Tag Archives: Notre Dame

Traces of toxic lead from Notre Dame fire found in Parisian honey

When it burned last year, the cathedral of Notre Dame in Paris released hazardous lead dust that landed in parks and buildings across the city, raising health alarms for its residents. Now, researchers have found that the lead found its way into honey produced by urban beehives.

Image Credits: Wikimedia Commons.

Researchers analyzed concentrations of metals, including lead, in 36 honey samples collected from Parisian hives in July 2019. All the honey was within tolerable limits for consumption, but the honey from hives near Notre Dame had lead concentrations four times higher than the samples from Parisian suburbs.

“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, in a press release.

Smith and her team compared the honey obtained after the fire with a Parisian blend from 2018 and with samples from 2017 from the region of Auvergne-Rhone-Alpes. A sample from a hive five kilometers west of Notre Dame had the highest concentration of lead, 0.08 micrograms, while the pre-fire honey had 0.009 micrograms.

The European Union allows a maximum lead content of 0.10 micrograms per gram for syrups, sweeteners, and juices. Lead is a potent neurotoxin and a high exposure to it can kill, while lower levels can lead to health problems, such as cognitive and physical damage and shortened attention spans.

Lead was a highly used building material in Paris during the time of the construction of Notre Dame, which dates back to the 12th century. The roof and the spire of the cathedral had several hundred tons of lead and while most melted during the fire, some flames reached temperatures high enough to aerosolize lead oxides.

“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 neighborhoods downwind of the Notre Dame fire, are a strong indicator of increased amounts of lead in honey,” said co-author Dominique Weis.

The fact that honey bees usually forage within a two- to three-kilometer radius of their hive allowed the researchers to use honey as a localized snapshot of the environment. Bees collect dust and airborne particles, which then end up in the honey. The researchers worked with an apiary company, which manages 350 hives in Paris and provided them with the samples for the study.

It’s the first time a heavy-metal analysis through honey has been done in a megacity. The method came out of previous work by the same researchers, in which they measured trace amounts of metals in honey from urban beehives in six Metro Vancouver neighborhoods, demonstrating the use of bees as an effective biomonitor.

The study was published in the journal Environmental Letters.

Digital reconstruction of Notre Dame cathedral performed with laser scanners. Credit: Andrew Tallon.

Notre Dame’s 3D virtual reconstruction offers hope for the cathedral’s full restoration

Digital reconstruction of Notre Dame cathedral performed with laser scanners. Credit: Andrew Tallon.

Digital reconstruction of Notre Dame cathedral performed with laser scanners. Credit: Andrew Tallon.

On Monday afternoon, the world was shocked by the sight of Notre Dame cathedral in flames. The iconic 850-year-old Paris landmark suffered extensive damage with all of its original medieval wooden roof falling to the fire, along with the 93-meter-tall spire that collapsed through the roof. But while the event is a cultural tragedy, there are good reasons to believe that the cathedral can be restored to its former glory almost exactly as it once stood, thanks to extensive interior and exterior 3D scans performed only a few years prior to the fire.

Notre Dame cathedral was built over a century between 1160 and 1260. Its ribbed roof was made up of hundreds of oak beams, some still dating back to the 13th century and measuring up to 110 meters long. The famous spire (flèche), however, was added much later during a restoration led by architect Eugène Viollet-le-Duc, which took place between 1845-1870. Viollet-le-Duc also added other elements such as the gargoyles. For instance, the most famous description of the cathedral in The Hunchback of Notre-Dame by French author Victor Hugo was quite different than what people who’ve seen it in person might remember because the book was written in 1831, before the restoration.

Hundreds of firefighters rushed to the scene where they managed to fully contain the blaze early the next morning. Experts are still assessing the full scope of the damage but what’s already clear is that the medieval wooden roof, whose once magnificent beams now look like used matchsticks, is completely destroyed. The spire, as well, has completely collapsed, and the once rose-round windows are now chared. Fortunately, most of the artworks and other valuable objects inside the church were evacuated. Notre Dame’s organ also survived, authorities reported.

The virtual Notre Dame

The damage could have been much worse but luckily the cathedral’s stone walls still stand, making repairs much easier. In fact, if the walls had fallen, Paris authorities would have had to perform a reconstruction. And since Notre Dame cathedral is one of the most famous landmarks in the world, it not only exists in countless books, magazines, and blog posts, but also in the virtual space.

In 2015, a now-deceased architectural historian called Andrew Tallon performed an exact digital reconstruction of Notre Dame. Tallon used laser scanners to capture the entirety of the cathedral’s interior and exterior in billions of points of light. When combined, these clouds reveal a living structure. In a short video documentary, Tallon explained the process for National Geographic.

Tallon’s work might one day be used to restore Notre Dam to its former glory — and repair work might start very soon. In an address to the nation just before midnight, President Emmanuel Macron vowed that “we will rebuild this cathedral.”

Before the fire, Notre Dam was already under restoration as recent tourists might have noticed. Funding for this restoration proved to be rather challenging to source but with the wave of emotion around Monday’s fire, money doesn’t seem to be an issue anymore. After French officials announced plans to launch a national and international fundraiser, François-Henri Pinault, a French luxury magnate, said his family would donate $113 million, while Bernard Arnault, the richest man in Europe, pledged $226 million.

Combined with Tallon’s intricate digital reconstructions, these funds will help restore the architectural masterpiece to its original state — and likely very fast, too.