Heavy metals in human and animal bones from ancient and contemporary France.

The concentrations of Cd, Pb, Zn, Ba, Mg and Ca have been determined in 180 human bones from the last five millenia, and in 22 contemporary and 20000-50000-year-old animal bones. The original concentrations of Cd and Zn in the ancient human bones were not changed by fossilization processes, whereas Pb and Mg tended to migrate out of the bones, and Ba and Ca concentrations increased with the age of the bones. The distribution of metals in the structure of both the ancient and contemporary bones is not uniform, and neglecting this may render it difficult to compare results obtained from different studies. In Europe and Peru in the late Middle Ages the concentration of Pb in human bones increased by one order of magnitude. The high level of Pb persisted in Europe for several centuries and only recently decreased by an order of magnitude. The concentration of Cd has increased in human bones in the 20th century, to about ten times above the pre-industrial level. The concentration of Pb in contemporary cow bones from France is below analytical detection limits, probably due to competition of Pb with Ca and P which are added to cow fodder as mineral additives.