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Exploring the Possibilities of 14C Bomb-Pulse Dating of Human Tissue Samples

Georgiadou, Elisavet LU (2014)
Abstract (Swedish)
Popular Abstract in Swedish

Levande organismer, inklusive människor, har en 14C/12C-kvot som återspeglar miljön. När materialet dör slutar kroppen att fylla på 14C och kroppens 14C börjar sönderfalla till 14N. Detta gav upphov till den klassiska 14C-dateringsmetoden, vilken utvecklades av professor W.F. Libby, 1949 och gav honom Nobelpriset i kemi 1960. 14C-datering används huvudsakligen inom arkeologi och geologi med en bästa nog- granhet i storleksordningen ±50 år.

Atmosfäriska tester av kärnvapen, som ägde rum i mitten av 50-talet huvudsakligen på norra halvklotet, ökade atmosfärens 14C-halt och gav upphov till den så kallade bombpulseffekten. Följaktligen ökade 14C/12C-kvoten i levande material också.

... (More)
Popular Abstract in Swedish

Levande organismer, inklusive människor, har en 14C/12C-kvot som återspeglar miljön. När materialet dör slutar kroppen att fylla på 14C och kroppens 14C börjar sönderfalla till 14N. Detta gav upphov till den klassiska 14C-dateringsmetoden, vilken utvecklades av professor W.F. Libby, 1949 och gav honom Nobelpriset i kemi 1960. 14C-datering används huvudsakligen inom arkeologi och geologi med en bästa nog- granhet i storleksordningen ±50 år.

Atmosfäriska tester av kärnvapen, som ägde rum i mitten av 50-talet huvudsakligen på norra halvklotet, ökade atmosfärens 14C-halt och gav upphov till den så kallade bombpulseffekten. Följaktligen ökade 14C/12C-kvoten i levande material också.

14C/12C-kvoten ändrades inte likartat på hela jorden. Det finns skillna- der både i atmosfären mellan de två halvkloten, och mellan atmosfä- ren och havet. Havet utgör en av de största kolreservoarerna på jorden och har lägre 14C/12C-kvot än atmosfären.

Bombpulseffekten möjliggjorde bombpulsdateringsmetoden, som ålders- bestämningen av moderna prover (levande efter 1955) kallas. Bombpuls- datering kan bli ett medicinskt hjälpmedel för att ge information om tidpunkten för bildning av nya celler eller för att följa en sjukdoms utveckling.

14C-mätningar av blodserumprov och plackprov från människokrop- pen utfördes i detta arbete. Resultaten visade en genomsnittlig för- dröjning på 1,5 år mellan 14C-halten i blodserum och atmosfärisk koldioxid. Fördröjningen beror troligen främst på en fördröjning mellan inbindning av 14C i födan och konsumtion av livsmedlet. Försök gjordes att koppla resultaten till personernas diet. Det visade sig att livsmedel från havet kan påverka bombpulsdateringen. Marin föda kan leda till att prov som bildas efter 1963 (Partiella Provstoppsav- talet) ger en för ung ålder i bombpulsdateringen, medan prov från före 1963 ger upphov till en för hög ålder. Jämförelse mellan prov från människor med olika kostvanor (t.ex. människor som kommer från olika länder) och mellan olika sorter av prov, ingick också.

Målet med detta arbete är att utvärdera och utveckla bombpulsdate- ringsmetoden för moderna prov från människans vävnader. Speciellt födan hör till de faktorer som kan påverka resultaten.

Syftet för framtiden är att ytterligare förbättra noggrannheten i 14C- dateringen på mänskliga prov och därmed kunna öka möjligheten till medicinska tillämpningar. (Less)
Abstract
The testing of nuclear weapons in the atmosphere, in the middle of the 20'h century, resulted in a bomb-pulse excess of atmospheric 14C. A bomb-pulse dating method was thus developed. The latter is a method to determine the time of formation of formerly living modern (i.e. living after 1955) material , based on the 14C/ 12C ratio in it. The objective of this work was to evaluate the factors that can affect the accuracy of bomb-pulse dating of samples originating from the human body. This method may be useful in medicine, for example, to elucidate the progress of an illness. Special importance was given to the effect of diet since the ingestion of food is the main pathway in which carbon enters the human body. Investigation of the diet may... (More)
The testing of nuclear weapons in the atmosphere, in the middle of the 20'h century, resulted in a bomb-pulse excess of atmospheric 14C. A bomb-pulse dating method was thus developed. The latter is a method to determine the time of formation of formerly living modern (i.e. living after 1955) material , based on the 14C/ 12C ratio in it. The objective of this work was to evaluate the factors that can affect the accuracy of bomb-pulse dating of samples originating from the human body. This method may be useful in medicine, for example, to elucidate the progress of an illness. Special importance was given to the effect of diet since the ingestion of food is the main pathway in which carbon enters the human body. Investigation of the diet may reveal the consumption of particular foodstuffs, such as marine ingredients, for example, that may have a different 14C/ 12C ratio from the local atmospheric one. A literature investigation was carried out of the 14C/ 12C ratio in the atmosphere and oceans at different geographical locations showing that ordinary intake of marine foodstuffs can lead to age alteration (atmospheric predicted age - diet predicted age) from -2.4 to 1.4 years.

14C/ 12C measurements were also conducted on blood serum from Swedish subjects and atherosclerotic plaque samples from Swedish and Portuguese patients. It was concluded from the blood serum study that the diet of the subjects studied can influence bomb-pulse dating results due to the marine effect, which leads to a time lag (positive or negative) due to the different 14C/ 12C ratio of marine food compared to terrestrial food. This effect can lead to samples after 1963 (the year of the Limited Test Ban Treaty) appearing to be younger, while samples before 1963 appear to be older. The average age deviation (CAL!Bomb date- sampling date) of the blood serum samples was found to be -1.5 ± 0.7 years. The kind of tissue analysed also plays an important role, since carbon turnover times vary in different tissues and organs. Study of atherosclerotic plaque samples from different plaque regions was performed. On average, cap fragments were the youngest (average age 5.54 ±

2.6 years), core fragments were older (average age 7.79 ± 3.7 years) and interface to media fragments were the oldest (average age 9.74 ± 2.4 years). A comparison between atherosclerotic plaque samples and blood serum samples was also performed, confirming the potential influence of the sort of tissue in bomb-pulse dating. Finally, differences were observed in 14C/12C ratios in the same type of samples (plaque) from subjects with different dietary habits (Portuguese and Swedish diets), reinforcing the concept of dietary influence on bom b-pulse

dating. A correction of the bomb-pulse dating, with the aid of o13C values for the blood serum samples of

this work, was also attempted. The results appeared to be eligible but confirmed that many factors, except for the diet, are potentially affecting the carbon content of samples from the human body. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • professor Cook, Gordon, SUERC Radiocarbon Dating Laboratory, Scottish enterprise Technology Park,East Kilbridge G75 0QF, UK
organization
publishing date
type
Thesis
publication status
published
subject
keywords
14C measurements, Bomb-pulse dating, human body, serum, plaque, Fysicumarkivet A:2014:Georgiadou
pages
143 pages
publisher
Department of Physics, Lund University
defense location
Rydbergssalen, Fysiska Institutionen, Lunds universitet
defense date
2014-10-24 09:15
external identifiers
  • Other:LUNFD6/(NFFR-1036)/1-58(2014)
ISBN
978-91-7623-022-0
language
English
LU publication?
yes
id
c86ff526-aef0-4199-9426-d9e51df24575 (old id 4690128)
date added to LUP
2014-09-30 09:52:17
date last changed
2016-09-19 08:45:04
@phdthesis{c86ff526-aef0-4199-9426-d9e51df24575,
  abstract     = {The testing of nuclear weapons in the atmosphere, in the middle of the 20'h century, resulted in a bomb-pulse excess of atmospheric 14C. A bomb-pulse dating method was thus developed. The latter is a method to determine the time of formation of formerly living modern (i.e. living after 1955) material , based on the 14C/ 12C ratio in it. The objective of this work was to evaluate the factors that can affect the accuracy of bomb-pulse dating of samples originating from the human body. This method may be useful in medicine, for example, to elucidate the progress of an illness. Special importance was given to the effect of diet since the ingestion of food is the main pathway in which carbon enters the human body. Investigation of the diet may reveal the consumption of particular foodstuffs, such as marine ingredients, for example, that may have a different 14C/ 12C ratio from the local atmospheric one. A literature investigation was carried out of the 14C/ 12C ratio in the atmosphere and oceans at different geographical locations showing that ordinary intake of marine foodstuffs can lead to age alteration (atmospheric predicted age - diet predicted age) from -2.4 to 1.4 years.<br/><br>
14C/ 12C measurements were also conducted on blood serum from Swedish subjects and atherosclerotic plaque samples from Swedish and Portuguese patients. It was concluded from the blood serum study that the diet of the subjects studied can influence bomb-pulse dating results due to the marine effect, which leads to a time lag (positive or negative) due to the different 14C/ 12C ratio of marine food compared to terrestrial food. This effect can lead to samples after 1963 (the year of the Limited Test Ban Treaty) appearing to be younger, while samples before 1963 appear to be older. The average age deviation (CAL!Bomb date- sampling date) of the blood serum samples was found to be -1.5 ± 0.7 years. The kind of tissue analysed also plays an important role, since carbon turnover times vary in different tissues and organs. Study of atherosclerotic plaque samples from different plaque regions was performed. On average, cap fragments were the youngest (average age 5.54 ±<br/><br>
2.6 years), core fragments were older (average age 7.79 ± 3.7 years) and interface to media fragments were the oldest (average age 9.74 ± 2.4 years). A comparison between atherosclerotic plaque samples and blood serum samples was also performed, confirming the potential influence of the sort of tissue in bomb-pulse dating. Finally, differences were observed in 14C/12C ratios in the same type of samples (plaque) from subjects with different dietary habits (Portuguese and Swedish diets), reinforcing the concept of dietary influence on bom b-pulse<br/><br>
dating. A correction of the bomb-pulse dating, with the aid of o13C values for the blood serum samples of<br/><br>
this work, was also attempted. The results appeared to be eligible but confirmed that many factors, except for the diet, are potentially affecting the carbon content of samples from the human body.},
  author       = {Georgiadou, Elisavet},
  isbn         = {978-91-7623-022-0},
  keyword      = {14C measurements,Bomb-pulse dating,human body,serum,plaque,Fysicumarkivet A:2014:Georgiadou},
  language     = {eng},
  pages        = {143},
  publisher    = {Department of Physics, Lund University},
  school       = {Lund University},
  title        = {Exploring the Possibilities of 14C Bomb-Pulse Dating of Human Tissue Samples},
  year         = {2014},
}