Nagoya University
NagoyaUniversity

CHANGESOF 14C CONCENTRATION
2,AndrzejRAKOWSKIi'

IN MODERN

WOOD

Tadeusz KUC3, ToshioNAKAMURAi,FROM URBAN

AREAAnna PAZDUR2,i-UniversityofNagoya, CenterforChronologicalResearch,Nagoya,Japan,
Silesian
UniversityofTechnology,
Instituteof Physics,
GADAM Center,Poland,
3AGH, Universityof Scienceand Technology,Krak6w, Poland.
2-INDTRDUCTION
AtmosphericC02 isincreasing
due to the emission of gasesfrombuming fbssil
fuels,
such as coal,petroleumand natural gas.Recentlythe C02 concentration has exceeded370 ppm [1,2].This
inthe atmosphere and subsequently inprocesscauses changes in theproportionof carbon isotopes
thebiosphereand ocean.
Radiocarbon
concentration inatmosphere rapidly increased
in 1ate1950s
and early 1960sdue to nuclear bomb tests,reaching a maximum
in l963,when the levelwas almost

doublethat of naturalconcentration
oceanic

wascarboni4Cconcentrationin the atmosphere
andreservoir

After the test ban treaty was[3].

enforced,

the i4C

decreased,due to carbon exchange mainly against thetheinputof
carbonfrom fbssilfuels.
In the 1990s,thelevel
slowly"dead"

10 % higherthanpre-bomb concentrations

around[4,5].Severa1laboratories

theworld are continuously
monitoring atmosphericC02 levelsand
concentrations, either directlyfrom the atmosphere[4,61,or in plants[5,7, 8].Resultsfrom such studies show that largelocal
emissionsof fossil-fuelC02 will canse changes in the carbon isotopecompositionof theatmosphereand local
biosphere.Thiseffect isstrongest inheavilyindustrialized
areas, butcan also
be observed inhighlyurbanized areas, where C02 isemitted from industrial
facilities,
vehicles andi4C
other commonsources.
[[hemagnitude of changes inconcentration
depends on thedistanceto
sources of C02 emissions[9].
still about

i4C

SAMPLES AND METHOD
Samples of annual growth ringsfrom Nagoya (Japan)
and Krakow (Poiand),as a radial section of adiarneterof 5mrn, in thepine tree weretaken using a hollow drili.
To obtain sufficient material fbr
AMS analysis, three core samples were collected from each tree and the annual growth rings wereseparated. A mixtureof early woodand 1atewood
wasused to represent
a single year sample.
Sampies were washed indistilledwaterand prepared using theA-A-A method.
The treatedresidues

intoglasstubes evacuated with a rotary pump. Thetubes were then placed in an electric furnacefor2 hours at g50eC. Carbon dioxideproduced fromthe sarnples was purifiedin a glasscryogenic vacuum 1inesystem and then reduced to graphite
werecombinedwithcupricoxideand sealed-120NII-Electronic Library ServiceNagoya University
NagoyaUniversity

using

ironpowder as a catalyst

The resulting mixture of graphiteand ironpQwderwas dried
[1O].

i4C
The stable carbon isotope
ratio wasmeasurements.
pressedinioa target holderfbrAMS
usinga Finningan MAT
252 isotope-ratio
mass
spectrorneter at the Center formeasured
contents are reported as Ai4C in permil
ChronologicalResearch,Nagoya University.
Radiocarbon
from thestandard sample, 95% activity ofNBS oxalic acid (SRM-4990C)[11].The(%o)deviations

andnotation
isotoperatio isexpressed in6i3CpDB

stabie carbon

RESULTSon

the PDB scale [12].

AND CONCLUSIONRadiocarbonconcentrations in the atmosphere oyer largecities dependon emissions of C02 from
intothreecomponents:
a backgroundcomponent
fossilfuels.
Concentrationsof C02 can be divided
fuelcomponeirt
related to the antkropogenic
ernissiona biogeniccomponent
and a fossil(Ca);(Cb);
in [61and [8],can be used te describe
theof C02 (CD.Mathematicalequations, widelydescribedcomposition,
and wereused to estimate
between each component and carbon isotopic
wasthe fbssilfuelcomponent.
The fossilfuelcomponent of C02 concentration in the atmospherecalculated
using
data obtained experimentally,
along with additional data that represent yearlyi4C4], whichair" at Schauinslandstation [2,average values of Aand C02 concentration inincludeboth,backgreund and biogeniccomponents. The yeariyaverage value foranalyzed period
seasonalvaluesof 27.5 ppmv
was 15.2ppmv forNagoya which fallsbetween the approximate
and 10 ppmv (summer),
calculated fortheperiod1983-1994 in theurban area of Krak6w(winter)
isaround +-8 % or lessof
The error ofestimation fortheanthropogenic emission ofC02[6].
(Csirelationships"clearthe totalvalue.
recordedin tree rings,
itispossible
tothat,withthe isotopicinforrnation
ringsof trees to obtain the secular
reconstmct
concentrations fbrthe past.The use of annuali4CvariationsofC02 providesus a valuable enviroumenta1 monitor.
concentration of atmospheric

The results showi4C

REFERENCES
KeelingCD, Whorf TP, van derPlichtJ,1995.Arbture375:666-9[t][2]GLOBALVIEW-C02:

Project- Carbon Dioxide.
CooperativeAtmosphericData Integration
anonymous
FTP to
CD-ROM, NOAA CMDL, Boulder,Colorado[Alsoayailable on Internetvia
fip.cmdl.noaa.gov,
2003.
Path:ccgfco2!GLOBALVIEW],[3]Nydal R, L6vsethK, 1996.0ak Ridge NationalLaboratoryNDP-057.
Levin I,Kromer B, 1997.Radioearbon 39(2):205-218.
[4]McNeely R. 1994.Environmentlhternational
20(5):675-9.
[5]
Kuc T, Zimnoch M. 1998.Radiocarbon40(1):417-23.
[6]
I,Horvatinei6N, Obeli6B. 1998.Radiocarbon40(1):399-416.
[7]Krajcar-Broni643(2B):679-689.
Rakowski AZ, Pawelczyk S,Pazdur A, 2001.Radiocarbon[8]-121NII-Electronic
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NagoyaUniversity[9]Awsiuk, R.,Pazdur,M.F.,1986.Radiocarbon28,655-660.
Kitagawa H, MasuzawaT, Nakamura T, Matsumoto E. 1993.Radiocarbon35:295-300.
[1O]
Smiver M, PolachHA. 1977.Radiocarbon 19(2):355-363.
[11]
CraigH. 1957.Geochimica and CosmochimicaActa 12:133-49.
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