Bomb-pulse 14C analysis combined with 13C and 15N measurements in blood serum from residents of Malmo, Sweden

The C-14 content of 60 human blood serum samples from residents of Malmo (Sweden) in 1978, obtained from a biobank, has been measured to estimate the accuracy of C-14 bomb-pulse dating. The difference between the date estimated using the Calibomb software and sampling date varied between -3 +/- A 0.4 and +0.2 +/- A 0.5 years. The average age deviation of all samples was -1.5 +/- A 0.7 years, with the delay between production and consumption of foodstuffs being probably the dominating cause. The potential influence of food habits on the C-14 date has been evaluated using stable isotope delta C-13 and delta N-15 analysis and information about the dietary habits of the investigated individuals. Although the group consisting of lacto-ovo vegetarians and vegans (pooled group) was not completely separated from the omnivores in a stable isotopic trophic level diagram, this analysis proved to add valuable information on probable dietary habits. The age deviation of the sampling date from the respective Calibomb date was found strongly correlated with the delta C-13 values, probably due to influence from marine diet components. For the omnivore individuals, there were indications of seasonal effects on delta C-13 and the age deviation. No significant correlation was found between the age deviation and the delta N-15 values of any dietary group. No influence of sex or year of birth was found on neither the C-14 nor the delta C-13 and delta N-15 values of the serum samples. The data were also divided into two groups (omnivores and pooled group), based on the level of delta N-15 in the samples. The consumption of high delta N-15-valued fish and birds can be responsible for this clustering.