The Notre Dame cathedral in Paris, which was partially destroyed in a fire in April 2019, appears to have resulted in lead contamination in honey collected downwind of the fire.
About 300 tonnes of lead is thought to have melted from the building’s spire and roof during the blaze, some of which later appeared in honey collected from hives in the Paris’ western suburbs and nearby countryside. The highest concentration of lead, four times more than usual, was 0.08 micrograms per gram, found in a sample from a hive located 5km from the cathedral.
Bivariate concentration plots for selected trace elements (versus Pb) for the Paris honey
Pre-fire Parisian honey had, on average, 0.009 micrograms of lead per gram, and honey from the RhÃ´ne-Alpes department had 0.002 to 0.009 micrograms. The EU’s maximum allowable lead content is 0.10 micrograms.
Bees forage within a 2-3km radius of their hives, collecting dust and airborne particles as they do so, and unwittingly providing a snapshot of the air quality in their environment.
The results were published in the journal Environmental Science & Technology Letters by the Pacific Centre for Isotopic and Geochemical Research (PCIGR) at the University of British Columbia.
Kate Smith, lead author of the study, said: "Because of the way the wind was blowing the night the fire burned, the direction that the smoke plume traveled is well-defined. The elevated lead concentrations were measured in honey that was collected from beehives within that plume footprint."
Dominique Weis, PCIGR’s director, said: "The fact that the Notre Dame spire was loaded with lead was absolutely a unique research opportunity. We were able to show that honey is also a helpful tracer for environmental pollution during an acute pollution event like the Notre-Dame fire.
"The highest levels of lead that we detected were the equivalent of 80 drops of water in an Olympic sized swimming pool. It’s actually not higher than what we see in honey from downtown Vancouver. In a city as young as Vancouver, we are able to trace sources of the metal using distinct isotopic signatures."
The cathedral’s 96m-tall spire, erected in 1859, was designed by EugÃ¨ne Viollet-le-Duc to replicate the original spire built in 1230, which had to be removed due to decay.
It was announced earlier this month that the cathedral’s spire would be restored to its 19th-century design in accordance with the wishes of the French Senate, which rejected the idea of a modern reinterpretation.
Top image: Notre Dame on fire (Wandrille de Préville/CC BY-SA 4.0)