Test of the Biological Origin

Biologically-derived compounds may be distinguished from similar compounds produced from a petrochemical source or from fossil fuel carbon by dual carbon-isotopic fingerprinting. This method can distinguish chemically identical materials (96). In addition, such methods have gained some importance in discriminating between natural and industrial pollution (97). 

The isotopes, and give complementary information to this problem. The radiocarbon dating isotope with its nuclear half life of 5730 y, clearly allows to differentiate between fossil and biospheric feedstocks (98). 

The basic assumption in radiocarbon dating is that the constancy of the concentration in the atmosphere leads to the constancy of 

t is the age, 5730 years is the half life time of radiocarbon, and is the specific activity of the sample and of a modem standard (99). 

However, because of atmospheric nuclear testing since 1950 and the burning of fossil fuel since 1850, has acquired a second, geochemical time characteristic. Its concentration in atmospheric CO2 and thus in the living biosphere, approximately doubled at the peak of nuclear testing, in the mid-1960s. Afterwards, it has gradually returned to the steady-state baseline isotope rate of ca. 1.2 X 10- 2 (96) 

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