A delicate question here. Does anybody know of data for 13c compositions of
methane from human emissions? I am writing up data for CO2 and methane
isotopes of cave air and I am seeking alternative explanations for one or
two 'anomalous' data points with methane d13C as light as -53 permil.  Cave
air methane is otherwise significantly heavier than background atmosphere
due to microbial oxidation. Methane emitted from mammals is normally around
30 permil lighter than food intake but wondered if any data existed for
specifically for the human species....

Thanks

dave


-- 
David Mattey 
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