164-3 Bile Acids as a Geoarchaeological Tool: a Method Proposal

Session: Advances and Applications of Geochemistry in Archaeology

Presenting Author:

Zarina Bikmullina

Authors:

Bikmullina, Zarina¹, Yamamoto, Masanobu²

(1) Hokkaido University, Sapporo, Hokkaido, Japan, (2) Hokkaido University, Sapporo, Hokkaido, Japan,

Abstract:

Bile acids (BAs) are cholesterol derivatives involved in various hepatobiliary processes. Due to taxa-speci city and relatively high resistance to degradation, the BAs preserved in soils and sediments are prominent palaeoenvironmental biomarkers indicating the past activity of vertebrates, including humans and domestic animals, on Holocene timescales. Recently, the interest to BAs increased, but routinely applied method, gas chromatography-mass spectrometry (GC-MS), requires complex pre treatment. Liquid chromatography-mass spectrometry (LC-MS) allows to identify BAs without derivatisation, but as of now, there is a lack of LC-MS procedures for BAs in non-faecal sediments and soils reported, and these do not include the column chromatography fractionation step. The purpose of this study was in establishment of LC-MS method that will ll the above‑mentioned gaps. The proposed LC-MS method shows appropriate repeatability in a range of concentrations 0.0001-0.1 μg/μl (CV<10 %). In addition to comparison of different extraction methods (sonication and accelerated solvent extraction (ASE)), the analysis of the behaviour of naturally occuring BAs and added standards (IS) was performed. Notably, the recovery of added standards differed from the one of BAs in feces. Thus, the quanti cation using internal standard method requires further consideration. The method was tested on faeces of different species and on archaeological soils. Faecal BAs pro le of ezo sika deer is newly reported. DCA and LCA (2.96 and 2.66 μg/g dry soil, respectively) were found in soil layer from Kashiwagigawa 9 archaeological site (Hokkaido, Japan) containing most artifacts preliminarily attributed to the Jomon period. The BAs ratio in this sample is close to one found in modern human faeces.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-4704

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