Determining the geochemical fingerprint of the lead fallout from the Notre-Dame de Paris fire: Lessons for a better discrimination of chemical signatures

Justine Briard; Sophie Ayrault; Matthieu Roy-Barman; Louise Bordier; Maxime L'Héritier; Aurélia Azéma; Delphine Syvilay; Sandrine Baron

doi:10.1016/j.scitotenv.2022.160676

Determining the geochemical fingerprint of the lead fallout from the Notre-Dame de Paris fire: Lessons for a better discrimination of chemical signatures

Sci Total Environ. 2023 Mar 15:864:160676. doi: 10.1016/j.scitotenv.2022.160676. Epub 2022 Dec 10.

Authors

Justine Briard¹, Sophie Ayrault², Matthieu Roy-Barman¹, Louise Bordier¹, Maxime L'Héritier³, Aurélia Azéma⁴, Delphine Syvilay⁴, Sandrine Baron⁵

Affiliations

¹ Laboratoire des Sciences du Climat et de l'Environnement, LSCE UMR 8212, CEA-CNRS-UVSQ, Université Paris Saclay, France.
² Laboratoire des Sciences du Climat et de l'Environnement, LSCE UMR 8212, CEA-CNRS-UVSQ, Université Paris Saclay, France. Electronic address: sophie.ayrault@lsce.ipsl.fr.
³ Archéologie et Sciences de l'Antiquité, ArScAn UMR 7041, CNRS, Université Paris 8, France.
⁴ Laboratoire de Recherche des Monuments Historiques, CRC USR 3224, Muséum National d'Histoire Naturelle - CNRS - Ministère de la Culture, France.
⁵ Laboratoire Travaux et Recherches Archéologiques sur les Cultures, les Espaces et les Sociétés, TRACES UMR 5608, CNRS - Université de Toulouse, France.

PMID: 36513227
DOI: 10.1016/j.scitotenv.2022.160676

Abstract

On 2019, the fire of Notre-Dame de Paris cathedral ("NDdP") spread an unknown amount of lead (Pb) dust from the roof of the cathedral over Paris. No data describing the geochemical fingerprint of the roof lead, as well as no particle collected during the fire, were available: a post-hoc sampling was performed. To discriminate the potential environmental impact of the fire from multiple Pb sources in Paris, it was mandatory to define unequivocally the fire dust geochemical signature. A dedicated and in hindsight geochemistry-based strategy was developed to eliminate any source of potential contamination due to sampling substrates or previously deposited dust. Radiogenic Pb isotopic signatures (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb ratios) and elemental ratios were determined in 23 Pb-rich samples collected inside NDdP. We determined that the dust collected on wood substrates on the first floor was most representative of fire emissions. These samples were the analyzed for the 4 Pb isotopes (204, 206, 207, 208) and the fire dust signature is characterized by ratio values of ²⁰⁶Pb/²⁰⁷Pb: 1.1669-1.1685, ²⁰⁸Pb/²⁰⁶Pb: 2.0981-2.1095, ²⁰⁸Pb/²⁰⁴Pb: 38.307-38.342, ²⁰⁷Pb/²⁰⁴Pb: 15.633-15.639 and ²⁰⁶Pb/²⁰⁴Pb: 18.242-18.275. In addition, the fire dust presents typical element-to-Pb ratio. This fingerprint was compared to the signatures of the known local Pb sources. The geochemical fingerprint of the fire is significantly different from that of the dominant urban Pb source. This will allow future evaluation of the contribution of the fire to Paris Pb pollution and of the real extent of the area affected by the Pb-containing dust plume. Moreover, the geographical origin of Pb used for the roof restauration and the spire building was identified. These findings open new ways to study the Pb sources in historical monuments for environmental impacts evaluation, as well as for historical perspectives.

Keywords: Environmental pollution; Historical monuments; Lead isotopes; Metals; Tracing pollution.