Birch-bark tar, used continuously in the territory of modern Europe from the Middle Palaeolithic to the Iron Age, is conspicuous by its absence in the archaeological record of the Roman period, suggesting its replacement by conifer-based products. The results of chemical analyses of residues on Roman hinges, however, now challenge this interpretation. The presence of birch-bark tar in most of the samples demonstrates the persistence of a long-established practice into the Roman period. Examined in relation to textual and environmental evidence, these results illuminate the transmission of technical knowledge and the development of long-distance trade networks associated with birch-bark tar.

The distribution of the volatile components in four regions, Rind, Exterior, Intermediate, and Interior, of hand-made Idiazabal cheese which had been ripened for two months was studied in detail. It is proved that the headspace of this ripened sheep cheese is non-homogeneous in the different cheese regions. The Rind is the richest region in volatile compounds, followed by the Exterior region. A large number of compounds with different functional groups have their greatest abundances in the Rind with negative abundance gradients towards the interior regions. Many of these are undetectable in the Intermediate and Interior regions. Other compounds such as aldehydes having a great number of carbon atoms, and most of the acids have their greatest abundances in the Exterior region. Alcohols, ketones and esters of small size have their greatest abundances in the Intermediate region. And finally, a reduced number of compounds are distributed homogeneously in all cheese regions. The origin of the compounds, the conditions that favour their formation, their functional groups, size, shape and reactivity could be factors involved in their distribution in the cheese, which in turn is associated with the microbial ecology, chemical reactions and physical effects.

The authors identify natural bitumen on stone implements dating to 70 000 BP. It is proposed that this represents residue from hafting, taking the practice back a further 30 000 years from the date previously noted and published in Nature. The bitumen was tracked to a source 40km away, using gas chromatography-mass spectrometry and carbon isotopes.

An analytical method consisting in enzymatic deconjugation, solid phase extraction and purification, and gas chromatography/mass spectrometry analysis after derivatization was used in this study to quantify Polycyclic Aromatic Hydrocarbon (PAH) metabolites in the bile of fish. The method has been applied in a laboratory experiment studying the fate of pyrene in basin containing soles. This study has allowed the identification of 1-hydroxypyrene as the single metabolite in bile after enzymatic deconjugation. In a second time, 1-hydroxypyrene has been used as a biomarker of exposure in the case of the “Erika” oil spill. This biomonitoring was successful in demonstrating the exposure of juvenile soles to PAHs present in the “Erika” fuel oil.

The authors discuss the first evidence for the use of birch-bark tar on Late Neolithic pottery from Greece. This appears to have been used for two different purposes, to seal a fracture and to line the interior walls. The authors also discuss other possible uses.