14C from atmospheric nuclear weapons testing – a versatile tracer still sticking around

Kristina Stenström

Lund University, Sweden

SSAMS at Lund University

14C in atmospheric CO2 until today…

Something drastic happened in the 1900’s!

-25000 -20000 -15000 -10000 -5000 0 5000

0

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14 C

(‰

)

Calendar year

n + 14N→ 14C + p

14C+O2→ 14CO2

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

0

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400

600

800 INTCAL98 Vermunt, CO

2

Schauinsland, CO2

Måryd, Juncus

14 C

(‰

)

Calendar year

14C in atmospheric CO2 (clean air)year 1900-2007

Combustion of fossil fuels

Bomb-effect

14C-specific

activity

Absorption in biosphere and

oceans

226 Bq/kg

300 Bq/kg

400 Bq/kg

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

0

200

400

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800 INTCAL98 Vermunt, CO

2

Schauinsland, CO2

Måryd, Juncus

14 C

(‰

)

Calendar year

14C in atmospheric CO2 (clean air)year 1900-2007

14C-specific

activity

226 Bq/kg

300 Bq/kg

400 Bq/kgBomb-pulse

dating

Bomb-14C – some applications

Dating - forensic science

- retrospective cell dating in man

Studies of • the carbon cycle

• turnover times in biological tissues

Uptake in biosphere and oceans

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

0

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800 INTCAL98 Vermunt, CO

2

Schauinsland, CO2

Måryd, Juncus

14C

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)

Calendar year

Checking vintages of wineBurchuladze et al, 1989

Zoppi et al, 2004

Tracking narcoticsZoppi, 2004

Bomb-14C – some applications

Identification of furs of illegaly hunted animals

Geyh, 2001

Growth rate of gallstonesDruffel & Mok, 1983

Bomb-14C – some applications…… in man

Age of senile plaques in Alzheimer’s disease

Lovell et al, 2002

Retrospecive cell dating in the brain

Spalding et al, 2005

Dynamics of fat cell turnover

Spalding et al, 2008

Carbon turnover in the human eye lens crystallines

Lynnerup et al, 2008

Bomb-14C – can it tell the history of atherosclerotic placks causing

heart attacks and strokes?

Retrospective cell dating can…

• Provide fundamental insight on the rate of formation of new cells in the human body

• Help to develop new therapies to cure diseases

What is the precision???

Is clean air data from various geographical zones representative for the 14C levels in

man?

• Ingestion (main pathway)• Inhalation• Dermal absorption

How does 14C reach man?14C-level of the diet is

crucial!

Some factors influencing bomb-14C from atmospheric CO2 in various food components of the diet:

• Age (storage time)• Reservoir (terrestrial versus aquatic)• Route through the food chain• Turnover time of cells in animals

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

0

200

400

600

800 INTCAL98 Vermunt, CO

2

Schauinsland, CO2

Måryd, Juncus

14C

(‰)

Calendar year

Different reservoirsFrom D.D. Harkness, A. Walton, Nature 302 (1972) 302:

14C specific activity in the late 1960ies: Beef: 360 Bq/kg C Fish: 240 Bq/kg C

1940 1950 1960 1970 1980 1990 2000

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14C

(p

erm

ille

)

Calender year

Beef

Fish

The percentage of sea foods is significant for 14C specific activity in

the diet!

CO2

MAN

Different routes from atmospheric CO2 to man

Varying time lag in the different routes ⇒

different 14C-specific activity in different

dietary components

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

0

200

400

600

800 INTCAL98 Vermunt, CO

2

Schauinsland, CO2

Måryd, Juncus

14C

(‰)

Calendar year

Can we date by the year?

What influences the contemporary 14C specific

activity???

Natural 14C Bomb-14C

How do local variations of 14C in the environment

affect the 14C levels in man?

Volcanos

Coal fired power plants

TrafficFossil carbon

Nuclear power generates 14C!

Reactor water

Fuel rods

Steam

Turbine

Condensor

Generator

Sea water

Nuclear power-14C14C is produced in• the fuel• reactor water• construction materials

Waste

14CO2

14C

14CWaste disposal facility

SFR

How much 14C is released to air, land and water?

In what chemical form is 14C released?

How is 14C distributed in the environment?

Nuclear power-14C

Reactor water

Fuel rods

Steam

Turbine

Condensor

Generator

Sea water

Nuclear power-14C indeed gives local14C-varations…

in the vicinity of a reprocessing plant for

spent nuclear fuel

1940 1950 1960 1970 1980 1990 2000 2010

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Grass 1,5 km from Sellafield,UK

14 C

(pe

rmill

e)

Calender year

447 Bq/kg C

226 Bq/kg C

1950 1960 1970 1980 1990 2000 2010 2020 2030

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15000

20000

Grass 100 km

Grass 2 km NE

Grass 0,8 km NE

Grass 0,7 km E

Grass 1,5 km from Sellafield, UK

14 C

(pe

rmill

e)

Calendar year 226 Bq/kg C

268 Bq/kg C511 Bq/kg C

1 530 Bq/kg C

4 820 Bq/kg C

NOTE! The bomb pulse!

Nuclear power-14C indeed gives local 14C-varations…

in the vicinity of a Canadian nuclear power plant

Murmansk, 2004The ship LISA, used for

temporary storage of spent nuclear fuel.

1950 1960 1970 1980 1990 2000 2010

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14 C

(p

erm

ille

)

Calender year

448 Bq/kg C Tree leaves grown close to

LISA

226 Bq/kg C

Man also produces14C on purpose…

…to use as a tracer e.g. in:• Pharmaceutical industry• Ecology, chemistry, biology…

Release to environment

How are bomb-peak applications affected?

Incorporation into workers using 14C

Risks for personnel?

Man also produces14C on purpose…

…to use as a tracer e.g. in:• Pharmaceutical industry (e.g. microdosing)• Ecology, chemistry, biology…

Research centre Rossendorf, GermanyAt least two potential sources of 14C release to the environment:

1) a research reactor, which was in operation year 1957-1985, and 2) a radioisotope laboratory, in operation until year 1990.

NOTE! The bomb pulse!

1960 1970 1980 1990 20000

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Tree 1) Located just outside the radioisotope laboratory and about 400 m west of the reactor

Tree 2) Located about 350 m south of the reactor and 750 south-east of the radioisotope laboratory

14C

(pe

rmill

e)

Calender year

2 370 Bq/kg C

226 Bq/kg C

Research centre, JülichPotential sources of 14C:• several research reactors• laboratories handling radioactive materials

Results:Large local variations•Max 29 % excess for one grass sample (309±4 Bq/kg C),•Max 35 % excess for a moss/soil sample (324±4 Bq/kg C).

Måryd clean air 2004: 240 Bq/kg C

14C in personnel Hair: Indicator of integrated exposure

Urine: Indicator of recent exposure

Research departments e.g. at Universities

HospitalsPharmaceutical industry

Nuclear power industry

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20000 University Laboratory (national) Pharmaceutical industry Nuclear power industry Bomb peak max in 1963 Background hair (16 persons)

14C

sp

eci

fic a

ctiv

ity (

Bq

/kg

C)

Subject

14C in personnel, hair samples, 2007

Note the bombpulse max

in 1963!

Summary and conclusions

Large variations in 14C specific activity can be seen in:

• Diet of terrestrial origin versus sea food in the late 1960ies• Environment (e.g. close to nuclear installations) • Workers handling 14C

How is bomb-pulse dating affected?