Lead released in Notre Dame Cathedral fire detected in Parisian honey


Date:
July 29, 2020
Source:
University of British Columbia
Summary:
Elevated levels of lead have been found in samples of honey from
hives downwind of the Notre Dame Cathedral fire, collected three
months after the April 2019 blaze.



FULL STORY ========================================================================== Elevated levels of lead have been found in samples of honey from hives
downwind of the Notre Dame Cathedral fire, collected three months after
the April 2019 blaze.


==========================================================================
In research outlined in Environmental Science & Technology Letters,
scientists from UBC's Pacific Centre for Isotopic and Geochemical Research (PCIGR) analyzed concentrations of metals, including lead, in 36 honey
samples collected from Parisian hives in July 2019.

While all the honey fell within the EU's allowable limits for safe
consumption, honey from hives downwind of the Notre Dame fire had average
lead concentrations up to four times that of samples collected in the
suburbs or countryside surrounding the city, and up to three and a half
times the amount found in Parisian honey pre-dating the fire.

"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," said Kate Smith, lead author of the study
and PhD candidate at PCIGR.

The researchers compared honey collected after the fire to a Parisian
honey blend from 2018 and to samples from the Auvergne-Rho?ne-Alpes region collected in 2017. The highest concentration of lead, 0.08 micrograms per
gram, was found in a sample from a hive located within five kilometres
west of the cathedral.

The pre-fire Parisian honey had 0.009 micrograms of lead per gram, and
honey from the Rho?ne-Alpes had 0.002 to 0.009 micrograms of lead per
gram. The EU's maximum allowable lead content is 0.10 micrograms per
gram for syrups, sweeteners, and juices.

Cathedral roof and spire contained tonnes of lead Lead was a common
building material in Paris throughout the time of construction of Notre
Dame, which dates back to the 12th century. The cathedral's roof and
spire contained several hundred tonnes of lead. While most of it simply
melted in the fire, some flames reached temperatures high enough to
aerosolize various lead oxides, and an estimated 180 tonnes of lead
remain unaccounted for in the rubble.

"The fact that the Notre Dame spire was loaded with lead was absolutely
a unique research opportunity," said co-author Dominique Weis, director
of the PCIGR. "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. It is no surprise, since increased amounts of lead in
dust or topsoil, both of which were observed in neighbourhoods downwind of
the Notre Dame fire, are a strong indicator of increased amounts of lead
in honey." Because honey bees forage within a two- to three-kilometer
radius of their hive, honey can provide a useful localized snapshot
of the environment. As the bees forage, they collect dust and airborne particles, which make their way into the honey.

Smith and Weis worked with Parisian apiary company Beeopic, which manages around 350 hives throughout the city, and collected the samples for
this study.

Honey was sampled directly from each individual hive and sent to the
PCIGR's clean laboratory for testing.

This study marks the first time this method of heavy-metal analysis
using honey has been used in a megacity, and one with a history of lead
use dating back for millennia. It came out of previous work by Smith
and Weis, in which they measured trace amounts of metals in honey from
urban beehives in six Metro Vancouver neighbourhoods, demonstrating the
use of bees as an effective biomonitor.

"The highest levels of lead that we detected were the equivalent of 80
drops of water in an Olympic sized swimming pool," said Weis. "So even
if the lead is relatively elevated, it's still very low. 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. In Paris, however, the long history of lead
use throughout the city made the interpretations more challenging. This provides an important consideration for future lead sourcing studies in
very old cities."

========================================================================== Story Source: Materials provided by University_of_British_Columbia. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kate E. Smith, Dominique Weis, Catherine Chauvel, Sibyle
Moulin. Honey
Maps the Pb Fallout from the 2019 Fire at Notre-Dame Cathedral,
Paris: A Geochemical Perspective. Environmental Science & Technology
Letters, 2020; DOI: 10.1021/acs.estlett.0c00485 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200729114752.htm

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