine environment and in resident killer whales habitat and food-web.

Conclusion

137Cs-Bioconcentration Factor (BCF) in Phytoplankton: 20 L/kg, based on Vive i Batlle (2012) & IAEA (2004).

The basic kinetic mass balance, time dependent model for the bioaccumulation of 137Cs in aquatic biota is described as follows:

For air respiring organisms, the differential equation is:

Dietary Uptake Rate Constant (kD): Values for kD were derived from Alava et al. (2012) 137Cs-Elimination Rate Constant (kE) in invertebrates: kE values for zooplankton (0.053d-1), the

blue mussel, Mytilus edulis (0.04d-1) and Pacific giant oyster, Crassostrea gigas (0.01d-1) were calculated (using the biological half life:t = Ln/kE) or data reported elsewhere (Vive i Batlle 2012; IAEA 2004; Cranmore & Harrison 1975). For polychaetes (0.118 d-1) and benthic crustaceans (i.e. 0.130 d-1 for amphipods and mysid shrimp, Mysis sp., and 0.224 d-1 for Crangon shrimp and Dungeness crab, Metacarcinus magister), kE values were adopted from Topcuolu (2001).

Elimination Rate Constants (kE) in fish: because the apparent elimination of 137Cs in fish is predominantly due to growth dilution, the growth rate constant can be an adequate descriptor for the apparent elimination of 137Cs from fish (i.e. kE can be considered negligible).

Elimination Rate Constants (kE) in killer whale: the 137Cs-half life of 28d estimated for marine mammals by Watson et al. (1999) was used here to calculate a plausible elimination rate constant (kE) for resident killer whales (i.e. kE = Ln/t =0.693/t =0.693/ 28 d = 0.025 d-1).

Growth Rate Constant (kG) estimates for all species were retrieved from Alava et al. (2012).

Objective: To model the bioaccumulation of 137Cs in an offshore food web of the Pacific Northwest with the aims of improving our understanding of the bioaccumulation potential and health effects of 137Cs in top predators and of conducting an eco-toxicological risk assessment.

Nuclear fall out and long-range atmospheric transport

Muscle/Fat-soluble chemicals

- (137Cs)

-

Water - soluble (137Cs)

(137Cs)

-

- bound

chemicals (137Cs)

Water - soluble

-

Particle -

Water - soluble chemicals (

Phytoplankton

Zooplankton

Polychaete sp.1

Polychaete sp.2

Blue mussel

Pacific oyster

Amphipod

Mysid shrimp

Dungeness crab

Crangon shrimp

Shiner surfperch

Pacific herring

Walleye pollock

Northern anchovyDove sole

Chum salmon

Gonatid squidCoho salmon

Lingcod

Sablefish

Halibut

Chinook salmon

Killer whale ()Killer whale ()

0.0001

0.001

0.01

0.1

1

10

100

1000

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000

137 C

s (B

q/kg

wet

wei

ght)

Time (days)

137Cs-Japan Consumption Guideline (100 Bq/kg)

137Cs-Canada Consumption Action Level (1000 Bq/kg)

Phytoplankton

ZooplanktonPolychaete sp.1

Polychaete sp.2

Blue musselPacific oyster

Amphipod

Mysid shrimp

Dungeness crab

Crangonshrimp

Shiner surfperchPacific herringWalleye pollock

Northern anchovy

Dove soleChum

salmon

Gonatid squid

Coho salmonLingcod

Sablefish

Halibut

Chinook salmon

Killer whale (male)

Killer whale (female)

Log 137Cs= 0.0231(TL) - 2.0655r = 0.0014, p > 0.05

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

0 1 2 3 4 5

Log

137 C

s (B

qkg

-1w

et w

eigh

t)

Trophic Level (TL)

90 days

Phytoplankton

Zooplankton

Polychaete sp.1Polychaete sp.2

Blue mussel

Pacific oyster

Amphipod

Mysid shrimp

Dungeness crab

Crangon shrimp

Shiner surfperch

Pacific herringWalleye pollock

Northern anchovy

Dove sole

Chum salmonGonatid

squidCoho salmon

LingcodSablefishHalibut

Chinook salmon

Killer whale (male)Killer whale (female)

Log 137Cs = 0.818(TL) - 3.3764r = 0.5099, p < 0.0001

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

0 1 2 3 4 5

Log

137 C

s (B

qkg

-1w

et w

eigh

t)

Trophic Level (TL)

730 days

Phytoplankton

Zooplankton

Polychaete sp.1Polychaete sp.2

Blue musselPacific oyster

Amphipod

Mysid shrimpDungeness crab

Crangon shrimp

Shiner surfperch

Pacific herringWalleye pollock

Northern anchovy

Dove sole

Chum salmonGonatid

squidCoho salmon

LingcodSablefish Halibut

Chinook salmon

Killer whale (male)Killer whale (female)

Log 137Cs= 1.1731(TL) - 4.129r = 0.6298, p < 0.0001

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

0 1 2 3 4 5

Log

137 C

s (B

qkg

-1w

et w

eigh

t)

Trophic Level (TL)

10950 days

N 60

50

40

180 150 120

Alaska

Vancouver I.

Gulf of Alaska

Strait of Georgia

Aleutian Is.

CANADA

USA

British Columbia

Puget Sound Pacific Ocean Washington 137Cs 137Cs

137Cs

Figure 1. Through the oceanic life stage cycle , Pacific salmon species are likely to deliver Fukushima associated 137Cs to the resident killer whales food-web in waters off the Pacific Northwest coast.

Trophic Magnification of 137Cs over time

Offshore

The Fukushima nuclear power plant lies within 200km of the core of the Kuroshio Current Extension

Position and direction of the

Kuroshio Current Extension

Resident Killer Whale TL =4.5

Chinook, Chum and Coho salmon

TL= 3.4-4.2Halibut & Sablefish

(Demersal fish) TL= 3.85-4.13

Small pelagic fish

TL=3

Zooplankton TL=2

Phytoplankton TL= 1

Benthic biota TL = 2.1-2.9

sediments

seawater

Gonatid squid TL =3

137Cs

137Cs

Salmon make up 96% of the killer whales diet, of which 71.5% is Chinook salmon (Ford and Ellis, 2006; Ford et al., 2010).

PhytoplanktonZooplankton

Polychaete sp.1Polychaete sp.2

Blue musselPacific oyster

Amphipod

Mysid shrimpDungeness crab

Crangonshrimp

Shiner surfperchPacific herring

Walleye pollock

Northern anchovy

Dove soleChum salmon

Gonatid squidCoho salmon

Lingcod

SablefishHalibut

Chinook salmon

Killer whale (male)

Killer whale (female)

Log 137Cs = -0.4029(TL) - 1.4306r = 0.3274; p =0.0035

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

0 1 2 3 4 5

Log

137 C

s (B

qkg

-1w

et w

eigh

t)

Trophic Level (TL)

30 days

Phytoplankton

ZooplanktonPolychaete sp.1

Polychaete sp.2

Blue musselPacific oyster

Amphipod

Mysid shrimp

Dungeness crab

Crangonshrimp

Shiner surfperchPacific herring

Walleye pollockNorthern anchovy

Dove sole

Chum salmon

Gonatid squid

Coho salmon

Lingcod

Sablefish

Halibut

Chinook salmon

Killer whale (male)

Killer whale (female)

Log 137Cs = -0.1371(TL) - 1.8221r = 0.0497, p > 0.05

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

0 1 2 3 4 5

Log

137 C

s (B

qkg

-1w

et w

eigh

t)

Trophic Level (TL)

60 days

Phytoplankton

Zooplankton

Polychaete sp.1Polychaete sp.2

Blue musselPacific oyster

Amphipod

Mysid shrimp Dungeness crab

Crangon shrimp

Shiner surfperch

Pacific herringWalleye pollock

Northern anchovy Dove

sole

Chum salmon

Gonatid squid

Coho salmon

LingcodSablefishHalibut

Chinook salmon

Killer whale (male)

Killer whale (female)

Log 137Cs= 0.5734(TL) - 2.9374r = 0.3743; p =0.0015

-6.00

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

0 1 2 3 4 5

Log

137 C

s (B

qkg

-1w

et w

eigh

t)

Trophic Level (TL)

365 days

Figure 3.

BENGDDAAB CkkkCkCk

dtdC ).(.. +++=

BENGDDWWB CkkkCkCk

dtdC ).(.. +++=

Legends: CB = 137Cs-activity in biota; CW= 137Cs-seawater activity; CA= 137Cs-air activity ; CD= 137Cs-activity -diet; kW = 137Cs-water uptake rate; kA= air uptake rate; kN = 137Cs-nuclear decay rate.

A) Current scenario B) Future scenario

Figure 5. Linear regressions showing the bioaccumulation behavior and trophic magnification of 137Cs activities versus trophic

levels in the resident killer whales outer coast food web for a simulation with CW = 5.0 x 10-4 Bq/L; and, CS = 0.05 Bq/kg dw

at: A) 30 days, B) 60 days, C) 90 days, D) 365 days (1 year), E) 730 days (2 years); and, F) 10950 days (5 years), following the

the Fukushima nuclear accident in the North Pacific. 137Cs activities significantly increase in the food web after one year.

A) B) C)

D) E) F)

Slide Number 1