Séminaire

Use of faecal stanols to distinguish specific mammalian species in modern and past environments

(L. Harrault, K. Milek, E. Jardé, L. Jeanneau, M. Derrien, R. Bindler, J. Klaminder, D. G.Anderson)

Tracking the origin of faecal material in modern and past environments is of primaryimportance as it permits the identification of pathogenic contamination hazardous for human health inwater, sediment or shellfish, and helps archaeologists and paleoecologists identifying animal activityareas for example. For the past few decades, sterol-derived compounds have been used as faecalbiomarkers to identify the main sources of faecal inputs in different environments, and especially todistinguish a human/omnivore origin from a herbivore one. Simple compound ratios of a limitednumber of these biomarkers have been used as sourceidentification proxies, but these ratios havelimited ability to distinguish the origin of faecal material at the species level, especially amongherbivore species.

In combination with multivariate analysis,the analysis of faecal biomarkers from differentmammal species faeces allowedto build faecal signature databases able to track species identity inwater samples.Nevertheless, this methodsufferslimitations in soil and sediment samples as they botharenaturally rich in steroid-derived compounds.

Therefore, we developed a new method based on5β-stanols, direct faecal biomarkers,andanalysed their compositionfrom90faeces of ten mammal species to create a faecal fingerprintdatabase.This new tool allows the distinction of faecal fingerprints atthe species level even amongherbivores.We tested its applicability todistinguish faecal signaturesin soil andsedimentsamplesfromdifferent modern and archaeologicalcontexts involving various mammal species.Our faecalfingerprint database model successfully confirmed the main species origin of faecal material inputs inmodern and archaeological sites and allowed to refine theirarchaeological interpretations.

This database and its ongoing developmentcould haveimportant applications not only inarchaeology, but alsoin watershed management, paleoecology, geochemistryand forensic soil science.